The Evolutionary Development
of the
Patrol Aircraft in the United States Navy
By
M.A. Joenks
Master of Arts in Diplomacy and Military Studies
Fall 2008
Abstract
During the 20th Century, the United States fought the submarine forces of
Germany and later against the forces of the Soviet Union. This struggle required the
cooperation of land, air, and sea assets along with development of new technologies. It
was during World War I that naval authorities discovered that the airplane could play a
critical role in the defeat of the submarine. This initiated a race of competing
technologies between the airplane and the submarine that continues to this day.
The capabilities of the submarine and aircraft have evolved greatly throughout the
20th Century. At the beginning of both world wars and the Cold War, the submarine held
a technological advantage. It was only through the expenditure of vast amounts of
resources were the capabilities of the maritime patrol aircraft improved to such a degree
that they became capable of contesting submarine operations.
Following the surrender of Germany and the collapse of the Soviet Union,
political and naval leaders have elected to slow the development and procurement of a
new maritime patrol aircraft. Many see little need for the United States Navy to continue
the development of its anti-submarine forces, as there appears to be no true submarine
threat.
Historically the submarine has been the naval weapon of choice of many small
navies. With the proliferation of advanced technologies, such as air-independent
propulsion systems, cruise missiles, and wake-homing torpedoes, countries such as Iran,
Pakistan, and China can challenge the largest of navies. To counter these emerging
technologies, the United States must continue to develop its own capabilities as the race
of competing technologies between the airplane and the submarine continues into the 21st
Century.
This project will trace the development of the maritime patrol aircraft and the role
technology played in its battle with the submarine in the 20th Century.
ii
Table of Contents
Table of Contents
………………………………………………………
i
Introduction
………………………………………………………
1
World War I
………………………………………………………
14
Interwar
………………………………………………………
58
World War II
………………………………………………………
91
Cold War
………………………………………………………
148
Conclusion
………………………………………………………
210
Bibliography
………………………………………………………
214
i
Introduction
Introduction
While neither fast nor sleek, the long-range maritime patrol aircraft (MPA) has
proven to be a vital component of the United States Navy. During both world wars, the
maritime patrol aircraft proved critical to the defeat of the U-boat in the Atlantic Ocean.1
In combination with the fast attack submarine (SSN) and Sound Ocean Surveillance
System (SOSUS), the maritime patrol aircraft were instrumental in controlling the former
Soviet Union’s submarine fleet during the Cold War.2 Anti-submarine warfare (ASW)
has evolved from its primitive beginnings of World War I, too complex coordinated
operations, utilizing state-of-the-art technology in order to defeat its adversary, the
submarine. Technology and its application are critical components to successfully ASW
and when combined with highly trained aircrews, and a robust ASW doctrine it has been
possible to defeat the submarine. .
The United States Navy began its initial foray into aviation in 1908, when
Lieutenant George C. Sweet and William McIntee observed the pioneering work of the
Wright brothers.3 On May 8, 1911, Captain Chambers prepared requisitions for two
Curtiss biplanes. Designated the A-1, and purchased for a total of $4,400, this action was
to mark the beginning of naval aviation.4 The Navy established a Board of Aeronautics
on October 1913 to coordinate its efforts and under the tutelage of Captain Washington I.
1
German U-boats did not operate in the Pacific during WW-I, they were used in WW-II to transfer critical
war material between Germany and Japan.
2
Tom Stefanick, Strategic Antisubmarine Warfare, and Naval Strategy (Lexington: Institute for Defense &
Disarmament Studies, 1987), 5.
3
Michael D. Roberts, Dictionary of Naval Aviation Squadrons, the History of VP, VPB, VP (HL) and VP
(AM) Squadrons, Volume 2 (Washington D.C.: Naval Historic Center, 2000), 1.
4
Elretta Sudsbury Jackrabbits to Jets, the History of North Island, San Diego California (San Diego:
Neyenesch Printers, Inc., 1967), 21.
1
Chambers, naval aviation was born.5 From this humble beginning, naval aviation
changed the nature of war at sea.
The story of the maritime patrol aircraft is a tale of technology and the people
who were to develop it. Cooperation between the political, military, scientific, and
commercial communities proved critical to the defeat of the submarine in World War I.
This meshing of disciplines proved critical and continued into the future.
In World War I, Secretary of the Navy Josephus Daniels established the Naval
Aircraft Factor (NAF). Established by the government to address the shortage of aircraft
confronting the United States in the early stages of the war the NAF was a leader in
aircraft development. The Navy working with civilian engineers, such as J.G. Vincent of
Packard Motor Car Company and E.J. Hall of the Hall-Scott Motor Car Company was
able to create the “Liberty Engine” considered by many to be the finest aircraft engine
built during the war.6
Professor George Ellery Hale led the scientific community in its effort to develop
various technologies for ASW use. Respected by the academic community for his
research in solar astronomy, he brought academic and naval leaders together in an effort
to combat the submarine menace in World War I. This proved critical to the success of
the American effort to develop the necessary technologies to combat the submarine.
This blend of disciplines continued in the interwar years. Naval officers Bradley
Fiske, David R. Taylor, and Frederick G. Coburn successfully dropped a torpedo from an
aircraft, while Edgar H. Dix Jr., a metallurgist working for Alcoa, revolutionized aircraft
construction with his pioneering work with duralumin.
5
W.H. Stiz, U.S.M.C., A History of U.S. Naval Aviation (Honolulu: University Press of the Pacific, 2005),
5. Originally published by the Navy Department in 1930 as “Technical Note No. 18.”
6
Stiz, 4.
2
Admiral Francis Stuart Low, the commanding officer of the “Tenth Fleet” was
instrumental in leading the American ASW forces during the Battle of the Atlantic. A
gifted leader, he coordinated the efforts of all in this massive effort to defeat the U-boat
during World War II. He ensured the continued cooperation of the military and the
scientific communities. Universities, such as Columbia, Harvard, and University of
California at San Diego each established laboratories dedicated to the development of
new and improved ASW methods. Additionally to be successful at ASW it is necessary to
understand the submarine’s environment therefore it was critical to enlist the help of
Wood’s Hole Oceanographic Institute and Scripps Institution of Oceanographic.
Through two World Wars and the long struggle with the former Soviet Union, the
maritime patrol aircraft continued to evolve, and its abilities expanded. It was a struggle
that pitted the technology of the aircraft against that of the submarine. In an attempt to
achieve a clearer understanding of the role played by the maritime patrol aircraft in antisubmarine warfare, an examination of the technologies utilized in the struggle will be
necessary. Some the technologies were revolutionary in nature, while many were
evolutionary as systems developed in the early years of World War I are still in use
today.
Anti-submarine warfare is a complex form of naval warfare as it involves surface
combatants, submarines, aircraft, and shore-based command and control centers and
while technology plays a critical role in ASW, the tactics used are of equal importance. It
will be possible to achieve an appreciation of the maritime patrol aircraft in its ASW role
by examining the evolution of the various technologies and the tactical application of
these systems in its battle against the submarine. By presenting the development of the
3
maritime patrol aircraft in such a manner, the reader will achieve a complete
understanding and appreciation of the anti-submarine warfare.
The development of the maritime patrol aircraft has undergone four designative
phases. The emphasis of the initial phase of development occurred as a direct result of
the introduction of unrestricted submarine warfare by Germany on 1 February 1917.7 The
submarines ability to submerge had changed naval warfare. These primitive craft proved
capable of disrupting maritime commerce to such an extent that the very definition of sea
power underwent a change. This new weapon required new technologies and methods if
it was to be defeated. World War I saw the development of many of the theories that
were to guide the evolution of the maritime patrol aircraft.
During the inter-war years of 1920, to1940 development antisubmarine warfare
systems and the development of suitable tactics slowed. Politics, finances, and military
doctrine all hindered and curtailed the development of the maritime patrol aircraft in its
ASW role.8 The political and military leaders of the United States soon forgot hardlearned lessons of the carnage of World War I. International disarmament, treaties
outlawing war convinced many of the world’s political and military leaders that
submarine warfare, as practiced in World War I, was a type of warfare that civilized
nations need no longer fear. In part, because of these attitudes many saw no need to
develop an effective ASW aircraft.
World War II initially saw the Navy ill prepared to combat the new German
submarine threat. Hindered by prewar doctrine and the lack of effective weapons and
sensors, the early years of the war saw the American forces pay for this lack of
7
Paul G. Halpern, A Naval History of World War I (Annapolis: Naval Institute Press, 1994), 338.
Though development of ASW systems and weapons slowed in the inter-war era, aircraft and engine
development continued at a rapid pace.
8
4
preparedness as the U-boat ravaged the Allies merchant fleets. Only by combining the
efforts of science, aircraft designers, and the Navy was the U-boat threat contained.
During the Cold War development of the maritime patrol aircraft accelerated as
the technologies continued to mature. To defeat the post-war nuclear submarine threat,
ASW grew in complexity. Computers replaced men, knowledge of the ocean grew at a
startling rate, and while the era saw the introduction of new aircraft and more powerful
aircraft it was the introduction of new sensors that permitted the Navy to contain the large
Soviet submarine force.
Following the collapse of the Soviet Union, many saw the era of the MPA in the
anti-submarine warfare role archaic. As when Germany collapsed following the end of
World War I, many in and out of uniform saw ASW as a form of warfare no longer
pertinent in today’s world. This may prove to be premature with the rise of the People’s
Republic of China’s Navy (PLAN) and other potential underwater threats.9 Though the
rise of terrorism has many political and military leaders focused on asymmetric warfare,
the submarine with its unique attributes still is a threat and our leaders must realize its
potential unless we wish to repeat the mistakes of the past.
Anti-submarine warfare is complex and by its nature a slow process. Commonly
referred to as “awful slow warfare,” few works address the role of the maritime patrol
aircraft in its anti-submarine role. The development of the maritime patrol aircraft has
been evolutionary and has received little attention. From its humble beginnings in World
War I, to the use of advance technologies in the latter half of the 20th century the MPA
has undergone vast changes as it confronted an ever more potent threat.
9
Jeb Babbin, and Edward Timberlake, Showdown, Why China wants War with the United States
(Washington D.C., Regnery Publishing, Inc., 2006), 167-168.
5
Of the available works, Alfred Prince has produced an excellent account of the
airborne anti-submarine warfare in his work, Aircraft versus Submarine, The evolution of
the anti-submarine aircraft 1912 to 1972. Written for a popular audience, he succeeds in
describing the actions of both American and British forces. Unfortunately, with eight of
the book’s eleven chapters dedicated to World War II, Prince provides scant attention to
World War I and the Cold War. While providing a broad overview of the airborne ASW
mission it lacks the necessary technical information of the various aircraft, weapons, and
electronic systems for the reader to appreciate the evolution of the maritime patrol
aircraft.
Building upon the work of Alfred Prince, John Terraine’s Business in Great
Waters is a thorough examination of the ASW effort in World War I and II. Unlike
Prince’s earlier book, this is a scholarly work providing the reader with a highly technical
and well-documented account of the ASW effort during the war years. Like Prince’s
work, this work concentrates upon the British effort and provides only a cursory
examination of American contributions.
World War I has received considerable attention with Anti-submarine Warfare in
World War I: British Naval Aviation and the Defeat of U-Boats, by John J. Abbatiello
being the most useful in understanding the role of aircraft in the ASW role. As the title
would suggest, the work’s focus is the British and while it does not address the American
warfare effort in detail it does provide a large amount of useful information in regards to
airborne anti-submarine warfare in general. As the British and American efforts against
the U-boat tended to overlap, this work provides a wealth of data concerning the use of
airpower to defeat the U-boat threat.
6
Other works, such as R.D Layman’s work Naval Aviation in the First World War,
Its Impact, and Influence, provides a short account of early naval aviation, in which he
dedicates one chapter to anti-submarine warfare. Dwight R. Messimer’s Find and
Destroy, Antisubmarine Warfare in World War I, is an excellent account of the overall
effort to defeat the German submarine.
The continuing evolution of the maritime patrol aircraft during the interwar years
of 1920 to 1940 has received little attention. To grasp the complexity of the development
it is necessary to examine a variety of works. An excellent starting point is William F.
Trimble’s work Wings for the Navy, a History of the Naval Aircraft Factory, 1917-1956.
This book provides a wealth data regarding the construction and development of aircraft
in the interwar years. Technical Note No.18, Series of 1930, A History of U.S. Naval
Aviation, written by Captain W.H. Sitz, USMC, provides a look at the early years of
Navy aviation. A short work, it is a superb source of technical data of early naval
aircraft.10
Anti-submarine warfare is dull, and successful missions require patience, and a
certain degree of luck. A typical flight by a maritime patrol aircraft would last for hours
and frequently result in no contact with a submarine. While this has resulted in few
works dedicated to ASW flights, there are numerous popular accounts of specific aircraft.
One such work is Andrew Hendrie’s book the Flying Cats: the Catalina Aircraft in
World War II, a general account of the work performed by the Consolidated PBY
Catalina. A more recent work is US Navy PBY Catalina Units of the Atlantic War by
Ragnar J. Ragnarsson, a short work detailing the Catalina’s contributions in the Battle of
10
This work is available from the Naval Historical Center at http://www.history.navy.mil/ or the
University Press of the Pacific, Honolulu, Hawaii.
7
the Atlantic during World War II. The Lockheed P-3 (Orion) and the P-2V (Neptune)
workhorse during the Cold War receive similar attention. David Reade’s The Age of
Orion, the Lockheed P-3 Story and Wayne Mutza’s work, Lockheed P2V Neptune, an
Illustrated History provide a wealth of technical data concerning the aircraft’s
performance and capabilities.
The Battle of the Atlantic during World War II is perhaps the most well
researched era of anti-submarine warfare. Clay Blair’s massive two-volume work,
Hitler’s U-Boat War, the Hunters, 1939-1942, and the Hunted 1942-1945 provided a
detailed examination of the combined ASW effort of the Allies to defeat the U-boats.
The Tenth Fleet, by John Smith, provides an excellent account of the American effort
combating the German U-boat during the Battle of the Atlantic. Other general accounts
include Terry Hughes and Terry and John Costello’s, The Battle of the Atlantic, and
Samuel Eliot Morison’s, The Battle of Atlantic, September 1939 – May 1943, vol. 1 of
History of United States Naval Operations in World War II.
The Cold War literature has focused on the strategic picture rather than the
tactical aspects of anti-submarine warfare. Donald C. Daniel’s work Anti-Submarine
Warfare and Superpower Strategic Capability is an example of a work that emphasizes
the strategic vice tactical aspects of submarine warfare. Strategic Antisubmarine Warfare
and Naval Strategy, by Tom Stanick is a technical examination of anti-submarine
warfare. Works of these types, while of great use in understanding ASW fails to address
the function of the patrol aircraft accept in general terms.
The memoirs of various naval leaders, such as Admiral Sims, Scheer, King, and
Doenitz, allow the reader to appreciate the impact of the MPA on the overall war effort.
8
However, these works provide little in the way of understanding the technology and
development of the MPA. Though written by a British officer, The Spider Web, the
Romance of a Flying-boat War Flight, published in 1919, provides a fascinating look at
the trials and tribulations of an ASW flight in World War I. A unique work is Sub
Chaser, by Edward M. Brittingham Capt., U.S.N. (ret). Brittingham was the
commanding officer of a patrol squadron during the 1960’s and his memoir provides
valuable insight into the function of the maritime patrol aircraft during the Cold War.
The availability of Aviation Weekly, a weekly Navy magazine captures the
thoughts and opinions of the era. Available online, they provide a picture from 1943 to
2007 on the status of naval aviation.11 Additionally, All Hands, though not dedicated to
aviation, another magazine published by the Navy, provides much needed information
concerning personnel issues.12 Naval History, a monthly magazine published by the
United States Naval Institute provides articles on wide range of historical subjects, while
Jane’s Defense Weekly is an excellent source for information concerning various avionic
systems.
Another obstacle that has hindered research into the maritime patrol aircraft and
its role in combating the submarine has been the classification of many of the sources
dealing with the MPA’s capabilities and limitations. A quick examination of such
documents as the formerly classified Office of Naval Intelligence (ONI) publication
number 46, Kite Balloons in Escorts, published in November of 1918, clearly
demonstrates this problem of military classification. This publication described the
tactical use of the kite balloon in submarine warfare; this type of balloon was soon
11
12
Available at the Naval Historical Center at http://www.history.navy.mil/
Issues from as early as 30 August 1922 are available at the Naval Historical Center.
9
obsolete. The authorities did not declassify this publication, until 7 August 1972. It has
been only in recent years that some of the necessary material is becoming available to
scholars.
To appreciate the evolutionary development of the MPA and its impact upon the
ASW effort it is necessary examine a variety of works. Key technologies, such as sonar
and radar along with navy doctrine and tactical application all influenced the
development and use of the various aircraft. To see the impact of the maritime patrol
aircraft it is necessary to combine the information from these varied sources.
The evolution of the maritime patrol aircraft has been a long and complex
process. Over the years, the roles of the MPA have changed little even though tactical
doctrine and technology have continued to evolve. Through the years, the missions of the
MPA have included its use as a high altitude bomber, a reconnaissance platform, and a
transport, in addition to its role of sub-hunter. Of the various missions undertook by the
MPA, it is in its role of sub-hunter that is perhaps the most intriguing. The submarine
presented a challenge that could only be defeated through the proper use of technology
and tactics. By presenting the material chronologically, from its early beginnings in
World War I, to the end of the Cold War, the reader will come to understand and
appreciate the evolutionary changes that have taken place.
This paper will examine the development of the MPA in four eras. Beginning
with World War I, through the inter-war years, followed by World War II, and ending
with the Cold War, the paper’s overarching goal is to attempt to answer three questions.
In its battle against the submarine, did the maritime patrol aircraft affect its employment?
How did the changing technologies effect its employment and how did the MPA interact
10
with other ASW forces? These broad questions will form the foundation of the paper, and
guide the research.
Throughout its evolutionary development, patrol aircraft have undergone
considerable changes. In the early years, the Navy experimented with a plethora of
aircraft designs and models such as the Large America, designed by the Curtis Company,
evolved into the successful H-12 flying boat.13 This type of experimentation continued
until 1962, with the introduction of the Lockheed P-3A Orion, which remains the Navy’s
premier maritime patrol aircraft.14 While interesting, it will not possible to discuss in any
detail all of the various aircraft. The paper will examine only those aircraft that saw
extensive use in an operational role.
The development of technology was varied and extensive therefore only those
directly related to anti-submarine warfare will merit detailed examination. Specifically
the paper will explore three areas of technology that influenced the ASW battle. From the
beginning, the ability to communicate was critical to the defeat of the submarine.
Whether it was the use of homing pigeons or satellites, secured communications proved
vital to the ASW forces. Reliable communications provided the ability to concentrate the
ASW forces to a specific geographical area, thereby increasing the likely-hood of
detecting and destroying the submarine.
Detection of the submarine has proved to be the most daunting problem facing the
maritime patrol aircraft. While there have been attempts at other types of systems, it has
been the development of radar and sonar that has provided the greatest success. Early
13
John J. Abbatiello, Anti-Submarine Warfare in World War I, British naval aviation and the defeat of the
U-boats (London: Routledge Taylor & Francis Group, 2006), 14.
14
The P-3C, the current model of the Orion flown by the United States Navy’s patrol squadrons and is
scheduled to be replaced by the Boeing 767 in 2010.
11
radar systems transmitted electromagnetic energy toward objects, commonly referred to
as targets, and provided the range to them. Some modern radar systems have the ability
to provide a “picture” of the target.15 There are two basic types of sonar systems, active
and passive. “Active sonar” acts like an underwater radar system, while “passive sonar”
systems use sensitive microphones to detect the sounds created by the submarine.
The development of guns, bombs, rockets, and torpedoes carried by the MPA will
be the third technology addressed. From the dumb bombs of first and second world wars
to the smart weapons of the 21st century, the weapons needed to defeat the submarine
have continually improved as submarines operate at faster speeds and deeper depths.
By limiting the focus of the paper in such a manner, it will be possible to achieve a clear
picture of the history of the MPA.
To understand the complexity of the ASW problem it is necessary to understand
that the maritime patrol aircraft is but just one part of the ASW team. To appreciate these
“team concept” it will be necessary to examine how the MPA interacted with the convoy
system Room 40, Ultra, and SOSUS.16 Used in both wars, the convoy system shepherded
the merchant ships across the Atlantic Ocean and the MPA played a critical role in
protecting these large groups of ships from submarine attack. Room 40 and Ultra
intercepts allowed the MPA to concentrate its searches to a much smaller area. The use
of SOSUS in the Cold War was similar in its ability to refine the search area.
To ensure an accurate account of the evolutionary development of the MPA, it
will prove beneficial to incorporate both primary and secondary sources. Squadron
15
Synthetic Aperture Radar (SAR) produces an image of a scene that is similar, but not identical, to an
optical photograph.
16
Room 40 was the British intelligence unit responsible to decipher German radio communications. Ultra
was the Allie project that intercepted high-level German communications. SOSUS, sound surveillance
system, is a passive sonar array used in the years of the Cold War to detect submarines.
12
histories, declassified messages, and technical publications provide the bulk of the
primary sources. Though the primary focus of this paper is the technical evolution of the
maritime patrol aircraft, its weapons and systems, it will not ignore the human element as
it applies to the mission. The use of memoirs, interviews and the author’s personal
experiences will allow the reader appreciate the human factor as it applies to antisubmarine warfare and the maritime patrol aircraft.17
17
The author logged 7754 hours of flight time the P-3C Orion from 1975-1999.
13
World War I
World War I
On 6 April 1917, the United States entered World War I on the side of the Allies.
The decision to declare war was a direct result of the German decision to resume its
policy of unrestricted submarine warfare. During the early months of the war, naval
leaders viewed the submarine as merely another naval weapon, just one weapon to seek
out and destroy the opponent‘s naval forces. However, with their armies‘ staled
Germany looked for other means to defeat the Allies. This requirement forced Kaiser
Wilhelm II to declare the water around Great Britain and Ireland a ―war zone,‖ and that
all merchant ships were subject to attack.1
This declaration brought swift condemnation by the United States. Unwilling to
anger the United States, Germany quickly caved into the American demands and on 14
February 1914 issued new instructions to their submarine crews. Neutral ships, hospital
ships, and Belgium Relief ships were exempt.2 The practical effect of this order was to
negate the submarine‘s primary asset of surprise and place the submarine in grave
danger.3 Forced to operate on the surface the submarine ceased to be an effective
weapon.4
While this policy may have appeased the Americans, it failed to produce the
needed results sought by the Germany. By 1917, the war entered a critical phase for
1
Robert M. Grant, U-Boats Destroyed, the Effect of Anti-submarine Warfare 1914-1918 (Cornwall:
Periscope Publishing Ltd., 2002), 20-21.
2
Reinhard Scheer, Germany’s High Sea Fleet (Nashville: The Battery Press, 2002), 230-231. The first
edition of Scheer's account was published in 1920.
3
For an understanding of the various opinions regarding unrestricted submarine warfare see Germany’s
High Sea Fleet in World War I, Chapter XIII by Admiral Scheer, The World in Crisis, 1911-1918, Chapter
XLV, by Winston S. Churchill and The United States in the World War, Chapter IV, by John Bach
McMaster.
4
This occurred as they attempted to determine the legal status of the merchant ship. These Q-ships were
heavily armed trawlers or small and by merchant ships, that attempted to lure the U-boats in close before
firing upon them.
14
Germany. The stalemate on the Western Front had to be broken. As part of this plan,
Germany turned to unrestricted submarine warfare in its attempt to defeat the Allies.
While the United States opposed the unrestricted use of the submarine, Germany came to
believe it was necessary for their survival. Through diplomatic efforts it appeared for a
brief time, the two countries could resolve their conflicting views however this was not to
be. All attempts at compromised ended when Germany inform the United States that as
of 1 February 1917, the Imperial German Navy would sink any vessel that approached
either Great Britain or Ireland.5
Believing that he had no options, President Woodrow Wilson summoned
Congress to meet on 6 April in order to request a declaration of war. While the infamous
Zimmermann Telegram has received much credit for driving the United States to war, it
was Germany‘s decision to resume unrestricted submarine warfare that tip the scale in
favor of war.6 A brief examination of President Wilson‘s speech delivered on the
evening of the 6th clearly demonstrates that it was the submarine and not the Zimmerman
Telegram that forced Wilson to request permission to send the nation to war.
Wilson began by stating that German policy of unrestricted submarine warfare
had swept aside all restrictions and that:
Vessels of every kind, whatever their flag, their character, their cargo, their
destination, their errand have been ruthlessly sent to the bottom without warning
and without thought of help or mercy for those on board, the vessels of friendly
neutrals along with those of belligerents.7
5
John Bach Master, The United States in the World War (New York: D. Appleton and Company, 1918),
351. This was a return to the original policy of 1915, with no restrictions placed upon the submarine crews.
6
Foreign Secretary Arthur Zimmermann, the author of the Zimmermann Telegram, offered Mexico an
alliance with German. Mexico was to attack the United States and in return, Mexico would receive the
states of New Mexico, Texas, and Arizona.
7
President Wilson outlined the case for declaring war upon Germany in a speech before the joint houses of
Congress on2 April 1917. http://www.firstworldwar.com/source/usawardeclaration.htm.
15
In the early years of the 20th century, the submarine was a new and deadly weapon that
went beyond the bounds of civilized warfare. Civilized nations did not condone or
practice this type of warfare. Following his description of the effects of unrestricted
submarine warfare Wilson stated that:
The present German submarine warfare against commerce is warfare against
mankind. It is a war against all nations. American ships have been sunk,
American lives taken, in ways, which it has stirred us very deeply to learn of, but
the ships and people of other neutral and friendly nations have been sunk and
overwhelmed in the waters in the same way. There has been no discrimination.
The challenge is to all mankind. Each nation must decide for itself how it will
meet it.8
Following fifty speeches attacking and defending Germany, the Congress, at three
o‘clock in the morning, pass a joint resolution empowering the President to issue a
proclamation declaring that a ―state of war exists between the United States and the
Imperial German Government.‖9 The shocking brutality of unrestricted submarine
warfare had driven the United States to involve itself in a war in Europe, abandoning its
historical position of neutrality.
The declaration of war found the Navy ill prepared. The Americans possessed no
adequate war plans, nor were they prepared to cooperate with their British counterparts.10
Further, the material condition of the fleet was poor with only one-third of the ships fit
for active service.11 The fledgling air arm of the Navy was even in a poorer state of
readiness. Though it had been six years since the acquisition of its first aircraft, there had
8
Master, 351.
Ibid., 359. The vote passed 373 for, and 50 against war.
10
Paolo E. Coletta, The American Naval Heritage in Brief (Washington D.C.: University Press of
America, Inc., 1980), 260.
11
Ibid.
9
16
been little progress in establishing operational squadrons.12 In the years prior to the war,
the Navy had utilized aircraft in various fleet exercises and had achieved a degree of
success, however limited funding, and resistance by senior officers had prevented the
procurement of large numbers of aircraft.
As with the conflicts of the past and those of the future, the United States Navy
went to war ill prepared. In typical American fashion, the political leadership of the
nation addressed the problems of men and material only after declaring war. Due in part
to the swiftness of the war, many items procured by the Navy arrived only after the end
of hostilities. Much of the equipment used by the American naval air force was obsolete
and foreign built.13 Despite the poor state of their equipment and their limited
experience, the Navy quickly threw the officers and men of the naval aviation service
into the fray. In May 1917, in response to the urgent request of the French Government,
the United States Navy assembled a force of 7 officers and 122 men that represented the
first United States military or naval presence to land in Europe for service ashore.14
World War I saw the introduction of numerous new and deadly weapons. The
machine gun, poison gas, the airplane, and the submarine each radically changed the
conduct of war. All brought a new dimension to the battlefield, be it on land, sea, or air.
Few military leaders, prior to the war, understood the impact these new and deadly
weapons were to have upon the nature of war.
12
. The United States Naval Aviation, 1910-1980, NAVWEPS 00-80P-1, 1970, p. 4. Prepared at the
direction of the Deputy Chief of Naval Operations (Air Warfare) and the Commander, Naval Systems
Command. March 1911 the government appropriated the first funds for naval aviation
13
The United States was at war from 5 April 1917 to 11 November 1918. Naval air squadrons used either
British or French bombs, and American crews flew aircraft such as the French built Tellier seaplane.
14
W.H. Sitz, A History of U.S. Naval Aviation (Honolulu: University Press of the Pacific, 2005), 20.
Originally published in 1930.
17
In 1914, the world‘s navies possessed 400 submarines and most naval experts
believed that the submarine was capable of only limited defensive roles.15 This opinion
changed as various technical advancements improved the submarine‘s offensive and
defensive capabilities. As speed, range, and the lethality of its weapons improved,
potential uses of submarine grew.
The outbreak of the war found the belligerent nations of Europe in possession of
relatively large numbers of submarines. The British Navy had the largest submarine fleet
numbering 75, with the navies of France, Russia, and Italy operated 67, 36, and 14
respectively.16 Germany entered the war with 30 submarines, while Austria-Hungry
maintained a submarine force of eleven.17 Both, Germany and Great Britain had various
plans to use the submarine in conjunction with their respective battle-fleets, but few
thought to employ the submarines in the role of guerre de course.
Germany began its offensive campaign against Allied shipping with only twentyfour combat ready submarines.18 In spite of these small numbers, it became painfully
apparent that the British Navy was not prepared to battle the submarine threat. The
submarine represented something new in naval warfare and was a threat that found the
Allies ill prepared to confront. In the autumn of 1916, the destruction of their merchant
fleet had assumed serious proportions for the British, Allied forces with monthly
mercantile losses with of 122,793 tons in May, 111,719 tons in June, 110,757 tons in
July, 160,077 tons in August, 229,687 tons in September, 352,902 tons in October, and
John Merrill ―From the Heavens to the Depths‖ Naval History, June 2000, vol. 14, Issue 3, page 56.
Alfred Price, Aircraft versus Submarine (Annapolis: Naval Institute Press, 1975), 10.
17
Germany‘s ally the Ottoman Empire had according to Jane’s Fighting Ships of World War I, originally
published in 1919, and had no submarines in its fleet.
18
Owen R. Cote, Jr., The Third Battle, Innovation in the U.S. Navy’s Silent Cold War Struggle with Soviet
Submarines (Newport: Naval War College, 2003), 6.
15
16
18
327,245 tons in November.19 According to Admiral of the Fleet Viscount John R.
Jellicoe the whole of the British war efforts, ashore as well as afloat, depended first and
last on an adequate volume of merchant shipping.20 To achieve victory the Allied forces
had to neutralize the submarine threat.
Two individuals, one American and one British had a profound effect on naval
theory in the early 20th century. In the United States, Captain Alfred T. Mahan (USN) in
his groundbreaking work The Influence of Sea power upon History advocated the need
for a large, blue-water fleet. Mahan believed the principal conditions affecting sea power
were a nation‘s geographical position, physical conformation, extent of its territory, size
of its population, and the character of its people and government, including therein the
national institutions.21 Mahan placed little faith in guerre de course as he placed a great
emphasize on the battleship and the classic fleet action of the Nelson era. Sir Julian
Stafford Corbett, advocated the concept of the ―fleet in being,‖ a concept that has been
misunderstood by many.22 Corbett insisted that the object of naval warfare must always
be directly or indirectly either to secure the command of the sea or to prevent the enemy
from securing it.23
Prior to World War I the number of capital ships, specifically the battleship,
possessed was the principle measurement of naval strength. Mine-warfare, the
submarine, and the airplane received little attention except in context of a fleet action.
19
John R. Jellicoe, Admiral of the Fleet, The Crisis of the Naval War (London: 1920) @
http://gutenberg.net, e-book #10409, released December 8, 2003.
20
Ibid.
21
Alfred T. Mahan, The Influence of Sea power upon History (New York: Dover Publications Inc., 1987),
28-29.
22
Clark G. Reynolds, ―The U.S. Fleet-in-Being Strategy of 1942,‖ The Journal of Military History, vol. 58,
no. 1 (Jan. 1994), 103-118.
23
Julian Corbett, Some Principles of Maritime Strategy (London: 1911), 89. @ http://gutenberg.net, ebook #15076, released February 16, 2005.
19
Command of the sea and a fleet action in the style of Trafalgar was the function of a
nation‘s navy.
According to Admiral Reinhard Scheer, in 1916 the German High Seas Fleet
added 38 large U-boats, 7 large minelayers and 34 Type UB-boats to the fleet, with and 8
additional boats undergoing sea- trails.24 A further 53 large U-boats, 10 large minelayers,
27 UB-boats, and 66 UC-boats were under construction.25 Each class of submarine
differed in size and capabilities, and as the war progressed, they were to continue to
evolve.
Germany commissioned its first submarines in 1906 when it accepted the U-1
class coastal submarines. Just as the airplane was to evolve, the submarine likewise
underwent a series of evolutionary advancements. These early units used two Körting
heavy oil engines driving two shafts for propulsion while surfaced. A precursor to the
diesel engine it achieved ignition by bringing superheated fuel into contact with fresh-air.
In part because of it‘s a poor compression ratio, it was soon replaced on subsequent
designs by the diesel engine. Even though these engines emitted large clouds of dark
exhaust gas and sparks through the upper deck of the submarine, they were considerable
safer then the gasoline engines found in most foreign submarines of the era.26
Poorly armed, the U-1 was equipped with a single eighteen-inch diameter torpedo
tube in the bow. Subsequent units, the U-2, U-3, and U-5 added an additional tube in the
stern. By modern standards, these submarines were extremely limited but when
24
Scheer, 259. The Germans used letters to designate classes of submarines in World War I, while
Germany used Roman numerals in World War II. The letters U, UB, and UC represented different type
and classes of submarines. U designated the large ocean-going boats, while UB designated coastal torpedo
boats, and UC designated mine-laying boats.
25
Scheer, 259.
26
Jane’s Fighting Ships of World War I, 3rd ed. (London: Butler & Tanner Ltd., 2001), 124. This is a
reprint of the 1919 edition of Jane’s Fighting Ships. Germany built a single U-1, U-2, three U-3, and five
U-5 units.
20
compared to the gasoline-powered vessels of other navies, the German undersea fleet was
safe and capable.27 Displacing between 238 and 506 tons, with submerged speeds of 9 –
10 knots, these craft represented Germany‘s initially attempts at constructing an effective
submarine.28
The last classes of German submarines to use a heavy oil engine were the U-9, U13, U-16 and U-17 classes. With little increase in displacement, the German engineers
doubled the torpedo armament from the previous single tube in the bow and stern to four
tubes with two tubes in the bow and stern. Additionally, deck guns were added, with the
U-9 and U-17 classes mounting a single 37 mm gun, while the U-13 and U-16 classes
mounting one four pounder.29
The U-19 class ushered in a major advancement with its use of diesel engines for
surface propulsion.30 With its additional power, surface speed of the submarine was
increased. The U-19 had a surface displacement of 650 tons, with a maximum surfaced
speed of 12 knots and carried nine, 50-cm. caliber torpedoes.31 With two torpedo tubes in
the bow and stern, and mounting either one or two 3.4 inch cannons the U-19 was highly
effective in its role of commerce raider.32
As the war progressed, Germans found it desirable to increase the number of
torpedo tubes and the size and number of cannon on their submarines. Suitably powerful
cannon allowed the U-boat to conserve its limited number of torpedoes for high value
Jane’s, 124.
Ibid.
29
Ibid.
30
The diesel engine gains its energy by burning fuel injected or sprayed into the compressed, hot air charge
within the cylinder. The air is heated to a temperature greater than the temperature needed by the injected
fuel can ignite. Fuel sprayed into air that has a temperature higher than the ―auto-ignition‖ temperature of
the fuel spontaneously reacts with the oxygen in the air and burns.
31
Scheer, 259.
32
The follow on units were refinements of the U-19 class.
27
28
21
targets by using number n fire to sink less valuable targets. This lead to the mounting of
two 3.4 or 4.1 inch cannon on most submarines, with the U-139 and U-142 class
mounting two massive 5.9 inch weapons. The number of torpedo tubes increased in later
units from two in the bow and stern, to four in the bow and two in the stern.33
When the United States entered the war, the need for additional range and
weapons became important as U-boats widened their hunting ground. This was to result
in an increase in size for the U-80 class and later models to approximately 800 tons. The
additional displacement resulted in surface speeds of 17 knots, an endurance of 7,630
miles and the ability to carry twelve torpedoes.34 The majority of this type of U–boat
patrolled the waters west of Ireland, with patrols lasting between 21 to 28 days.35
For the waters in and around the English Channel and the North Sea, Germany
produced the UB class of submarines. Smaller, with a corresponding reduction in
weapon load and endurance, these boats were nonetheless deadly in the confined waters
in which they patrolled. The UB series of submarines underwent a series of changes.
The first units of this type were a mere 125 tons, and had a combat radius of
approximately 1,650 miles. The UB-III grew to 500 tons, with a corresponding increase
in range to 8,500 miles.36 From a single heavy oil engine in the UB-I class driving a
single shaft, to dual diesel engines in shafts of the larger UB-II and UB-III class units the
capabilities of this coastal attack submarines continued to improve. Armament increased
Jane’s, 124 – 126.
Scheer, 259. U-90 and later models had a torpedo load of sixteen.
35
The number of torpedoes carried and their use predicated the length of the patrol. Once a submarine
expended its torpedo load it would return to port.
36
Selected Technical Data of Imperial German U-boats and their torpedoes, found at U-boat.net.
http://uboat.net/histoy//wwi/part7.htm
33
34
22
from two bow torpedo tubes on the UB-I units to four bow and one stern tube for the
improved UB-III class.37
The third type of submarine used by Germany was the mine-laying submarine.
Unlike the other types discussed, the primary weapon of these units was the mine. Just as
there was an ocean going and coastal attack submarines, so there was corresponding
minelayers. The U-71 through U-75 classes was large submarines, specifically designed
to plant minefields. Unlike the standard attack submarines, they add external torpedo
tubes, which allowed room to carry up to 32 mines internally in two tubes.38 The larger
U-117 and U-122 class were equipped with four bow torpedo tubes and was capable of
carrying 42 mines. With its 5.9-inch deck-gun, these were highly capable submarines.39
The UC class of coastal minelayer as with the other types underwent similar
changes to its propulsion plant and weapons suite. Initial the UC-I class was powered by
a single heavy oil engine, later UC-II and III units utilized twin diesel engines for surface
propulsion. Likewise, armament increased from no armament on UC-I class to two
external torpedo tubes and one internal stern tube on UC-II and III units. Additionally
the machine-gun of the UC-I was replaced by either a 3.4 or 4.1 inch gun on UC-II and
UC-III class submarines. As with other types of submarines the displacement and range
of the UC boats grew from 150 tons and an endurance of 750 miles of the UC-I boats, to
474 tons and 8,400 of the later UC-III class.40
The primary mission of the small UC class submarines was to plant minefields in
British waters. Owing to the small number of mines carried, it was critical for the crew
Jane’s, 126.
Ibid., 124.
39
Jane’s, 126.
40
Selected Technical Data of Imperial German U-boats and their torpedoes, found at U-boat.net.
http://uboat.net/histoy//wwi/part7.htm
37
38
23
to know its exact position as it was frequently necessary to lay a new minefield adjacent
to the previous one. During the war, Germany developed a mine for the UC class
submarine. Possessing a charge of 120 t0 200 kilos, it was effective to a depth of 365
meter.41 Though designed specifically for the mission of mine laying, it remained a
dangerous job, as numerous UC class submarines were lost to their own mines.
During 1915 and 1916, four UC-I class boats were lost to their own mines.
Initially German authorities hoped the improved UC-II boats would elevate this problem.
This was not to be the case. On February 13, 1917, while laying mines, the new UC-33
suffered severe damage when a mine detonated under her keel. In May, the UC-76 was
lost while loading mines when the soluble safety plug dissolved from a mine accidentally
released causing it to float to the surface and strike the boat.42
The last type of submarine used by Germany was the large commercial submarine
referred to as the Deutschland type.43 Built to transport critical war material through the
British blockade these were large submarines with a submerged displacement up to 2,483
tons and with a range of 12,630 nautical miles.44 Converted to naval combatants they
proved to handle poorly and had a limited torpedo armament of only two bow torpedo
tubes.45 However, their great range pointed the way for additional improvements to
Germany‘s submarine force.
Small, cramped, and wet, life aboard these early submarines was difficult at best
even for the larger class of submarine. Of the various dangers encountered, the lead
41
Robert M. Grant, U-Boats Destroyed, the Effect of Anti-submarine Warfare in 1914-18 (Penzance:
Periscope Publishing Ltd.: 2002), 69.
42
Ibid., 70.
43
O.N.I. Publication No. 32, German Submarines in Question and Answer, Navy Department Office of
Naval Intelligence, June 1918 (Washington D.C.: Government Printing Office, 1918), question #1.
44
‗Selected Technical Data of Imperial German U-boats and their Torpedoes, found at U-boat.net
http://uboat.net/history/wwi/part7.htm
45
Jane’s, 127.
24
battery presented the greatest hazard for the crew. The storage battery cells were located
under the living spaces and filled with acid and distilled water that generated hydrogen
gas when either charging or discharging. The gas removed through the ventilation
system and failure risked an explosion, a catastrophe that occurred in several German
boats. Another danger associated with the battery was that of seawater leaking into them,
as the mixture would generate a poisonous chlorine gas.46
Regardless to the size or type of submarine, speed and endurance limited their
actions. Unlike modern nuclear submarines, diesel submarines of World War I spent the
greater portion of their time surfaced in part because of their slow speed while
submerged. German submarines of the era were limited to a submerged speed of
approximately nine knots, with some classes further limited to a maximum submerged
speed of only five knots.47
Submerged speed was but one part of the equation as speed and battery life are
inversely proportional. In other words, the battery was depilated quicker the faster the
submarine travel, forcing the submarine to the surface. U-boats could maintain their
maximum speed for approximately one to two hours. This use of high speed would drain
the battery forcing the U-boat to the surface in order to recharge them.48
The limitation of the battery resulted in a radius of action that was relatively short
while submerged. The large U-boats was capable of traveling 75-80 nautical miles at 5
knots, while the smaller UB and UC class submarines were in general limited to 40-50
46
Johannes Speiss, First Watch Officer of the U-9, wrote this account of life in a German U-boat. The
original document is in the Royal Navy Submarine Museum. Submitted by Dr. Geoffrey Miller @
http://www.vlib.us/wwi/resources/
47
‗Selected Technical Data of Imperial German U-boats and their Torpedoes, found at U-boat.net
http://uboat.net/history/wwi/part7.htm
48
O.N.I. Publication No. 32, question #15.
25
nautical miles at a mere 4 knots.49 As a hunter waits in a blind for a flock of ducks to fly
overhead, the submarine of the era waited for its prey to come to it.
The torpedo used by the German crews was complex and unreliable. All were
steam powered which left a visible wake upon the surface of the water and had ranges
that varied from 3,600 to 9,800 meters. The number of torpedoes varied from as few as
two on the early UB class, to twenty-four on the large U-117 class.50 Primitive, with a
maximum speed of approximately 27 knots these weapons were able to sink the largest
warships of the war.51 These technical limitations when combined with the inability to
coordinated attacks due to the unreliability of radio communications adversely affect the
combat effectiveness of the U-boat in Germany‘s quest to defeat the Allies.52
Of the technical shortcomings discussed the slow speed and limited endurance of
the submarine while submerged had the greatest effect on the nature of anti-submarine
warfare. Due to these limitations, German captains spent much time of time on the
surface.53 During the ―restricted‖ submarine campaign of 1916, only 20% of the Allied
ships were sunk by torpedoes, while approximately 75% were sunk by gun fire.54 Only by
utilizing its superior speed during surface operations was the U-boat capable of
intercepting the average merchant ship of the era. Convoy speeds were generally
between 8.5 and 12 knots which prevented a submerge U-boat from overhauling a
‗Selected Technical Data of Imperial German U-boats and their Torpedoes, found at U-boat.net
http://uboat.net/history/wwi/part7.htm
50
Robert M. Grant, U-Boats Destroyed, the Effect of Anti-submarine Warfare in 1914-18 (Penzance:
Periscope Publishing Ltd.: 2002), 166.
51
Ibid.
52
John Terraine, Business in the Great Waters, the U-Boat War, 1916-1945 (London: Wordsworth
Editions, 1989), 143, Radio communications was a new science and as with much of the technology of
World War I was in a state of continuing evolution.
53
R.D. Layman, Naval Aviation in the First World War, Its Impact, and Influence (Annapolis: Naval
Institute Press, 1996), 80.
54
Paul G. Halpern, A Naval History of World War I (Annapolis: Naval Institute Press, 1994), 336. During
the ―restricted‖ campaign, U-boats alerted their potential victim prior to attack, while during the
―unrestricted‖ campaign the U-boat would attack without warning.
49
26
convoy while submerged.55 This speed disadvantage forced the U-boats commanders to
attack while surfaced and by 1918, two-thirds of all U-boat attacks were to occur at night,
while the submarine was on the surface.56
As a result of the convoy and their airborne escorts, the Germans were forced to
abandon the lucrative coastal waters and seek easier prey else were.57 No longer able to
lie in wait for their target, they had to pursue their targets. The Allies were well aware of
the situation and in O.N.I. Publication 30, ―Analysis of the Advantage of Speed and
Changes of Course in Avoiding Attack by Submarine,‖ sought to establish a tactical
doctrine to exploit this known weakness.58
Though limited by the technology of the day, the U-boats were able to inflict
tremendous loses upon the Allied merchant fleet. As the German crews mastered their
craft, the number and frequency of merchant ships sunk continued to increase. So serious
were the losses in the spring of 1917, that Rear-Admiral William S. Sims, the
commanding officer of the American naval forces in Europe stated, ―the military
situation presented by the enemy submarine campaign is not only serious but critical.‖59
The first three months of 1917 saw the world‘s merchant tonnage reduced by more than
two million tons, causing many to believe that the Allies were in danger of collapsing.60
A close examination of the tonnage sunk, clearly shows that 1917, was the critical
year in the war against the U-boat. Following the resumption of unrestricted warfare on 1
February 1917, the situation become so critical that the British authorities calculated that
55
Terraine, 63.
Paul G. Halpern, A Naval History of World War I (Annapolis: Naval Institute Press, 1994), 426.
57
Ibid.
58
The doctrine addressed the use of speed as a defense against submarines and the effect speed on the
angles-of-approach taken by the submarine.
59
William S. Sims, The Victory at Sea (Annapolis: Naval Institute Press, 1984), 43.
60
Halpern, 341.
56
27
one in four merchant ships leaving the United Kingdom never returned.61 The losses of
British, Allied, and neutral vessels increased each month from a low of 181 in January, to
259 in March, to a staggering 432 in April.62 Sir Winston Churchill, the First Lord of the
Admiralty and Minister for War and Air, believed that the U-boat threat not only
undermined the life of the British islands but also could destroy the foundation of the
Allies‘ strength and that the danger of total collapse in 1918 was imminent.63
During the twenty-one months of unrestricted submarine warfare, the Allies were
to lose 3,842 merchant ships to German attacks. The monthly average loss from
February 1917 to October 1918 was 183 ships, a rate that the Allies could not endure.64
A year-by-year comparison clearly shows that 1917 was the high-water mark of the Uboat offense and that it was imperative for the Allies to stop the carnage.
Year
Gross Tonnage Sunk
1914
1915
1916
1917
1918
312,672
1,307,996
2,327,326
6,235,878
2,666,94265
With their cause in danger of collapse, the Allies needed to develop the means and a
strategy to defeat the U-boat menace.
Prior to the declaration of war, the Navy‘s air forces consisted of 1 air station, 54
aircraft, and 38 aviators.66 The Navy had 163 enlisted personnel assigned to maintain the
61
Winston S. Churchill, the World Crisis, 1911-1918 (New York: Free Press, 2005), 744.
Ibid., 742.
63
Ibid., 744.
64
William Sims, The Victory at Sea (Annapolis: Naval Institute Press, 1984), 400.
65
John Terraine, Business in Great Waters, the U-Boat Wars, 1916-1945 (Hertfordshire: Wordsworth
Editions Limited, 1999), 766.
66
United States Naval Aviation, 1910-1980. Prepared at the direction of the Deputy Chief of Naval
Operations (Air Warfare) and the Commander, Naval Air Systems Command, (Washington D.C.: U.S.
Government Printing Office, 1981), 381.
62
28
aircraft.67 Small, inadequately equipped and manned, naval aviation was to undergo
tremendous growth and change during the war years. Funding increased to include
1,400% in material, 3,000% in personnel training, and 3,200% in stations and training
schools.68 This infusion of money resulted in a massive expansion as seen by comparing
the size of the force of 1917 to that of 1918.
6 April 1917
Officers (naval aviators)
Officers (student naval aviators)
Officers (ground)
Student officers
Total officer personnel
Enlisted men (aviation ratings)
Enlisted men (general service ratings)
Total enlisted personnel
Total personnel
38
0
0
0
38
163
0
163
201
11 November 1918
1,656
288
891
3,881
6,716
21,951
8,742
30,693
37,40969
By examining the training accomplished at the various air stations, it is possible to see
rapid growth of naval aviation. One such station was NAS North Island located in
southern California. During a six-month span from June to November of 1918, the flight
school graduated 206 officers.70 In the processes, they logged over 35,000 flight hours.71
With the requirement for large numbers of trained aviators came the need to
develop a more efficient means of training. To achieve this goal the Navy divided the
training syllabus into three distinct phases. The students began by attending a basic
ground school. The purpose of this school was to introduce the students to the
fundamental of aviation. Following ground school, the students then entered an
Joseph Charles Cline, ―The Lost Detachment,‖ in The Golden Age Remembered, U.S. Naval Aviation,
1919-1941, ed. E.T. Wooldridge (Annapolis: Naval Institute Press, 1998), 3.
68
Paolo E. Coletta. The American Naval Heritage in Brief, 2nd edition. (Washington D.C.: University
Press of America, Inc.), 262.
69
Walter H. Sitz, A History of U.S, Naval Aviation (Honolulu: University Press of the Pacific, 2005), 9
70
Jackrabbits to Jets, the History of North Island, San Diego California. (San Diego: Neyenesch Printers,
Inc., 1967),
71
Ibid.
67
29
elementary flight phase where they learned basic flying techniques. Having mastered the
basics, they proceeded to the advanced flight and ground school.72
The Navy established ground schools at the Massachusetts Institute of Technology,
University of Washington, and Dunwoody Institute in Minneapolis. The young aviators
then attended one of the advanced flight training schools located at Bay Shore Miami,
Key West Florida, or San Diego California. It was at these bases the young aviator
learned the art of gunnery, aerial bombing, and navigation. Those assigned to the large
flying boats received additional training. These aviators were then sent to Pensacola
Florida were they received additional training.73
While the Navy rushed to expand its training facilities, as a short-term solution,
the American military turned to their new allies for aid. On 19 July 1917, twenty-four
trainees, under the command of Ensign Frederick S. Allen reported to the University of
Toronto to begin their flight training. As part of an arrangement between the U.S. Army
and the Canadian Royal Flying Corps (RFC), the 25 men from the Navy were included in
the 100 aviation trainees that the Canadian government had agreed to train.74
Even as the Navy began its massive wartime expansion in the America, the first
contingency of naval aviators arrived in France in June of 1917.75 This group designated
the ―First Naval Aviation Unit,‖ consisted of 7 officers and 122 enlisted men and
constituted America‘s initial contribution to the war effort.76 Their initial training was
with the French built Caudron G-3, which was equipped with a 90 horsepower (hp)
72
Stiz, 11.
Ibid.
74
Roy A. Grossnick, United States Naval Aviation, 1910-1995, 4th edition. (Washington D.C.: Naval
Historical Center, Department of the Navy), 27
75
Sitz, 20.
76
E.T. Wooldridge, ed., The Golden Age Remembered, U.S. Naval Aviation, 1919-1941 (Annapolis: Naval
Institute, 1998), 280-281.
73
30
engine; the instrumentation consisted of an oil gauge, altimeter, and tachometer.77
Demand for pilots was high resulting in the young pilots receiving the minimum amount
of training necessary to certify them safe. The pilots soloed after receiving only 3 hours
of flight training. Transferred to the naval station at Le Croisic following basic flight
training, the pilots and crewmembers, under the command of Lt. M. Corry, flew the
French built Tellier seaplane.78
This was a time for experimentation and development of heavier-than-air aircraft.
In the years prior to the war, the Navy experimented with three basic types of heavierthan-air aircraft. The types possessed in 1917 were the seaplane, the flying boat, and
landplanes.79 Unlike today were it is common to use the term seaplane to describe any
aircraft that takes off and lands on the water, in the early years of aviation this was not
the case.
A seaplane was an aircraft equipped with pontoons. The number of pontoons
varied with either one or two pontoons used to support the aircraft on the water. Prior to
1916, the Navy used the term hydroaeroplanes to describe this type of aircraft.80 Flying
boats were those aircraft with a fuselage that was boat-like in shape. The seaplane rested
upon its pontoons while the flying boats with their boat-like fuselage sat upon the water.
Landplanes was the term used to identify aircraft that took off and landed from airfields
the term landplanes.
As with training, the production of large numbers of aircraft was a new
undertaking for the American military. On May 16, 1917, the Aircraft Production Board
77
Cline, 8.
Ibid., 16.
79
United States Naval Aviation, 1910-1980, 381.
80
Ibid.
78
31
was established. It was the supreme authority with regard to aircraft production by the
Navy and Army.81 On 6 November 1917, the board adopted a resolution stating that air
measures to defeat the submarine threat would take precedence over all other air
measures.82 Later that same month, Secretary of War Newton D. Baker demonstrated his
approval by stating, ―That priority is given by the War Department to naval needs for
aviation material necessary to equip and arm seaplane bases.‖83 With the support of this
committee and the Secretary of War, the Navy had adequate funding for the development
and production of the aircraft needed to counter the submarine.
To solve the problem of aircraft procurement for naval use, on 27 July 1917, the
Secretary of the Navy Josephus Daniels authorized the establishment of the Naval
Aircraft Factory (NAF).84 Daniels was concerned with the Navy‘s dependence on private
contractors, believing there was a lack of competition among the builders.85 Built on land
adjacent to the Philadelphia Navy Yard, it took only 110 days to complete construction of
the factory.86 On 27 March 1918, the first aircraft built by the NAF made its maiden
flight.87 Employing 3,642 people, including 900 women, most who had no previous
experience or training in the manufacturing of aircraft or aircraft parts, it was soon
determined that prewar methods of aircraft were unacceptable in the rush to provide
aircraft to the Navy.
81
Sitz, 12.
Ibid., 13.
83
United States Naval Aviation, 1910-1980, 30.
84
Ibid., 27.
85
Daniels believed that large business combinations limited competition. Companies such as Carnegie and
Bethlehem steel had allegedly colluded on their bids to supply armor plate to the navy and Daniels wanted
to prevent the fledgling aero-industry from doing the same.
86
Sitz, 15.
87
Ibid. The H-16 was the first aircraft built by the Naval Aircraft Factory.
82
32
The fabrication of large wooden aircraft during the World War I era had more in
common with cabinetmaking, boatbuilding, and sail making than with modern aircraft
manufacturing.88 Wood, cotton material, and varnish were the principle materials used in
the fabrication of airplanes, and the use of metal reserved for use in the fittings.
Wood was the preferred material and not just any type but very specific woods for
the various parts of the plane. Builders used Sitka spruce, grown along the Pacific coast,
to construct the wing spars.89 The longerons and other smaller critical parts were built of
white ash from the second-growth forest of the Midwest and Mid-Atlantic States.90 Kilndried to obtain the proper moisture content, inspectors then carefully examined each
piece for knots and spiral grain. The laminated wood was stored under very specific
temperature and humidity-controlled conditions buildings.
Problems of construction first materialized during the construction of the Curtiss
H-16 flying boat, the first aircraft built by the Naval Aircraft Factory. Lack of
standardization played havoc on the construction schedule. Prior to the war, the Curtiss
Company built aircraft one at a time, with expert mechanics, engineers, and drafters. All
of these individuals understood aviation, while at the NAF; the Navy employed various
businesses to manufacture the aircraft components, some such as the Victor Talking
Machine Company and the Singer Sewing Machine Company, who had no experience in
aircraft construction.91 This led to the redrawing and standardization of aircraft drawings.
It also allowed for the ―outsourcing‖ of work, a critical step if large numbers of aircraft
were to be constructed.
88
William F. Trimble, Wings for the Navy, a History of the Naval Aircraft Factory, 1917-1956 (Annapolis:
Naval Institute Press, 1990), 21.
89
Ibid.
90
Longerons are longitudinal fuselage strength members.
91
Sitz, 17.
33
The need to develop a reliable engine seriously affected the evolution of these
aircraft. Additionally the Navy desired that these engines be capable of being produced
utilizing mass production techniques. The solution was the Liberty engine, designed by
the Dayton-Wright Airplane Company.92 Taking delivery of five prototype models on 4
June 1917, the Navy then faced the problem of adopting the engine to mass production
techniques.93 In a remarkable display of American ingenuity, E.J. Hall of Hall-Scott
Motor Car Company, and Jesse Vincent of Packard Motor Car Company, in a
Washington hotel room solved the production issues leading to the production of over
20,000 Liberty engines.94
The first fifteen Liberty engines were 8-cylinder and produced 270 hp, which was
later, increased to 330 hp.95 However, a 12-cylinder engine soon replaced this model due
to its serious vibration problems. The 12-cylinder engine was one of the wars most
powerful and reliable aircraft engines. Producing up to 400 hp it incorporated numerous
unique features.96 Unlike most engines of the era that that a 60˚ angle between the
cylinder banks, the angle on the Liberty engine was reduced to 45˚.97 This resulted in a
much narrower cross-section that aided in mounting it in the aircraft. Additionally the
engine used a coil ignition system similar to those used in automobiles because of
American companies could not produce enough magnetos.98 To facilitate maintenance,
―U.S. Centennial of Flight,‖ http://www/entennialofflight.gov/essay/Aerospace/earlyengines/Aero4.htm
United States Naval Aviation, 1910-1980, 26.
94
―Aviation Engines, Liberty Aero Engines,‖ http://www.oldengine.org/members/diesel/ Duxford/
liberty.htm
95
―U.S. Centennial of Flight,‖ Later versions were equipped with a turbocharger, increasing the power to
442 hp.
96
John M. Elliot, ―Aircraft Data—Technical Information and Drawings, Appendix 1.‖ In the Dictionary of
American Naval Aviation Squadrons, vol. 2 The History of VP, VPB, VP (HL) and VP (AM) Squadrons, ed.
Michael D. Roberts, (Washington D.C.: Naval Historic Center, Department of the Navy, 2000), 643.
97
―U.S. Centennial of Flight.‖
98
Ibid
92
93
34
the engine's design used individual cylinders. This enabled mechanics to perform routine
repairs on the engine without having to remove it from the aircraft. Each of these
developments contributed to the success of the Liberty engine.
An examination of the work of aircraft designer Glenn H. Curtiss of the Curtiss
Aeroplane Company provides an excellent example of the evolutionary nature of aircraft
development during this era. Curtiss designed and built many types and styles of aircraft
only to find them unable to perform their assigned mission. One such aircraft was the
HS-1, a single engine flying boat. With its crew of two sitting in tandem, it was powered
by a single Curtiss V2 200 engine.99 These aircraft were grossly underpowered to the
point it was incapable of flight.100
This trial-and-error approach of development resulted in a constant stream of
improvements and modifications to existing airframes. An example of this is the Curtiss
HS-1 becoming the HS-1L when equipped with the 375 hp Liberty engine.101 As stated
earlier this engine proved totally inadequate and was quickly replaced by the larger 400
hp Liberty engine during its first set of upgrades as the early HS-1L models carried a
payload of two 180 pound depth bombs which proved inadequate against the U-boats.102
To increase the bomb load to two 230 pounds and the crew to three, along with the
change of power plants, it was necessary to increase the lift provided by the wings. To
achieve these improvements it was necessary to increase the length of the upper wing by
twelve feet and a six-foot panel between the hull and each lower wing panel.103
99
Elliot, 643. Naval aircraft did not have names assigned them in this era. The Navy used a numeric
designation system to identify these aircraft.
100
Ibid.
101
Ibid.
102
Ibid.
103
Ibid.
35
Following these modifications, the designation of the plane was change to HS-2L. Even
with these improvements, the HS-1/2 series of flying boats were small, with a limited
patrol radius.104 The requirement for a larger, longer-range aircraft was soon recognized
and these improved aircraft soon made their appearance.
Of the various aircraft utilized by the United States, and her Allies during World
War I, the finest was the Curtiss Large America and its derivatives.105 The Curtiss
Company designed and built the Large America in an attempt to win Lord Northcliffe‘s
prize of ₤10,000 as the first aircraft to fly across the Atlantic in 72 hours.106 War
prevented the attempt but development of the Large America continued resulting in the
introduction of the Curtiss H-12 flying boat.
The Navy accepted the first models of the H-12 in January of 1917.107 As with
many initial designs, the H-12 proved to be woefully underpowered for operational use.
Equipped with two Curtiss V-2-3 engines producing 200 hp, it was upgraded with twin
Liberty engines which were capable of producing 330 hp each.108
The H-12 and its successor the H-12L were large flying boats that retained the
laminated wood veneer hull of the Large America. With a length if 46 feet, 5.5 inches,
and a wing span of 96 feet, the H-12 series of flying boats had an endurance of six hours
and were capable of carrying a bomb load of four 100 pound or two 230 pound bombs
under the lower wing.109
104
Elliot, 643. The effective range of the H-1/2 flying boats was 517 miles.
John J. Abbatiello, Anti-submarine Warfare in World War I, British naval aviation and the defeat of the
U-Boats (London: Routledge, 2006), 14.
106
Ibid.
107
Ibid., 641.
108
Ibid., 640.
109
Abbatiello, 15.
105
36
The Royal Naval Air Service (RNAS), in order to fulfill their need for a longrange flying boat, purchased the H-12 from the United States. The endurance of the
various flying boats and seaplanes of the RNAS in the early years of the war was between
two and three hours.110 The greater endurance allowed for greater tactical flexibility and
an increased change of detecting a surfaced submarine.111
While the H-12 was a great improvement over earlier models, American design
suffered from a weak hull, and its self-defense capability was poor. Under the guidance
of Wing Commander J.C. Porte, the RNAS found solutions to these weaknesses resulting
in a much more capable aircraft. To strengthen the hull, Porte experiment with other
Curtiss aircraft and discovered the solution was to steepen the ―vee‖ of the hull.112 The
hull of the H-12 was relatively flat resulting in hydroplaning and poor seaworthiness.113
The change provided a stronger landing platform and greatly increased its seaworthiness.
Other improvements included the installation of six Lewis machine guns, and replacing
the American power plant with the more powerful, 345 hp. Rolls-Royce engine.114
Designate by the British the Felixstowe F2a, it proved an excellent anti-submarine
aircraft.
Building upon its wartime experience, the Navy contracted with the Curtiss
Company to build a new aircraft whose primary mission would be ASW and patrol.
Incorporating many changes made to the H-12, the Curtiss H-16 entered service on 1
110
Abbatiello, 15.
Price, 21. The British began using the H-12 in 1917. The increased endurance permitted the British to
utilize such tactics as the ―Spider Web.‖
112
Abbatiello, 15.
113
Ibid.
114
Ibid. These engines increased the F2a‘s bomb load to 2 x 230-lb bombs.
111
37
February 1918. Larger and heavier than its predecessors it continued the evolutionary
advancement of the MPA.115
Like its predecessors, the H-16 had a crew of four. Unlike earlier aircraft, the
cockpit was enclosed greatly improving crew comfort and efficiency. Capable of
carrying a bomb load of four 230-pound bombs, it was equipped with five or six 30caliber machine guns for self-protection. Built by both the Curtiss Company and the
Naval Aircraft Factory, the H-16 remained in the Navy‘s inventory until 1930.116
The success of the British modifications were such, that the Navy, in 1918, placed
an order with the Curtiss Company, to produce an aircraft with the capabilities of the
British F-5, to be designated the F-5L.117 Designed to fulfill the Navy‘s need for a longrange, heavily armed aircraft, the F-5L was the most capable aircraft of the World War I
era utilized by the United States Navy.
A monster of a plane, the F-5L had a wingspan of 103 feet and had a gross takeoff
weight of 13,256 pounds. While the bomb loads of the H-16 and F-5L were the same, the
massive F-5L, with its twin 330 hp Liberty engines had a combat radius of 765 miles
compared to the 452 miles of its predecessor.118
Advancements in technology brought corresponding improvements to the
capabilities of the various aircraft. Improvements in technology allowed for theory to
become reality. One such example of this was the work of Lieutenant (Lt) H.A.
Williamson.119 An officer in the Royal Navy, Williamson, a qualified submariner and
115
Elliot, 641. The American H-16 was roughly equivalent to the British F-3.
Ibid.
117
Ibid., 638. The F-5 was the follow-on to the F-3, which incorporated the earlier changes.
118
Ibid., 638, 641.
119
The papers of H.A. Williamson are held at the Churchill Archives Centre on the campus of Churchill
College, University of Cambridge.
116
38
aviator, in March 1912, published a paper titled ―The Aeroplane in use against
Submarines.‖120 Williamson‘s insightful paper established the four fundamental
requirements for all future ASW aircraft. First, a successful maritime patrol aircraft
needed good visibility as the ability to visually sight the contact was of great importance.
Long endurance and a reliable engine were the second and third principles, with a large
payload being the last of the four requirements needed.121
An examination of the evolutionary development of the various aircraft used by
the United States Navy during World War I clearly shows that whether directly or
indirectly designers and builders of maritime patrol aircraft were attempting to fulfill the
requirements set forth by Lt Williamson. While these changes came slowly, it becomes
apparent that by 1918 aircraft such as the F-5L were meeting these theoretical
requirements.
Throughout World War I, the capabilities of submarine and the aircraft
continually improved. Submarines went deeper and faster, while the aircraft could fly
longer and faster. However, for the aircraft to be effective tool in the battle against the
submarine advancements in various other technologies were necessary. Much of the
equipment used by the airplane was revolutionary in nature and development of new
techniques was necessary to exploit these advanced capabilities. It was a time of
experimentation and innovation. Many of these systems proved to be of limited military
value but the work of these early pioneers of anti-submarine, warfare established the
necessary working relationships between the Navy and scientific community that proved
critical to future developments.
120
Alfred Price, Aircraft versus the Submarine (Annapolis: Naval Institute Press, 1973), 7.
R.D. Layman, Naval Aviation in the First World War, Its Impact and Influence (Annapolis: Naval
Institute Press, 1996), 78-79.
121
39
As America stood by and watched the nations of Europe engage in the brutality of
submarine warfare, some in Congress sought technological initiatives for military
preparedness. Unfortunately, Congress acted only after a German U-boat sank the
Lusitania on 7 May 1915.122 Following the sinking of the Lusitania, Congress
established two groups to explore the exploitation of these emerging technologies in an
attempt to find newer and more efficient methods of combating the U-boat.
On July 1915, Congress established the Naval Consulting Board (NCB), and the
National Advisory Committee on Aeronautics, and while these actions taken by the
government were important, it was the actions of individuals, such as George Ellery Hale,
that ensured the cooperation of the scientific community and the military in the battle
against the submarine.123 The coordination of the National Academy of Science (NAS)
and the military was due in large part to Hale‘s efforts. On June of 1916, the NAS
formalized the creation of the National Research Council (NRC) whose primary function
would be to coordinate the scientific war effort.124
While there were numerous problems facing the American military at the
outbreak of the war, none were greater the German U-boat threat. Learning to detect,
locate, and destroy German U-boats became the primary task of the NRC. Following a
meeting with French and British scientist in May 1917, Hale and his team gathered
critical information regarding the development of antisubmarine devices.125 Building
upon the work of British and French scientist the American scientists examined numerous
John Merrill, ―From the Heavens to the Depths,‖ Naval History 14, no. 3 (June 2000): 56-60.
George Ellery Hale, well known for his work in solar astronomy, recognized the challenges of modern
war, and was able to obtain a promise of cooperation from the leading scientific societies, schools of
technology, heads of universities, medicine, research foundations, and industrial laboratories.
124
Merrill, 56-60.
125
Ibid.
122
123
40
concepts to defeating the U-boat. Exploring the use of sound, light, heat, and electricity
as detection techniques, the members of the NRC rushed to discover a reliable method of
detection.
The United States developed numerous passive listening devices during the war.
While very primitive by modern standards, these devices provided the base for future
development. The three most successful systems were the C-tube, K-tube, and the MVtube. The C-tube was aural listening system that consisted of two rubber spheres,
mounted 5 feet apart on an inverted T-shaped hollow pipe that terminated in a
stethoscope.126 The K-tube was a towed electrical device, consisting of three microphones
mounted on an equilateral triangle.127 Used extensively, the system had the capability to
detect targets up to a range of 16 miles.128 To use the K and C-tube systems it was
necessary to stop the ship and lower the device over the side. The MV-tube system
represented a major technical innovation in passive sonar, as it was the first hull mounted
passive sonar system used by the Navy.129
Having had a degree of success with shipboard passive acoustic systems, the
Navy attempted to apply the technologies to an airborne system. Building upon these
shipboard systems, the Navy attempted to design systems that airplanes and dirigibles of
the era could use. One such system was a modification of the K-tube system, known as
the OK-tube, it was an airborne towed array system used by dirigibles.130 Another one of
these early airborne systems was the PB-tube. Developed for use by seaplanes while
126
Dwight R. Messimer, Find and Destroy, Antisubmarine Warfare in World War I (Annapolis: Naval
Institute Press, 2001), 117-118.
127
Ibid., 119.
128
Ibid.
129
Ibid.
130
L.S. Howeth, USN, History of Communications-Electronics in the United States Navy (Washington
D.C.: Bureau of Ships and Offices of Naval History, 1963), 297-312.
41
drifting on the water, it consisted of three microphone units suspended separately from
three rings on the plane‘s bow.131 While none of these early systems was of practical use,
they did represent the initial steps in the development of a reliable airborne passive
acoustic detection system.132
Along with detection equipment, communications technology, especially radio,
was another emerging technology that the Navy attempted to exploit.133 Radio was in its
infancy and underwent a series of improvements during the war years. The Navy‘s first
successful tests occurred on 26 July 1912, when Ensign Charles H. Maddox, transmitted
the message, ―We are off the water, going ahead full speed on a course for the Naval
Academy," received by the U.S.S. Stringham at a distance of three nautical miles, the test
demonstrated the promise radio held for naval aviation.134 However, not all aviators
favored the radio, flying underpowered aircraft that had difficulty maintaining a safe
altitude, the added weight of radio equipment, and the tasks of mastering the telegraphic
code and operating the equipment while flying the plane did not appeal to them. . Many
in naval aviation believed that without a reliable radio scouting planes had little value.
The ability to report enemy contacts by radio and remain on station to provide updated
information was highly desired by naval leaders. Likewise, spotting planes would be of
little value unless they could continuously radio corrections in range and deflection.
With war clouds gathering on the horizon, on 25 July 1916, Chief of the Bureau
of Steam Engineering, Rear Adm. R. S. Griffin placed an initial requisition for 75 radio
131
Howeth, 297-312
While towed array systems had little future with airborne systems, submarines, and surface units use the
ancestor of the OK-tube system. The PB-tube was in some respects the precursor to the sonobuoy and the
dipping sonar found on modern helicopters.
133
For a detailed account of the development of radio, communications and other various electronic
systems see the History of Communications-Electronics in the United States Navy, by Captain L.S. Howeth
USN (retired). Published by the Bureau of Ships and Office of Naval History, Washington D.C.: 1963.
134
Howeth, 187-191.
132
42
sets.135 Lieutenant (Lt) E. H. Loftin, USN, a brilliant engineer whose pioneering work in
radio had brought him to prominence, was ordered to assist in the preparation of the
necessary specifications.136 For its day, the requirements were daunting. The radio was
to not exceed 100 pounds, have a trailing wire antenna of 200 feet, and be capable of
transmitting 100 miles or more.137 Thirteen companies placed bids on the contract.
Marconi Wireless Company of America, the De Forest Radio Telephone and Telegraph
Company, the Western Electric Company, and the Sperry Gyroscope Company declared
the winners. The Navy awarded each company a portion of the contract.138
Of the winning bids, that of E.J. Simon and Company showed the greatest
promise. Powered by a wind-driven generator, it came with a completely insulated
antenna reel that permitted the tuning of the antenna circuit while the 500-watt
transmitter was in operation by varying the length of the trailing antenna. The receiver
used one three-element vacuum tube and a regenerative circuit. The entire system
weighed approximately 100 pounds and during testing, proved capable of transmitting
signals over 150 miles.139
The Navy established the Aircraft Radio Laboratory at the Naval Air Station,
Pensacola, Florida in the summer of 1916. The Navy tasked the laboratory to study and
devise methods for providing intercommunication between crewmembers, to reduce
ignition and other aircraft generated noises, and to adapt a radio direction finder to fit
135
Howeth, 267-281.
Lt. E.H. Loftin a brilliant radio engineer was a member of the Inter-Allied Radio Committee and of the
Inter-Allied Technical Radio Committee. He convinced General Ferrie of the French Communications
Service that the U.S. Navy had the experience and ability to build large 1,000 kw arc radio transmitting
stations.
137
Howeth, Chapter XXIII.
138
The Navy divided the contract in four parts with DeForest to deliver 16 sets and American Marconi,
Speer Gyroscope, and E.J Simon each 15. The navy reduced the original contract of 75 when discovering
there were not 75 suitable aircraft in the inventory.
139
Howeth, 267-281.
136
43
aircraft requirements.140 Assembling experts from the Navy and the scientific
community, the laboratory made great strides in solving the various problems confronting
the use of radio equipment in naval aircraft.
Due to the capabilities and limitations of the various aircraft flown, it was soon
determined that a single radio would not fulfill the Navy‘s needs therefore two basic
types of radios were procured. To expedite the development of needed systems the
Aircraft Radio Laboratory moved to the Naval Air Station (NAS), Hampton Roads, and
Virginia on 1 January 1918, where flying boats of the two standardized types were
available. Flying boats and dirigibles needed radios with long range therefore they were
equipped with spark transmitters. Though spark transmitters were the heaviest type of
radio, they provided greater range then the lighter tube transmitter. The smaller singleengine aircraft were equipped with tube transmitters.141
The most successful of the wartime transmitters were the CQ 1115, 200-watt, and
the CQ 1111, 500-watt, spark transmitters.142 The CQ 1115 weighed 65 pounds and had
a range of 100 miles, while the CQ 1111 weighed only 20 pounds more and had a range
of almost 1,500 miles when transmitting to a shore radio station and 500 miles when
communicating with a warship. Powered by a wind-driven generator that was contained
in a streamlined case mounted on a wing of the plane, a tuning variometer was located in
the cockpit.143 These transmitters were the best of the spark transmitters developed
during the war, with both the Navy and the Army Signal Corps using the CQ 1115.144
140
Howeth, 267-181
These were radio transmitters only; later in the war, aircraft were equipped with radio receivers.
142
Howeth, Chapter XXI, 267-281.
143
Variometer was an instrument for measuring magnetic declination
144
Howeth, Chapter XXI, 267-281. The CQ 1111 was designated SE 1310 and the CQ 1115 was
designated SE 1300.
141
44
The single-engine flying boats used the CG 1140, a 50-watt vacuum tube
transmitter. A wind-driven generator or dry batteries provided electrical power. With its
100-mile range, smaller single-engine flying boats used it as the primary radio and larger
multi-engine flying boats used it as an auxiliary radio. A variation of the CG 1104 was
the CG 1104A, weighing a mere 50 pounds, it had an effective range of only 30 miles.
Used primarily for spotting the fall of shot, it proved to be adequate for fleet use.145
As with other technologies, radio communications underwent a series of
evolutionary improvements to meet the demands of the Navy. The end of the war saw
the introduction of the SE 1375 and SE 1385 transmitters. Both produced a clear 500cycle note and neither was voice modulated. Designed for use in small aircraft, the SE
1375 produced 20 watts, and used four three-element tubes that operated on frequencies
between 570 and 750 kHz. Used in the large flying boats, the heavier SE 1385, 500
watts, used two 50-watt three-element tubes and operated in the 300-600 kHz frequency
band.146 These two radios formed the backbone naval airborne communications in the
post-war years.
The final months of the war saw the introduction of radio receivers. The best of
these early receivers was the SE 950 receiver. .Consisting of an inductively coupled
three-element vacuum tube receiver, it operated in the 125-1,000 kHz frequency range.
Of note, the SE 950 was the first receiver designed with the amplifying circuits as an
integral part. Another successful receiver of the era was the SE 1414. A unique aspect of
145
146
By eliminating the batteries, the engineers saved considerable weight.
Howeth, 267-281.
45
the receiver was the use of a rubber suspension to mount the entire receiver that instead
of providing the individual tubes with shock mountings.147
With ability to find a submarine, and to communicate its location, came the need
to destroy, or at least damage it. This proved to be a difficult endeavor, one that
continues to plague ASW forces.148 With its narrow beam, a pressurized hull made of
high-tensile steel, the submarine was an extremely difficult opponent to kill. The ability
to release bombs quickly and accurately was critical to destroy the U-boat. According to
intelligence estimations, an efficient boat, operating both engines, could reach periscope
depth in 1 1/2 minutes once given the order to dive. If the boat is proceeding with one
engine and one electric motor running for propulsion the time taken will be even less.149
Prior to entering the war, the Navy began experimenting with small bombs carried
inside the rear observer‘s cockpit. Released by hand while over the target, this method
was extremely hazardous to the crew as these primitive bombs were prone to premature
denotation.150 This led to the development of bomb racks placed under the wings, which
increased safety and permitted a quicker release.
Early in 1915, the Navy began work on aerial depth charges and anti-shipping
bombs.151 While producing effective bombs, the Navy failed to develop a reliable fuse
for the depth charge. This resulted in the bomb failing to work at all or to detonate
prematurely. Eventually the Navy produced three different sizes of bombs, a light case
147
Howeth, 267-281.
The ability to destroy submarines in shallow coastal waters is a major problem facing the Navy in the
21st century.
149
O. N. I. Publication No. 32 German Submarines in Question and Answer. Naval Department Office of
Naval Intelligence, June 1918 (Washington D.C.: Government Printing Office, 1918), 19.
150
Michael D. Roberts, Dictionary of American Naval Aviation Squadrons, Volume 2, The History of VP,
VPB, VP(HL), and VP(AM) Squadrons (Washington D.C.: Naval Historical Center, Department of the
Navy, 2000), 635. On 8 July 1916, Lieutenants Clarence K. Bronson and Luther Welsh died when the
bombs carried exploded prematurely.
151
Messimer, 135.
148
46
163-pound bomb, a 230, and 270-pound pounds. Large flying boats stationed in the
United States, generally carried an ordnance load of two 230-pound bombs.152 Because of
the poor reliability of the American fuses, squadrons in Europe used either British or
French depth charges. Squadrons assigned to British bases used 100, 230, and 520-pound
bombs, while those in France used 52, 75, and 150-kilogram bombs.153
The problem with anti-shipping or the depth charge was the need to fly over the
U-boat in order to release the weapon. This took time, a commodity in short supply as
the U-boat raced to submerge. One attempt to develop an effective long-range ASW
weapon was Davis recoilless gun. Designed by Commander (CDR) Cleland Davis it was
first test on 3 October 1912 at the Naval Proving Ground, Indian Head, and Maryland.154
An ingenious weapon, it was capable of firing a shell large enough to damage a
submarine but with little recoil. CDR Davis had developed a gun with a single chamber
and two opposite barrels. One barrel carried the projectile, the other an equal weight of
grease and lead shot. The explosion of the central cartridge ejected both loads, and, since
the recoils had the same weight and velocity, they canceled each other out and the gun
remained stationary.155 Mounted in the bows of flying boats, the Davis gun had enough
power to penetrate the hull of a U-boat, which would prevent it from submerging.156
The other weapon carried by the patrol aircraft was the machine-gun. Following a
series of test in 1917, the Navy selected the British Lewis gun, manufactured by Savage
Arms over the French designed Benet-Mercie machine gun. The Lewis gun was air152
Roberts, 689
Ibid.
154
United States Naval Aviation, NAVWEPS-00-80P-1, prepared at the direction of the Deputy Chief of
Naval Operations (Air Warfare) and Commander, Naval Air Systems Command (Washington D.C.:
Government Printing Office, 1981), 7.
155
Big Ordnance, the Davis Gun, http://www.big-ordancne.com/Davis/davis_ammunition.htm
156
Roberts. 688
153
47
cooled and had a 97-round pan magazine.157 In July 1918, the Navy took delivery of one
thousand Marlin guns. A modified Colt-Browning 30 caliber machine-gun, it was aircooled, loaded via a 250-round belt, with a cyclic firing rate of approximately 650 rounds
per minute.158
World War I saw the birth of anti-submarine warfare and the Navy soon
discovered the need to harness science and technology in order to be successful. While
there were, many technical developments made during the war it was in the areas of
communications, sonar, and ordnance that had greatest effect upon the antisubmarine
warfare effort. Though many ideas and systems proved ineffective due to the primitive
nature of the technology, they did lay the foundation for future development.
In April 1917, Rear Admiral William Sims, the commander of the American fleet
met with his British counterpart, Admiral Sir John Jellicoe.159 The subject of this
meeting was to discuss the German submarine threat. At the meeting, Admiral Sims
learned how precarious the British position had become in its fight against the U-boat.
Following his meeting with the British authorities, Admiral Sims, in a letter to the
Secretary of the Navy Josephus Daniels, stated that ―the Allied Governments have not
been able to, and are not now, effectively meeting the situation presented,‖ and that ―the
Command of the Sea is actually at stake.‖ that the Allies were losing the war.160
So serious was the situation that on 26 April, Admiral Jellicoe sent the following
telegram to Rear-Admiral Sir Dudley de Chair, the naval representative on the British
mission to the United States.
157
Roberts. 688
First World War.com http://www.firstworldwar.com/atoz/mgun_marlin.htm
159
William Sowden Sims, Read Admiral, USN, The Victory at Sea (Annapolis: Naval Institute Press,
1984), 8. Doubleday, Page & Company, 1920, originally published The Victory at Sea.
160
Ibid., 377.
158
48
You must emphasize most strongly to the United States authorities the very
serious nature of the shipping position. We lost 55 British ships last week
approximately 180,000 tons and rate of loss are not diminishing. Press most
strongly that the number of destroyers sent to Ireland should be increased to
twenty-four at once if this number is available. Battleships are not required but
concentration on the vital question of defeat of submarine menace is essential.
Urge on the authorities that everything should give way to the submarine menace
and that by far the most important place on which to concentrate patrols is the
S.W. of Ireland. You must keep constantly before the U.S. authorities the great
gravity of the situation and the need that exists for immediate action.161
With few ocean going escorts and no available aircraft for patrol, the Navy was ill
prepared to help the British combat the U-boat menace.
Fortunately, for the United States no submarine threat materialized in the western
Atlantic in 1917. The U-boats of 1917 lacked the trans-Atlantic capability needed to
patrol the eastern seaboard of the United States and the Caribbean Sea. However, this
situation changed as Germany continued developing newer and more capable
submarines. In the Office of Naval Intelligence (O.N.I.) Publication No. 32, entitled
German Submarines in Question and Answer, published in June of 1918, American
intelligence specialists warned of the development of larger and more capable U-Boats.162
As the large U-boats became available, the German Imperial Navy elected to
deploy these powerful vessels to the eastern seaboard of the United States, the Caribbean,
and the Gulf of Mexico. Though warned of the impending German attack through
wireless intercepts of German radio communications, Sims elected not to react.
In the spirit of cooperation, the British Admiralty through the remarkable work of
―Room 40‖ had provided information detailing the intentions of the German forces. The
ability to intercept and decipher German communications provided a tremendous advance
161
Jellicoe, 123-124.
O.N.I. Publication No. 32 is a formerly classified publication that discusses the capabilities and
limitations of various U-boats. Written in June 1918, it was not until 17 August 1972.
162
49
to the Allied forces. Sims believed that inaction outweighed any response of part of the
American forces in order to protect the work of ―Room 40.‖163
On 22 May 1918, the U-151 made the first successful attack in American
waters.164 Sinking a 5,300-ton tanker, the U-151 followed up the attack by sinking three
coastal sailing ships north of Norfolk, and another six vessels south of New York.165
This marked the beginning of a successful campaign off the eastern seaboard of the
United States. From the opening attack in May until October 1918, the Americans lost
79 vessels to gunfire, 14 to torpedo attack, and 7 to submarine laid mines.166
This threat prompted the Navy to establish a series of air patrols around major
harbors. HS-1 and HS-2 flying boats flew the initial patrols. Due to the limited
endurance of the HS-1/2 flying boats, the patrols were limited to approximately 75 miles
from land.167 The patrols consisted of three basic types: standard, emergency, and escort
patrols. When required to search a fixed area, the crews would fly a standard patrol.
This type of patrol consisted of a flight of two aircraft, flying in formation, at an altitude
of 1000 feet.168 The launching of an emergency patrol would occur after receiving news
of a ship sinking or a submarine sighting. Two or more aircraft would fly to the location
of the sinking ship or sighting and begin a search for either survivors or the U-boat.
Convoy patrols consisted of two aircraft flying at 1000 feet in front of the convoy.169
163
Room 40 was a room in the Old Admiralty Building and the initial location of the British cryptanalytic
group. Officially, designated Section 25 of the Intelligence Division, Sir Alfred Ewing was in charge of
cryptology for the British Navy. Section 25 broke the German naval codes and was capable of intercepting
and reading the radio traffic of the German Navy. This allowed for prior knowledge of unit movements.
164
Paul G. Halpern, A Naval History of World War I. Annapolis: Naval Institute Press, 1994, 430.
165
Ibid.
166
Roberts, 6.
167
Ibid.
168
Ibid.
169
Ibid. The word ―datum‖ designates this location. Webster‘s Dictionary defines the word ―datum‖ as
something given or admitted especially as a basis for reasoning or inference.
50
The HS-1 and HS-2 were capable of searching approximately 1,500 square miles
during a standard five-hour mission.170 This proved to be inadequate if the U-boat threat
was to be contained. Soon larger and more capable twin-engine seaplanes, such as the H12, H-16, and F-5 L, supplemented the air-fleet. These larger aircraft were capable of
flying eight-hour missions permitting the search of areas up to 3,000 square miles.171
While the United States conducted some ASW flights in the western Atlantic, in
the English Channel and the western approaches to Great Britain the vast majority of the
flights were to take place as the majority of the U-boats operated in these waters. As with
any form of warfare, the forces needed a philosophy to guide their actions. The
American philosophy found in O. N. I. Publication No. 42, Antisubmarine Tactics, which
stated that:
Whenever possible, the attitude of the hunted, rather than that of the hunter,
should be imposed upon the enemy submarines. Every time that an enemy
submarine is forced to submerge it enters a danger area where machinery
accidents and errors of personnel produce their maximum effect.172
The concept of the hunter becoming the hunted was the fundamental principle of antisubmarine warfare in the United States Navy. It guided all aspects of the ASW problem.
At the outbreak of the war, the American naval air forces stationed in France
initially flew small French-built aircraft such as the single engine, Tellier, Le Pen, and
DD seaplanes due to a the lack of larger American built aircraft.173 Constrained by short
range, and with limited payload, these types of aircraft required a change in tactics.
170
Roberts, 6.
Ibid., 6
172
O. N. I. Publication No. 42, Antisubmarine Tactics. Washington D. C.: Washington Government
Printing Office, Navy Department Office of Naval Intelligence, October 1918.
173
Roberts, 6.
171
51
Quickly adapting to the new environment standardized patrols were soon established.
One such patrol consisted of flying a 250 nautical mile sector from Quiberon to St.
Nazaire.174 Escorting a convoy required a flight of two aircraft. After rendezvousing
with the convoy, the aircraft would fly a racetrack pattern with one aircraft on each
side.175 Another type of patrol was consisted of a flight of two aircraft that would fly
parallel to the coast in search of U-boats. Generally flown 50-60 miles from the French
coast, the flights lasted approximately 4 hours.176
Communications continued to present serious problems because of the limited
payload of these small seaplanes; consequently, these aircraft used pigeons to send
contact reports to their base.177 The pilot, after sighting a submarine, wrote a message
describing the situation and placed it into a vial on the pigeon‘s leg. Releasing the
pigeon, it returned the loft. At the loft, a messenger would retrieve the message and
relayed to the command center.178
While these aircraft, by modern standards, may seem to be severely limited in
terms of their ability to destroy a submarine, destruction of the target was rarely
necessary for success. It became apparent that the primary object of hunting by sight was
to force the enemy submarine to remain submerged until its battery was exhausted
thereby forcing it to surface.179
Joseph Charles Cline, ―The Lost Detachment,‖ in The Golden Age Remembered, U.S. Naval Aviation,
1919-1941, ed. E.T. Wooldridge (Annapolis: Naval Institute Press, 1998), 16.
175
Ibid., 16.
176
Ibid.
177
See ―Instructions on Reception, Care, and Training of Homing Pigeons in Newly Installed Lofts at U.S.
Navy Air Bases,‖ Navy Department Office of Naval Operations (Aviation) Washington, D.C. March 20,
1918. http://www.history.navy.mil/library/special/homing_pigeons.htm for detailed information.
178
Cline, 16.
179
O.N.I. Publication No. 42, 14.
174
52
With the addition of the H-12 large flying boats in January 1917, the Allies
developed a patrol pattern known as the ―Spider Web.‖180 Designed to search the narrow
stretch of water separating southeastern England and Holland, the ―Spider Web‖ forced
U-boats to submerge.181 U-boats used this area to reach the rich hunting grounds of the
English Channel. The ―Spider Web‖ was an octagon centered on the North Hinder Light
Vessel. Sixty miles in diameter, with eight radiating arms, each 30 miles long, and three
joining arms, spaced at ten-mile intervals, it covered a total of 4,000 square miles of
sea.182 Due to its slow speed, the U-boat, even while surfaced, required approximately
ten hours to transit through the ―Spider Web.‖ The H-12 searched two of the sectors in
five hours or less this forced the U-boat to submerge in order to protect itself.183 Even if
the attack was unsuccessful by forcing the U-boat to submerge, the flying boat achieved a
―mission kill.‖184
The Allies, by 1918, had a clear understanding of the capabilities of the U-boat.
In part, because of this knowledge, it was possible to develop search tactics, such as the
―Spider Web.‖ O. N. I. Publication No. 42 stated that:
A submarine can proceed 25 miles submerged in 3 1/2 hours at 7 knots –
batteries exhausted; 5 hours at 5 knots – batteries 40 per cent exhausted; 12 hours
at 2 knots – batteries 20 per cent exhausted.185
Knowledge of the enemy was critical to the development of effective tactics. Only
through the proper use of military intelligence was it possible to build the needed aircraft
180
Elliot 640.
P.I.X., The Spider Web, the Romance of a Flying-boat War Flight (London: Williams Blackwood and
Sons, 1919), 8.
182
John Terrain, Business in Great Waters, the U-Boat War, 1916-1945. London: Wordsworth Editions,
1989, 74.
183
O.N.I. Publication No. 32, 15 & 16.
184
―Mission kill‖ is preventing the enemy from executing its mission. A submerged U-boat had a speed of
approximately 3-4 kts. Unable to transit to the English Channel, the effect was the same as sinking the Uboat.
185
O.N.I. No. 42, 14.
181
53
and equipment to combat the submarine. As part of the ASW team, the aircraft when
properly employed was a serious threat to the submarine.
As part of the ASW team, the airplane was a perfect complement to the surface
escorts of the convoy. They brought increased visibility to the tactical picture. The
primary role of the aircraft, whether flying an area patrol or escorting a convoy, was to
interrupt U-boat cruises by forcing them to dive at inopportune times and to direct surface
attacks against them.186
To evaluate the impact of the airplane in its battle against the submarine, it is
necessary to examine various factors. Success in ASW is more than just the number of
submarines sunk for it success was based solely upon the number of U-boats sunk most
would consider the effort of the early aircraft a failure. According to Admiral Reinhard
Scheer, the German High Sea‘s Fleet lost 184 of 360 U-boats during the war.187 Of these
184 U-boats destroyed, the British Admiralty attributed the destruction of six submarines
to aircraft alone.188 According to Admiral Sims, the British Air Service sank five, and the
French Admiralty gave credit for the destruction of one submarine to the American
forces.189 However even this miniscule number was no to stand the test of time. After
extensive research, British authorities reached the conclusion that the air forces of the
Allies succeeded in sinking only one submarine, the UB-32, and all other U-boat losses
were the result of a combined effort with surface assets.190
186
Herman Whitaker, Hunting the German Shark (New York: The Century Co., 1918), Chapters XXIII
and XXVI. Though written with nationalistic overtones, this early account of ASW warfare does provide an
understanding to submarine warfare in WW-I
187
Reinhard Scheer. Germany’s High Seas Fleet. (Nashville: The Battery Press, 2002), 263.
188
Alfred Prince, Aircraft versus Submarine, The evolution of the anti-submarine aircraft, 1912 to 1972
(Annapolis: Naval Institute Press, 1973), 29.
189
Sims, 320.
190
Prince, 30.
54
The true strength of the aircraft was its ability to complement the surface escorts
of the convoy. By increasing the visibility of the tactical picture, the surface escorts were
able to concentrate along the threat axis, forcing the U-boat to either retreat or to attack
from a poor position.191 While the speed of some convoys was a mere seven knots, it was
still considerable faster than a submerged U-boat of World War I.192 The average U-boat
had submerged speed of 4 knots and if forced to submerge, by making a simple course
change the convoy would be able to escape from the U-boat threat.193
Captured U-boat commanders tended to down play the effectives of the airplane,
comparing them to a ―tiresome mosquitoes which forced the vessel to dive, but whose
stings are only superficial.‖194 However, the aircraft of the era had a limited ability to
―kill‖ a submarine; its presence forced the U-boat to submerge thereby increasing the
survivability of the merchant ship. The final eighteen months of the war saw 84,000
voyages made by merchant ships in convoy with only 257 of these ships sunk. Of the
257 sunk, only two were lost when the convoy enjoyed air protection.195 Following the
war Admiral Sims explained how the airplane contributed to the Allies victory when, in
his biography, he stated:
These achievements, compared with the tremendous efforts involved in equipping
air stations, may seem at first look like an inconsiderable return; yet the fact
remains that aircraft were an important element in the defeating the German
campaign against merchant shipping.196
Threat axis is the direction of the enemy‘s attack.
John Terraine, Business in the Great Water, the U-Boat Wars, 1916-1945 (London: Wordsworth
Editions, 1989), 63.
193
R.D. Layman. Naval Aviation in the First World War, Its Impact, and Influence (Annapolis: Naval
Institute Press, 1996), 80.
194
John J. Abbatiello, Anti-Submarine Warfare in World War I, British Naval Aviation and the Defeat of
the U-Boats (New York: Routledge, Taylor & Francis Group, 2006), 154.
195
Ibid.
196
Sims, 320.
191
192
55
It is necessary to use numerous tools to defeat the submarine and aviation‘s role in the
struggle was as an element of a strategic weapon system.197
While the testimony of captured U-boat members minimized the effectiveness of
the airplane, the German authorities did not ignore the airplane. Late in the war, U-boats,
in a direct response to the airborne threat, had the altiscope, a periscope with an upward
viewing angle, installed. This allowed the U-boat commander to scan the skies before
surfacing.198
World War I provided a plethora of lessons learned but four were to prove critical
to the future development and use of the airplane in anti-submarine warfare. The most
basic lesson learned was any sort of air cover was better than no air cover. Second, a
patrol aircraft with a long endurance was worth several aircraft with limited endurance.
Third, bombs needed to be larger enough to damage the submarine and finally the aircraft
was far more effective in preventing attack then in hunting the submarines as they moved
to and from their operating areas.199
The new technologies introduced during World War I radically changed the
nature of war. Strategies and concepts of old were no longer applicable to these new
methods of warfare. The submarine had changed naval warfare; successful containment
of the opponent‘s fleet did not guarantee victory. The submarine had radically changed
the concept of sea control. Naval supremacy no longer defined by merely counting the
number of ships and size of the guns carried. Control of the seas in the old ―Nelsonian‖
sense was a concept that no longer held true.200
197
R.D. Layman, 88.
Abbatello, 148.
199
Prince, 30 – 31.
200
Sims, 20.
198
56
In the nineteen months following, the declaration of war naval aviation was to
experience a rapid expansion that was to alter the force structure of the Navy. From a
single air station at the beginning, the aviation shore establishment had grown to 27 in
France, England, Ireland, and Italy, one in the Azores, two in Canada, one in the Canal
Zone, and 12 in the United States in full operation. The Navy flew more than 3,000,000
nautical miles of war patrols in their attempt to counter the submarine threat.201 It
required a vast team effort to bring the U-boat threat under control in 1918.202 Utilizing
extensive coverage by airplanes and airships, improved depth charges and hydrophones,
combined with the convoy system, and signal intelligence the success of these early
pioneers provided a blueprint for future antisubmarine operations
201
Adrian O. Van Wyen, Naval Aviation in World War I (Washington D.C.: U.S. Government Printing
Office, 1969), 89.
202
Paolo E. Coletta. The American Naval Heritage in Brief, 2nd edition (Washington D.C.: University
Press of America, Inc., 1980), 266
57
Interwar
Inter-war
In the years that followed World War I, the Navy underwent a series of changes
as the nation struggled to deal with a host of post-war issues. From a public wishing for a
return to it isolationist roots, to a world economic depression, the nation, and its naval
leaders attempted to create a naval policy capable of supporting the country‟s needs.
As the war ended, naval aviation and particularly the maritime patrol aircraft
confronted various hurdles that contributed to the slow pace of development during the
interwar years. Maritime patrol aircraft development suffered from a lack of monetary
funds, while at the same time post-war naval doctrine failed to support development of
the anti-submarine forces. .
The end of World War I brought a halt to the expansion of the American military
forces. Manufactures saw contracts cancelled for aircraft indented to battle the German
submarine force, as the American people were eager to turn its back to the problems of
Europe. Defense spending decreased drastically throughout the coming years with the
Navy‟s budget reduced by 76%, from its high of $2,002,311,000 in 1919, to
$476,755,000 in 1922.1 The reduction of funds from $20 million in FY 1920, to less than
$7 million for FY 1921 shocked the proponents of aviation.2 The reduction in
government spending and the corresponding cancellation of contracts saw five of seven
aircraft manufacturers bankrupted by 1921.3
Throughout the 1920‟s, spending was not to exceed $3.5 million as the country
saw little need to expend resources for war. The concepts of international disarmament
1
Michael D. Roberts, Dictionary of American Naval Squadrons, the History of VP, VPB, VP (HL0 and VP
(AM0 Squadrons, Volume 2. (Washington D.C.: Naval Historic Center, Department of the Navy, 2000),
11.
2
Ibid.
3
Ibid.
58
and passivism guide the world‟s leaders during the 1920‟s. While it would be logical to
assume a reduction in funds during the Great Depression of the 1930‟s, this was not the
case as the budgets of both decades were similar. It was only in the latter half of the
decade that saw budgets return the $500 million level.4 This reduced funding ensured
that the Navy was to operate aging F-5L and H-16 seaplanes well past their prime.5
The carnage of World War I had a profound effect on American political leaders
and on January 8, 1918, during a joint session of Congress, President Woodrow Wilson
presented his famous Fourteen Points. Stating in his fourth point that the nations of the
world should reduce national armaments to the lowest point consistent with domestic
safety, Wilson established the goal of universal arms reduction.6 While the Paris Peace
Conference Treaty failed to address arms control on a global scale, the Treaty of
Versailles did, in its drive to prevent future military adventurism on the part of Germany,
force disarmament upon their defeated foe.
The Treaty of Versailles, a huge document consisting of 440 articles, greatly
influenced the development of the maritime patrol aircraft. Part V, consisting of five
sections and fifty-four articles dealt specifically with military issues. The terms of the
treaty allowed for a gradual reduction to the German military with a goal of reducing the
German military to 100,000 by 31 March 1920. Reduced to 6 battleships, 6 cruisers, and
12 destroyers and 12 torpedo boats and no submarines the German Navy was a shadow of
4
Naval Budgets, http://www.history.navy.mil/library/online/budget.htm The 1933 the budget was highest
single year at $571 million until in 1939 the budget exceeded $673 million.
5
Roberts, 638, 641. The F-5L remained in the Navy‟s inventory until January 1931, and the H-16 was in
operational squadrons until May 1930.
6
Wilson‟s Fourteen Points, http://wwi.lib.byu.edu/index.php/President_Wilson%27s_Fourteen_Points
59
its former self.7 Of the various articles, Article 191 had the greatest influence upon the
development of the maritime patrol aircraft. Article 191 stated:
The construction or acquisition of any submarine, even for commercial purposes,
shall be forbidden in Germany.8
The neutralized by a stroke of the pen, the submarine no longer represented a threat. To
the political and naval leaders of the 1920‟s there was no need for further developments
of anti-submarine warfare forces, this however was just the beginning to arms reduction.
With no potential enemy possessing, a submarine force there was little military need to
continue the development of airborne ASW forces.
The Treaty of Versailles by stripping Germany of its military and naval power put
into motion a series of treaties that attempted to rein in the naval arms race between the
great powers. Limiting German warships to 10,000 tons set the stage for future naval
arms limitation talks. Navies formed a large part of national defense budgets in the postwar era, coast that needed reduced in order to passive civilian populations.9 The first of
these talks was the Washington Naval Conference held from 12 November 1921 to 6
February 1922.10 The United States, the British Empire, France, Italy, and Japan, signed
the treaty at Washington, February 6, 1922.11
Establishing limits to numbers, size, and armaments of various classes of
warships, the treaty was but one that attempt by the international treaty to limit arms
Primary Document: “Treaty of Versailles: Article 159-213,” http://www.firstworldwar.com/ source/
versailles159-213htm
8
Primary Documents: “Treat of Versailles: Articles 159-213,”
http://www.firstyworldwar.com/source/versailles159-213.htm
9
Richard W. Fanning, Peace and Disarmament, Naval Rivalry & Arms Control, 1922-1933 (Lexington:
The University Press of Kentucky, 1995), 4. Naval expenditures were the largest single expenditure in
1921-22.
10
Fanning, 3.
11
Conference of the Limitations of Armament, Washington, November 12 1921-February 6, 1922. From:
Papers Relating to the Foreign Relations of the United States: 1922, Vol. 1, pp. 247-266 Treaty Series NO.
671. @ http://www.ibiblio.org/pha/prewar/1922/nav lim.html.
7
60
expenditures and even outlaw war itself. The Kellogg-Briand Pact, multilateral
agreement attempted to eliminate war as an instrument of national policy.12 It was the
most grandiose of a series of peacekeeping efforts after World War I. A key aspect to
this treaty was its support by such isolationists as Senator William E. Borah of Idaho.
Individuals such as Senator Borah, and Senator Gerald P. Nye, all staunch isolationists,
had a profound effect upon the inter-war development of the United States military
forces.13
While their politicians argued over budgets and international law, advocates of
airpower were engaged in their own conflict. The desire of some military leaders to see
the creation of an independent air force complicated the situation. Airpower advocates
such as Brigadier General William (Billy) Mitchell not only campaigned for an
independent air force but also argued that “strategic bombing” made older methods of
war obsolete. Additionally Mitchell in his zeal to advance his theories claimed that
money spent on battleships was a waste and that national security could ensured through
the creation of an independent air force.14 The theatrics of Mitchell spurred an interservice battle that greatly influenced the acquisition of land-based maritime patrol aircraft
by the Navy. This rivalry greatly influenced the development of coherent national policy
for the use and development of air assets.15
12
Kellogg-Briand Pact 1928, http://www.yale.edu/lawweb/avalon/imt/kbpact.htm
Wayne S. Cole, Roosevelt, & the Isolationists, 1932-45 (Lincoln: University of Nebraska Press, 1983),
380.
14
Wesley Frank Craven and James Legate, ed., The Army Air Forces in World War II, Volume I, Plans and
Early Operations, January 1939 to August 1942 (Washington D.C.: Office of Air Force History,1983,
Originally published : Chicago : University of Chicago Press, 1948-1958), 25-26.
15
In July 1921, Mitchell‟s First Provisional Air Brigade sank three German ships, a destroyer, the cruiser
Frankfurt, and the battleship Ostfrieslmd Disputes arose as to the manner in which the experiment had been
conducted. While spectacular to the public, the exercise had little effect to air-power doctrine of the United
States. .
13
61
At the center of the debate, was the question of which service, the Army or Navy,
was responsible for coastal defense in the modern era? Historically protecting American
territory from hostile attack has been the task of both services, with the Navy ready to
engage and destroy any potential enemy on the high sea, and the Army committed to
repelling any invasion.16 This arrangement had stood the test of time but with the
introduction of the long-range bomber, combined with the theory of “strategic bombing”
the lines of responsibility became blurred. Further complicating the issue was the
economy minded Congress who saw the basing of aircraft ashore by both the Army and
the Navy as a costly duplication that the nation could not afford and did not need. The
1921 Army Appropriations Act read, “The Army Air Service shall control all aerial
operations from land bases.”17
There was little progress made in resolving this highly charged issue until a
change of service leadership occurred in 1930. Admiral William V. Pratt was appointed
the Chief of Naval Operations in September and in November, General Douglas
MacArthur became the Army‟s Chief of Staff.18 Both desired a solution to this pressing
problem. In January 1931, the two service chiefs reached an agreement that broke the
long-standing stalemate between the Army and Navy over the question of control of
aviation engaged in coastal defense. The MacArthur-Pratt Agreement acknowledged the
Army and not the Navy had the primary responsibility for coastal defense.19
To achieve this agreement, the Navy, under the leadership of Admiral Pratt
instituted a new aviation policy. In November 1930, Pratt promulgated a policy that
John F. Shiner, “The Air Corps, the Navy, and Coast Defense, 1919-1941,” Military Affairs, vol. 45, no.
3 (Oct. 1981) 113.
17
Ibid., 114.
18
Ibid., 114-115.
19
Carven, 30.
16
62
stated, “All aircraft assigned to tactical units will be mobile in order to operate with the
fleet. Mobility will be achieved by the use of carriers or tenders.” Pratt additionally
stipulated that naval air-stations and their aircraft “are not intended for and will not be
allowed to be diverted from their fleet objectives, for reason of coastal defense.”20
Pratt‟s new policy seemed to resolve two issues, the first being which service
was responsible for coastal defense and the rejection of land-based patrol aircraft for
naval use. In his annual report, General MacArthur defined the agreement in the
following terms:
Under it the naval air forces will be based on the fleet and move with it as
an important element in performing the essential missions of the forces afloat.
The Army air forces will be land based and employed as an element of the
Army in carrying out its missions of defending the coasts, both in the homeland
and in overseas possessions. Through this arrangement the fleet is assured
absolute freedom of action with no responsibility for coast defense, while the
dividing line thus established enables the air component of each service to
proceed with its own planning, training, and procurement activities with little
danger of duplicating those of its sister service.21
With the MacArthur-Pratt Agreement, the political infighting over land-based aircraft and
coastal defense appeared to be at an end. Unfortunately this was not to be the case, by 1932
the debate resumed when General Benjamin Delahauf Foulois the air chief of the fledgling
Army Air Corps, recommended a three phase air defense of the American homeland. The
doctrine entitled, “Employment of the Army Air Forces in Defense of our Seacoast
Frontiers,” asserted that plans for “the defense of the coast would be based upon the
assumption that no assistance would be expected from the navy.” Additionally the Army Air
Corps would operate reconnaissance and strike aircraft to locate and attack the enemy
invasion fleet out to the limit of the combat of the Air Corps aircraft.22 On 3 January 1933,
20
Shiner, 115.
Carven, 62.
22
Shiner, 115.
21
63
General MacArthur published the policy letter entitled “Employment of Army Aviation in
Coastal Defense” which established the Army‟s official position concerning coastal
defense.23 The doctrine accepted the Air Corps need for long-range over-water
reconnaissance capability as well as the right of Army aircraft to patrol out to sea.24
While this position may have been acceptable to Admiral Pratt, his replacement,
Admiral William H. Standley firmly rejected the Army‟s position and rescinded Pratt‟s Air
Operating Policy of November 1930.25 Publishing a new policy in May of 1934, it
reemphasized two naval air functions, which Pratt had minimized. Both directly influenced
the employment of the maritime patrol aircraft. The policy emphasized the need for “timely
information of the approach of an enemy in sea areas both of the continental United States
and of overseas possessions” and for the “protection of commerce on the high seas, of coastal
zones, and in sea lanes.”26 Additionally it challenged the Army‟s policy against deployment
of naval strike aircraft ashore as the new policy tasked Navy land-based aircraft with the
“protection of commerce in coastal zones and sea lanes, by means of patrol and scouting over
the sea and offensive action connected therewith.”27
Unable to resolve the issue, a joint board was convened in 1935 which resulted with
the publishing of a new version of the Joint Action of the Army and Navy manual.28 The
result was a confusing doctrine that failed to establish clear and precise lines of authority. Of
special interest is Chapter V, Coastal Frontier Defense, as it attempts to delineate the various
tasks to the appropriate service. It defined the destruction of shipping in the coastal zone
23
Shiner,116.
Ibid.
25
Standley served as C.N.O. from 1933-1937.
26
Shiner, 117.
27
Ibid.
28
FTP-155 Joint Action of the Army and the Navy, prepared by the Joint Board of 1927, revised by the
Joint Board of 1935. J.B. No. 350{Serial No. 514} (Confidential) (Washington D.C.: United States
Government Printing Office, 1936).
24
64
by the enemy as a minor operation and that enemy submarines conduct attacks on
combatant vessels, gather information, perform reconnaissance, blockade harbors,
conduct raids, and perform minor bombardments.29 At times appearing deliberately
ambiguous, the FTP-155 failed to address the problems associated with anti-submarine
warfare or the development of a land-based long-range patrol aircraft for naval use.
While the Navy and Army haggled over coastal defense, a much larger debate
further hindered the development of the maritime patrol aircraft. Following World War I
the military leaders of the United States took stock of the international situation
determined which of the world‟s nations might threaten America in the near future.
Russia was in the midst of a revolution, German neutralized, France and Italy lacked the
naval power to attempt any major operation in the Western Hemisphere, and leaving only
Great Britain as a potential threat but such a possibility was remote at best. This left
Japan as the only potential threat to American interests and safety.
Throughout the inter-war years, the preparation of strategic war plans was the
responsibility of the Joint Board, a board that consisted of the Army Chief of Staff, the
Chief of Naval Operations, and their deputies. Additionally the chiefs of the War Plans
Divisions of each service served on the board.30 It was the function of the board to
coordinate the actions of the two services.
The major work of the board immediately following the end of World War I was
War Plan Orange, the plan to defeat Imperial Japan.31 For the next fifteen years, War
29
FTP-155, Chapter V, Section II, Possible Enemy Operations, 38.
Louis Morton, “Germany First: The Basic Concept of Allied Strategy in World War II,” in Command
Decisions, ed. Kent Roberts Greenfield (Washington D.C.: Center of Military History, Department of the
Army, 2000), 13.
31
From 1904 to 1939, colors were used to designate war plans. Color war plans and the intended foe
included Ruby: India, Tan: Cuba, Olive: Spain, Scarlet: Australia, Green: Mexico, Violet: China
30
65
Plan Orange formed the basis for most American war planning. Additionally, this
preoccupation by American naval authorities greatly influenced the Treaty for the
Limitation of Naval Armament signed in Washington on 6 February 1922 and the
International Treaty for the Limitation and Reduction of Naval Armament of 1930.32
The significance of this obsession with a war against Japan affected the maritime
patrol aircraft and its anti-submarine warfare role, due in part because American naval
leaders saw little threat from Japanese submarines. In a titanic battle between the
opposing battle-lines, the American fleet would defeat Japanese fleet thereby ensure
victory. Scouting and mopping up were the missions assigned to the naval aviators.
Naval war games during the inter-war era consisted of lines of battleships engaging in a
repeat of Jutland. Regulated to scouting and conduct attacks designed to slow the enemy
in order for the main battle-fleet to close to within gunnery range, few saw the aircraft
carriers as the primary striking force of the fleet. Aircraft such as the P2Y-2 were to
range over the Pacific localizing the Japanese fleet in order for the battle-line to close and
while the Navy practiced its trade against its enemy of choice, on the Atlantic seaboard, a
rearmed Germany was preparing to confront an America that was ill prepared.
A brief examination of some the annual fleet exercises held during the inter-war
era demonstrates this fascination with the Battle of Jutland and the battleship. Fleet
Problems IX, X, and XI, held in 1929 and 1930, investigated the use of aircraft carriers
and scout aircraft. Though scout planes from the aircraft carriers proved useful other air
assets, such as the long-range patrol aircraft received no use in the exercises. Fleet
(intervention in internal matters) and Red: Great Britain. Most were mere academic exercises, but some
such as Mexico, China, and Spain were grounded in reality.
32
This preoccupation resulted in the 5-5-3 ration of capital ships, with the United States and Britain
allowed five vessels, and Japan 3.
66
Problem XII, held in the Bay of Panama in February of 1931, had the “White Fleet”
under the command of Captain Ernest J. King defend the Galapagos Islands from the
invading “Black Fleet.” Kings fleet consisted of the U.S.S. Lexington, two cruisers, and
destroyer division. As in previous exercises, patrol aircraft had no part in the exercise.33
Later exercises such as Fleet Problem XVII and XVIII saw greater use of patrol
aircraft but they contributed little. According to Admiral King, following Fleet Problem
XVIII, his squadrons had flown a good deal but to little purpose, as the prescribed
maneuvers were hardly adapted to the efficient use of aviation.34 King believed that as
late as 1937 few senior admirals understood how to employ aircraft, especially patrol
aircraft to good advantage in fleet problems.35
In spite of reduced funding the evolutionary progress of the maritime patrol
aircraft continued during the inter-war era. Throughout the 1920‟s and 1930‟s the
capabilities of the navy‟s patrol aircraft continued surge ahead. Advancements in speed,
endurance, and payload produced aircraft with capabilities far superior to those flown
during World War I.
Following the war, in May 1919, the Navy undertook its long awaited attempt at a
transatlantic flight.36 Weighing 28,000 pounds when fully loaded, the NC flying boats
marked the culmination of the war development of aircraft. The hull of the NC was 45
feet long with a beam of 10 feet. The keel was constructed of Sitka spruce while the
bottom planking was of Spanish cedar.37 The use of two girders of ash braced with steel
33
Ernest J. King and Walter Muir Whitehill, Fleet Admiral King, a Naval Record (New York: WW Norton
& Company Inc., 1952), 220-223.
34
Ibid., 274.
35
Fleet Problem XIII saw the U.S.S. Lexington and Saratoga launch a surprise attack on Oahu.
36
W.H. Sitz, A History of U.S. Naval Aviation (Honolulu: University Press of Hawaii, 2005, reprint of
1930 edition), 37
37
Ibid., 36.
67
wire provided longitudinal strength. Powered by four Liberty engines, rated at 400
horsepower, the NC had a range of 1,400 miles.38 With a five-man crew, the NC
represented the most advanced flying boat in the Navy‟s inventory.
In May, 1919, Seaplane Division One, under the command of Commander (CDR)
John H. Towers, took off from NAS Rockaway, New York, on the first leg of its
projected transatlantic flight.39 The flight consisted of NC-2 flown by CDR Towers, NC1 commanded by Lieutenant-commander (LCDR) P.N.I. Bellinger, and NC-4
commanded by LCDR A.C. Read.40 After flying to Trepassey Bay, Newfoundland, the
squadron on 16 May at approximately 6 pm began its long flight to the Azores. Though
only the NC-4 was the only aircraft reach the Azores, the endeavor was a tremendous
success and demonstrated the potential of the large flying boat.41
Even prior to the success of Seaplane Division One, the Navy was so enamored
by the potential presented by the large flying boat that on 30 July 1918 the Chief-ofNaval Operations (CNO) issued a letter for the development of “great types of flying
boats.”42 This desire for this type of aircraft was a result of the wartime requirement for
an antisubmarine aircraft that was capable of flying across the Atlantic.43 A massive
airplane, it dwarfed the NC series of flying boats.
The “Giant Boat” truly amazing, with a take-off weight of 70,000 pounds, it was
powered by nine Liberty engines mounted in three huge nacelles. Each group of engines
38
Sitz, 37.
United States Naval Aviation, 1910-1980, NAVAIR 00-80P-1 (Washington D.C.: U.S. Printing Office,
1981), 37.
40
Ibid.
41
Both NC-1 and NC-3 were forced to land in an attempt to determine their position by taking radiocompass bearings on destroyers positioned along their protected flight path.
42
William F. Trimble, Wing for the Navy, a History of the Naval Aircraft Factory, 1917-1956 (Annapolis:
United States Naval Institute, 1990), 49.
43
Adrian O. Van Wyen ed., Naval Aviation in World War I (Washington D. C.: U.S. Printing Office,
1969), 54. Issued by the office of the Chief of Naval Operations.
39
68
drove an 18-foot diameter propeller and it was possible to disengage a single engine in
flight for repair.44 The flying boat had a top speed of 78 miles per hour, and a range of
1,630 miles. This new aircraft met many of the requirements sought by the Navy in its
maritime patrol aircraft.
To achieve this remarkable range, designers squeezed ten cylindrical fuel tanks,
capable of holding 400 gallons each, into its 65-foot long hull.45 Armament consisted of
five 0.50 caliber machine guns and six 1,000-pound bombs. With its nine man crew, the
“giant flying boat‟ represented the pinnacle of aircraft development. However, it was not
to be as the Navy cancelled the project in 1921.46
The fundamental weakness of the “giant flying boat” was as it was made of wood
it represented the past. By the 1920‟s most designers argued for the use of steel and
aluminum instead of wood, the material of choice for aircraft designers in World War I.
Metal solved the water-soakage problem inherent with a wooden hull. However, for this
change to occur advancements in the field of metallurgy had to occur.
Building upon German and British designs, the Naval Air Factory (NAF)
methodically proceeded with the development of all metal aircraft. British and German
metallurgists had, between 1901 and 1914 made significant progress in the development
of duralumin. This remarkable material was an aluminum alloy containing between 3%5% copper, 0.4%-1% manganese, and 0.3%-0.6% magnesium.47 The ability to be cut,
44
Trimble, 51.
Ibid.
46
Ibid., 53.
47
Ibid.,, 86.
45
69
pressed, and forged into various shapes made this a remarkable alloy. This lightweight
metal, when heat-treated and aged yielded a tensile strength equal to that of mild steel.48
While duralumin solved many of the problems associated with a metal aircraft,
one major problem remained. Duralumin was highly susceptible to corrosion. To
prevent surface corrosion, the Navy found it necessary to thoroughly clean the surface of
the duralumin and coat the outside with an anodic coating containing red lead or zinc
chromate, followed by a baked enamel finish.49 For all interior surfaces, a bitumen-base
paint pigmented with aluminum powder provided excellent long-term protection from the
harsh environment of the sea.50
Though surface corrosion was a serious issue, the problem of inter-crystalline
embrittlement was far more critical to the use of metal in the construction of naval
aircraft and unless solved the use of duralumin was of dubious value. Inter-crystalline
embrittelment is a phenomenon that penetrates deeply into the metal by tracing around
the microscopic crystalline patterns of the material resulting in seriously weakening the
structural strength of the material.
The solution was the development of a material known as Alclad. Introduced by
the Aluminum Company of America (Alcoa) in 1927, Edgar H. Dix, a metallurgist in
Alcoa’s Pittsburg research laboratory developed this remarkable material.51 Alcad was
nothing more than a sheet of duralumin 17ST sandwiched between layers of 99%
aluminum. Rolled under heavy pressure that resulted in a permanent chemical and
physical bond between the two metals, the new material while having 10% less tensile
48
Trimble, 86. Discovered and patented in 1910 by Alfred Wilm.
Ibid., 90.
50
Ibid.
51
Trimble, 91.
49
70
strength then duralumin 17ST had superior corrosion resistance characteristics.52 This
made Alclad the ideal material for use in aircraft construction. By 1931, Alcoa
introduced the alloy “2024” that had yield strength of 50,000-psi.53 This improved alloy
replaced earlier versions and the Douglas DC-3 was the first aircraft constructed of it. Of
note is that alloy “2024” and its derivatives have remained the primary material used in
the production of aircraft.54
By war‟s end, the Liberty engine powered the Navy‟s newest and best aircraft. A
supreme power plant in its day by 1923 it had reached the end of its usefulness. The
Navy was in need of a new engine to power its next generation of maritime patrol aircraft
one that was reliable, lightweight, and powerful. This was the challenge confronting
aircraft designers in the post-war era.
The fundamental question was should aircraft engines be liquid-cooled or aircooled? Those who opted for liquid-cooled engines had to be willing to accept the added
weight, greater possibility of battle damage and greater system complexity while those
who advocated air-cooling had a whole host of problems to overcome. Air-cooling
required the development of an effective engine cowling, extensive studies of
aerodynamic behavior of air inside the cowling and around the cylinders. To extend
engine life there was a plethora of metallurgical problems to overcome.
The purpose behind this requirement grew out of the Navy‟s desire to be able to
fly from the west coast to Hawaii. To accomplish this it was determined that the aircraft
had to be capable of a thirty-hour flight, and the liquid-cooled engines of the era were not
52
Ibid.
Alcoa Mill Products, Alloy 2024 Sheet Plate, http://www.alcoa.com/mill_ products/catalog/pdf/
alloy2024techsheet.pdf
54
D. Paul, L. Kelly, and V. Venkayya, “Evolution of U.S. Military Aircraft Structures Technology,”
Journal of Aircraft, vol. 39, no. 1 (January-February, 2002): 21.
53
71
capable of such a feat.55 This requirement resulted in the development of a powerful and
reliable radial engine. Spurred on by the Navy, the Wright Aeronautical Cooperation and
Pratt & Whitney engaged in a horsepower race throughout the second half of the 1920‟s.
As with most developments, the air-cooled radial engine required a relatively long
gestation period. The Lawrance Aero Engine achieved initial success was when while
working with both the Army and the Navy, developed the Model J-1, a nine-cylinder
radial engine. In 1922 having passed its 50-hour endurance bench test, the Navy placed
an order for these engines56 In response to the urging of the Navy, the Wright
Aeronautical Corporation bought the Lawrence Company and later models of the “J”
series became known as “Wrights.” 57
In 1929, the Wright Aeronautical Corporation named their P-2 engine, the
Cyclone; it was nine cylinders, air-cooled, radial engine. With an engine displacement of
1,832 cubic inches, it evolved into the R-1820 engine. An improved version of the P-2
this remarkable engine remained in production through the 1950‟s.58
In 1926, Pratt & Whitney introduced the R-1340 Wasp and like the Cyclone, it
was nine cylinders, air-cooled engine, with a displacement of 1,344 cubic engines. It
produced 425 hp and weight only 625 pounds.59 Remaining in production until 1960, the
Wasp, like its competitor the Cyclone proved to the Navy that the air-cooled radial engine
was the answer to their quest for a reliable, powerful, and lightweight engine.
Trimble, 94. The PN-9 was the Navy‟s primary flying boat of the time and had a range of only 1,800
nautical miles; to reach Hawaii was necessary to achieve a range of 2,100 nautical miles.
56
George Genevro, Air-Cooled Aircraft Cylinders an Evolutionary Odyssey, Part 2 – Development in the
U.S., http://www.enginehistory.org/aircooled cylinders 2.htm
57
The Wright “J-5” Whirlwind was used to power Charles Lindbergh‟s “Sprit of St. Louis” on his
historical trans-Atlantic flight.
58
Wright R-1820 Cyclone 9, http://www.kensaviation.com/engines/R-1820.htm
59
Pratt & Whitney R-1340 Engine, http://www.aviation-history.com/pr-1937.htm
55
72
With the development of more powerful engines came the need to build a
propeller that was capable of harnessing the additional horsepower. To achieve this goal
it became apparent that to get the full performance out of any engine the pitch of the
propeller had to be changeable in flight. In 1929, Frank Caldwell, working for the
Hamilton Standard Propeller Corporation, developed a functional controllable-pitch
propeller.60 His initial goal was to build a propeller automatically adjusted its pitch to
the needs of the airplane. This was the so-called "constant speed" design in which the
speed of the propeller and engine remain at a constant rpm. Overly ambitious, Caldwell
compromised the design. This resulted in a simpler two-position propeller that could be
set at one position for takeoff and another for cruising. Hamilton-Standard soon began
selling its first two-position variable-pitch propellers to engine manufacturers in 1932.61
The Naval Aircraft Factory was responsible for the development of aircraft for
naval during the 1920‟s. Continuing the practice established during World War I, the
Navy designed the aircraft and would have a civilian company produce them. Having the
Navy bear, the expense of research and development allowed the civilian companies to
avoid the inherent risks of such experimentation.
In 1921, the Navy introduced a new designation system for the aircraft produced
by the NAF. The F-5L‟s and F-6L‟s became PN-5‟s and PN-6‟s respectively and in a
“Variable Pitch Propeller” Propellerhttp://www.centennialofflight.gov/essay/Evolutionof
Technology/props/Tech14.htm
61
W.R. Turnbull, a Canadian, first proposed using an electric motor to vary the pitch of the propeller.
Curtiss-Wright licensed the design and began to modify it, but it took several years before the company
began to incorporate the new propeller into its Navy and Army Air Force aircraft. The Curtiss-Wright
propeller soon became a rival for the Hamilton-Standard propellers. Propellerhttp://www.centennial
offlight. gov/ essay/Evolutionof Technology/props/Tech14.htm
60
73
decade long process the NAF slowly found solutions to the problems confronting the
development of the modern maritime patrol aircraft.62
In January the Navy authorized the construction of two new flying boats
designated the PN-7, it was the first in a series of flying boat produced for the Navy
following the war.63. Replacing the obsolete Liberty engines with Wright T-2 engines
capable of 525 hp and using a more efficient high-lift airfoil wing design the PN-7
represented an interim step in the development of a modern maritime patrol aircraft. Still
constructed of wood and fabric it was not until the PN-10, authorized in April 1925, that
the Navy used metal construction and installed radial engines in its construction.64
In August of 1923, the Bureau of Aeronautics (BuAer) authorized NAF to
construct the follow-on aircraft in the PN series with a metal hull.65 The Navy used
welded steel tubing, with a covering of duralumin to construct the hull. Designated the
PN-8, the change to a metal hull resulted in a 500 pounds reduction in weight.66 In order
to further save weight the Packard water-cooled V-12 replaced the original Wright T-3
engines. The Packard produced the same horsepower and was 300 pounds lighter.67
In the later part of 1927, the Navy introduced the PN-10 series of flying boats.
Incorporating the various advancements of the earlier models, the PN-10 / PN-12 proved
to be remarkable flying boats. The PN-10 / PN-12 established a series of altitude,
endurance, and speed records. Throughout the spring and summer of 1928, the new
flying boats powered by the radial engines of Pratt & Whitney and Wright Aeronautical
62
Trimble, 92.
Ibid.
64
When the PN-10 was refitted with a radial engine, their designation was changed to PN-12.
65
Trimble, 92.
66
Naval Aviation 1920-1929 http://www.history.navy.mil/branch/avchr3.htm The first all-metal airplane
designed for the Navy was the ST-1 twin-engine torpedo plane, made its first flight on 25 April 1922.
67
Trimble, 93. The PN-8 were re-designated PN-9 with the change in engines.
63
74
Corporation proved the value of the new technologies. In May of 1927, Lieutenant (Lt)
Zeus Soucek and Lisle Maxson in a PN-12 powered by two Wright engines set a world
speed record of 80.288 miles-per-hour (m.p.h.) with a useful 1,000 kilogram (kg) load
over 2,000 kilometers (km). Additional they established an endurance record of 17
hours, 55 minutes, and 13.6 seconds.68 The following month Lt Arthur Gavin was to
pilot his PN-12, powered by two 525 hp Pratt & Whitney to an altitude to 19,593 ft while
carrying a useful payload of 1,000 kg.69
With the PN-12, the Navy had found an aircraft that met many of the
requirements needed in a maritime patrol aircraft. As the NAF was not capable of
meeting the demand for large numbers of aircraft, the Navy issued contracts to various
companies to produce the PN-12. The PN-12 aircraft built by civilian companies were
assigned unique alphanumeric designations, though these aircraft all based upon the PN12 design. The Douglas Aircraft Company produced 25 PD-1, the Keystone Aircraft
Corporation received an order for 18 PK-1, while the Martine Aircraft Company
produced 55 PM-1 & 2.70
Throughout the years following World War I, the Navy had taken the lead in the
development and design of the aircraft that were to equip the Navy‟s squadrons. This
changed in 1928 when the Navy awarded Consolidated Aircraft Corporation a new type
of contract. Unlike previous contracts, the NAF would not wholly control the design of
the aircraft. Instead the Navy only specified that the hull lines would be provided by
Captain Holden C. Richardson of BuAer and the aircraft should have an operational range
68
United States Naval Aviation, 1910-1980, NAVAIR 00-80P-1 (Washington D.C.: U.S. Printing Office,
1981), 65.
69
Ibid., 66.
70
Roberts, 674 – 680. March 29, 1922 the Navy established a new designation system. The second letter
was used to identify the manufacture.
75
of 2,000 n.m..71 Other preliminary design specifications include air-cooled engines, all
metal construction except for fabric covered wings, was to be a monoplane, and have a
cruising speed of 110 m.p.h.72 On the 28 February 1928, Consolidated Aircraft
Corporation was awarded the contract for the XPY-1.73 Named the “Admiral” by
Reuben Fleet, the president of Consolidated Aircraft, this new flying boat was to mark
the beginning of a long and fruitful teaming of the United States Navy and Consolidated
Aircraft Corporation.74
Though the XPY-1 met the Navy‟s expectations, it was not a success in terms of
profit for Consolidated Aircraft Corporation. This type of contract was new as prior to
the XPY-1 the companies invested little money into research and development as the
NAF provided a completed design to the civilian manufacture. This was not the case with
the XPY-1 contract. The Consolidated Aircraft Company invested over a half a million
dollars in engineering cost in excess of the original $150,000 provided by the contract.75
Unlike modern contracts, following the successful development of the new flying boat,
the Navy requested bids to produce the XPY-1 and in a strange turn of events, the Martin
Company won the contract. The Martin Company received funding to build nine P3M1/2 flying boats, the production version of the XPY-1.76
71
William Wagner, Reuben Fleet and the Story of Consolidated Aircraft (Fallbrook: Aero Publishers, Inc.,
1976), 112-113. Captain Richardson contributed to the design features of the NC-1 flying boat.
72
Ibid., 112.
73
United States Naval Aviation, 65. Since the letter “C” was already assigned to the Curtiss Company,
Consolidated was assigned the letter “Y” in the new designation system.
74
Wagner, 113.
75
Ibid., 158. Consolidated recouped its financial investment by selling 14 “Commodore” commercial
transports. These were civilianized versions of the XPY-1.
76
John M. Elliot, “Aircraft Data – Technical Information and Drawings,” in Dictionary of American Naval
Squadrons, the History of VP, VPB, VP (HL0 and VP, by Michael D. Roberts (AM0 Squadrons, Volume 2.
(Washington D.C: Naval Historic Center, Department of the Navy, 2000), 659. The P3M-1 / 2 were the
production version of the XPY-1.
76
The P3M-1 with a crew of four or five had an effective range of 1,570 miles and
mounted two 525 hp Pratt & Whitney Hornet R-1690-32 engines on its upper wing.77
While the flying boat met the Navy‟s requirements, the Martin Company was to require
twenty-eight months to build the nine aircraft, a rate unacceptable to naval authorities.
Following this debacle, the Navy awarded the contracts for development and production
to a single company.78
The next step in the development of the modern maritime patrol aircraft was taken
with the introduction of the P2Y-1 Ranger by Consolidated Aircraft Corporation.79 The
P2Y-1 built upon the XPY-1 with further refinements and innovations.
The Navy accepted first of twenty-three P2Y-1‟s in February 1933.80 With twin
575 hp Wright Cyclone R-1820E engines and three-bladed controllable pitch propellers
mounted under the upper wing, the P2Y-1 met the needs of a long range flying boat.81
While the performance of the P2Y-1 was impressive, through a series of improvements
and new design features, Consolidated Aircraft Corporation created a new model
designated the P2Y-3. Unlike previous flying boats that mounted their engines below or
above the wing, the P2Y-3 had their Wright Cyclone R-1820-90 engine mounted on the
leading edge of the wing. This reduced drag, thereby increasing the range and endurance
of the flying boat.82
The PBY Catalina, also designed by Consolidated Aircraft Corporation, was the
final flying boat introduced prior to World War II. On 28 October 1933, BuAer issued a
77
Elliot, 659.
During World War II, this policy was modified to allow multiple companies to build a specific aircraft.
79
The name “Ranger” was not used by the Navy but by Consolidated Aircraft Corporation.
80
Wagner, 161.
81
Elliot, 652.
82
Ibid., 165. In January 1933, six P2Y’s flew from San Francisco to Pearl Harbor a distance of 2408 miles
in 25 hours, 35 minutes
78
77
contact for the prototype of the PBY, the XP3Y-1. Due to its ability to carry a large
bomb load, the Navy elected to change its official designation to “patrol bomber.”83 A
remarkable aircraft the PBY Catalina had the largest production run for any Navy patrol
aircraft with 2,387 built for the Navy.84
An all-metal monoplane, the XP3Y-1 had the cleanest lines of any flying boat yet
designed. The new aircraft used two 850 hp Twin Wasp engines built into the leading
edge of the wing center section like those of the P2Y-3. The wing was mounted above
the hull on a flared pedestal with two struts on each side contacted the wing and the hull.
Further refinements included retractable floats that folded into place after take-off and
became the outer tips of the wings.85
In the pursuit of increasing the range of the new aircraft, the designers introduced
the integral fuel tanks. Instead of building separate fuel cells, as been the practice in
previous designs, the engineers sealed off internal sections of the wing and used these as
gasoline reservoirs. The engineers calculated a weight saving of a half-pound per gallon
of fuel capacity.86 These savings resulted in the XP3Y-1 prototype established a new
world distance world record when in October 1935 it flew 3,443 statute miles in 33 hours
and 40 minutes.87
The Navy took delivery of the first production aircraft on 5 October 1936. VP-11
was to be the first operational squadron to receive the new flying boat.88 The PBY-1, had
a less angular fin and rudder, was powered by the Pratt & Whitney R-1830-64 engines
83
Elliot, 674.
Ibid. An additional 637 were built for other organizations and countries.
85
Wagner, 178.
86
Ibid., 179
87
Ibid.180.
88
United States Naval Aviation, 1910-1980, NAVAIR 00-80P-1, 413.
84
78
remained in frontline service until 1941. The Navy transferred these early models to
training squadrons at this time.89
The majority of the Navy‟s patrol squadrons entered the war flying one of three
versions of the PBY. Prior to the delivery of the PBY-1, the Navy placed an order for
fifty PBY-2 flying boats. It was generally the same as the PBY-1 except a one-piece
solid horizontal stabilizer with inset elevators replaced the full span elevators of the
earlier model. Additionally 900 hp. Pratt & Whitney R-1830-66 replaced the less
powerful R-1830-64 engines.90
The PBY-3 continued the process of up grading the engines, with the installation
of 1,050 hp R-1830-72 engines. The only change made to the PBY-4 was to cover the
propeller hubs with spinners. With a range of 2,280 miles and the ability to carry four
1,000-pound bombs, the PBY-3/4 represented the best the pre-war aircraft designers had
to offer.91
By the latter half of 1939, recognizing the need for a replace for the PBY, the
Navy issued, on 23 July 1936, a contract to Consolidated Aircraft Corporation for the
PB2Y Coronado, a large four-engine seaplane. A year later, the Navy awarded Martin
Company a contract for the PBM Mariner, a twin-engine gulled-wing seaplane.92 Both
aircraft entered service in the fall of 1940.93
Through the inter-war years, saw numerous improvements and refinements made
to the flying boat. Of note, was the lack of development of a long-range land-based
89
Ragnar J. Ragnarassan, US Navy PBY Catalina Units of the Atlantic War (New York: Osprey Printing
Limited, 2006), 8.
90
Elliot, 674.
91
Ibid.
92
Elliot, 667 & 671. The Martin Company contract was issued on 30 June 1937.
93
Both aircraft will be discussed in detail in later sections.
79
aircraft for naval use and while the PBY was an excellent aircraft for the day, it lacked
numerous attributes needed to be an effective maritime patrol aircraft in the upcoming
battle against the German U-boats. Politics and doctrine prevented the development of a
land-based ASW aircraft and only the need to counter the onslaught of Nazi submarines in
1942 brought about the necessary changes to allow such development.94
The end of the war brought much of the research and development in the various
disciplines critical to the ASW mission slowed as many so little needed for continued
research. Though slowed, research continued in the fields of communication, sonar, and
in the newly discovered field of RADAR (radio detection and ranging).95
Not all developments were in the field of electronics. Improvements in aviation
fuels ensured the effective use of the new and more powerful radial engines. In the early
years of aviation, aircraft engines used the same gasoline used to power automobiles, a
fuel that proved inadequate for the new radial engines developed in the 1930s and 1940s.
To realize the potential of these new engines there was a need to develop better fuels.
To achieve the goal of a better fuel it was necessary to improve the antiknock
properties of so that the engines‟ power output would not be knock-limited. The
antiknock characteristic of a fuel is its ability to resist knocking, which indicates that the
combustion of fuel vapor in the cylinder is taking place too rapidly for efficiency.
Engineers assigned fuels an octane number to express this value. To reduce this problem
tetraethyl lead to the gasoline. Additionally developments included the identification of
94
The Martin Company had been issued a contract for the PBM Mariner. Its first flight was on 18
February 1939, and the first squadron to receive the PBM was VP-55 in September 1940.
95
L.S. Howeth, USN, History of Communications-Electronics in the United States Navy (Washington D.C.:
Bureau of Ships and Offices of Naval History, 1963), 443-469. RADAR is word coined from a contraction
of the phrase “radio detection and ranging” and its coinage s attributed to E.F. Furth and S.P. Tucker.
80
crude oils with the best lead response and the identification and production of specific
hydrocarbons with good antiknock properties.96
In 1930, the Army Air Corps specified a “Fighting Grade” gasoline with a
minimum octane number of 87. This was the first instance of the military using an
octane number to define the antiknock properties of aviation fuel and was much more
specific then the specification of the Navy‟s instruction 24G5 issued in 1907 which called
for a “high grade refined gasoline, free from all impurities.”97 Since octane number is
used to rate a fuel, a higher octane number allowed a piston engine to burn its fuel more
efficiently, a quality needed in military aircraft. Individuals such as Jimmy Doolittle
recognized the critical need of high-octane fuel. While heading the aviation fuels section
of the Shell Oil Company, Doolittle pushed hard for the development of 100-octane
fuel.98
Following termination of hostilities, with the sole exception of the Naval
Experimental Station at New London Connecticut, the government disestablished all
groups engaged in sonar research. While much of the research ceased due to lack of
funds, work continued with supersonic echo ranging, with the first experimental sets
installed in several naval vessels in 1927.99 A supersonic echo-ranging system was
desired in part because it eliminates much of the inherent ocean noises, utilizes a
narrower beam, and the received signal is more easily electronically amplified. Utilizing
a transducer which consisted of quartz slabs between steel discs about sixteen inches in
96
Greg Heminghaus et al., Aviation Fuels Technical Review (Huston: Chevron Global Aviation, 2006), 47.
Alexander R. Ogston, “A Short History of Aviation Gasoline Development, 1903-1980, Paper No
819848,” in History of Aircraft Lubricants (Warrendalle: Society of Automotive Engineers, 1981), 4.
98
“U.S. Centennial of Flight,” http://www/entennialofflight.gov/essay/Aerospace/aviationfuels/Aero4.htm
Jimmy Doolittle was to lead the B-25 raid on Tokyo in 1942.
99
Howeth, Chapter XXXIX, 471-478.
97
81
diameter, it protruded through the bottom of the ship and transmitted at a frequency
between 20,000 and 40,000 Hz.100 Though this work was initially intended for use on
naval combatants, the theory and basic research eventually would be applied to airborne
systems.
While most of the research involved what is commonly referred to as active sonar,
work continued in hopes of developing a passive sonar system. The major hurdle was the
need to increase the sensitivity of the systems in order to exploit the noise generated by
the submarine. In 1929, the Naval Research Laboratory produced passive sonar system,
designated the JK, with an effective range of approximately five miles. Utilizing a
Rochelle salt crystal, it proved more sensitive than the older quartz crystal.101
By 1934, the magnetostriction tubes replaced the various forms of crystals in
sonar systems. Major development in sonar systems occurred when transducers utilizing
these tubes were constructed. Transducers are small electromagnets and were a critical
building block in the evolution of sonar systems. Made of hollow nickel alloy tubing a
few inches long and approximately 3/8th‟s of an inch in diameter, a coil of wire was
wound about it and when the magnetic flux was changed the tubes elongate or contact
causing a vibration of the attached diaphragm which results in a "ping." When a sound
wave struck the diaphragm, the resultant vibrations caused a change in the magnetic flux
that generated an electric current. It was possible then to hear the sounds produced by
using headsets. These sounds corresponded to those of the target.102 As with the active
100
Ibid. A transducer is a device containing both the receiving and transmitting assemblies.
A crystalline salt with a chemical structure of KNaC4H4O6y4H2O.
102
Howeth, Chapter XXXIX. This basic technology is still used in various sonar systems.
101
82
sonar systems, the pre-war research fulfilled the requirements of the various surface
escorts. Additionally this research aided the development of submarine systems.103
Work continued in the communications field as the Navy recognized the need for
reliable communications. Unlike the sonar development, which had little value other
then in antisubmarine warfare, radio had applications in other aspects of naval warfare
thus ensuring continued research. During the war considerable effort had be put forth in
the attempt to develop a powerful and reliable vacuum tube transmitter but with the
termination of the war, the commercial companies refused to continue the development
of the tube transmitter because they considered it of little commercial value.104
To ensure continued support in the civilian sector, the Navy in late 1919 through
the Bureau of Engineering spent $250,000 for tube transmitters in order to create an
incentive for the commercial companies to continue development. The Navy requested
two types of transmitters, the Model TC for installation on battleships, and the Model TD
for use by air stations. The cost of this contract was approximately $125,000 and while
the performance of these systems was disappointing, research continued.105
Other developments included the expansion of the radiofrequency spectrum
thereby providing additional circuits. Technical advancements in antenna construction
that permitted simultaneous reception of different frequencies using the same antenna,
high-powered tubes and transmitters and the development of lighter weight equipment for
aircraft with the further reduction in aircraft-generated noise and ignition interference all
contributed to more reliable communication systems.
103
The development of the sonobuoy will be discussed in later, it should be recognized that the success of
the sonobuoy could be attributed to the developments in sonar of the inter-war era.
104
Howeth, Chapter XXVIII. The companies in involved in the development were General Electric and
Western Electric Cos.
105
Ibid.
83
Of the various technological advancements made during the inter-war era, none
was to have a greater impact upon the next war then the discovery and development of
radar. In 1922, Dr A. Hoyt Taylor and his assistant Mr. L.C. Young noted the distortion
in radio signal caused by the reflection from the S.S. Dorchester. Reporting the
discovery to the Navy, along with a request to continue the research, Taylor believed
further research would yield a method of determining the range and bearing to a target.106
Unfortunately, the authorities denied the request and the development of radar would
have to wait.
Development of radar continued throughout the inter-war years, with all major
powers exploring the military potential of this phenomenon. In March 1934, Leo Young
of the Naval Research Laboratory stumbled upon the concept of pulse transmission as a
solution to the problems of a collocated transmitter and receiver.107 This proved to be a
major innovation and other countries soon developed similar solutions to the problem.
In Great Britain, a four-man team lead by Dr. Edward Bowen, attempted to solve
the complex problems of developing an airborne radar system. In 1934, the initial test
was preformed. Though primitive by today‟s standards, Bowen proved that an airplane
could receive radio energy reflected off another airplane.108 With the concept proven, it
now became necessary to solve the problems of weight and size.109
While aircraft capable of carrying larger bomb loads were developed, the Navy
expended little effort in creating a better anti-submarine warfare weapon. The only real
106
Howeth, Chapter XXXVIII, 443-469.
Until this discovery, the radar receiver and transmitted were placed in different locating.
108
Alfred Price, Aircraft versus Submarine, the Evolution of the anti-submarine aircraft, 1912-1972
(Annapolis: Naval Institute Press, 1973), 36. Bowen‟s team consisted of A.G. Touch, Robert HanburyBrown, and Percy Hibberd.
109
The cooperation between the United States and Great Britain will be discussed in the next section.
107
84
improvement to the armament of the maritime patrol aircraft was the development of the
Browning 30-caliber and 50-caliber machine guns for aircraft use.110 With a cyclical rate
of 1,100 rounds per minute and a muzzle velocity of 2,600 to 2,740 feet per second, the
30-caliber machine gun was standard weapon for Navy aircraft. Mounted in a flexible
gun carriage all pre-war patrol aircraft carried this weapon.111 The heavier 50-caliber
machine gun had a cyclical rate of 750 to 850 rounds per minute and a muzzle velocity of
2,865 to 3,100 feet per second. Mounted in flexible gun carriages on the PBY series, in
1937 the XPBM-1 Mariner seaplane became the first Navy aircraft to mount single 50caliber guns in turrets.112
The introduction of these new and more powerful machine-guns added greatly to
the defensive capability of the maritime patrol aircraft but contributed little to its ability
to damage or destroy a submarine. To ensure a successful attack the Navy needed to
develop depth bombs as ordinary bombs had little value against a submarine once it had
submerged. A depth bomb is a special type of bomb that has a high percentage of filler
along with a hydrostatic fuse. The fuse was a critical component for it ensured that the
bomb would detonate at a prescribed depth. During World War I, the United States
failed to develop a reliable fuse and used those of France and Great Britain.
The need for such weapons was recognized and designers worked on various
weapons during the 1930‟s, however budget constraints and the perceived lack of threat
prevented the Navy from initiating production of these new weapons. The United States
John M. Elliot, “A summary of Patrol Aircraft Ordnance Equipment, Appendix 2.” in Dictionary of
American Naval Aviation Squadrons, vol. 2 the History of VP, VPB, VP (HL) and VP (AM) Squadrons, ed.
Michael D. Roberts, (Washington D.C.: Naval Historic Center, Department of the Navy, 2000), 690.
111
See Appendix 1 in Dictionary of American Naval Aviation Squadrons, vol. 2 The History of VP, VPB,
VP (HL) and VP (AM) Squadrons, ed. Michael D. Roberts, (Washington D.C.: Naval Historic Center,
Department of the Navy, 2000)
112
Elliot, 671, 690.
110
85
Navy entered World War II with no effective depth bomb and not until after the
declaration of war was this critical weapon fully developed.113
While the American public turned inward and her Navy looked west, the naval
situation in Europe underwent a radical change in June 1935. In their continuing effort to
appease the Nazi regime of Adolph Hitler, the British government agreed in June 1935 in
a bilateral agreement to allow Germany to build and operate submarines. No longer was
the Germans ban from developing a new generation of U-boats.114 Allowed by this treaty
to build up to 35% of British warship tonnage, the two parties agreed to allow Germany
to build 45% of British submarine tonnage.115 Of equal importance to the German war,
effort was the appointment of Karl Dönitz as commander of the German undersea fleet.116
According to international treaties, Germany had received the legal right to begin
U-boat research and construction in 1935. However, the Reichsmarine (State Navy)
continued U-boat research and development through the naval engineering firm
Ingenieuskaantor voor Scheepshouw (IvS) established in the Netherlands throughout the
interwar era.117 The company produced a series of submarine designs from 1922 until
1932 for Argentina, Turkey, and Finland.118 These submarines were in realty test models
for future German U-boats.
In the summer of 1935, the German Navy had three classes of submarines in
commission. The most numerous, the diminutive Type II class, was armed with three
torpedo tubes, all located in the bow, and weighed only 250 tons. The Type I boats,
113
Elliot, 690.
Anglo/German Agreement of 1935 http://www.navweaps.com/index tech/tech-089 Anglo German
Agreement 1935.htm
115
Karl Dönitz, Memoirs, Ten Years and Twenty Days (New York: Da Capo Press, 1997), 10.
116
Dönitz was placed in charge of the u-boat arm of the German Navy in 1935.
117
Robert C. Stern, Type VII U-boats (London: Brockhamton Press, 1998), 12.
118
Stern, 12.
114
86
while larger and better armed handled poorly and only two were constructed. The ten
Type VII class submarines were excellent craft, processing good handling characteristics
and for its size the greatest possible firepower. The initial Type VII boats weighed 500
tons, had four torpedo tubes mounted in the bow, and one tube in the stern. With a
weapon load of twelve to fourteen torpedoes, it was an ideal submarine for commerce
raiding and this class was to be the foundation of the German U-boat force in World War
II.119
As the Germans began construction of a new submarine fleet, Dönitz provided the
new U-boat fleet a tactical doctrine that proved highly successful. A seasoned U-boat
captain from World War I, Dönitz believed in the use of group tactics. U-boats were to
operate in unison and not as lone wolves. While the United States Navy practiced large
scale fleet exercises pitting battle fleet against battle fleet, the Germans were
experimenting with wolf pack tactics in exercises such as the „German Armed Force
Maneuvers‟ held in the autumn of 1937.120 With modern submarines and a tactical
doctrine that exploit the strengths of these boats, the German Navy prepared to confront
the Allied ASW forces once again.
Following the collapse of the Central Powers and the signing of the Versailles
Treaty, many hoped that world would achieve universal peace. During these post-war
discussions, the British and American governments favored the outright abolition of
submarines as weapons of war and only France‟s opposition prevent this from
occurring.121 In February 1922, the world powers met once again in grand attempt to
119
Dönitz, 29.
Ibid., 21.
121
Richard Dean Burns, “Regulating Submarine Warfare, 1921-1941: A Case Study in Arms Control and
Limited War,” Military Affairs vol. 35, no. 2 (April 1971), 57.
120
87
restrict and reduce the size of the world‟s navies.122 Here they not only attempted to limit
the number of vessels, but the also the caliber of weapons to be carried.123 While most
limited their concern to these issues, President Wilson and his administration had other
goals to pursue. Wilson‟s administration proposed not only a limitation to submarine
tonnage but also demanded a clarification of the rules for submarine warfare. On 28
December 1921, former Secretary of State and War Elihu Root introduced a series of
resolutions designed to comply the submarine to adhere to the same rules of visit and
search that governed surface raiders.124 The nations of the world had no desire to see a
repetition of the carnage wrought by the German U-boats of World War I.
Meeting again in London in April 1930, the limitations enacted in 1922 were to
continue and as before some questioned the legality of submarine warfare. H.W. Maklin,
the British legal advisor presented a compromise which became Part IV of the 1930
London Treaty.125 This treaty ensured that guerre de course, as conducted by the U-boats
of World War I was a method of warfare rejected by the great powers, but as with most
treaties it was a treaty of convenience.
While advancements in aircraft construction, the introduction of powerful and
reliable radial engines resulted in aircraft capable of greater capabilities then those of an
earlier time, the Navy lacked any sort of master antisubmarine warfare plan. Ignoring the
lessons of World War I, the leadership failed to provide the necessary guidance to combat
the submarine threat. A brief examination of Rear Admiral William S. Sims‟ work, The
Victory at Sea, his account of the battle against the German U-boats of World War I,
122
The United States, British Empire, France, Italy, and Japan signed the treaty on 6 February 1922.
Article 7 limited the displacement of submarines to 2,000 tons and guns were limited to 5.1-inch caliber.
124
Burns, 57.
125
Part IV, Article 22, paragraph 1 stated that in their action with regard to merchant ships, submarines
must conform to the rules of International Law to which surface vessels are subject.
123
88
should have provided the naval leaders of interwar era amply guidance in how to
conduct antisubmarine warfare.126 Unfortunately, few American naval leaders saw the
submarine as a threat in any future conflict. With the governments of the world working
to restrict the use of the submarine in commerce raiding, the naval leaders look for other
uses of the submarine.
During the interwar years, most American naval leaders saw Japan as the greatest
threat. The goal of the American naval forces was to locate and to bring to battle the
Imperial Japanese Navy. To some, this was to be a reenactment of the Battle of Jutland
but fought in the Pacific instead of the North Sea.127 This led to the development of the
fleet type submarine, a large submarine, capable of high speeds on the surface whose
primary function was to serve as a scouting screen well ahead of the battle group.128 Just
as the Navy saw submarines as eyes for the battle-fleet, the primary function of the
Navy‟s patrol aircraft was to help locate enemy forces thereby permitting the battleships
to converge upon the enemy forces. In the pre-war navy, there existed no plan to counter
the submarine.
The failure to capitalize on the lessons of World War I meant that the United
States entered into World War II unprepared for antisubmarine warfare. There was no
attempt to integrate new technologies for finding submarines with better weapons for
killing them nor was there any sort of anti-submarine training program. With little
appreciation for the value of the airplane as an anti-submarine warfare platform, the Navy
126
Originally published in 1920, Sims provides an excellent description of the complexity of antisubmarine
warfare.
127
The Battle of Jutland was the largest naval battle of WW-I. Fought on 31 May – 1 June 1916, the battle
was a tactical victory for the Germans, but a strategic victory for the British forces.
128
Ernest Andrade, Jr., “Submarine Policy in the United States Navy, 1919-1941,” Military Affairs, vol. 35,
no. 2 (April 1971), 52.
89
made no effort to develop either weapons or doctrine. With Germany disarmed following
their defeat and with the rise of the Imperial Japanese Navy, the Navy turned its attention
to the vast Pacific Ocean.129
While the German submarine force under the guidance of Admiral Karl Dönitz
developed better weapons and improved tactics, the American Navy, having no such
vision found itself ill prepared for the upcoming battle.
129
The Anglo-German Naval Agreement of 1935 limited the German navy to 35% of the British fleet.
90
World War II
World War II
On September 1 of 1939, Germany invaded Poland. Two days later Great Britain
and France declared war on Germany beginning the world‟s bloodiest war.1 With the
outbreak of hostilities in Europe, President Franklin D. Roosevelt, on 3 September, spoke
to a worried nation. Much of the speech was an attempt by Roosevelt to insure the
American people that the country would remain out of the war and at the conclusion of
the speech, Roosevelt proclaimed:
I hope the United States will keep out of this war. I believe that it will and I give
you assurance and reassurance that every effort of your Government will be
directed to this end.2
Assured by their president that their country would remain neutral the American people
turned their attention inward, confident that the Neutrality Act of 1935 and its various
amendments would keep America out of another European war. As Roosevelt assured
the public of his desire for peace, he ordered the Navy to establish a Neutrality Patrol.
Initially established to observe and report by classified means any movement of warships
of the belligerents within a designated area, in time it would become actively involved in
aiding the British war effort.3
During the second half of the decade, patrol aviation was undergoing a series of
changes as missions and threats changed. In 1937, the Navy began using numbers to
designate the five patrol-wings. Navy leaders of the era believed that patrol planes‟
primary function was to search and patrol for approaching hostile naval forces and
William E. Scarborough, “The Neutrality Patrol, To Keep Us Out of World War II,” Naval Aviation
News, vol. 72, no. 3 (March-April 1990), 18.
2
Franklin Roosevelt, “September 3, 1939, Outbreak of War in Europe Speech,” The Authentic History
Center, http://www.authentichistory.com/ww2/news/19390903 FDR Fireside Chat on War in Europe.html
3
Scarbourgh, 19. The patrol initially covered an area bounded on the north by a line east from Boston to
latitude 42:30, longitude 65˚ south, to latitude 19˚, then around the windward and leeward islands to
Trinidad.
1
91
initially assigned the wings to the Base Force. Abandoning the concept in 1937, the
patrol-wings became part of the Scouting Force. Other organizational changes occurred
in July 1936 when the Navy adopted a standard system of numbering patrol squadrons.
The new system, reflect the wing in which the squadron was assigned.4 This system
lasted only briefly as in 1940, the fleet underwent reorganization and the Navy elected to
divide the patrol wings between the two oceans.5
In September of 1939, the Navy had twenty operational patrol squadrons
organized into five patrol-wings (PatWing).6 Assigning three of the wings to the Pacific,
they were home-ported at San Diego California, Seattle Washington, and Pearl Harbor
Hawaii. One wing was assigned to the Canal Zone at Coco Solo Panama, leaving only
Patrol Wing Five at Norfolk Virginia to carry out the mission of the Neutrality Patrol.7
Flying PBY-1‟s, 3‟s, and P2Y-2‟s, the crews mission was to report the name, nationality,
tonnage, color, and markings of surface ships sighted. Additionally, the crew recorded
the ship‟s course and speed and reported this information to the staff after returning to
base.8 On 2 October 1939, the Neutrality Patrol was expanded into a Neutrality Zone
when twenty-one American republics issued the Declaration of Panama.9 The Neutrality
Zone established a 300-mile wide neutrality zone off the coast of the Americas, excluding
Canada. The American authorities hoped this declaration would curtail all military
4
Michael D. Roberts, Dictionary of American Naval Aviation Squadrons, The History of VP, VPB, VP
(HL), and VP (AM) Squadrons, Volume 2. (Washington D.C.: Naval Historic Center, 2000), 807. As an
example under this system, VP-23 would indicate the third squadron assigned to Wing 2.
5
Ibid.
6
Most squadrons had twelve aircraft assigned to them.
7
Ibid., 22.
8
Ibid., 19 Patrol squadrons primarily involved in these flights were VP-51, VP-52, VP-53, VP-54 from
PatWing 5, and VP-33 from PatWing 3.
9
John Terraine, Business in Great Waters, the U-boat Wars, 1916-1945 (London: Wordsworth Editions,
1989), 339.
92
operations by the belligerent powers in this area. The Navy believed it necessary to track
all warships and suspicious vessels in this zone. Until the actions of the vessels were
considered satisfactory aircrews continued to track their location.10
With the fall of France on 22 June 1940, Britain turned to the United States for
aid and assistance. Within a year, on March 11, 1941, the Lend-Lease Act was signed
into law, allowing the United States government to lend, lease, sell, barter arms, ammo,
food, or any “defense article,” “defense information”, to any country whose defense the
President deemed vital.11 With this agreement came an expansion of the scope of patrols
during the latter half of 1940 and the early months of 1941. No longer were the
American forces content with reporting suspicious vessels, during the summer of 1941,
patrol planes involved in convoy escort duties began carrying general-purpose and depth
bombs.12
Throughout 1941, the Navy took an increasingly more active role in the war in the
Atlantic and by the fall, the ASW forces in the Atlantic were actively involved in
combating the U-boat threat. With orders authorizing attacks on forces threatening
United States or non-Axis shipping, American units were cooperating with their British
and Canadian counterparts in attempting to protect convoys carrying war material and aid
to the British Isles.13 In September and October, a series of events occurred that clearly
demonstrated that regardless of public perception, the United States was at war with the
German U-boat force.14
10
Scarborough, 21.
It is worth noting that under international law a neutral country is not permitted to provide munitions,
arms, or implements of war to warring countries.
12
Scarborough, 22.
13
Ibid., 27.
14
In May 1941, Ensign Leonard B. Smith (USNR) while flying a British PBY Catalina from squadron No.
209 located the German battleship Bismarck. This led to the destruction of the German warship with a loss
11
93
The first of these incidents occurred in 4 September 1941, in the waters off
Iceland when a German U-boat attacked the U.S.S. Geer. During the early morning hours
of 4 September 1941, the U.S.S. Geer had been shadowing the U-boat. In attempt to
escape, the U-boat fired three torpedoes at the Geer, all of which missed their intended
target. The incident was widely reported in the American press as an example of Nazi
aggression. What the press failed to report to the American people was that prior to the
German attack the Geer in concert with British air assets tracked the U-boat for three.15
The Geer gained sonar contact at 0920. Transmitting the submarine‟s location to the
circling British patrol aircraft, the aircraft dropped four 350-pound depth charges in an
attempt to destroy the submerged U-boat. In response to the aerial attack, the U-boar
fired three torpedoes at the Geer, who then made two attacks dropping nineteen depth
charges. In his radio address of September 11, 1941, Roosevelt stated that:
She (U.S.S. Greer) was carrying American mail to Iceland. She was flying the
American flag. Her identity as an American ship was unmistakable. She was
then and there attacked by a submarine. Germany admits that it was a German
submarine.16
The attack resulted in a change to the “rules of engagement.” Roosevelt stated that
American forces would attack without warning any Axis submarine found in waters
deemed necessary for the defense of America.17 Additionally Roosevelt stated:
That means, very simply, (and) very clearly, that our patrolling vessels and planes
will protect all merchant ships--not only American ships of any flag--engaged in
of 2,122 officers and men. “Bismarck: British / American Cooperation and Destruction of the German
Battleship,” Department of the Navy, Naval Historical Center.
15
Naval Message from COMTASKROUP 1.5, dated 6 September 1941. Box 4, Folder title: Navy
Department 1934-Feb. 1942 Index. Franklin D. Roosevelt Presidential Library,
http://www.fdrlibrary.marist.edu/psf/box4/
16
“On Freedom of the Seas,” Radio address, broadcast from the White House, 11 September 1941.
http://www.fdrlibrary.marist.edu/091141.html
17
Ibid.
94
commerce in our defensive waters. They will protect them from submarines; they
will protect them from surface raiders.18
The shoot first policy placed the United States Navy in a de-facto war with Nazi
Germany.19
On 1 October 1928, the Hindenburg government appointed Admiral Erich Raeder
as head of the Reichsmarine, the new German navy. Under his leadership the
Reichsmarine embarked on an ambitious naval construction plan that included
battleships, cruisers, and destroyers.20 Cultivating friendly relationships with the Royal
Navy, Raeder and other long-range military planners saw France and not Great Britain as
the most likely and formidable opponent in another war. Raeder believed that surface
action groups composed of fast battleships, cruisers, and aircraft carriers would force the
French Navy to fragment and disperse its forces to escort its convoys. This would allow
Germany to avoid the crippling naval blockade of World War I.
In need of a leader for the new submarine arm of the German naval forces, Raeder
turned to Karl Dönitz, a WW-I submarine veteran. Dönitz after careful study of U-boat
records, official and unofficial naval histories of World War I, and his own experiences
came to believe that if the German government had authorized unrestricted submarine
warfare at the outset of World War I, Germany could have achieved an early and decisive
naval victory. While Raeder desired a balanced fleet, Dönitz believed that war with
18
Ibid.
The U.S.S. Kearny was attacked on the night of 17 October and was struck by a single torpedo. The
U.S.S. Reuben James was attacked and sunk with the loss of 100 men.
20
Clay Blair, Hitler’s U-Boat War, the Hunters, 1939-1942 (New York: Random House, 1996), 31. This
naval build up included the popular “pocket-battleship” Deutschland class.
19
95
Great Britain was inevitable and Germany should cease building big surface ships and
begin building hundreds of submarines.21
The Nazi submarine force confronting the America in 1942 was highly trained,
well equipped, and designed to wage a war of guerre de course. German submarine
doctrine stressed aggressiveness and attacks by groups of U-boats, commonly known as
“Wolf Packs.” To appreciate the professionalism and capabilities of the German
submarine force in the early years of American involvement in the Battle of the Atlantic,
a brief examination of the pre-war training of the U-boat crews is necessary.
.
One week after the signing of the Anglo-German Treaty of 1935, on June 29, the
Reichsmarine (state navy) commissioned its first submarine, the U-1.22 Built in secret,
the launching of this single boat shocked the nations of the world. The U-1 was the first
of the Type II submarines built. Small, weighing only 254 tons, with a length of 134 feet,
these boats represented the rebirth of the German submarine force. Equipped with three
bow torpedo tubes, these small coastal craft were capable of caring a weapons load of six
torpedoes.23
On September 28, 1935, Germany commissioned its first operational submarine
flotilla. Under the command of Admiral Karl Dönitz, the training the crews underwent
went was grueling and intense. Training under wartime conditions as much as possible,
the crews practiced torpedo attacks day and night with attacks made at 600 yards. Dönitz
believed the torpedo was the submarines primary weapon and developed an attack
doctrine that awarded aggressiveness and daring. This aggressive style minimized errors
21
Blair, 37.
Ibid., 30 and 55. The German Navy underwent a series of changes in the summer of 1921, including a
change in its name to Reichsmarine.
23
Ibid., 42. Modifications and improvements to the basic design were resulted in a sub-class, identified by
a letter. The Type II was followed by the Type IIB and IIC class boats.
22
96
and greatly reduced the targets response time.24 Crews were required to carry out sixtysix submerged daylight attacks and sixty-six night surface attacks with “water slugs”
during their initial training. Following these 132 simulated attacks, crews graduated to
fire real torpedoes.25 Dönitz, by combining the intense training with handpicked officers
and crews, produced a force ready for war.
Along with the small coastal Type II submarines, the Germans developed other
general types of submarines. These were the medium size Type VII, the larger Type I,
and IX classes of submarines, as well as the giant “U-cruisers.26 Within the German
High Command there were conflicting philosophies regarding the size and number of
each type of submarine needed. Many in the German High Command saw a need for the
large cruiser boats but Dönitz‟s opinions persevered and the bulk of the U-boat built were
the Type VII and Type IX classes.27
The German engineers used the highly successful UB-III class submarines as a
template for the new Type VII class. The initial units of the Type VII while meeting
most of Dönitz‟s needs did have one serious failing, its radius action of only 4,300 miles,
which proved inadequate for the war in the Atlantic.28 Otto “Papa” Thedsen the chief
engineer of the Weddigen Flotilla solved this critical problem by designing external
24
Karl Dönitz, Memoirs, Ten Years and Twenty Days (New York: Da Capo Press, 1997), 13.
Blair, 41. A “water slug” is shots of compressed air, used instead of actual torpedoes.
26
Dönitz, 31. These U-boat cruisers were to weigh approximately 2,000 tons and capable of fighting a
gun-battle on the surface.
27
The belief in medium size submarines was not universally accepted in naval circles. The United States
Navy settled on the fleet type submarine of approximately 250-300 feet long and weighing 1400 tons. For
further information see Ernest Andrade Jr, “Submarine Policy in the United States Navy, 1919-1941,
Military Affairs, vol. 35, no. 2 (April 1971): 50-56.
28
Robert C. Stern, Type VI U-boats (London: Brockhamton Press, 1991), 14.
25
97
saddle tanks.29 The addition of these tanks gave the modified design a range of 6,500
miles at 12 knots while surfaced.30
The engineering plant for the Type VII was a flexible and robust system.
Propulsion during surface operations was provided by two six cylinder, four-cycle diesel
engines while surfaced and electric motors powered by electricity from lead-acid
batteries while submerged. Built by either the Maschinentabrik Augsburg-Nuremberg
(MAN) or the Germania Werft (GW) company, these engines were lightweight and
powerful. The engines initially used produced 1,160 bhp while later engines with an
exhaust driven turbocharger or a geared driven mechanical supercharger produced 1,400
bhp.31
Other changes to the basic Type VII design included replacing the single rudder
with a twin rudder configuration. This change not only greatly improved the turning
radius of the new boats but the new arrangement permitted the aft external torpedo tube
to be internally mounted.32 Speed was increased 20% by installing superchargers on the
two main diesel engines resulting in a maximum speed of 17.2 knots surfaced and 8 knots
submerged. With an armament of five 53.3 cm torpedo tubes and nine reloads the new
model, designated the Type VIIB represented the ideal boat to execute Dönitz‟s wolfpack tactics.33
During the developmental history of the Type VII, there were eventually six
distinct sub-types. The Type VIIC was the most numerous of these sub-types of the Type
29
Blair, 44. Thedsen was a 50-year-old former member of the Imperial Navy.
Stern, 16.
31
Ibid., 56. The MAN engines used the exhaust driven turbo-charger, while the GW used a geared
supercharger to produce the additional horsepower.
32
Ibid., 16.
33
Ibid.
30
98
VII design. In general, the modifications were minor or made to incorporate new
technologies. The Type VIIC is one such example. Its modification was motivated not
by any dissatisfaction with the basic Type VIIB but rather by a need to install new active
sonar.34 To accommodate the new sonar system the engineers lengthened the hull by 60
centimeters. The additional length reduced the maximum achievable speed to 17 knots
while surfaced and 6 knots submerged.35
Examples of other sub-types include the Type VIID and the Type VIIE. The
Type VIID class was a mine-laying variant of the Type VIIC class. Ordered in February
1940, the Type VIID were not used as minelayers until April 1943 as their primary
weapon the Type SMA mine was not ready for operational use.36 The Type VIIE was a
test-bed for the lightweight Deutz V-12 two-stroke diesel engine. German engineers
hoped to utilize the weight saved to increase range and weapons loads on the new type.37
The other class of U-boat used by the Germans during the Battle of Atlantic was
the Type IX. The Type IX represented the largest boat deployed by the Germany until
the advent of the Type XXI “electro-boats.” The treaty weight of the Type IX class was
740-750 tons, with a wartime weight of 1,032.38 To compensate for the additional size,
the Germans replaced the smaller six cylinder engines of the Type VII with two nine-
34
Stern, 17. The system referred to as S-Gerät, was an active sonar system designed to allow U-boats to
detect minefields and other targets.
35
Ibid. 18.
36
Ibid., 96.
37
Ibid., 21.
38
Dönitz, 71, Blair, 42 “Treaty weight” was the weight used in relationship to the tonnage allowed by the
Anglo-German Agreement of 1935. Dönitz lists the treaty weight at 740 tons for the Type IX, while Blair
lists the treaty weight at 750 tons and the war load at 1,032 tons for the Type IX. Of interest, the ONI
publication 220-M Axis Submarine Manual, published in 1942, fails to mention the large Type IX class
submarine, however it does mention a large mine-laying submarine that is comparable to the Type IX.
99
cylinder engines producing 4,400 bhp.39 This provided for a top speed of 18.2-19.2 knots
while surfaced and 6.9-7.3 knots while submerged.40
As with the smaller Type VII, the Type IX underwent a series of modifications
during the war. The additional size allowed the Type IX class to carry twenty-two
torpedoes, with twelve storied internally, and ten stored in external torpedo containers.41
The Type IXB had an operational range of 12,400 nautical miles, the Type IXC 16,300
nautical miles, and the last of this class the Type IXD had an astounding range of 23,700
nautical miles.42 While the smaller Type VII possessed certain tactical advantages, the
large Type IX could operate in distance waters off New York, Trinidad, and Key West.43
Though built too late to have a profound effect on the Battle of the Atlantic, the
third type of submarine that the Americans confronted in the Atlantic was the Type XXI
“electro-boats.” The Type XXI incorporated new and revolutionary technologies, in part
to counter the growing ASW forces of the Allies. The German‟s delayed production of
the Type XXI to concentrate construction on the proven Type VII and Type IX class
submarines. However, by 1943, it was clear that if Germany was to win the Battle of the
Atlantic, there was a critical need for new and improved submarines.
39
Report on the Interrogation of Survivors from U-177, Sunk 6 February 1944, Final Report – G/Serial 34.
Op-16-Z, Navy Department, Office of Chief of Naval Operations Washington.
http://www.uboatarchive.net/U-177.htm
40
Dönitz, 479.
41
U-boat Type IX http://uboats.net/types/ix.htm The Type IX sub-types are the Type IXB, IXC, IXC/40,
and the IXD. All carried twenty-two torpedoes with the exception of the Type IXD class. The IXD carried
twenty-four torpedoes.
42
Ibid.
43
Dönitz, 198. The distance from bases on the Biscay coast to New York was 3,000, Trinidad 3,800, and
Key West 4,000 miles.
100
The capabilities of the Type XXI were revolutionary in nature.44 Conceptually
these submarines incorporated advancements that pushed the envelope of submarine
performance. The Type XXI was an attempt to produce a true submarine, a craft that
would spend its time submerged rather than on the surface. By 1943, the Germans had
come to realize that the Allies‟ measures against the “surface U-boat” had resulted in
unacceptable losses to the U-boat fleet.45 Dönitz recognized the need for new technology
to counter the growing power of the ASW forces confronting his forces.
The Type XXI was a large boat weighing 1,819 tons while submerged, with an
endurance of 15,500 miles. It had a maximum submerged speed of 17.5 knots and a
submerged cruising speed of 5.5 knots. With its ability to fire its torpedoes from a depth
of 150 feet, the Type XXI, in theory, would be capable of defeating any opponent.46
Additionally the type XXI was equipped with the latest electronic systems, and a snorkel,
allowing for the operation of the diesel engines while at shallow depths. With six sets of
storage batteries comprised of 372 cells, the Type XXI had the capability of staying
submerged longer than any previous submarine, allowing it to transit the Bay of Biscay
from their French ports.47 Equipped with six bow torpedo tubes, and a rapid reload
capability, the Type XXI was capable of defeating any surface opponent and with its
ability to stay submerged for long periods remain hidden from its airborne opponents.48
In his massive work Hitler’s U-Boat War, the Hunters: 1939-1942 and The Hunted: 1942-1945, Clay
Blair correctly notes the various limitations to Germany‟s “electro-boat.” Many of the problems associated
with the Type XXI were the result of hurried construction and incomplete research and development. See
pages X and XI of The Hunters and pages 708 and 709 of The Hunted for details.
45
Dönitz, 353.
46
Ibid. 427.
47
The Type XXI had three times the electrical power of the Type VII. U-boat Types XXI
http://uboats.net/types/xxi.htm
48
Blair, x. The Type XXI was equipped with a hydraulic reload system that permitted the reloading of all
six tubes in five minutes.
44
101
Fortunately, for the Allies, the Type XXI failed to meet the goals of its builders.
In part due to the bombing campaign and the need to rush the boat into service, the Type
XXI was poorly constructed. Additionally the lack of a prototype prevented the Germans
from correcting serious design flaws in its engines, hydraulic and snorkel system.49
Though the Type XXI failed to live up to expectations and arrived too late to influence
the war‟s outcome, it did point the way for future submarine development.
During World War II, German submarines used three types of weapons, the
torpedo, the mine, and various cannons and machine guns during surface operations.
While both the mine and cannons were important, the primary weapon of the
German U-boat force was the torpedo. The most basic type was the T1, powered by the
burning of alcohol and compressed air. With three-speed setting, the TI was capable of a
range of 6 kilometers at 44 knots, 7.5 kilometers at 40 knots, and 12 kilometers at 30
knots. The other basic design was the electric powered T2. While the alcohol powered
T1 left a visible wake, the electric powered torpedoes left no such wake. The T2
underwent various improvements during the war resulting in the production of four new
models, known as the T3, 3a, T4, and the T5.50
While there were only two basic propulsion types, there were major differences in
guidance systems. The standard guidance of a German torpedo allowed for the tuning of
the torpedo up to 90° off its base course. Once on its assigned course the weapon would
run until it struck a target or exhausted its fuel. As the war progressed, the Germans
introduced newer and more capable guidance systems.
49
50
Blair, xi.
Stern, 79.
102
One such system designed by German engineers was an acoustic homing system
designed to counter the naval escorts guarding the convoys. Guided to the target by the
noise produced by the propellers of the ship, it would home-in and strike them in the
stern. The Germans installed this advanced guidance unit on the T4 and T5 torpedoes.51
A short-range defense weapon, the warhead of these anti-escort weapons were smaller
than earlier models, with the weight of the warhead reduced from 280 to 274 kilograms.52
The other advanced torpedoes designed by the Germans, were the
Flächemabsuchender Torpedo (FaT) and the Lagenunabhängiger (Lut).53 Designed for
use against merchant ships, both weapons preformed a ladder search as it searched for its
attended target. This type of search pattern permitted greater flexibility when attacking
as the submarine need not know the exact course and speed of the convoy.54
Torpedo loads varied with the availability of the torpedoes. According to the
survivors of U-1229, sunk in August 1944, the boat carried fourteen torpedoes. The loadout consisted of four T1, 2 and 5‟s and two T3 torpedoes.55 The survivors of the U-73,
sunk in December 1943, reported a torpedo load of 12, consisting of four T5 and FaT
torpedoes, with the remaining four being standard electrically driven weapons.56
At the outset of the war, Germany faced a crisis with regard to the torpedo‟s firing
pistol. The most sophisticated of these pistols was the Pi1 model. It combined a contact
51
Stern, 79.
Ibid., The T4, and T5 used the T3a chassis. The larger seeker size dictated the reduction.
53
Ibid., 84 and 86. The FaT was known as a shallow searching torpedo and the LuT was known as a
bearing independent torpedo.
54
Ibid., 85.
55
Report on the Interrogation of Survivors from U-1229, Sunk August 1944. Washington D.C.: Navy
Department, Office of Naval Operations, copy 21 of 51, p. 2. http://www.uboatarchive.net/U-1229.htm
The U-1229 was a Type IXC class.
56
C.B. 04051(95) “U-73” Interrogation of Survivors, February 1944, Naval Intelligence, Admiralty, S.W.
1 N.I.D. 0671/44, p. 2. http://www.uboatarchive.net/U-73INT.htm The U-73 was a Type VIIB class.
52
103
function, with a magnetic exploder.57 Early in the war, it became apparent that the Pi1
failed too frequently for wartime use. Following the Norwegian Campaign, the German
High Command established a Torpedo Commission to determine the cause of these
failures.58 By December 1942, with the introduction of a new magnetic pistol, the
problems of reliability had been resolved.59
Though German U-boats underwent few structural changes during the war, the
addition of the snorkel was an attempt to counter the airborne threat. Building upon
experiments preformed by the Dutch Navy prior to the war, the snorkel was nothing more
than two pipes that protruded above the water aspirating the diesel engines while the
vessel was submerged. During a meeting in March 1943 in an attempt to find solutions
to the growing airborne threat, the Germans turned to the snorkel as a possible solution.
During the initial tests conducted in the Baltic Sea in 1943, found that despite limitations
the snorkel did permit the U-boat to remain submerged for extended periods.60
The Germans retrofitted both Type VII and IC classes with the snorkel. While the
snorkel permitted the submarine to remain submerged with the exception of the snorkel
mast, it did have various limitations. Sea-state greatly affected the use of the snorkel.
Too high of a sea-state the mast would be swamped resulting in the floater valve
actuating, cutting off the air supply and greatly reducing the pressure within the boat.
The engines would stop if the pressure dropped to 850 mill-bars.61 In a low sea state, the
57
Stern, 79.
Döenitz, 483. For a detailed account, see Memorandum No. 83/2/42.
59
Ibid., 95
60
Stern, 58.
61
Report on the Interrogation of Survivors fromU-1229, Sunk August 1944. Washington D.C.: Navy
Department, Office of Naval Operations, copy 21 f 51, p. 8. http://www.uboatarchive.net/U-1229.htm
58
104
wake created by the snorkel was readily visible by aircraft.62 Other problems included
the inability to dispose of trash, but the greatest weakness of the snorkel was it robbed the
U-boat of its speed advantage. While operating the snorkel the submarine was deaf and
blind. Visibility was limited to the restricted view provided by the periscope and the
boat‟s sonar equipped was useless unless the engines were secure.
Unlike World War I, which saw the extensive laying of mines by submarines, and
the construction of boats dedicated to the mission, World War II saw far less use the
mine. The standard mine used by the Germans was the Torpedomine (TM) series. By
the start the TMB had become the standard U-boat mine. With a length of 2.31 meters
and weighing 740 kilograms, it was possible to carry three mines in place of one torpedo.
In November 1939, the Germans introduced the TMC, a much larger weapon. Weighing
1,000 kilograms and having a length of 3.39 meters, two of this model replaced a single
torpedo.63 As the war progressed the Germans introduced the Type SMA, an anchored
mine, it was meant to be used with the Type VIID submarine. As with many of
Germany‟s wartime weapons development programs it suffered from various technical
problems delaying its introduction.64
The deck gun used by the Germans during the war was the 88-millimeter cannon
on the Type VII and the 105-millimeter on the larger Type IX.65 The crews used these
weapons during a surface action. While the deck gun remained the same, the anti-aircraft
armament changed as the air threat grew. An example of these changes is the various
weapons carried by U-177. One its first patrol, the U-177 carried one 20 millimeter and
This wake is commonly referred to as a “feather.” On a clear day and calm sea, it is possible to sight a
“feather” at three to five miles.
63
Stern, 95.
64
Ibid., 96.
65
Blair, 86.
62
105
one 37-millimeter cannon for defense against air attack. Prior to its second patrol,
defensive armament had grown to two 20-millimeter cannons, one 37-millimeter cannon
and three MG-15 machine guns. By its three and final patrol, the number of MG-15s had
grown to four, and a new more powerful 37-millimeter cannon had been added.66
As the war progressed, it became apparent to the German naval authorities that
the development of airborne radar had resulted in the loss of submarine‟s ability to travel
safely on the surface. While the snorkel provided a degree of protection, airborne
centrimetric radars were capable of detecting it. This lead to the development of antiradar coatings that would make the snorkel invisible to radar signals. In June 1943, under
the code name Schornsteinfeger, the Germans embarked on the development of anti-radar
coatings.67
The program led to the development of two coatings. The coating known as
Tarnmatte, was the simpler of the two. It was a compound of synthetic rubber and iron
oxide. Created in 2-centimeter thick sheets it was flexible which allowed it to cover
complex shapes. First used in 1944, Germans hoped Tarnmette would defeat the British
H2S radar.68
The more advanced material, known as IG-Jaumann Absober, was composed of
seven thin layers of conductive material separated by layers of a dielectric material. The
varying conductivity of the seven thin layers allowed for radiation of wavelengths
between 2 and 50 centimeters to be absorbed. Able to reduce the radar reflective strength
66
Final Report on the Interrogation of the Survivors from U-177 Sunk 6 February 1944. G/Serial 34.
Washington D.C.: Navy Department, Chief of Naval Operations, Copy 46 of 46. Chapter IV, page 19-23.
http://www,uboatarchive.net/U-177INT.htm
67
Stern, 131.
68
Ibid. The H2S was the code name of the British MK III radar and operated at 9.7 cm
106
of a snorkel head by 15-30%, the material held the promise of making the U-boat
invisible to existing patrol aircraft radar systems.69
German scientist struggled to develop advance materials to hide the snorkel head;
the installation of radar detectors provided a degree of protection from the radars of the
maritime patrol aircraft. The first such radar detector was the FuMB
(Funkmessbeobsrcher) Metox R.600 system and was capable of detecting radar signals
operating from 1.3 to 2.6 meters.70 This primitive system provided warning of the early
radars, but proved incapable of detecting the new MK-III radar operating the 9.7-cm
band. It was not until late November 1943, that the combination of the FuMB 7 Naxos,
Wanz G2, and FuMB 10 Borkum systems did the Germans succeed in providing full
coverage of the radar spectrum.71
While the Americans and Allies employed radar extensively, the Germans found
it difficult to develop radar suitable for use on submarines. For a submarine radar system
to be useful, it needed to be small, lightweight, and robust. Of the various problems
encountered, the ability to develop an antenna proved to be extremely difficult.
The other fundamental issue that hindered the use of radar on a submarine is RF horizon.
Since RF range is a function of the height of the antenna, radar systems on submarines
had a short detection range.
To compensate for the lack of reliable radar, the Germans deployed the FockeAngelis FA-330, a motor-less tethered observation autogyro.72 An ingenious system,
know by German crews as the "Bachstelze"(Water Thrush), it was a lightweight, single
69
Stern, 132.
Ibid., 124. A Pairs based firm produced the system.
71
Ibid., 126.
72
Report on the Interrogation of Survivors from U-177, Sunk 6 February 1944 (Washington D.C.: Office of
Chief of Naval Operations, 1944), 35-46.
70
107
man observation helicopter. Made of wood and aluminum, an experienced crew could
have the device assembled in 6-8 minutes. Once assembled, the U-boat would increase
speed causing the rotor to spin between 130-250 rpm, lifting the pilot aloft. Connected to
a 300-meter tether, the Bachstelze could rise to approximately 150 meters, increasing the
visual range of the U-boat to 25 miles.73
With capable submarines and highly trained crews, the German forces were ready
to challenge the Americans and their Allies for control of the Atlantic Ocean. The battle
proved to be one of endurance and attrition with the advantage shifting from one side to
another as the war progressed.
On 7 December 1941, the Navy placed all twelve-patrol squadrons in the Atlantic
under the command of Commander Patrol Wings, U.S, who assigned each squadron to
one of the five wings. The Atlantic patrol squadrons were equipped with various models
of the Consolidated PBY Catalina , with one squadron equipped with the new Martin
PBM Mariner and one transitioning to the Lockheed PBO Hudson.74 The sudden and
unexpected attack on Pearl Harbor on 7 December 1941 radically altered the fore
structure of the United States Navy. Responding to the heavy losses in the Pacific, Patrol
Wing 8 with its four PBY squadrons rushed to the Pacific theater in an attempt to
compensate for the losses suffered during the initial Japanese attacks.75 With a
patchwork chain-of-command, the remaining patrol squadrons were to confront the full
onslaught of the German U-boats in the Atlantic.
73
Final Report on the Interrogation of the Survivors from U-177 Sunk 6 February 1944. Chapter V, p. 3546. The Bachstelze was used on Type IX class.
74
Albert L. Raithel, Jr. “Patrol Aviation in the Atlantic in World War II,” Naval Aviation News, Volume
77, No. 1, November-December 1994, 28.
75
Ibid.
108
The development of maritime patrol aircraft during in World War II saw gradual
improvements to pre-war models, the introduction of new seaplane models and the
addition of large, long range land-based aircraft to the inventory. By the end of the war,
the Navy‟s patrol squadrons flew a mixture of seaplanes and land-based aircraft. Each
type fulfilled a specific tactical need as aircraft technology continued to evolve.
In December 1939, the Navy placed an order for 200 PBY-5 Catalina flying
boats. The additional aircraft were need if the duties of the Neutrality Patrol were to be
carried out.76 The Pratt & Whitney R-1830-92 engines that produced 1,200 horsepower
powered the new aircraft.77 With a modified fin and blister fairings over the waist gun
positions, the PBY-5 with its crew of eight or nine it was at war‟s beginning the mainstay
of the maritime patrol force. All of the PBY models up to and including the PBY-5 were
flying boats however, the next model, the PBY-5A, was to be an amphibian. The Navy
placed an order for the prototype of the PBY-5A on 7 April 1939.78 The greater utility,
combined with negligible decline in performance, made the PBY-5A a highly effective
aircraft.79 The conversion included the addition of retractable tricycle landing gear. The
nose wheel retracted into the hull while the main wheels retracted into the recesses of the
hull.80
While the PBY was a capable aircraft, to meet the new challenges of war, the
Catalina needed further improvements. As Consolidated Aircraft strived to meet the
“Naval Aircraft, Catalina,” Naval Aviation News, June 1972, page 20.
The total number of PBY’s built was as follows: Consolidated – 2,387, Boeing – 290, NAF – 155,
Vickers – 230.
78
United States Naval Aviation, 1910-1980, NAVWEPS 00-80P-1 (Washington D.C.: Government Printing
Office, 1970), 92.
79
The tricycle landing gear removed the need to use beaching gear.
80
John M. Elliot, “Aircraft Data – Technical Information and Drawings,” in Dictionary of American Naval
Squadrons, the History of VP, VPB, VP (HL0 and VP, by Michael D. Roberts (AM0 Squadrons, Volume 2.
(Washington D.C: Naval Historic Center, Department of the Navy, 2000), 674
76
77
109
Navy‟s needs for long-range patrol aircraft, the Bureau of Aeronautics (BuAer) ordered
the Naval Aircraft Factory (NAF) to explore ways of improving the PBY-5‟s
performance. In order to prevent any interruption to the production line the Navy tasked
NAF to find ways to improve the PBY.
In their attempt to achieve these goals, engineers made major changes to the hull
of the aircraft, hoping to improve the handling and take-off properties. The hull of the
new aircraft was 64 feet, 8 inches long vice the 63 foot, 10 inch hull of the standard PBY.
In order to improve water handling and takeoff characteristics engineers made changes to
the bow and added a new twenty-degree diagonal step along with a five-foot extension of
the rear-planning surface. Designated the PBN-1 and named Nomad it was hoped it
would provide the necessary improvement in performance sought by Navy officials.81
Unfortunately, for those involved the Nomad proved to be a failure. Maximum speed and
range were both less than the PBY-5 and poor workmanship and quality control plagued
production. While the Navy formally accepted the aircraft, it had no use for it
consequently the 137 of 155 PBN-1 produced were transferred to the Soviet Union in
1944.82
To appreciate the versatility of the PBY-5A, a brief examination of the
operational history of VP-63 will demonstrate this quality. The Navy‟s maritime patrol
squadrons underwent a series of changes to their official designation from their original
designation as patrol squadrons (VP) reflecting their primary mission of patrol, to their
later designation as patrol bombing squadrons (VPB), reflecting the more aggressive role
81
William F. Trimble, Wings for the Navy, a History of the Naval Aircraft Factory (Annapolis: United
States Naval Institute, 1990), 241.
82
United States Naval Aviation, 1910-1980, NAVWEPS 00-80P-1 (Washington D.C.: Government Printing
Office, 1970), 412.
110
taken in the later years of the war. Nicknamed the Mad Cats, VP-63 was established at
NAS Alameda, Calif., under the operational control of Patrol Wing (PatWing) 8 on 19
September 1942.83 Originally intended for use in the South Pacific as a Black Cat
squadron, it was decided to use the squadron as a test bed for new ASW technologies.84
These new technological innovations included magnetic anomaly detection (MAD)
equipment, retro firing rockets, and the passive-listening sonobuoy.85
The final version of the venerable Catalina was the PBY-6A. Incorporating all
the various wartime improvements, the PBY-6A was the final model of the Catalina.
The Navy used the PBY-6A as a patrol plane, bomber, and torpedo plane. With its hull
divided into five watertight compartments and with self-sealing fuel tanks, the PBY-6A
was capable of absorbing considerable damage. In its ASW role, the PBY-6A was
capable of carrying eight 325-pound depth bombs and was equipped with the AN / APS-3
radar. During a typical ASW mission, the PBY-6A carried a bomb load of four 325pound depth charges that allowed for a combat radius of 1,705 nautical miles at 102
knots. Defensive fire was provided by two .50 caliber waist guns and a single twin .30
calibers machine-gun in the bow. Like its predecessor, the Pratt & Whitney R-1830-92
engines were equipped with a single stage supercharger.86
Though the PBY proved to be a highly successful aircraft, the Navy sought newer
and more capable aircraft. The Navy on February 1936 awarded Consolidate Aircraft a
contract for the XPB2Y-1 and in June of 1937, awarded the Martin Company the contract
83
Established as Patrol Squadron Sixty- three (VP-63), it was re-designated Patrol Bombing Squadron
Sixty Three (VPB-63) on 1 October 1944 and disestablished on 2 July 1945.
84
Black Cat was the name used for night fighting PBY squadrons that operated in the South Pacific.
85
Michael D. Roberts, Dictionary of American Naval Aviation Squadrons, the History of VP, VPB,
VP(HL), and VP(AM) Squadrons ( Washington D.C.: Naval Historical Center, 2000), 485
86
“Standard Aircraft Characteristics, PBY-6A “Catalina,” Naval Historical Center, Department of the
Navy, http://www.history.navy.mil/branches/hist-ac/patrol.html In aircraft piston engines, supercharging
compensates for the reduced atmospheric pressure at high altitudes.
111
for the XPBM-1.87 Both aircraft were large flying boats that incorporated changes and
advancements that the Navy sought to meet the challenges of future wars.
Unlike earlier seaplanes built by Consolidate Aircraft, the XPB2Y-1 Coronado
was an all-metal constructed, four-engine seaplane. With its wingspan of 115-feet, the
Coronado carried twice the payload of the PBY. Capable of carrying four 1,000 lb
bombs external and eight 1,000 lb bombs internal in its massive wings, the Coronado
represented a new type of patrol bomber. Powered by Pratt & Whitney XR-1830-72
Twin Wasp engines and with retractable wing tip floats, the XPB2Y-1 was a remarkable
aircraft for the era.88 However, as the complexity of the aircraft grew, new and
unforeseen problems developed. An example of this was the stability problems suffered
by the XPB2Y-1. It suffered serious directional stability problems requiring a redesigned
vertical and horizontal tail assembly. This required the replacement of the single vertical
stabilizer by a dual rudder configuration. This new configuration solved the existing
control problems.89
With its stability problems solved, the modified aircraft was designated the
PB2Y-2. Along with its new tail, other changes included an increase to its bomb load to
8,000 pounds, and .50 caliber machine guns replaced the smaller .30 caliber machine
guns of the prototype. To offset the increase in weight of the new model, the Navy
elected to install the more powerful Pratt & Whitney R-1830-78 engines, with a twostage supercharger.
87
United States Naval Aviation, 1910-1980, NAVWEPS 00-80P-1 (Washington D.C.: Government Printing
Office, 1970), 89-90.
88
William Wagner, Reuben Fleet, and the Story of Consolidated Aircraft (Fallbrook: Aero Publishers, Inc.,
1976), 198.
89
Hal Andrews, “PB2Y Coronado,” Naval Aviation News, Vol. 72, no. 1, Nov-Dec, 1989, page 22-23.
112
Various problems continued to plague the PB2Y. The plane‟s engines failed to
provide the necessary power and fuel leaks plagued its crews. Additionally its range was
inadequate when equipped with self-sealing fuel tanks. These problems needed fixing if
the PB2Y was to meet the designer‟s goals. To rectify the fuel leak problem a series of
solutions, some models received synthetic rubber cells, while others used new sealing
compounds. Additional fuel tanks placed into the hull increased the aircraft‟s range to
equal those aircraft with self-sealing tanks.90 Needed power was found by replacing the
earlier engines with Pratt & Whitney R-1830-92, single stage supercharger engines.91
These modified aircraft were designated PB2Y-5 and proved their worth both in combat
and the transport role.
The other flying boat developed prior to the war was the PBM Mariner and while
the PB2Y had a relatively short wartime career, the Navy squadrons flew the PBM until
1956.92 First flown on 18 February 1939, two 1,600 hp Wright Cyclone R-2600-6
engines powered the XPBM-1. This allowed the Mariner to carry a 2,000-pound
payload. With its gull wings, twin tails and retractable tip floats the PBM presented a
radically different appearance from previous flying boat designs. However, as with the
PB2Y, the XPBM-1 experienced various handling problems both on the water and in
flight. The hull was redesigned to correct the problems while waterborne and with the
addition of a dihedral to the horizontal tail, resulting in the vertical surfaces being canted
Andrews, 23. Aircraft involved in combat retained the self-sealing fuel tanks. PB2Y‟s used as transports
and air ambulances were not equipped with self-sealing tanks.
91
Roberts, 667.
92
Ibid, 667, 671. The last PB2Y’s were reported in the Navy‟s inventory on 30 November 1945. VP-50
was the last Navy squadron to operate the PBM.
90
113
the PBM was ready for fleet use.93 The first of these aircraft entered the fleet in
September 1940 and the Navy assigned these aircraft to VP-55.94
Of the numerous models of the PBM it was the PBM-3C, -3S, and 5S that were
used in the ASW role.95 The PBM-3 had fixed floats instead of the complex folding wing
floats additionally the engine nacelles were lengthened to increase bomb bay capacity.96
Two Wright R-2600-12 engines, resulting in a maximum speed of 211 mph and a service
ceiling of 19,800 feet, powered the PBM-3, 3C, and 3S. The PBM represented a
significant improvement over the older PBY flying boats.97
The PBM-3C saw the addition of twin .50 caliber machine guns in three power
operated turrets plus two flexible mounts in the waist positions, and the APS-15 radar in a
dome behind the cockpit. It was soon determined that in the additional capability of the
power turret was of little use in the ASW role. With the need for greater range the PBM3S saw the removal of the power turrets and armor and while powered by the same
engines as the earlier models, the -3S had a 25% greater range then the PBM-3C.98
The final model was the PBM-5 which was also the most numerous variant built
for the Navy. Two Pratt & Whitney R-2800-34 Double Wasp engines, equipped with
93
Roberts, 671.
Ibid, 223. Established as Patrol Squadron Fifty-five (VP-55) on 1 August 1940. Redesignated Patrol
Squadron Seventy-four (VP-74) on 1 July 1941. Redesignated Patrol Bombing Squadron Seventy-four
(VPB-74) on 1 October 1944. Redesignated Patrol Squadron Seventy-four (VP-74) on 15 May 1946.
October 1944. Redesignated Patrol Squadron Seventy-four (VP-74) on 15 May 1946. Redsignated Patrol
Squadron Forty (VP-40) on 1 September 1948. Disestablished on 25 January 1950.
95
Norman Polmar, “Historic Aircraft, a Very Capable Mariner,” Naval History, Vol. 21, no. 6 (December
2007), 14-15. Including pre-production aircraft, there were nineteen versions of the PBM built. A
precursor to the use of JATO (jet-assist-take-off) was the XPBM-2, which had a strengthened hull for
launching from a giant barge-mounted catapult designated AVC-1.
96
The engine nacelles served as bomb bays on both the PBM and PB2Y.
97
Martin Aircraft Specifications, The Glenn L. Martin Maryland Aviation Museum,
http://www.marlandaviationmuseum.org/pdf/PBM_spec.pdf
98
Roberts, 671.
94
114
single stage, two-speed supercharger, powered the PBM-5 series.99 To achieve additional
power for take-off the PBM-5 used jet assisted take-off (JATO) bottles. With an
impressive bomb load of 4,000 pounds and a combat radius of 860 miles at 135 mph, the
Navy built the PBM-5 in larger numbers than other flying boat other than the venerable
PBY Catalina.100
Though the PBM-5S did not fly until December 1945, it is a part of the World
War II development of the MPA in its ASW role. The -5S represented the beginning of
the electronic age in ASW. No longer limited by the airframe and engines, success in
ASW was now dependent upon the electronic systems carried by the aircraft. The
Mariner carried the AN/APA-11 or -38 electronic counter-measures system (ECM), the
AN/APS-2F or -15A search radar, AN/ARR-31 sonobuoy receiver system, the AN/ASQ-1 a
magnetic anomaly detector and the L-11 search light capable of producing 50-million
candlepower.101
The PBM was a capable ASW aircraft but suffered from its relatively short range.
The need to achieve greater range led the Navy to explore the use of land-based aircraft
in the patrol and ASW roles. The first such aircraft was the PBO-1 Hudson built by the
Lockheed Aircraft Corporation. With the increase in tensions prior to World War II, the
Navy needed an aircraft to conduct patrols over the North Atlantic. The British Royal
Air Force, (RAF) had already placed orders for the Hudson so the Navy requisitioned
twenty for its own use.102
“Standard Aircraft Characteristics,” NAVAER 1335C (Rev.1-49), 1 September 1950.
Polmar, 15.
101
NAVAER 1335C (Rev.1-49)
102
Roberts, 673
99
100
115
A relatively small aircraft, it had a crew of five and was powered by two 1,000 hp
Wright-Cyclone R-1820-40 engines. It had an impressive armament of two fixed and at
three flexible .30 caliber machine guns along with a bomb load of four 325 pound depth
bombs.103 The Hudson had a short career in the Navy as VP-82 received the first Hudson
on 29 October 1941 and the Navy removed the last Hudson from active service exactly
one year later.104
Although the Navy only operated twenty of these twin-engine aircraft, their
combat record was impressive. On 1 March 1941, while flying a PBO-1 Hudson, Ensign
William Tepuni, attached to VP-82 based at Argentia, attacked and sank the German
submarine U-656 near Cape Race. The submarine commanded by Kapitanleutnant Ernst
Kroning and represented the first German submarine to bed sunk by American forces in
World War II. Two weeks later, on 15 March, VP-82 reported that they had heavily
damaged a Germany U-boat. This report however was in error as postwar examination of
German records indicated that U-503, commanded by Kapitanleutnant Otto Gericke
actually sank following the attack.105
To fulfill the need for a medium range land-based patrol aircraft, the Navy
selected the PV-1/2. Each aircraft received its own name, with the PV-1 named Ventura,
and PV-2 named Harpoon. Built by Vega Aircraft Company, a division of Lockheed, the
Ventura, and like the Hudson, used British specifications. Two Pratt & Whitney R-280021 engines powered both models providing a top speed of 312 mph for the PV-1 and 282
103
Roberts, 673.
Ibid.
105
Ibid., 574.
104
116
mph for the PV-2.106 The Navy elected to redesign the PV-2. The changes resulted in
greater wingspan and while it increased the range and payload, speed and
maneuverability suffered on the PV-2. Heavily armed with up to five .50 caliber machine
guns in the nose of the aircraft, with two .30 or .50 caliber machine guns in ventral
position, the PV-1/2 was capable of considerable firepower. With an internal bomb bay
large enough to carry six 500-pound bombs or one torpedo and up to two 1,000-pound
bombs on the wings it presented a serious threat to a surfaced submarine.107
By the middle of 1942, it had become apparent to Navy leaders there was a need
for long-range land-based aircraft to help contain and defeat the U-boat threat. On 7 July
1942, the Navy and Army officials reached an agreement that provided for the transfer of
a number of Army B-24 Liberators, B-25 Mitchells, and B-34 Venturas to meet the
pressing need for patrol aircraft.108
To meet the need for long-range aircraft, the BuAer issued a contract to
Consolidated Aircraft Company for the PB4Y-1 Liberator on 7 July 1942.109 The PB4Y1 the Navy‟s version of the Army Air Forces‟ B-24D and had been designed as a strategic
bomber capable of carrying a maximum bomb load of 12,000 pounds.110 When used in
an ASW role, PB4Y-1 was capable of carrying either eight 650 or 325 pound depth bombs
or the MK-24 homing torpedo. Other systems added included the APS-15 RADAR, the
Long Range Navigation system (LORAN) and the AN/ARR-31 sonobuoy receiving
“Naval Aircraft,” Naval Aviation News, August 1974, p. 20-21 and “Airplane Characteristics &
Performance,” Model PV-1, NAVAER 1335C, 1 December 1943, Bureau of Aeronautics, Navy Department.
107
Roberts, 683.
108
United States Naval Aviation, 1910-1980, NAVWEPS 00-80P-1 (Washington D.C.: Government
Printing Office, 1970), 117.
109
Ibid., 669, VP-51 received the first of 977 PB4Y-1s in October 1942.
110
Ibid., In the strategic bomber role, the B-24 could carry a bomb load of either four 2,000 lb bombs,
eight bombs at either 1,600 or 1,000 lbs each, twelve 500 or 250 lb bombs, or forty 100 lb bombs.
106
117
system.111 Defensive armament consisted of eight flexible .50 caliber machine guns and
while the Liberator met many of the Navy‟s needs, it was not the ideal platform for naval
use.112 Its high altitude capability was not required and there was a need for additional
crew space and room for more electronic equipment. In addition, when employed as a
strategic bomber the B-24 flew in large formations, which provided supporting defensive
fire in the event of attack but in the ASW role, it operated alone. This necessitated an
increase to its defensive armament. These requirements resulted in the development of
the PB4Y-2 Privateer a highly modified version of the Liberator.
The Privateer, while owing much of its design to the B-24, was in many ways a
radically different aircraft. With its single large vertical stabilizer, and longer nose, the
PB4Y-2 presented a very different appearance. Navy‟s desire for a flight engineer in the
cockpit resulted in a longer nose. To compensate for the additional seven feet forward of
the wing, engineers extended the fuselage aft, and the large single vertical tail replaced
the twin tail configuration of the B-24 / PB4Y-1.113
Other changes included the replacement of the turbo-supercharged Pratt &
Whitney R-1830-43 engines with the Pratt & Whitney R-1830-94 engine with a single
stage two- speed mechanically driven supercharger. The new engine provided higher
power ratings at lower altitudes at which patrol missions were generally flown.114 Armed
with twelve flexible .50 caliber machine guns, the PB4Y-2 could defend itself against all
111
Roberts, 527.
Ibid., 669. LORAN is a navigation system, which uses hyperbolic fixing to obtain a position.
113
Wagner, 257.
114
Standard Aircraft Characteristics, PB4Y-2 “Privateer,” Declassified operating manual, Bureau of
Aeronautics, Navy Department.
112
118
attacks. With a combat range of 1,920 miles and a bomb load of up to twelve 325-pound
depth bombs, the Privateer represented, in many respects, the ideal ASW aircraft.115
The war saw numerous changes to aircraft construction. Fabric replaced metal,
large radial engines were the power plant of choice, and the age of electronics had begun.
However, in the years immediately following the end of hostilities, aircraft such as the
PB4Y-2 and the PBM-5S would soon prove to be inadequate against the new and
improved submarine threat.
World War II saw the rapid advancement and maturity of numerous electronic
sensors that proved critical to combating the German U-boat in the Battle of the Atlantic.
Some of these technologies were entirely new, while others were refinements to older
technologies and systems. Work continued on passive sonar systems and on ways to
improved navigational accuracy. Additionally the development of radar continued at a
rapid pace. New technologies such as the ability to detect a submarines magnetic field
led to the development of magnetic anomaly detection devices. Once the submarine was,
detected new and improved weapons increased the probability of its destruction. When
combined with new aircraft, these sensors and weapons posed a grave threat to the Uboat.
With Europe at war, the United States turned to the scientific community for help.
At the urging of the Doctor F.B. Jewett, at the time the President of the American
Academy of Sciences, President Franklin D. Roosevelt, on 27 June 1940 established the
National Defense Research Committee (NDRC) with the expressed mission to
“coordinate, supervise, and conduct scientific research on the problems underlying the
ASW sensors of the PB4Y-1 and PB4Y-2 were the same except some of the PB4Y-2‟s were equipped
with the AN/APS-2G or AN/APS-15B RADAR systems.
115
119
development, production, and use of mechanisms and devices of warfare.”116 Worried
that the NDRC lacked sufficient authority and funds to carry research forward into
development and production on 28 June 1941, Roosevelt issued Executive Order 8807,
establishing the Office of Scientific Research and Development (OSRD).117 The OSRD
consisted of nineteen divisions, two of which had dealt extensively with issues of
submarine warfare. Division 6 was responsible for sub-surface warfare, while Division
14 addressed the problems associated with the development of radar.118 With all research
and development, there was considerable cooperation among the various divisions as new
and more effective war fighting systems were developed.
On 3 October 1940, the Chief of Naval Operations, Admiral Harold R. Stark,
requested from the Naval Attaché in London to obtain all available information
concerning the British radar program.119 The development of an improved ASW radar
system was the result of the combined efforts of both American and British scientists.
The British breakthrough came in February 1940, when they successfully built a high
power „magnetron‟ oscillator that generated 500 watts and 3,000 megacycles.120
American scientists developed the duplexing system, which permitted the use of a single
antenna instead of a complicated radar array required by the early British radars. These
116
Franklin D. Roosevelt Presidential Library, Box 2, Bush, Vannevar Index, Report of the National
Defense Research Committee-6/27/40-6/28/42. http://www.fdrlibrary.mairst.edu/psf/box2/a13f01.html
117
John T. Woolley and Gerhard, The American Presidency Project {online}. Santa Barbara, CA,
University of California (hosted), Gerhard Peters (database) Available http://www.presidency. uscb.edu
/ws/?pid=16137.
118
The Library of Congress, Science Reference Services, http://www.loc.gov/rr/scitech/trs/trsosrd.htm
119
United States Naval Aviation 1910-1980, NAVAIR 00-80P-1, prepared at the direction of the Deputy
Chief of Naval Operations and the Commander, Naval Air Systems Command. (Washington D.C.:
Government Printing Office, 1981), 105.
120
Alfred Price, Aircraft versus Submarine (Annapolis: Naval Institute Press, 1975), 10, 58.
120
advancements result in the creation of the ASB medium wave search radar.121 Production
began in the spring of 1942, with over 26,000 units eventually produced for use by
American and British forces.122 Initial units had a maximum effective range against a
surfaced submarine of 8 miles while later models extended this range to 15 miles. With a
minimum range of 350 yards and a bearing accuracy of ± 3˚, the ASB radar provided
ASW crews an effective system to locate the German submarine threat.123
The development of radar during the war was the driven by the desire to produce
radars with short wavelengths. The first radars had wavelengths measured in meters, but
as technology advanced, wavelengths became shorter, first measured in centimeters and
finally millimeters. The shorter wavelengths allowed for the detection of much smaller
objects and the use of smaller antennas than the earlier lower frequency radars, and just
as aircraft underwent a series of changes during their development, so did the radar
systems used by maritime patrol aircraft.
On 18 July 1941, the Navy installed British type AVS radar in one PBY-5 each of
VP-71, VP-72, and VP-73 and two PBM-1‟s of VP74.124 In August 1941, the Chief of
Bureau of Aeronautics issued a preliminary plan for the installation of radar in naval
aircraft. The various patrol aircraft received British ASV long wave or American ASA
121
ASB was the acronym used by the Navy to designate all airborne medium-wave search radar sets for
carrier-based aircraft.
122
L. S. Howeth (USN retired), History of Communications-Electronics in the United States Navy
(Washington D.C.: Government Printing Office, 1963), Chapter XXXVIII, 443-469.
123
FTP-217, U.S. Radar, Operational Characteristics of Radar, Classified by Tactical Application
(Prepared by Authority of the Joint Chiefs of Staff, by the Radar Research and Development SubCommittee of the Joint Committee on New Weapons and Equipment, 1 August 1943), page: 68.
124
United States Naval Aviation 1910-1980, NAVAIR 00-80P-1, 108. AVS stood for “air-to-surface
vessel.”
121
medium wave systems.125 The ASA system had a maximum detection range of 10 miles
when a surfaced submarine was broadside to the radar beam.126 However, this plan
underwent radical changes as microwave radars soon superseded the long and medium
wavelength systems.
In the early months of the war, National Defense Research Committee turned its
attention to the development of a microwave radar system. In order to expedite the
development, the Navy divided the work among various civilian companies, including
Bell Telephone Laboratories and the Radio Corporation of America (RCA).127 On 18
March, using a B-18 to test a laboratory model, the equipment proved very effective in
locating ships at sea. The tests appeared sufficiently promising to warrant turning it over
to the RCA to be engineered for production. By the end of 1941, development had
produced an airborne microwave set for detection of surface vessels that was ready for
production.128
At the outset of World War II, both the Navy and the Army were conducting
airborne ASW operations. This resulted in both conducting research into tactical use of
radar systems. On 30 May 1942, General Henry H. Arnold, Chief of the Army Air
Forces, established the Sea-Search Attack Development Unit (SADU). Its mission was to
develop tactics and doctrine for Army aviation units involved in antisubmarine
warfare.129 At the urging of the Army, 90 old B-18 bombers were equipped with the
125
United States Naval Aviation 1910-1980, NAVAIR 00-80P-1,, 109. ASA indicated a medium-wave
airborne search system designed for installation in large patrol bombers, while ASV, and was a long-wave
airborne system designated for installation in the same type of aircraft.
126
FTP-217, 67.
127
Howeth, 443-469.
128
Ibid., 443-469.
129
Arthur B. Ferguson, “The AAF in the Battle of the Atlantic,” in The Army Air force in World War II, ed.
Wesley Frank Craven and James Lea Cate (Washington D.C.: Office of Air Force History, 1983), 550.
122
ASV-10 radar. The AVS-10 was second-generation microwave radar with a wavelength
of 10-centimeters and proved the usefulness of this new sensor.130
It is possible to categorize the radars used by the Navy‟s patrol aircraft in World
War II by wavelength. Long wavelength systems include the SCR-521-A and SCR-521B radar sets, also known as the ASVC and ASE sets respectively. All were American
versions of the British AVS II radar that had a wavelength of 1.5 meters, which were
capable of detecting a surfaced submarine on the beam at six miles.131 The Navy
installed the ASVC and ASE systems in the B-17, B-24, PBY-5, 5A, and the PBN
aircraft.
Unlike later systems, the ASVC and ASE did not use the familiar plan position
indicator (PPI) rather it used the AVS scope of the British system. The AVS scope was a
modified version of an A-scope display. These early radar systems did not use a single
rotating antenna, rather from fixed antennas on the side of the aircraft. Displaying the
signal on a vertically oriented A-scope, the distance from the bottom of the scope to the
target was the range. Displacement of the target to the left or right of the aircraft would
indicate what direction to turn to intercept the target. The PPI indicator placed the
aircraft in the center and sweeps around displaying targets on the scope allowing for easy
recognition of orientation of the target from the aircraft. In addition, it early radars did
not sweep 360˚ rather they swept an 180˚sector in front of the aircraft.132
An additional limitation to this early system was the need to use multiple
antennas. The SCR-521 / ASVC and SCR-521-B / ASE provided coverage of a 150˚
130
Montgomery C. Meigs, Slide Rules, and Submarines (Washington D.C.: National Defense Press, 1990),
65.
131
FTP-217, 66.
132
Prince, 56.
123
forward sector when searching and a 40˚ sector when homing on a target.133 The later
ASA and ASB medium wave sets used the same scope as the long wave systems but
provided search coverage of 180˚, while retaining the same 40˚ homing sector.134 The
Navy installed the majority of the ASA systems in the PB2Y-3 Coronado, adding 353
pounds to the aircraft‟s weight and reducing its top speed by 4 to 5 knots.135
There were eight models of the ASB and ASB Series medium wave radar sets.
With a wave length of 60-centimeters and weight of only 152 pounds the systems was
installed in a plethora of aircraft, including the PBY-5 / 5A, PB4Y, and PV-3 patrol
aircraft.136 Though replaced by microwave systems the ASB and ASB series of radars
produced excellent results when hunting German submarines.
The first microwave radars used by naval aviation were the SCR-517-A, SCR517B, ASC-1 and SCR-517-C sets. Not only were these 10 centimeter wavelength
systems but the SCR-517-B and ASC-1 introduced the PPI scope for fleet use along with
360˚ coverage. The B-17, B-18, B-25, and B-34 received either the SCR-517-A or the
SCR-517-C system, while the Navy installed the ASC-1 in the PB2Y-3 and the SCR517B. The B-24 was capable of having any of the four radars installed.137
With the ability to detect a surfaced submarine at 18 miles a 4,000-8,000 ton ship
at 40 miles, and the coast at 40 miles these microwave systems greatly improved the
probability of detecting a submarine before it went “sinker.” The earlier long and
medium wavelength systems provided detection ranges of only eight and ten miles, a
133
FTP-217, 66.
Ibid., 66-68.
135
Ibid.
136
Henry Guerlac and Maie Boas, “The Radar War against the U-Boat,” Military Affairs, vol. 14, no. 2
(Summer, 1950), 104.
137
FTP-217, 69.
134
124
distance not much greater than visual range on a clear day. Thus, it became a race
between the aircraft and submarine as to who would see whom first and react.
The follow on to the SCR-517-A, SCR-517B, ASC-1 and SCR-517-C series were
the SCR-717-A and SCR-717-B radar systems. Commonly referred to as “small package
microwave radar systems,” they represented improvements to the SCR-517 system. The
SCR-717- A used a B-scope to present the radar data to the operator instead of the Ascope. A B-scope display was essentially an A-scope with the range line rotated about a
zero point at the bottom of the display sweeping upward along the Y-axis with distances
up the display indicating range. This version was capable of searching either the front or
rear 180° sector but not both. The introduction of the SCR-717-B saw the introduction of
the PPI scope and continuous 360° coverage.138
The SCR-717-A / B were heavy systems, weighing a total of 560 pounds, which
limited it installation to land based aircraft, such as the B-24 and B-25. Installed in a
retractable belly turret that replaced the lower gun turret in the B-24 or B-25, the single
rotating antenna was capable of detecting a surface submarine at 20 miles.139
As technology progressed, engineers began to integrate surface search radars into
bombing systems the AN/APS-2 was one such radar. The AN/APS-2 was one of a group
of similar radars built by the Navy. The Navy installed the ASG and AN/APS-2A in “K‟
blimps, while the ASG-1 and AN/APS-2 was installed in PBM-1, PBM-3C, PBJ, and
PB4Y patrol bombers. Using a PPI display, the crew used the AN/APS-2 for locating
and homing on surface craft and for general navigation and the AN/APO-5 for blind
138
139
FTP-217, 70-71.
Ibid., 70.
125
bombing.140 As with the SCR-717-A / B, the installation of the ASG-1 and AN/APS-2 in
the PBJ and PB4Y-1 required the removal of the lower ventral gun turret.141 The ASG-1
and AN/APS-2 weighed 360 pounds and reduced top speed of the aircraft by 2 to 5
knots.142
Other bombing radars employed were the AN/APS-15 and the AN/APS-3, and the
AN/APS-4 lightweight ASV and Interception set representing the future. The AN/APS15 radar provided critical information to the crew such as ground and slant range, relative
and true bearing of target, and true bearing of aircraft on "PPI" scopes.143 Installed in the
PV-2, PBN, and PBY-5 patrol aircraft and used as a search and torpedo-laying radar, the
AN/APS-3 provided range and bearing on a B scope to the operator and pilot.
Though not used by patrol aircraft the AN/APS-4 represented a future trend of
radar development. All major components were contained in a single pressurized
housing similar to a depth bomb, and detachable in the same manner as an ordinary
bomb. This enabled aircraft such as the SC-1 Seahawk to carry this radar.144
While radar could and did detect submarines and force them to submerge, once
submerged, traditional methods of attack achieved poor results as the submarine‟s
position changed as the submarine altered course, speed, and depth. What the crews
critically needed were systems capable of determining the submarine‟s position and
weapons that could destroy the submerged submarine. NDRC sought to utilize radio
140
FTP-217, 73.
The PBJ was the Navy's version of the B-25 Mitchell medium bomber.
142
FTP-217, 70.
143
The AN/APS-15 was installed on the B-17 and sometimes described as the H2X.
144
FTP-217. 74.
141
126
sonobuoys and magnetic anomaly detection equipment to locate the submerged while
using retro-bombs and acoustic torpedoes to attack.145
Magnetic anomaly detection or MAD detects a submerged submarine by using the
principle that metallic objects disturb the magnetic lines of force of the earth as they
travel.146 The typical strength of the earth‟s magnetic field is 50,000 gammas and the
typical 700-ton submarine of World War II had a magnetic field of 10 gammas at a
distance of 400 feet.147 As a submarine beneath the ocean's surface causes a distortion or
anomaly in the earth's magnetic field as it travels. It is detectable from a position in the
air above the submarine. The detection of this anomaly is the essential function of MAD
equipment. Working in cooperation with the National Defense Research Committee, a
PBY from Naval Air Station Quonset Point Rhode Island detected the American
submarine S-48, proving the potential of this new detection system.148 These tests
performed on 21 October 1941, achieved detection ranges of 300 feet against its
American target.149
By spring of 1942, on 10 April, the Navy formally established Project Sail with
the specific goal of developing and fielding functional MAD equipment.150 Testing
showed enough promise that the Navy placed an order for 200 of these early sets.151 The
early MAD systems consisted of a single sensor in a towed array further research resulted
in the development of a twin sensor system that placed the sensor in the wingtips.152 By
145
Meigs, 101.
MAD is the term used to identify these systems.
147
Prince, 104.
148
NAVAIR 00-80P-1, 110.
149
Meigs, 33.
150
NAVAIR 00-80P-1, 116.
151
Ibid.
152
FTP-217.106.
146
127
war‟s end, the Navy had produced four MAD systems, the Type 4B2, AN/ASQ-1,
AN/ASQ-1a, and AN/ASQ-3.153
The third sensor developed to counter the submerged submarine was the passive
sonobuoy. A passive sonobuoy is a small receiver-transmitter dropped from either an
aircraft or blimp and detects the sounds generated by the machinery in the submarine.
The transmitter section then transmits the information to the crew for evaluation. On 26
February 1942, the Navy requested the National Defense Research Committee begin
development of an expendable radio sonobuoy and during a test on 7 March 1942, off the
coast of Connecticut, a sonobuoy dropped by the blimp K-5 was able to detect the sounds
generated by the propellers from a submerged submarine at a distance of three miles.154
The Navy authorized the procurement of 1,000 sonobuoys and 100 receivers in
October 1942. Designated the AN/CRT-1 it was a floating container, incorporating a
non-directional hydrophone suspended on a 20-ft. line below the buoy itself, and
electronic equipment including a frequency modulated radio transmitter for transmitting
the underwater sounds received by the hydrophone to the AN/ARR-3 receiver located in
the aircraft. The sonobuoy transmitted on one of four frequencies and had a lifetime of
approximately 3 hours before self-scuttling. Though the transmitter had little power, the
radio reception range was approximately 10 miles when the aircraft was at 300 feet.
Detection range of a submerged submarine varied from 200 to 3,000 yards depending on
the water conditions.155
Through the Battle of the Atlantic, the Allies exploited the radio transmissions
made by the German submarines. In the summer of 1942, the Allies established a chain
153
FTP-217. 106.
NAVAIR 00-80P-1 113. The test was preformed with S-20, an American submarine.
155
FTP-217. 107.
154
128
of shore based high-frequency direction finding stations (HFDF).156 Though ineffective
in plotting transmissions from mid-Atlantic, they did provide positioning data to
submarines in the Caribbean Sea. Soon the Allies developed a ship-borne HFDF system
that allowed convoy escorts to pinpoint a submarine‟s location once it broke radio
silence. To exploit this tactical advantage, the need for accurate long-range navigation
became critical. This need in part, led to the development of the Long Range Electronic
Navigation (LORAN) system.
LORAN determined the position of the aircraft or ship by the time difference in
reception of the pulse signals originating simultaneously from a master and slave stations.
These signals locate the ship or aircraft on a charted hyperbolic curve. This curve
represents the locus of all possible positions that observe this time difference. The
intersection of the two lines fixed the position of the aircraft or ship.157
Hurried into production, by early 1943, the system had become operational. By
establishing stations in Greenland, Iceland, the Faeroes, and Hebrides, accurate
navigation became possible in the North Atlantic.158 Aircraft equipped with the APN-4,
after several hours of training had the capacity to fix their position to within 4 miles at a
range of 1,200 to 1,500 miles from the transmitting LORAN stations.159 Accurate
navigation permitted rapid concentration of ships and aircraft.
The primary airborne weapon used to attack submarines during much of the war
was the depth bomb. A depth bomb is a highly specialized type of bomb that is need
when attacking a submarine. Unfortunately, the United States entered the war with no
156
Prince, 109.
Megis, 101
158
Loran, Vol. I, Early Electronic History, and the Bridging of the North Atlantic and North Pacific.
December 1944. U.S. Coast Guard Headquarters, Office of Engineering, Washington, D.C. C-67847-1
159
Meigs, 105.
157
129
effective depth bombs and it was only after entering the war that the Navy fully
developed and procured these weapons.160 Unlike a general-purpose bomb that exploded
upon impact, a depth bomb was required to explode at a preset depth in order to damage
or sink a submarine.
The depth bombs used in the early part of the war were only marginally better
than those of World War I. Problems such as a slow sink rate and poor flight
characteristics once dropped all contributed to poor performance. Additionally, the fuses
used in these weapons were complex and required considerable time and effort to set.
These early depth bombs used a transverse fuse that operated by water pressure and it
was necessary to set them prior to loading on the aircraft. To set, the ordnance-men first
removed the five bolts that secured the fuse head to the bomb and withdrew the exploder
mechanism from the transverse fuse well. Once disassembled the desired depth setting
was set by a combination of springs of various colors that indicated their strength. Using
the appropriate springs, depth settings from 25 to 150 feet, in steps of 25 feet, could be
set. Reassembled and reinserted into the bomb, the weapon was now ready for use.161
The first type available was the Mark 17, weighing 325 pounds and based on
designs of the 1930s. Intended for release at low altitudes, the MK-17 did not become
available in large quantities until the spring of 1942. The second design to become
available was the Mark 29. It was a much larger weapon and weighed 650 pounds.162
These weapons underwent a series of changes. To prevent the bomb from
“skipping” a problem that occurred from early round nose bombs, designers utilized a flat
160
Roberts, 690.
John M. Elliot, “Aviation Ordnance, 1939-1941,” Naval Aviation News vol. 73, no. 5 (JulyAugust 1991): 28.
162
Roberts, 690.
161
130
nose with later designs. A simple tail hydrostatic fuse replaced the early complex fuses.
It was possible to set the depth bomb by adjust a knob on the side of the fuse. Explosive
power was increased first by replacing TNT first by the more powerful but unstable
TORPEX and then by the less sensitive HBX.163
With the development of new sensors came the need for new weapons. The
standard depth bomb did not provide the needed flexibility to exploit data provided by
such sensors as MAD and the passive sonobuoy. To allow crews to attack a “MADMAN” the engineers at the California Institute of Technology designed a retro-rocket that
fired aft at a velocity equal to the forward velocity of the aircraft.164 This allowed the
weapons to fall vertically. Successfully test on 3 July 1942 by LCDR J.H. Hean,
Gunnery Officer of Transition Training Squadron, Pacific Fleet, from a PBY-5A. VP-63
received the first fleet installation of the weapon in February 1943, and on 24 April 1944,
the squadron scored the first kill with the retro-rockets.165
Passive sonobuoys gave the aircraft the capability to track a submerged
submarine giving rise to a weapon that could destroy such a target. One of the limitations
of a depth bomb is that it needs to explode at a depth similar to that of the submarine. If
it exploded at a too shallow or too deep of a depth, the submarine could escape. To
overcome this limitation in 1940 initiated a program headed by Western Electric to
develop an acoustic homing torpedo. Following successful evaluation of the prototypes,
the Navy, in 1942, placed an order for 10,000 units. Code named “Fido,” and designated
163
Roberts, 691.
“MAD-MAN” is the term used by the operator to inform the crew that a magnetic anomaly has been
detected, generally indicating the detection of a submarine.
165
Roberts, 691.
164
131
the Mk 24 mine for security reasons, this remarkable weapon made its combat debut in
July 1943 with the sinking of German U-160.166
Following its debut the United States placed the Mk-24 into operation with
American and Allied forces. Allied forces launched 204 Mk24‟s against German Uboats, sinking 37 (18%) and damaging 18 (9%). American forces made 142 attacks on
U-boats, sinking 31 (22%) and damaging 15 (10%). Comparing the effectiveness of the
Mk-24 with aircraft-launched depth bombs show that attacks by depth bombs sank 9.5%
of the U-boats attacked, while the Mk-24 sank 22% of the U-boats when attacked.167
Other weapons used by MPA include unguided rockets and various machine guns.
The twin-engine aircraft, such as the PV-1 Ventura, utilized rockets based on the British
3.5-inch model. Weighing 55 pounds, and propelled by a powerful rocket motor, they
were effective to a depth of 60 feet. Capable of penetrating the tough pressure hull of a
U-boat, they proved highly effective when used by the smaller more nimble twin-engine
patrol aircraft.168
Though generally not capable of causing serious damage to the hull of a U-boat,
machine guns, such as the M2 50-caliber, were able to injury or kill exposed U-boat
crewmembers. In 1943, the M2 was upgraded to be able to fire 1,200 rounds per minute
and was designated the M3. To appreciate the ferocity of an attack by a patrol aircraft the
examination of a post-action report provides an illustration of the violence a U-boat
faced. Lieutenant L.D. Crockett of VP-204 submitted the report on 6 August 1943,
following the attack on U-615. Piloting a PBM-3S, Crockett dropped six depth bombs
166
E.W. Jolie, A Brief History of U.S. Navy Torpedo Development, Naval Underwater Systems Center
Technical Document 5436, 15 September 1978, Newport, Rhode Island, 36-37.
167
Jolie, 37.
168
Roberts, 692.
132
and his crew expended 700 rounds of 50-caliber ammunition.169 Part of a three plane
assault, the crew of U-615 was forced to scuttle their submarine following this swarming
attack.170
Beginning the war with old and obsolete weapons, the Navy quickly put into a
motion a series of developments that provided torpedoes, depth bombs, rockets, and
machine-guns that proved capable of sinking the U-boats of Nazi Germany. However,
for these new sensors and weapons to be effective, the Navy would need to develop
tactics and strategies that exploited these advanced capabilities.
The tactical use and control of the land-based patrol aircraft in the battle against
the U-boat threat underwent considerable changes in the first years of the war as Navy
and Army leaders clashed over these issues. Having its roots in the controversy of the
early 1920‟s, the American leaders struggled to resolve the problems of control and
tactical use.
At the strategic level, fundamental issue confronting the leaders of the Navy and
Army Air Corps was what was the best means of combating the U-boat threat? Admiral
Ernest J. King argued for a preventative approach to ASW by concentrating on the
protection of convoys and leaving offensive action to escorts vessels following attacks by
German U-boats. The Army Air Corps on the other hand, advocated an offensive
approach to the ASW problem, one that sought to seek out and attack the U-boats
wherever they were and destroy them before they attacked.171
169
Antisubmarine Action by Aircraft (ASW-6) report completed LT. Crockett.
http://www.uboatarchive.net/U-615ASW-6Crockett.htm.
170
The other two aircraft were a PV-1 Ventura and a B-18 bomber.
171
Ladislas Fargo, The Tenth Fleet (New York: Ivan Obolensky, Inc., 1962), 103
133
This philosophical difference reached a critical state when in early 1942, RearAdmiral John H. Towers, chief of the Bureau of Aeronautics, requested that
approximately 200 B-24‟s, 900 B-25‟s and B-26‟s be transferred to the Navy. On 14
February 1942, a formal request by Admiral King to the Chief of the Army Air Forces,
General Henry H. Arnold, for 400 B-24‟sand 900 B-25 bombers.172 This request was
unacceptable to Army leaders, as they believed that the proper role of heavy and medium
bombers was offensive in nature and the Navy‟s defensive doctrine was an improper
utilization of these critical war assets. According to Air War Plans Division Plan 1
(AWPD-1), the air activities in the various theaters were subordinate to the strategic bombing
campaign of Germany.173
According to King, convoying represented the best approach to defeating the
submarine threat. Espousing a concept called “convoy vicinity” King believed that all
surface craft and aircraft whether flying from escort carriers or land-based should be
concentrated in and around the convoy. By enlarging this defensive area around the
convoys, King hoped to inflict more casualties on the U-boats as they pressed home their
attacks. The AAF, drawing upon the experiences of the British Royal Air Force Coastal
Command, believed the proper use of long-range land based aircraft was to search for
and destroy the submarine. While the Navy‟s doctrine was one of response to an attack
the AAF believed that given some sort of approximate position of a submarine a longrange aircraft should be sent to the spot for intensive search.174
Arthur B. Ferguson, “The AAF in the Battle of the Atlantic,” in vol. 1 of The Army Air Forces in World
War II, ed. Wesley Frank Craven and James Lea Cate (Washington D.C.: Office of Air Force History,
1983), 539.
173
Arthur B. Ferguson, “The Origins of the Combined Bomber Offensive,” in vol. 2 of The Army Air
Forces in World War II, ed. Wesley Frank Craven and James Lea Cate (Washington D.C.: Office of Air
Force History, 1983), 210.
174
Ferguson, 545.
172
134
Though at the strategic level there was a degree of differences, at the operational
level, in the summer of 1942, there was little real difference to the use of airborne ASW
assets. In the opening months of the war, Army ASW flights consisted of three basic
types, routine, special, and convoy escort. Army crews flew routine patrols in areas
where enemy action frequently occurred, special patrols in areas where a particular Uboat existed, and convoy escort flights provided cover for the convoys.175 An
examination of the Navy‟s ASW flights during the early months shows that the tactics
used were similar to those of the AAF.
An examination of the actions of VP-92 in the winter and fall of 1942 present an
excellent account of the employment of a typical patrol squadron in the opening stages of
the war.
Established as a seaplane squadron flying the PBY-5A at NAS Alameda on 26
December 1942, the Navy assigned VP-92 to PATWING-3 stationed at Naval Station
(NS) San Juan in March of 1942.176 Upon arrival in San Juan, the squadron was broken
into detachments and sent to Guantanamo Bay, Trinidad, and other islands including
Antigua, and St. Lucia.177 Initially there was no central command to coordinate the ASW
operations rather operations the individual detachments conceived and controlled locally.
VP-92 concentrated its operations on high-density shipping routes such as the Windward
Passage. In addition to these patrols of specific geographical areas, by the summer of
1942 VP-92 aircraft had begun to escort individual convoys.178
175
Ferguson, 553.
Roberts, 497.
177
Ibid.
178
Wayne H. Packard, Century of U.S. Naval Intelligence (Washington D.C.: Office of Naval Intelligence
and the Naval Historical Center, 1996), 99.
176
135
On the various types of flights flown by the crews, it was when escorting convoys
the probability of action was at its greatest as the German submarines pressed home their
attacks.179 One such encounter occurred on August 27, 1942, while escorting Convoy
TAW-15 en route from Trinidad to Key West, a PBY-5A, piloted by Lieutenant (Lt) G.
R. Fiss, dropped four 650- pound depth charges on the German U-boat, U-94.180
According to testimonies from the survivors, U-94 had been on the surface for an hour as
it stalked the convoy. Under the glare of a full moon, the submarine maneuvered into
firing position. Before it could fire however, LT Fiss began his attack run. As the
submarine attempted to escape by executing a “crash dive,” the PBY, piloted by Lt Fiss,
descended to 50 feet and released the four depth chargers. Set to explode at 50 feet, the
German survivors estimated the submarines depth to be between 30 and 60 feet when the
depth charges detonated. Forced to the surface the crew worked frantically to regain
control and once again submerge. As the German crew struggled with their damaged
craft the Canadian corvette, HMCS Oakville arrived on the scene and proceeded to ram
the German submarine three times. With their boat taking on water, the German crew
abandoned their submarine and surrendered to the Canadian boarding party.181
In the initial stages of the war, the primary method of detecting a submarine was
by visually means; unfortunately, the U-boat would frequently sight the aircraft first and
take evasive actions. An example of this occurred on 12 June 1942, when a B-17E,
piloted by Lt Arthur H. Tuttle of the second Bombardment Group (H) based at Langley
179
Once a convoy was located, wolf-boat tactics dictated the concentration of numerous submarines against
it.
“Report on the Interrogation of the Survivors form U-94, Sunk on August 27, 1942 (Washington D.C.:
Navy Department, Office of Chief of Naval Operations, O.N.I. 250-G/ Serial No.5, September 16, 1942),
Chapter XIII, p. 1.
181
Report on the Interrogation of the Survivors form U-94, Sunk on August 27, 1942, Chapter XIII, p. 2.
180
136
Field, Virginia sighted a large wake produced by the periscope of a German submarine.
Descending to 200 feet, he dropped a row of six bombs on a 30˚ angle diagonally across
the bow of the submarine. Spaced 50 feet apart, with the midpoint of the row only 100
feet ahead of the periscope, barring any unexpected changes, the attack should have an
excellent chance for success. Unfortunately, for the American crew as they approached
the target, the submarine‟s wake disappeared seconds before the attack and the submarine
managed to escape the attack.182
In the early years of the war, missions, such as those of Lt Tuttle, were common.
Frequently attacks failed to achieve the desired results and the U-boat managed to escape.
To increase the likely-hood of success, detailed post-flight analysis of the attacks became
a standard practice. The post-flight analysis of Tuttle‟s attack shows that in the 16
seconds that transpired prior to the attack the U-boat at full speed of 8 knots would have
traveled 208 feet and at 5 knots 133 feet. At 8 knots the No. 2 bomb was 44 feet away
from the target, the No. 3 was 20 feet away, and the No. 4 was 36 feet away. It the
submarine maintained a speed of 5 knots then the No. 2 was 21 feet away, the No. 3 was
19 feet away, and the No. 4 was 42 feet away. At neither assumed speed was there a
bomb within the lethal radius of the weapon.183 A difference of 5 seconds permitted the
U-boat to escape. While these reports were highly complex, they were critical to the
development of new tactics and equipment.
“Report on Bombs Dropped, Post action report to Commanding Officer, 2nd Bombardment Group (H),
Langley Field, Va., Analysis of Attacks made by Lt Tuttle, B-17E, 2nd Bomb Group, at 1150, 12 June, 42,
position 3524N, 7506W, Office of the S-2 Officer. http://www.uboatarchive.net/U-701TuttleAttack.htm.
183
“Report on Bombs Dropped, Post action report to Commanding Officer, 2nd Bombardment Group (H),
Langley Field, Va., Analysis of Attacks made by Lt Tuttle, B-17E, 2nd Bomb Group, at 1150, 12 June, 42,
position 3524N, 7506W, Office of the S-2 Officer.
182
137
In these early years, there was no coordinated effort by American forces to defeat
the German submarine forces. To resolve this perplexing issue, on 10 June 1943, Rear
Admiral John S. McCain met with General Arnold and Lt General Joseph T. McNarney
in an effort to reach a comprehensive agreement between the two services. The
agreement stated that the Army was prepared to withdraw the AAF from antisubmarine
operations and turn their antisubmarine configured B-24‟s over to the Navy. In effect, the
Arnold-McNarney-McCain agreement constituted a division of responsibility in the
employment of long-range aircraft. The Navy relinquished all claims to control of longrange striking forces operating from shore bases and the Army turned all forces employed in
reconnaissance, offshore patrol, and protection of shipping to the Navy.184
While Navy and Army officials attempted to reconcile the question of responsibility,
losses continued to mount. On 20 May 1943, the Navy established the Tenth Fleet, an
organization formed specifically to counter the German offensive.185 Under the command of
Admiral Francis Low, the Tenth Fleet was to exercise control over all American
antisubmarine warfare operations in the Atlantic. Along with operational control, the Tenth
Fleet oversaw the introduction of new technologies and their use.186
By late summer of 1943, the Navy began deploying patrol squadrons to Britain to
aid the British Coastal Command in its battle in the Bay of Biscay and the southwest
approaches to the English Channel. To support this mission the Navy sent three
squadrons, VBP-103, 105, and 110 to Great Britain. The Navy augmented the initial
Arthur B. Ferguson, “The Antisubmarine Command,” in vol. 2 of The Army Air Forces in World War
II, ed. Wesley Frank Craven and James Lea Cate (Washington D.C.: Office of Air Force History, 1983),
406-407.
185
Farago, 67.
186
In June 1945, the Navy disbanded the Tenth Fleet.
184
138
force with the addition VBP-112 and 114.187 These squadrons flew the PB4Y-1 Liberator
equipped with the APS-15 radar, LORAN, sonobuoy receiver, and provisions to carry the
Mark 24 Mine.188
These five squadrons operated under the command and control of the British
Coastal Command, who used all available intelligence sources in scheduling the patrol
flights. The patrol areas were small, and centered on a very specific to location.189 In the
later part of 1943, the Germans had elected to fight it out on the surface instead of
submerging when detected by a patrol aircraft. This led to prolonged and fierce battles
between the two. On 10 November 1943, VBP-103 participated in one of the longest
surface battles between an aircraft and surfaced U-boat.190
This historical battle began when a RAF aircraft notified a VBP aircraft, piloted
by Lt. L.E. Harmon of a radar contact near the coast of Spain. Harmon and his crew soon
located the German submarine U-966 on the surface and proceeded to make two strafing
attacks. The submarine, commanded by Oberstleutenant Eckehard Wolf, returned fire,
damaging Harmon‟s aircraft and forcing him to break off the attack. A British fighter
arrived on the scene and made an attack run at which time Harmon and his crew made a
third strafing attack but had to break off afterwards due to a fuel shortage.
Lieutenant K.L. Wright, of VB-103, located U-966 near Ferrol at 1040, and
delivered a strafing and depth charge attack. Again, intense anti-aircraft fire from the
German submarine force forced the Americans to withdraw. Low on fuel Wright‟s plane
187
Wyman, 99. These five squadrons were under the administrative command of Fleet Air Wing 7 (FAW7). Each of these squadrons was to undergo numerous changes to their alphanumeric designation. In 1943
the designation for patrol squadrons changed from VP, to VB (bombing squadron), and in 1944 they
underwent and additional change to VBP (patrol bombing squadron). The final designation will be used
throughout this section
188
Roberts, 507. VBP-103 was the first squadron to be equipped with these various ASW systems.
189
Wyman, 99.
190
Roberts, 509.
139
left the scene. At this time, Lieutenant W. W. Parish and crew then arrived on the scene
along with a British Liberator and at 1230 made the final attack on U-966. Under the
onslaught of combined attack of depth charges and rockets, the Germans abandoned their
sinking submarine.191
Most attacks conducted by American patrol aircraft during World War II were
with either standard aerial bombs or depth bombs, however the development of the
acoustic homing torpedo demonstrated a new a more potent method of attack. The first
successful attack utilizing the Fido homing torpedo occurred on 14 May 1943, when a
PBY-5A, attached to VP-84 sank the German submarine U-640. Piloted by Lt. P.A.
Bodinet, the attack occurred off Iceland killing all 49 members of the German crew.192
By 1945, the Germans, with their snorkel equipped submarines, had altered their
tactics, and no longer attempted to slug it out on the surface. With the use of the snorkel,
they hoped to be able to transit the dangerous waters west of Brest in the Bay of Biscay
It was on 25 April 1945, while using the snorkel in an attempt to evade Allied airpower
that a PB4Y-1 Liberator from VPB-103 attacked and destroyed U-326.
While on patrol in the Bay of Biscay, the crew of the Liberator, under the
command of Lt Nott spotted the wake of a snorkel. Dropping a salvo of torpedoes on top
of the unsuspecting submarine, the airdropped, acoustic homing torpedoes quickly found
their mark and struck the submarine, blowing the snorkel into the air. All that remained
was a large oil slick and the body of a single German submariner.193 Along with the Bay
of Biscay and the waters around the English Channel, the Americans also conducted
offensive ASW flights in the area surrounding the Straits of Gibraltar. It was here in
191
Roberts, 508.
Ibid., 706. According to post-mission reports, the attack took place at 60˚ 10'N, 31˚ 05'W.
193
Ibid., 710.
192
140
February 1944 that VPB-63, the Mad Cats, flying the PBY-5A, conducted a highly
successful ASW campaign against U-boats as they attempted to enter the Mediterranean
Sea.
Initially deployed to RAFB Pembroke Dock, South Wales, on 22 June 1943 for
operations with the RAF 19 Group Coastal Command, under the operational control of
FAW-7, VPB-63 was the first American patrol squadron to operate from the United
Kingdom.194 As the year ended, it soon became apparent to Navy authorities that U-boat
hunting in the Bay of Biscay was no longer productive and a waste of the squadron‟s
MAD equipment. In a decision that combined tactics with technology, VPB-63
transferred to Port Lyautey in French Morocco.195
Soon after arriving in North Africa, VPB-63 established a two-aircraft barrier
patrol between the southern tip of Spain and the tip of Spanish Morocco. The crew flew
the patrols at an altitude of only 50 feet from dawn to dusk regardless of the weather
conditions. Beginning the patrols on 8 February 1944, the squadron soon achieved a
remarkable degree of success against the German submarines.196
On 24 February, in the late afternoon, two PBY-5s, 63-P-15 and 63-P-14, piloted
by lieutenants Howard Baker and T.R. Woolley detected and tracked U-761 with their
MAD equipment. At 1559, ARM2c J.A. Cunningham Jr. received a MAD contact from a
submerged submarine. Lt (jg) Woolley, piloting 63-P-15, immediately marked the
location of the contact with Mark V float lights and commenced a cloverleaf-tracking
pattern.197 Soon joined by Lt (jg) Baker in 63-P-14, both aircraft began flying the
194
Roberts, 486.
Ibid., 764.
196
Ibid., 487.
197
ASW-6, Report of Anti-submarine Action by Aircraft, 24 February 1944. Report No. 6, VP-63.
195
141
cloverleaf pattern, marking each MAD with float signals, the course of the submarine was
quickly determined.
What occurred next was to hinder ASW operations between surface ships and
aircraft to this very day.198 Having localized the submarine, the British destroyer, H.M.S.
Anthony approached the area from a position two miles west of the point of contact.
Soon, the destroyer was within the cloverleaf pattern and posed a serious hazard to the
two aircraft, which were flying at 100 feet. After several attempts to continue tracking
the submarine, the aircraft broke off their pattern in order to avoid colliding with the
British destroyer. Both aircraft requested by voice communication for the H.M.S.
Anthony to remain in the area but to stay clear of the tracking. The destroyer reported it
had gained ASDIC contact and was going to attack.199 Unfortunately, the destroyer
headed for the wrong end of the line of floats and when promptly informed by Lt (jg)
Baker the destroyer turned in an attempt to position itself for attack at which time lost
ASDIC contact.200
As the destroyer departed the immediate area, the crews commenced to search for
the submarine once again. After several cloverleaf passes, Lt (jg) Woolley elected to use
a spiral search pattern in an attempt to regenerate contact. The spiral pattern is essentially
an expanding circle with an increasing diameter with the last known position of the
submarine as the starting point. On the sixth turn of the spiral, Woolley‟s crew regained
magnetic contact approximately one mile south-southeast of its previous contact.201
198
The inability to coordinate the efforts of various ASW platforms continues to plague the United States
Navy.
199
The acronym used for the active sonar system mounted on board destroyers. The name came from the
initial letters of the Allied Submarine Detection Investigation Committee.
200
ASW-6, Report of Anti-submarine Action by Aircraft, 24 February 1944. Report No. 6, VP-63
201
Report No. 6, VP-63
142
With both aircraft work in concert, the crews soon established the submarine‟s
course and position well enough to execute an attack run. Announcing his intentions to
attack, at 1656, after almost two hours of intense flying, Lt(jg) Woolley fired 23 retrobombs on a strong MAD contact.202 Two minutes later, Baker made his attack, launching
another 24 retro-bombs.203 Twenty seconds after Baker‟s attack, the H.M.S. Wishart,
having joined the battle, dropped ten depth charges on submarine‟s position, followed by
an additional ten depth charges by H.M.S. Anthony.
A few minutes later, following this combined attack, the conning tower and bow
of the U-boat broke the surface. Arriving on the scene was a British Catalina from RAF
Squadron 202 and a PV-1 Ventura of VB-127. Depth charges from both the Ventura and
the Catalina straddled the U-boat and at 1720, the U-boat exploded and sank.
This combined effort of aircraft and surface ships demonstrated that when
properly employed the U-boat stood little chance at escaping. This the first of three
combined attacks made by VPB-63 and destroyers that resulted in the Germans
abandoning any effort at entering the Mediterranean Sea.
By 1945, airborne ASW operations had developed into a fine art, no longer
preformed in a haphazard manner; the need for written procedures was now at hand. In
January 1945, the Navy published the tactical manual United States Fleet Anti-submarine
and Escort of Convoy Instructions established detailed procedures for the conduct of antisubmarine warfare and the duties of a convoy escort.204 The manual consisted of seven
202
The attack run was made at 100 feet and 109 knots ground speed.
Report No. 6, VP-63
204
The official designation of this manual was F.T.P. 223(A) United States Fleet
Anti-Submarine and Escort of Convoy Instructions, 1945.
203
143
parts, each part dedicated to a specific aspect of the mission, with Part I dedicated to
surface craft, Part II to aircraft, and Part III to joint air-surface operations.205
This manual established procedures and tactics still used in the 21st Century. A
key element to the development of tactics and procedures was the ASW-6 report. The
crew following an encounter with a U-boat submitted this report. Using the report to
evaluate the tactics employed during the encounter and the success or failure of the
attack, authorities were then able to validate the procedures employed.
Addressing all aspects of airborne ASW in Part II, the manual set forth tactical
procedures for the use of passive sonobuoys, MAD, and radar. The use of nomographs
allowed for quick, easy, and accurate decision-making. These detailed procedures
demonstrated the change in ASW from its amateurish beginnings to a more scientific form
of warfare in the closing years of the war.
An example of this is the procedures for deploying a sonobuoy pattern on a
submarine after it had submerged. The pilot would proceed to the last known position of
the submarine with the directional gyro set to 000˚ and drop the first sonobuoy 1,500
yards prior to reaching this point. Continuing on course, the crew dropped the second
sonobuoy was on the submarine‟s last known position frequently referred to as the datum
and continued on course for an additional 1,500 yards to drop the third sonobuoy of the
pattern. The pilot would commence a 270˚ turn to the left holding the turn until reaching
a heading of 090˚ at which time the crew dropped the fourth sonobuoy approximately
1,500 from the second sonobuoy. Flying over the datum, the crew proceeded outbound
another 1,500 yards dropping the fifth and final sonobuoy of the pattern.206 With the
205
206
F.T.P. 223(A), iii.
Ibid., 2-25.
144
submarine contained in the pattern, it was possible to develop a course and speed, which
allowed the crew to attack the submerged submarine with either depth bombs or a
homing torpedo.
MAD tactics were equally refined with patterns such as the “glover-leaf” and the
“3-minute hunting circle” in use by the end of the war. Designed to respond to a specific
tactical situation, standardized responds ensured a greater opportunity of success. The
crew used a cloverleaf pattern if it there was a need to track a submerged submarine,
while the hunting-circle was flown around a datum and quickly generated a course and
speed, allowing for a rapid attack.207
In the opening stages of the war, airborne ASW tactics consisted of little more
than a visual search of a given area with the hope of stumbling upon a submarine while it
was surface. Attacks were haphazard, requiring a great degree of luck to be successful.
With the introduction of new sensors, and weapons game the need to find ways to employ
these new and improved capabilities. It was due to ASW-6 reports, manuals like the
F.T.P. 223, and organizations such as the National Defense Research Committee that the
Navy‟s antisubmarine warfare squadrons developed and employed tactics that defeated
the German U-boat.
When evaluating the impact of the maritime patrol aircraft in the war against the
German U-boat, it is necessary to realize that the MPA was but one part of an ASW team
and as with any team effort, it takes all its parts to be successful. Numbers alone do not
tell the complete story. No was this more true than when examining the Navy‟s efforts in
207
F.T.P. 223(A), 2-27, 2-28.
145
the Bay of Biscay in 1943 and the efforts of FAW-7.208 From September to November of
1943, the wing flew 6,518 hours, loosing nine aircraft to enemy combat or accidents,
while only being credited with a single U-boat kill.209
Prior to the development of the snorkel, during the summer of 1943, Admiral
Dönitz ordered his U-boat crews to remain on the surface and defend themselves with
anti-aircraft fire.210 During its battles with the German submarine force, the Navy lost 57
aircraft to U-boat antiaircraft fire, while during these encounters sinking only twelve, a
ratio it would seem to favor the Germans.211 This however is a misconception as the
combined offensive and defensive warfare practiced by the Allied forces soon
demonstrated that the German concept of submarine operations was doomed to failure.
It was with the addition of large long-range aircraft such as the B-17, Flying
Fortress, the PB4Y-1 Liberator, and the PB4-Y2 Privateer, combined with technologies
such as centimeter-wavelength radar, Allied airpower began to make significant inroads
into controlling the submarine threat. By the end of the war, land-based maritime patrol
aircraft sank 307 German submarines unassisted, an astonishing 37% of all kills.212
In the early years of the war, the Germans based their submarine operations upon
the concept that submersibles would operated on the surface while remaining mainly
stationary while submerged.213 Transiting to and from their operating areas on the
surface and using their superior surface speed to intercept their targets, the submarine
submerged only as a last resort to evade detection.
208
Roberts, 812. The Navy established FAW-7 as Patrol Wing Support Force on 1 March 1941. The Navy
changed the designated to FAW-7 on 1 November 1942.
209
Blair, 419.
210
Prince, 152.
211
Roberts, 812.
212
Blair, 709.
213
Werner Rahn, “German Naval Power in the First and Second World Wars,” in Naval Power in the
Twentieth Century, ed. N.A.M. Rodger (Annapolis: Naval Institute Press, 1996), 96.
146
While this concept had merit in the opening, stages of the war, by 1943, the tide
had turned against the German forces. New long-range aircraft, sensors, and weapons
soon rendered the U-boats vulnerable to airborne attack. Forced to travel submerged,
even when equipped with the snorkel, the submarine of the era was no longer capable of
offensive operations.
The Navy was ill prepared to confront the German submarine assault in 1942.
Through the early years, there were struggles of doctrine, technology, operations, and
inter-service rivalries. However, the various political, military, and scientific leaders
soon found solutions to these problems. With the introduction of improved aircraft,
sensors, weapons, and tactics, the combined forces of the Allies forced the German
submarine force from the sea.
147
Cold War
Cold War
The end of World War II saw the United States in possession of the largest and
most capable navy the world had ever seen, but the total victory achieved saw the
elimination of the primary reason for the Navy‟s existence, the destruction of the Imperial
Japanese fleet. In its search for a mission, the Navy redirected its attention to Europe and
the growing power of the Soviet Union.
As the Navy sought new missions in the Mediterranean Sea and the waters in and
around Europe, the Navy confronted a far more dangerous enemy at home. The end of
the war and the use of the atomic bomb radically changed long held beliefs with regard to
national security and the various missions assigned to the Army and the Navy. With its
drive for independence, the leaders of the Army Air Force (AAF), fought once again for
control of all land-based aircraft and the ASW mission.
At the close of World War II, there was a desire by many to see the creation of an
independent air force. There were those both in and out of uniform that saw no need for
traditional military forces as the atomic bomb made all older forms of warfare obsolete.
Wars could be won with by dropping a handful of atomic bombs and the mere possession
of such weapons would deter any would be opponent. The proponents of strategic
bombing pointed to the conclusions found in the U.S. Strategic Bombing Survey of the
European and Pacific War as proof to the power of the large manned bomber. The
authors summarized the newfound power of the atomic bomb by stating that given
sufficient numbers of B-29 bombers, the Army Air Force could have destroyed every
Japanese city in excess of 30,000 people in a single day.1
1
The United States Strategic bombing Survey, Summary Report (Pacific Report), July 1,, 1946
(Washington D.C.: United States Printing Office, 1946), 31.
148
Throughout 1946, the future of the Navy‟s maritime patrol aircraft was in doubt.
General Carl Spaatz, the commanding General of the Army Air Forces, believed that the
AAF was capable of providing the land-based component used in conducting
antisubmarine warfare.2 Other military leaders, such as General of the Army Dwight D.
Eisenhower held the belief that the AAF should control all functions requiring the use of a
land-based aircraft. On 15 June 1946, President Harry Truman issued a letter that placed
the future of the Navy‟s land-based ASW aircraft in further jeopardy by stating that:
Land-based planes for naval reconnaissance, ant-submarine warfare, and
protection of shipping can and should be manned by Air Force personnel.3
With the support of President Truman, the possibility of the Navy losing its land-based
maritime patrol aircraft was real and it would take the combined efforts of Secretary of
War Robert P. Patterson and Secretary of the Navy James V. Forrestal to forester a
compromise acceptable to all.
As political and military leaders struggled with the establishment of an
independent air force, matters of money took central stage. When the Chief of Naval
Operations (CNO) Admiral Arthur W. Radford requested funding for new P2V Neptune
and the P5M Marlin, General Spaatz was highly critical of the request as he believed that
specialized aircraft were not need and that the Navy should consider using the B-29
Superfortress.4 Unwilling to bow to the pressures exerted by AAF leaders and various
political leaders, Navy leadership fought to retain these critical ASW assets and in March
1947, Spaatz agreed to the Navy‟s demands.
2
Jeffery G. Barlow, Revolt of the Admirals, the Fight for Naval Aviation, 1945-1950 (Washington D.C.:
Naval Historical Center, Department of the Navy, 1994), 33.
3
Ibid., 37.
4
Ibid..
149
On September 18, 1947, the Department of the Air Force was established when
President Truman signed the National Security Act of 1947.5 Though, there was to be
considerably more inter-service fighting in the years to come, the future of the maritime
patrol aircraft and the ASW mission was resolved. The Navy was to control and
coordinate the ASW effort in the Cold War.
In the years immediately following the end of World War II, under the leadership
of Joseph Stalin, the Soviet Navy adopted a policy that combined the elements of a
“fortress fleet” and a “fleet in being.” The “fortress fleet” consisted of the Soviet Navy‟s
Coastal Defense Service that consisted of coastal artillery, fortifications, antiaircraft
artillery, naval infantry, shore-based fighter aircraft, and coastal patrol craft. The “fleet
in being” was to consist of destroyers and cruisers that would operate in a strategically
defensive but tactically offensive nature.6 Ultimately, these destroyers and cruisers were
to serve as screening and supporting elements to Soviet carrier task forces. However,
following the death of Stalin in March of 1953 the Soviet Navy was to see its structure
and mission undergo a series of profound changes.
With Nikita Khrushchev assuming the reins of power, the leadership of the Soviet
Navy underwent a radical change with the replacement of Admiral Nikolai G. Kuznetsov
with Admiral Sergei Gorshkov. Kuznetsov, a Stalin appointee, was a believer in a
balanced fleet, while Gorshkov, in attempt to gain the support of Khrushchev and other
party leaders, advocated the use of missile technology in naval developments.7 This shift
to missile technology was critical to the survival of the Soviet Navy as Khrushchev held
5
Warren A. Trest, Air Force Roles, and Missions: A History (Washington D.C.: Air Force History and
Museum Program, 1998), 114.
6
Robert Waring Herrick, Soviet Naval Strategy, Fifty Years of Theory and Practice (Annapolis: United
States Naval Institute, 1968), 61.
7
Ibid., 70-71.
150
the Navy in low esteem. However, by merging missile technology with the submarine,
Gorshkov convinced Khrushchev of the practical need of the Soviet Navy and ensured its
future growth.8
Under the guidance of Admiral Gorshkov, Soviet research focused on the naval
application of guided missiles to provide a nuclear offensive capability for their
submarines, nuclear propulsion, and other technologies needed to defend the Soviet
homeland from American carrier-based nuclear-armed aircraft.9 During the post-war
period, the Soviet submarine force underwent two stages of development, which resulted
in extraordinary improvements to the war fighting capability of the Soviet Navy.10
Tactical and technical improvements of the diesel submarine were the primary
focus of the first stage. Building on knowledge obtained from captured German Type
XXI class submarines, the Soviets avoided years of research and development as they
strove to improve their submarine fleet. Improvements included increases in speed,
endurance, and operating depth. Additionally sonar, radar, and communications
equipment saw an increase to their capabilities.
The second stage of development saw the introduction of nuclear power as the
primary propulsion source. Nuclear power ushered in the first true submarines, vessels
designed to operate under the water continuously unlike the early diesel submarines.
With their high-submerged speeds, and unlimited endurance, the submarine, coupled with
nuclear propulsion revolutionized the art of naval warfare.
8
Paul H. Nitze, Leonard Sullivan Jr., and the Atlantic Council Working Group on Securing the Seas,
Securing the Seas, the Soviet Naval Challenge and the Western Alliance Options (Boulder: Westview
Press, 1979), 38-41.
9
Ibid., 38.
10
Sergei Gorshkov, The Sea Power of the State (Annapolis: Naval Institute Press, 1976), 191.
151
Along with advancements in propulsion came the introduction of cruise and
ballistic missiles. These weapons changed the basic mission of the submarine. No longer
just a commerce raider, the introduction of the ballistic missile, with its nuclear warhead,
the submarine was now a strategic weapon, capable of destroying whole cities. Cruise
missiles allowed submarines to strike from great distances, placing American carrier task
forces in serious peril.
Throughout the Cold War, the Soviet Union elected to continue building both
nuclear and diesel powered submarines. Designed to perform one of three basic missions,
general mission submarines were designated SS / SSN if nuclear powered. Submarines
whose primary weapon was the cruise missile were designed SSG / SSGN, while the
ballistic missile armed submarines were designated SSB / SSBN.11 With its numerous
classes and types of submarines, the Soviet Navy presented a serious challenge to the
ASW forces of the United States and its allies.
The first three classes of submarines constructed by the Soviet Union following
the World War II were the Whiskey, Zulu, and Quebec diesel submarines.12 Of the three,
the Quebec class represented an innovative and daring design. The Quebec was a small
coastal submarine with an overall length of 185ft 4.5 in and a submerged displacement of
460 tons. Designed to initially to use the Kreislauf closed-cycle diesel system for power,
it was to have a submerged speed of 16 knots. The Kreislauf closed-cycle process
recovered unburned fuel and unused oxygen from the diesel exhaust gases. Mixing these
gases with small amounts of stored liquid oxygen permitted the use of diesel engines
The “N” denotes nuclear power. Cruise missiles fly at relatively low altitudes and are primarily tactical
weapons. The ballistic missile flies a profile that takes them out of the earth‟s atmosphere and is a strategic
weapon.
12
The US/NATO code names used phonetic letters to indicate class designations.
11
152
while submerged. While an ingenious system, it proved to be highly dangerous, earning
the nickname of zazhigalka (lighters) or Zippos by their crews. After several accidents,
the Soviet authorities replaced the Kreislauf system with a standard diesel engine.13 This
represented the last attempt by the Soviet Union to produce an air-independent propulsion
system as all remaining diesel submarines utilized the conventional diesel engine for
surface operations and lead-acid batteries while submerged.
While the Quebec class explored new technologies, the Whiskey and Zulu class
submarines represented a continuation of older, more reliable systems. Both the Whiskey
and Zulu class submarines were conventionally powered diesel-electric submarines and
incorporated several features of the German Type XXI.14 Powered by diesel engines
while surfaced or snorkeling, lead-acid batteries provided electrical power while
submerged. Assigned the mission of anti-surface warfare, their primary weapon was the
torpedo.
The Whiskey was classified a medium-range submarine with a displacement of
1,050 tons surfaced and 1,350 tons submerged and had an operational range of 12,00015,000 nautical miles and had an endurance of approximately 40-45 days.15 Equipped
with two diesel engines, driving two shafts, the Whiskey had a surfaced speed of 17 knots
and a maximum submerged speed of 13.5 knots.16 With six 21-inch torpedo tubes, four
were located in the bow and two in the stern, the Whiskey class was capable of carrying
only twelve torpedoes. Built at the Gor'kiy, Baltic, Komsomol'sk, and Nikolayev/south
13
Norman Polmar and Jurrien Noot, Submarines of the Russian and Soviet Navies, 1718-1990 (Annapolis:
Naval Institute Press, 1991), 150, 284.
14
Ibid., 148 and 281.
15
Ibid., 280. The Whiskey class was first observed in the Leningrad area in July 1950.
16
Ibid., 281. While most diesel submarines are capable of submerged speeds of 13 to 21 knots, they are
unable to maintain this speed for only an hour. The faster the speed the quicker, the battery would be
depleted, forcing the submarine to either surface or utilize its snorkel.
153
shipyards, the 236 units of the Whiskey class represented the largest single class of
submarine built in the Cold War era.17 Additionally the Soviet Union exported this
submarine to Albania, Bulgaria, China, Egypt, North Korea, Poland, and Syria.18
The Zulu class was the first long-range submarine constructed by the Soviet
Union following World War II.19 With its three shafts, and three diesel engines, the Zulu
displaced 1,900 tons surfaced and 2,350 tons submerged and was capable of conducting
patrols of sixty days. Equipped with ten torpedo tubes, six forward, four aft, and a
weapons load of twenty-two torpedoes, the Zulu class would have made a formidable
commerce raider in World War II. With a maximum surfaced speed of 18 knots and a
submerged speed of 16 knots, it would have been capable of intercepting any convoy of
World War II.20
As with all other Soviet submarines of the post-war era, the Whiskey and Zulu
were equipped with radar and electronic support equipment. Both utilized the Snoop
Plate surface-search radar and the Stop Light electronic support system. The Snoop Plate
radar allowed for detection of surface contacts out to the horizon while Stop Light was
capable of detecting radar signals from potential foes allowing the submarine to
submerge prior to detection.21
Following the construction of the Whiskey and Zulu class, the Soviet Navy
commissioned four more classes of diesel attack submarines. The first of these was the
17
Polmar, 145, 281. The Soviet Navy used two sizes of torpedo tubes, the 21 inch / 53 centimeter tube, or
the 26 inch / 65 centimeter tube. Unless other wised noted, all references to torpedo tubes will be the 21
inch / 53 cm size tube.
18
Ibid., 340-341.
19
Ibid., 283. The soviet Navy launched the first of 26 units of the Zulu class in 1952.
20
Ibid.
21
Ibid., 281, 283.
154
Romeo class a medium range submarine designed to replace the Whiskey class.22
Though similar to the Whiskey in performance, the Romeo class had eight torpedo tubes
vice the six of the Whiskey. Its engineering plant was similar the Whiskey with two
engines driving twin shafts23
The Foxtrot with its long range of 20,000 nautical miles and a submerged
endurance of ten days at slow speeds replaced the earlier Zulu class.24 Like the Zulu, the
Foxtrot utilized three diesel engines and three shafts for propulsion, with later units using
a diesel-gear reduction system in lieu of the diesel-direct drive system used by previous
classes of submarines.25 Other improvements included new surface search radar, the
Snoop Tray. The Soviet Navy took delivery of sixty-two units, with seventeen built
specifically for foreign transfer.26
The final two diesel attack submarines built for the Soviet Navy were the Tango
and Kilo class.27 The Tango was the culmination of the Zulu and Foxtrot class
submarines. With a displacement of 3,200 tons surfaced and 3,900 tons submerged, the
Tango class was half again as large as the Foxtrot.28 With a maximum submerged speed
of 16 knots and the ability to remain submerged for up to two weeks at slow speeds, the
Tango was formidable foe.
22
Between 1958 and 1961, the Soviet Navy launched twenty Romeo class submarines.
Ibid.
24
Ibid., 286. The first hulls entered service in 1958 and the last of these hulls launched in 1973.
25
Ibid., 287. In an attempt to operate both the propeller and engine at their most efficient speeds, Soviet
engineers used a series of reduction gears. Earlier classes used a direct-drive system, resulting in the
propeller operating at too high of a speed.
26
Ibid., 286-287. The following countries took procession of Foxtrot class submarines: Cuba, India, and
Libya.
27
Ibid., 290, 292. The first Tango class were launched in 1972, and the Kilo class in 1982.
28
The Foxtrot had a surfaced displacement of 1,950 tons and a submerged displacement of 2,400 tons.
23
155
The last diesel submarine constructed for the Soviet Navy was the Kilo class.
Unlike previous diesel submarines, the Kilo class incorporated the Albacore hull form.29
Used to improve submerged performance, this new hull form resulted in the Kilo‟s
submerged speed being greater than its speed on the surface unlike previous diesel
submarines built by the Soviet Navy.30 Equipped with six torpedo tubes, all located in
the bow, and a low frequency active sonar design to detect other submarines, the Kilo
represents a significant change in capabilities over earlier diesel submarines.
Recognizing the inherent limitations to all diesel submarines, the Soviet leadership
elected to use the Kilo in chokepoints and as a floating minefield. The Kilo, like a spider
would sit quietly and allow its enemy to come to them rather than attempting to track
them down.
While the capabilities of the diesel submarines improved in the post-war era, their
fundamental weaknesses remained the life of the battery and its ability to provide power
limited the diesel submarine‟s actions. To remain submerged meant a slow speed of
advance a high speed would quickly deplete the battery forcing the submarine to the
surface in order to recharge the batteries, thus exposing it to detection by ASW forces. To
compound this problem, the primary weapon of these submarines was the torpedo, a
short-ranged weapon that required the submarine to close with its target.
The 53-51 was the first torpedo to enter service in the postwar era. The torpedo
had a top speed of 51 knots but a range of only 4,000 yards.31 To further compound the
29
The Albacore hull referrers to a teardrop hull form pioneered by the United States Navy.
Polmar, 292. The Kilo has a reported submerged speed of approximately 20 knots, while its top speed
while surfaced is approximately 12-14 knots.
31
Norman Friedman, The Naval Institute Guide to World Naval Weapons Systems, 1991/92 (Annapolis:
Naval Institute Press, 1991), 702. The Soviet Navy used various acronyms to identified various models and
makes of torpedoes. For example, ET-46, the "ET" denotes that this was an electrical torpedo and the
number "46" the year it was introduced to the fleet. SAET identified the torpedo as a “guided acoustic
30
156
submarine‟s problems, the weapon had no ability to home in on its potential victim.32 It
was not until 1950 that the SAET-50, first Soviet homing torpedo outfitted with a passive
seeker and an electromagnetic exploder, became operational.33 The SAET-50 had a top
speed of 21.5 knots and a range of 7,650 yards. The torpedo was capable of being set to
either a sector or circular search pattern. Its performance was marginally less than the
ET-46 but due to its ability to home-in on its target, greatly enhanced the probability of
hitting the target.34
In the mid 1960s, with the introduction of the SAET-60 and the 53-65 the Soviet
submarine fleet had truly become equipped with effective anti-ship torpedoes. The
SAET-60, entering service in 1965-66 was the Soviet‟s first anti-ship homing torpedo.
Electrically powered, the SAET-60 had a maximum speed of 35 knots and an effective
range of 16,400 yards.35 With the ability to passively home on to its target, the SAET-60
was an excellent anti-ship weapon. The 53-65 introduced new propulsion and guidance
system. In order to achieve higher speeds, Soviet engineers turned to a semi-closed-cycle
thermal system that reused exhaust gas. This resulted in the 53-65 achieving a maximum
speed of 55 knots at a range of 15,300 yards. At 40 knots, this weapon had a range of
26,200 yards.36 Utilizing a waking-homing guidance system, the 53-65 was the first
Soviet thermal torpedo capable of homing.37
electrical torpedo.” Torpedoes identified by numbers such as the 53-61 indicates it is a 53 cm weapon,
introduced in 1961, and thermally powered.
32
Russian / USSR Torpedoes, http://www.navweaps.com/Weapons/WTRussian_post-WWII.htm
33
Russian Military Analysis, WARFARE.RU http://warfare.ru/?linkid=1728&catid=267
34
Friedman, 703.
35
Richard Sharpe, ed., Jane’s Fighting Ships, 1998-99 (Alexandria: Jane‟s Information Group Inc., 1999),
546.
36
Friedman, 703.
37
Ibid.
157
In 1981, the Soviet Union introduced the 65-80. A massive weapon it was 65
centimeters in diameter, it had a remarkable range of 54,000 yards at 50 knots.38 With its
waking-homing capability and massive 1980-pound warhead, this weapon posed a grave
threat to the largest of naval warships. Due to its massive size, only second and third
generation nuclear powered submarines were capable of utilizing this potent weapon.
Though these torpedoes represented great improvements over earlier weapons,
they were still relatively short-range weapons and when used by diesel submarines, were
only marginally more lethal than those used during World War II. The first revolutionary
improvement to the submarine occurred with the development of cruise and ballistic
missiles. Using the proven designs of their diesel submarine fleet, Soviet engineers
undertook the job of incorporating the submarine with these new and potent weapons.
The world‟s first submarine launched ballistic missile was a modified Scud-A, a
35-foot, liquid-propellant missile.39 With a range of 150 nautical miles, the submarine
had to surface in order to launch. In 1956, the Soviet Union began modifications to five
unfinished Zulu class submarines that were equipped with two missiles in their sail.
While primitive and of limited value by modern standards, the Zulu V was the world‟s
first ballistic missile submarine.40
From this humble beginning, the Soviet Navy proceeded to build a series of
ballistic missile systems, each more capable than its predecessor. Building upon their
success with the Scud-A, Soviet engineers developed the SSN-4 which became the Soviet
Navy‟s first fully operational ballistic missile system. While the Soviet Navy installed
the Scud-A missile system in a modified hull, they installed the SSN-4 in the world‟s first
38
Sharpe, 546.
The first launch of a Scud-A by a submarine occurred in September 1955.
40
The Americans used the designation Zulu V to identify this submarine.
39
158
purpose-built ballistic submarine. The Golf class shared the basic hull characteristics of
the Foxtrot. With its three diesel engines and three shafts, it displaced 2,700 tons
submerged and with a length of 328 feet was approximately 28 feet longer then the
Foxtrot.41 The SSN-4 had a range of 350 nautical miles and carried a single one-megaton
nuclear warhead. With three of these nuclear tipped missiles, the Golf class represented a
tremendous advancement in the destructive power of the submarine.
Along with the development of ballistic missiles, the Soviet Navy, in their pursuit
of more capable weapons for their expanding submarine force, turned to the cruise
missile in both the strategic and tactical role. The SSN-3 Shaddock was the first of such
weapons developed by the Soviet Navy. A large, air-breathing missile, sub-sonic missile,
the land-attacked version was designated the SSN-3C and had a range of 400 nautical
miles.42 As with the SSN-4, the SSN-3C carried a nuclear warhead.
The anti-ship version was designated the SSN-3A. With a range of 250 nautical
miles, its guidance system consisted of inertial guidance, with a mid-course command
capability, and active radar homing in the terminal phase. With a massive 2,200-pound
warhead, this weapon system presented a new threat to American naval forces.43
In a manner similar to the introduction of the SSN-4 and the Zulu V, the Soviet
authorities modified the Whiskey class to carry the first SSN-3 missiles. The first of
these modified Whiskey class was the Whiskey single-cylinder. Carrying a single SSN-3
in a canister aft of the conning tower, the Soviet Navy used these boats to train crews in
the use of this new weapon system. Two other classes of Whiskey were modified to
carry the SSN-3 A/C missile these were to be the Whiskey twin-cylinder and the Whisky
41
Polmar, 159.
Ibid., 334.
43
Ibid.
42
159
long-bin. The twin-cylinder was similar to the original single-cylinder except that the
number of missiles were increased too two. The long-bin had its conning tower modified
to carry four SSN-3 missiles.44
Having proved the effectiveness of the weapon system, the Soviet Navy embarked
on the construction of diesel submarines specially design to employ the SSN-3A
missile.45 Referred to as the Juliett by western authorities, it was approximately 284 feet
and had a submerged displacement of 3,750 tons, and was capable of speeds up to 14
knots while submerged.46 The Front Door / Front Piece missile targeting radar provided
guidance to the missile. In order to shoot at targets over-the-horizon (OTH) targeting
information had to bed provided to the submarine. Aircraft, such as the giant Bear D,
flying ahead of the submarine provided such information.47
Though these diesel submarines were dangerous craft, they still were limited by
the amount of time they could remain submerged and while the increased range of the
cruise missile allowed them to attack from longer distances, they remained vulnerable to
ASW patrol aircraft. Modern radars forced the diesel submarine to submerge and as with
the German U-boats of World War II, once submerged, these submarines possessed little
ability to engage their opponent. It was only with the introduction of nuclear power that
a true submergible emerged on the battlefield.
The first Soviet nuclear-propelled submarine was Project 627, given the
US/NATO codename November, the lead unit was launched in 1958. Unlike the
American nuclear submarine program that was initially limited to torpedo-attack units,
44
Polmar, 282.
The Soviet Navy launched the first of sixteen Juliett class submarines in 1961.
46
The exact length of the Juliett class was 284 feet, 5.5 inches.
47
Friedman, 183.
45
160
the Soviet Navy embarked on an ambitious plan to build three unique types of nuclear
submarines. These submarines were to known in western intelligence circles as the
November SSN, Echo SSGN, and the Hotel SSBN. Referred to as the HEN or Type I
class these craft combined the inherent advances of nuclear power, with the destructive
power of modern torpedoes and guided missiles.48
Common features of the HEN class include the use of twin reactors and
propeller shafts. When first completed, the November class was the fastest submarine in
any navy. With a length of 358 feet, 7 inches and a displacement 5,300 ton while
submerged, the November powered by its two pressurized water reactors producing
35,000 horsepower, was capable of achieving a top speed of 30 knots. Equipped with
eight standard 21-inch torpedo tubes and capable of carrying up to 24 torpedoes, the
November represented the future of submarine warfare.49
The Soviet Navy built the Echo class in two variations, the Echo I for use in the
land-attack role, and the Echo II for use in the anti-ship mission. Between 1960 and 1962,
the Soviet Navy launched five of the Echo I class submarines. These units designed to
carry six SSN-3C land-attack cruise missiles. With a length of 373 feet 11 inches and a
displacement of 5,500 ton when submerged, the Echo I SSGN was capable of a
submerged speed of 25 knots. By 1970, the Soviet Navy no longer deemed the landattack mission necessary and converted the Echo I SSGN to a torpedo-attack unit with the
removal of its six SSN-3C missiles.50
While only a limited numbers of the Echo I were built, its big brother, the Echo-II,
proved to be highly successful and a total of twenty-nine units were built. Building upon
48
Polmar, 164.
Ibid., 165, 294,
50
Ibid., 296.
49
161
the success of the Juliett, the Echo II carried eight SSN-3C cruise missiles. Using the
same targeting radar as the diesel powered Juliett, the Echo II, working with the Bear D
reconnaissance aircraft was capable of launching a massive strike upon American battle
groups. In 1975, the Soviet Navy began arming the Echo II with the SSN-12 anti-ship
missile. Flying at super-sonic speed of 2.5 Mach, it had a range of 300 nautical miles,
and carried either a 2,200-pound high explosive or nuclear warhead. Additional
capabilities came with the installation of the Punch Bowl antenna that allowed the Echo
II to receive targeting data from a satellite.51
The third type of submarine of the HEN class was the Hotel SSBN. The first
units of the Hotel class were equipped with three SSN-4 missiles, the same type carried
by the Golf class SSB. The Soviet authorities soon modified these early units, referred to
as the Hotel I, to carry three SSN-5 ballistic missiles. Featuring underwater launch
capability and a range of 900 nautical miles, the marriage of nuclear power and the
ballistic missile was complete. Launched from a depth of 65 to 98 feet, the SSN-5
missile allowed the Hotel to remain hidden from detection by either radar or visual
means.52
The HEN class submarines, the first generation of Soviet nuclear submarines,
represented a new and powerful submarine force. With their high speeds, virtually
unlimited endurance, the HEN class were capable of operating anywhere in the world and
while impressive when compared to the earlier diesel-electric boats, were just the first in
many types of nuclear submarines to be built for the Soviet Navy.
51
52
Polmar, 298.
Ibid., 337.
162
The second-generation nuclear submarines were the Victor SSN, the Charlie
SSGN, and the Yankee and Delta class SSBN.53 The Victor class replaced the November
as the premier Soviet torpedo-attack submarine, with the first launched from the
Admiralty yard in Leningrad in 1968. While the Victor was 49 feet shorter then it
predecessor, the November, it was 3.5 feet broader. The additional width help reduce the
self-noise generated by the submarine thereby increasing its ability to perform in the ASW
role. For unlike the November whose mission was anti-surface warfare (ASUW), the
improved Victor was to be capable of stalking and destroying their opponent‟s
submarines. Displacing 5,100 tons while submerged, its twin-reactor propulsion plant
generated 30,000 horsepower, which permitted its single shaft to propel the submarine at
speeds up to 32 – 33 knots.54
In order to perform its ASW mission, the Victor class was equipped with low
frequency sonar, code named Shark Teeth by US/NATO authorities. Capable of
detecting and tracking of other submarines are greater distances, the need for long-range
weapon became a priority. Responding to this requirement, in 1972, the Soviet Navy
introduced the new SSN-15 and SSN-16 anti-submarine missiles.
The SSN-15 was the primary ASW weapon of the Victor I class. The SSN-15 was
the Soviet equivalent of the American SUBROC (submarine rocket). Like its American
counterpart that it was based upon, the SSN-15 had a range of 21.6 nautical miles and
carried a nuclear depth bomb.55 The SSN-16 was a larger weapon and required a bigger
tube, this lead to the development of the Victor II, the successor to the Victor I class. The
53
The Soviet Navy built three variants of the Victor class, two variants of the Charlie and Yankee class,
and three variants of the Delta class.
54
Polmar, 183-184.
55
Friedman, 600. The SSN-15 was copied from the American weapon that was reportedly compromised
about 1964.
163
Victor II was larger than the earlier boat, permitting the installation of two 25.5 inch / 650
millimeter torpedo tubes. This allowed for the development of the larger SSN-16, which
instead of the nuclear depth bomb carried the E45-75A series homing torpedo. The
larger diameter permitted an increase in range to a maximum of 54 nautical miles and
while the torpedo with a 198 pound warhead had a maximum speed of 38 knots and a
range of 8,700-9,000 yards.56
The last of the Victor class submarines, know, as the Victor III, was the first
Soviet submarine to match the quality of their American counterparts. The Soviet Navy
launched the first of twenty-five Victor III units in 1978. With a submerged
displacement of 6,000 tons, and an overall length of 347 feet, 8 inches, the single tandem
four or seven bladed propeller was capable of driving the Victor III at speeds of 29 – 30
knots.57 Though slower than the earlier models, the Victor III incorporated new
engineering technologies that resulted in self-generated sound levels equal to or less then
the American Sturgeon class.58 As with American submarines, the Victor III used a „raft‟
to mount the steam turbines and other machinery. Using numerous shock and sound
absorbers to isolate the „raft‟ from the hull resulted in this reduction in noise levels.
Additional improvements to the Victor III included the installation of a passive
towed array system. This new tow array was part of the Shark Gill sonar suite, an
intergraded system that combined both active and passive sonar. When combined with
its low self-noise, the Victor III was formidable anti-submarine warfare platform.
56
Friedman, 703-704.
Ibid., 305. A tandem four bladed propeller consisted of two, four bladed propellers, oriented 22.5˚ apart,
co-rotating on a single shaft.
58
Ibid.
57
164
To compliment the Echo II and the SSN-3 / 12 missile systems, the Soviet Navy,
in 1967, introduced the Charlie class SSGN, the least successful of the Soviet secondgeneration submarines. While all other Soviet submarines had two nuclear reactors, the
Charlie I and its successor the Charlie II had a single reactor, reducing their total shafthorse-power to 15,000 which in turned limited it to a maximum submerged speed of only
23 knots.59
With a submerged displacement of 5,000 tons for the Charlie I and 5,400 tons for
the Charlie II, both used a single five bladed propeller for propulsion and were capable of
carrying eight submerged launched cruise missiles. While the Charlie class submarines
were far from ideal, their missile systems, when introduced, present a plethora of
problems for the United States Navy.
The SSN-7 is a fire-and-forget, submerged launched missile. With a 1,100-pound
warhead and a speed of Mach 0.95, the missile had a maximum range of 30 nautical
miles, a minimum range of 4-5, and a probable operational range was 25 nautical miles.
Launched from depths of 150 feet and the missile would cruise at an altitude of between
100-300 feet and at a range of 25 nautical miles from its target, it would activate its Jband conical scanner. Diving toward its target at 3˚, it was capable of traveling 30 miles
in 3.2 minutes, giving its intended victim little time to react.60
The Soviet Navy upgraded the offensive firepower of the Charlie class with the
introduction of the Charlie II and the SSN-9 cruise missile. In order to carry the SSN-9,
which was approximately seven longer then the SSN-7, it was necessary to lengthen the
59
60
Norman Polmar, Guide to the Soviet Navy, 4th Edition (Annapolis: Naval Institute Press, 1986), 131.
Friedman, 184.
165
Charlie II by 26.5 feet.61 The SSN-9 had a maximum range of 58-65 miles and if
employed at these ranges outside targeting data was required. Handicapped by its slow
speed, which limited its role as an anti-shipping platform, the Charlie class did point the
way for the development of the Oscar class SSGN, the ultimate anti-carrier submarine.
The Yankee class SSBN was the replacement for the Hotel and Golf class ballistic
missile submarines. The Yankee class was a large, two-shaft submarine, 429 feet, 5
inches long, displacing 9,600 tons submerged, its engineer plant, of two nuclear reactors
was capable of producing 50,000 shaft-horse-powers.62 With a maximum speed of 27
knots, the Yankee was faster than the American Polaris class submarines.63
While much more capable then earlier ballistic submarines, the Yankee class
retained one major weakness. The Yankee class was initially equipped with sixteen SSN6 mod 1 missiles, which had a maximum range of only 1,300 nautical miles. This forced
the Yankee class to transit across either the Pacific or Atlantic Ocean in order to strike
targets in the continental United States. Improvements to the SSN-6 mod 1 came with
the development of the mod 2 and 3 both with a 1,600 nautical mile range. All three
versions weighed approximately 41,580 pounds and were 32 feet 10 inches long, which
permitted easy replacement of the older model with the newer, more capable missile.64
The SSN-6 mod 1 and 2 carried a single, 1 megaton warhead while the mod 3 carried two
multiple reentry vehicles (MRVs). With a circular error probability (CEP) of 1,640 yards,
the SSN-6 was capable of destroying most targets once the submarine had closed to the
61
Polmar, 187.
Guide to the Soviet Navy, 4th Edition, 121.
63
Polmar, 189.
64
Ibid.
62
166
appropriate distance from the American coast. Though the SSN-6 had, a modest range
the submarine proved to be highly successful, with thirty-four entering service.
65
In order to solve the range limitation of the SSN-6 and the corresponding
vulnerability of the Yankee class as it transited to its operational areas, the Soviet Navy
introduced the Delta I and the SSN-8 missile. In order for the Delta class to carry the
massive, 42 foot 8 inch, 66,000 pound, missile the Soviet Navy enlarged Yankee design.
With a submerged displacement of 11,750 tons and an overall length of 459 feet 2inches,
the Delta I was the world‟s largest submarine when first launched.66 Two nuclear
reactors producing 50,000 shaft-horse-powers provided power to the Delta class.
Equipped with two shafts, the Delta I was capable of attending a maximum speed of 25
knots. Later Delta II, Delta III, and Delta IV variants, due to increase in size; saw their
top speed reduced to 24 knots.67 The Soviet Navy commissioned a total of eighteen Delta
Is, four Delta IIs, fourteen Delta IIIs, and four Delta IVs.68
With a maximum range of between 4,240 to 4,950 nautical miles, the
introduction of the SSN-8 missile now permitted the Soviet Union to strike targets in
America will in coastal waters. A Delta I patrolling in the waters off the Kola Peninsula
could reach an arch running from mid-Florida through San Francisco, while a Delta I in
port at Petropavlovsk was capable of striking any target within an arch from northern
Maine through mid-Texas.69 The SSN-8 mod-1 carried a single 800-kiloton warhead,
65
Polmar, 300.
Ibid., 303.
67
The submerged displacement of the D-II was 12,750 tons and the D-III 13,250 tons. Much of the
increase in weight was the result of larger, heavier missiles.
68
Guide to the Soviet Navy, 4th Edition, 116-118.
69
Ibid., 190.
66
167
while the mod-2 carried two 500-kiloton warheads. Utilized stellar-inertial navigation
the SSN-8 had a CEP of only 0.84 nautical miles.70
Follow on missiles were the SSN-18 and the SSN-23. The Delta II carried twelve
SSN-18, and the enlarged Delta III so the number of missiles return to the sixteen, the
number carried on most modern soviet ballistic missile submarines. The Delta IV was
equipped with sixteen SSN-23 missiles. The range of the SSN-18 was not appreciably
greater than its predecessor was but was more accurate and was the Soviet Navy‟s first
multiple-independent-reentry-vehicles (MIRV). The SSN-18 mod-1, carried three 200
kiloton MIRV, the mod-2 a single 450 kiloton warhead, and the mod-3 seven 200 kiloton
MIRV.71
The Delta IV was the final variant of the Delta class built and was the first of the
new third generation submarines. Each generation of Soviet, submarines not only were
equipped newer and more capable weapons but also incorporated technology that reduced
the noise generated by the submarine, a highly desirable trait when attempting to counter
ASW forces. The Delta IV was equipped sixteen SSN-23 missiles that were capable of
traveling 5,000 nautical miles, had a CEP of 550 yards, and carried seven MIRV, making
the Delta IV one of the most dangerous naval craft ever constructed.72
Third generation Soviet submarines consisted of the Delta IV, Typhoon Oscar I
and II, Akula, Sierra, and Typhoon class. These submarines incorporated advanced
quieting technology that allowed the Soviet Navy to close the quality gap that had existed
between the American and Soviet submarine forces for much of the Cold War.
70
Friedman, 115.
Ibid.
72
Ibid., 116.
71
168
The Akula and Sierra class submarines are enlarged versions of the Victor class.
Incorporating additional quieting technology, advanced sensors and weapons these
submarines equal to the American Los Angles class in all aspects. First launched in 1984
and 1986 respectfully, the Sierra and Akula shocked American naval leaders. The Akula,
with broadband source levels equal to the Los Angles class, the acoustic advantage that
the Americans had possessed over their Soviet counterparts was gone.73
The Sierra class displaces 7,750 tons submerged and is 351 feet long.
Constructed of titanium, the use of this light, extremely strong metal permits the
submarine to dive to depths of 2,300 feet and reduces it magnetic signature. Propelled by
two reactors, driving a single seven bladed propeller, the Sierra is capable of speeds of
34-36 knots.74 Equipped with two 21 inch and four 25.5 inch torpedoes the Sierra is
capable of launching the SSN-15, 16 and the SSN-21, a land-attack cruise missile with a
range of 1,600 nautical miles.75
The SSN-21 is the Soviet equivalent to the American Tomahawk strategic cruise
missile. Launched from a 25.5-inch torpedo tube, a turbofan engine powers the missile.
Flying at an altitude of 600-650 feet and a speed of 0.7 Mach, the missile is guided to its
target by a combination of inertial guidance with terrain contour matching (TERCOM)
homing. Armed with a nuclear warhead, the introduction of the SSN-21 made all Soviet
submarines that were equipped with the 25.5-inch torpedo tube a strategic threat.76
73
Tom Stefanick, Strategic Antisubmarine Warfare, and Naval Strategy (Lexington: Lexington Books,
1987) 274.
74
Polmar, 210. The Soviets experiment with titanium hulls with the one-of-a-kind Papa and Alpha class
submarines. Both were extremely fast, 39-40+ knots and deep diving. The Alpha was referred to as the
“Gold Fish” due to its immense coast.
75
Freidman, 116.
76
Guide to the Soviet Navy, 4th Edition, 431.
169
The Akula displaces 9,100 tons submerged, is powered by twin reactors
producing 47,600 horsepower at a top speed of 28-30 knots.77 With four 21-inch and 425.5-inch torpedo tubes, the Akula is capable of carrying forty weapons. The Akula
continued the trend toward reduced self-noise levels, boundary layer suppression, and
active noise cancellation.78 Incorporating all of the evolutionary improvements, the
Akula was to be the quietest and most capable of all Soviet fast attack submarines.
The Oscar I and II are massive submarines, displacing approximately 18,300 tons
when submerged but still capable of speeds in excess of 28 knots.79 Twin nuclear
reactors that generate an amazing 98,000 horsepower power its twin shafts. Armed with
twenty-four SSN-19 anti-ship cruise missiles, with a range of 300 nautical miles, this
submarine posed a grave threat to American battle groups. The SSN-19 has a speed of
Mach 1+, negating the need for mid-course guidance. The Oscar once it receives its
targeting data from a radar satellite via its Punch Bowl downlink receiver can launch its
missiles while submerged unlike the earlier Echo II, which were required to surface to
fire.80 Combining the best features of the Charlie and Echo II class submarines the Oscar
class presented a complex problem for the American ASW forces to solve.
The first Typhoon reportedly laid down in 1975, with the lead unit beginning sea
trials in 1981 and becoming operational in 1983. The world‟s largest submarine, the
Typhoon displaces 26,500 tons when submerged. Its twin nuclear reactors, producing
81,000 horsepower are capable of driving this massive submarine at a maximum
submerged speed of 25 knots. As with all third generation submarines, the Soviets have
77
It should be noted that unofficial sources list the speed of the Akula from speeds as low as 28 knots in
Jane’s Fighting Ships, 1998-99 , page 552, to 30+ knots in Guide to the Soviet Navy, 4th Edition, page 139.
78
Sharpe, 552.
79
Ibid., 550.
80
Freidman, 185.
170
incorporated advanced quieting technologies into the Typhoon that have greatly reduced
any self-generated noise. The Typhoon‟s primary weapon is the SSN-20 ballistic missile.
With a range of 4,300 nautical miles and a CEP of between 550-650 yards, it is the first
solid fuel submarine launched ballistic missile (SLBM).81 Capable of carrying between
six and nine 100 kiloton MIRV warheads, the Typhoon, like the other third-generation
submarines, were equal to the best American had to offer.
Throughout the Cold War, under the guidance of Admiral Sergei Gorshkov, the
Soviet Navy and its ever-improving fleet of submarines presented a serious challenge to
the American ASW forces. From the early days of Whiskey to the later years of the
Akula, as the Soviet submarine force improved, the maritime patrol aircraft, as in the past,
had to find new and better methods of countering its foe.
At the end of World War II, the Navy was operating a whole host of aircraft in the
anti-submarine warfare role. Operating seaplanes, such as the PBY Catalina and the
PBM Marine, land based patrol aircraft such as the PB4Y-1 Liberator and the PB4Y-2
Privateer the Navy utilized these and many other types of aircraft in their battle against
the submarine.82 With the end of the war, the Navy sought aircraft with greater capability
to combat the growing Soviet submarine threat.83
Throughout much of the 1950s the two aircraft, the P5M Marlin, a seaplane, and
the land-based P2V Neptune, did yeoman duty in the early phases of the Cold War. Both
represented the last of their kind. Powered by radial engines, with unpressurized cabins,
81
Guide to the Soviet Navy, fourth Edition, 434.
The PB-1 was the Navy‟s version of the PB4Y-1 was the Navy‟s version of the Army Air Corp‟s B-24
and the P4Y-2 Privateer was a heavily modified version B-24
83
VP-50 was the last squadron to report the PBM Mariner in its inventory on 31 July 1956 and VP-32 the
last squadron to report the PBY Catalina in its inventory on 1 July 1949. VW-3 was the last squadron to
report the PB4Y-s in its inventory on 30 June 1954. VJ-62 was the last squadron to repot the PB4Y-1 in its
inventory on 31 March 1956, while VW-3 was the last squadron to report the PB4Y-2 in its inventory on
30 June 1054.
82
171
these aircraft were direct decedents of the aircraft that defeat the Nazi submarine fleet in
World War II.
On 26 June 1946, the Bureau of Aeronautics issued a contract for the P5M Marlin
to the Martin Company.84 The Marlin was a twin-engine anti-submarine patrol bomber
flying boat. Two 3,250 horsepower Wright Cyclone R-3350-30WA, turbo-compound
radial engines powered the first production models of the P5M-1.85 This gave the Marlin
a maximum speed of 234 mph and a cruising speed of 150 mph.86 The P-5M was a
relatively large aircraft, with a length of 94 feet, 6 inches and a height of 38 feet, 5 inches
which permitted a range of 2,880 miles.
Additional changes to the production models of the Marlin included the
replacement of the nose turret with the APS-80 search radar and the removal of the dorsal
turret. The P5M-1 did retain the two 20-milimeter radar-directed cannons in the tail
turret. As with all flying boats, the Marlin did not have a conventional bomb bay
therefore, it used the engine nacelles or on under-wing pylons to carry its bomb load.
The Marlin had the capability to carry a variety of weapons. This included the ability to
carry two torpedoes or two 2,000-pound bombs in each of the nacelles, while the underwing pylons could carry up to eight 1,000-pound bombs.87
84
Michael D. Roberts, Dictionary of American Naval Aviation Squadrons, The History of VP, VPB,
VP(HL), and VP(AM) Squadrons, Volume 2 (Washington D.C.: Naval Historical Center, Department of the
Navy, 2000), 663.
85
A turbo-compound engine uses a blow-down turbine to recover exhaust gases. The turbine was
mechanically connected to the crankshaft increasing the power output of the engine without any increase in
its fuel consumption. For additional information, see Facts about the Wright Turbo-Compound (WoodRidge: Field Engineering Department, Curtiss-Wright Corporation, Wright Aeronautical Division, 1956),
7.
86
Martin Aircraft Specifications @ The Glenn L. Martin Maryland Aviation Museum,
http://www.marylandaviationmusum.org/pdf/P5M_spec.pdf
87
Roberts, 663.
172
Initial service deliveries of the P5M-1 began in December 1951, with Navy patrol
squadron VP-44 receiving the first of these aircraft on 23 April 1952.88 In 1951, the
Marlin underwent a major redesign of the airframe. Designated the P5M-2, it first flew
on 29 April 1954. The P5M-2 had a distinctive tee tail, with the horizontal stabilizer at
the top of the vertical tail-plane instead of at the base as in earlier models.89 Other
structural changes included the lowering of the bow chine to reduce ocean spray. With
an increase in gross weight by over 12,000 pounds came the need to replace the original
R-3350-30WA engines with the more powerful Wright R-3350-32WA engines.
Supercharged, these engines produced 3,450 horsepower.90
The P5M-2 was to be the last major change to the airframe of the Marlin but as
with all ASW aircraft of the Cold War, the Marlin underwent numerous modifications and
upgrades to its electronic equipment. In the late 1950s, the P5M-1s underwent a
comprehensive update to their electronic suite in order optimize them for the ASW
mission, designated the P5M-1S, of the various changes to its avionic systems, the
installation of the AN/AQA-3 and AN/ASA-20 systems had the greatest impact on the
ASW mission.91 Other changes included the new magnetic anomaly system, the
AN/ASQ-8. To differentiate these modified aircraft from the standard P5M-1, the Navy
designated them the P5M-1S.92 The P5M-2s underwent a similar upgrade to their ASW
systems and were designated the P5M-2S.
88
http://www.marylandaviationmusum.org/pdf/P5M_spec.pdf The Navy took delivery of 160 P5M-1s.
Roberts, 247.
90
Martin Aircraft Specifications @ The Glenn L. Martin Maryland Aviation Museum,
http://www.marylandaviationmusum.org/pdf/P5M_spec.pdf
91
The capabilities of the AN/AQA-3, code-named “Jezebel,” and the AN/ASA-20, code-named “Julie,”
will be thoroughly discussed in a later portion of the paper.
92
Roberts, 663.
89
173
While the P5M-1/2 represented the last of the Navy‟s operational flying boats, the
P-2V Neptune and its derivates represented the last of the World War II type land-based
patrol bombers.93 The Neptune was the only designed-for-the-purpose land-based patrol
aircraft to se wide, general us in the Navy and had a production run of 1,036 aircraft, with
the last delivered in 1962.94
The Bureau of Aeronautics issued Lockheed a contract for the P2V on 19
February 1943 and in March 1947 VP-ML-2 became the first squadron to receive the
P2V Neptune.95 Designed as a long-range land-based patrol bomber, the prototype was
capable of carrying a crew of seven, a wide range of electronic equipment, and a bomb
bay large enough for either four 2,000-pound bombs, eight 1,000-pound bombs, sixteen
500-pound bombs, twelve 325-pound bombs, or two, 165-pound Mk-13 torpedoes.96 The
XP2V-1 had a wingspan of 100 feet, a fuselage 75 feet, 4 inches long and weighed
32,650 pounds empty, with a maximum gross weight of 54,527 pounds. With a 2,800pound bomb load, the Neptune had a range of 2,879 miles. Providing power to the
aircraft were twin Wright Cyclone R-3350-8 engines, capable of delivering 2,300
horsepower at 2,800 rpm for take-off.
The initial production model of the Neptune, the P-2V-1, differed from the
prototype in only minor details and .keeping with its World War II heritage, the early
models of the Neptune were equipped with a formidable defensive armament. In the
93
The Navy did pursue an all jet seaplane bomber, the P6M-1/2 Sea Master in the 1950s. A massive
aircraft, it had a maximum takeoff weight of 160,000 pounds with a payload of 30,000 pounds. The P-6M
was able to attain a speed of Mach 0.9 in low-level flight. Designed specifically as a nuclear strike bomber,
the Navy cancelled the project in the fall of 1959.
94
“Naval Aircraft, Neptune,” Naval Aviation News, October 1977, .21.
95
On 1 September 1948, the Navy changed the designation of VP-ML-2 (Patrol Medium/Land Squadron)
to VP-2 (Patrol Squadron).
96
Wayne Mutza, Lockheed P2V Neptune, an Illustrated History (Atglen: Schiffer Publishing Ltd., 1996),
30.
174
nose, twin 50-caliber machine guns were mounted and a late model Cheyenne B-17G tail
turret. Additional armament consisted of two 50-cabliber machine guns in the tail and in
a dorsal turret. Other changes included the Wright Cyclone R-3350-8A engines replaced
the R-3350-8 engines and incorporated an alcohol injection de-icing system for the
propellers.97 Additional modifications included the installation of the APS-8 surfacesearch radar forward of the bomb bay.98
The success of the P-2V-1 led the Navy to place an order for 151 P-2V-2s in
December 1944. Officials reduced this order to thirty aircraft following the end of World
War II. The major modifications applied to the P2V-2 were a redesigned nose, no nose
turrets and upgraded, Wright R-3350-24SW engines that produced 2,800 horsepower. In
place of the nose turret and its twin 50-caliber machine guns, there were six fixed
forward-firing AN-M2 20 millimeter cannon. The P-2V-3 saw the continuing need for
additional power as the weight of the aircraft continued to increase with 3,200 horsepower, Wright Cyclone R-3350-26W engines replacing the R-3350-24SW.99
The early models of the Neptune had only rudimentary ASW capabilities, with the
APS-20 surface-search radar installed on the P-2V-3W models in the spring of 1948. It
was with the introduction of the P-2V-4 that saw the primary mission of the Neptune
change to that of ASW. The P-2V-4 saw the introduction of the turbo compound R-335030W engine to the Neptune series.100
In order to improve its ASW capabilities, the Navy installed not only was the
APS-20 search radar but also AN/ARR-31 sonobuoy receiver set to permit the
97
Mutza, 31.
Ibid., 31.
99
Roberts, 648.
100
The first twenty-six P-2V-4s were equipped with the R-3350-26W engine. Standard Aircraft
Characteristics, P-2V-4 “Neptune” Standard Aircraft Characteristics, NAVAER 1335A (Rev. 1-49).
98
175
monitoring of passive sonobuoys.101 Installation of the AN/AVQ-2 search light in the
right wing-tip nacelle and the AN/APS-31 attack radar permitted attacks at night and in
inclement weather. To negate the use of radar by the submarine the crew could search
for radar signals with the AN/APR-9 search analyzer and classify the signals with the
AN/APA-64 pulse analyzer.102
With the introduction of nuclear power and the snorkel on most modern diesel
submarines, the Navy recognized there was little need for heavy cannon as the change of
encountering these submarines on the surface was unlikely. In the future, torpedoes and
depth charges would be the weapons of choice when combating the submarine. During
the production run of the P-2V-5 series the cannons and machine-guns of earlier models
were replaced. Changes included a clear-nosed observation station replacing the nose
cannon; a thirteen-foot boom housing the AN/AQS-8 magnetic anomaly detector
replaced the aft cannon, and the elimination of the dorsal turrets.
Of the various models of the P-2V-5 built, the P-2V-5FS, introduced in 1962,
embodied all the latest improvements in anti-submarine warfare. The electronic countermeasure suite (ECM) consisting of the AN/APA-9B auxiliary radar assembly, the
AN/APA-11 pulse analyzer, and the AN/APA-69 direction finding radar set.103 To
combat the submerged submarine it was necessary to install the AN/AQA-3 and
AN/ASA-20 sonar systems. Additionally modifications included the installation of the
AN/ASH-2 exhaust trail indicator.104
101
Mutza, 36.
NAVAER 1335A (Rev. 1-49).
103
Standard Aircraft Characteristics, P-2V-5 “Neptune” Standard Aircraft Characteristics, NAVAER
1335D (Rev. 1-49), 1 March 1955.
104
Mutza, 101.
102
176
Installation of the additional avionics increased the gross weight of the P-2V-5 to
more than 76,000 pounds. In order to offset this growth, two Westinghouse J34-WE-34
turbojet engines, capable of delivering 3,250 pounds of thrust each were installed beneath
the wings on pylons just outboard the engine nacelles.105 Use of the turbojet engines was
limited to assisting in take-offs and for additional combat speed
The final model of the Neptune series was the P-2V-7. As the weight of the
aircraft continued to grow, the Navy found it necessary to replace the aircrafts power
plant with a more powerful power plant. The Wright Cyclone R-3350-32W, producing
3,700 horsepower and the Westinghouse J34-WE-36 turbojet with its 3,400 pounds of
static thrust replaced the older engines.106 This gave the P2V-7 a maximum speed of 300
miles-per-hour and with “two turning and two burning” a dash speed of 360 miles-perhour.107
The P2V-7 was a true submarine hunter. The crew of nine consisted of the bow
observer who doubled as the MAD operator, two pilots, a plane captain, a navigator, and
three crewmembers that operated the ECM system, the A/AQA-3, and the AN/ASA-20
sonar systems.108 Capable of carrying up to 10,000 pounds of ordnance and with a range
of 4,350 miles, the P2V-7 was a remarkable aircraft, but one that reached its evolutionary
end.109 To meet the growing Soviet Union submarine threat, the Navy would need a new
and more capable aircraft.
105
Roberts, 649.
Ibid.
107
The phrase “two burning, two turning” referred to the propellers of the two Wright engines turning and
the burning exhaust of the Westinghouse turbojets.
108
Mutza, 42.
109
Roberts, 649.
106
177
By 1959, the Navy recognized the need for an aircraft to replace the Marlin and
Neptune. While still capable of performing the ASW mission, they represented old
technology. With their unpressurized cabins, lack of climate control, and radial engines,
they would not be able to meet the requirements of the future. This result in the issuing
of Navy type specification #146 by the Chief of Naval Operations (CNO), in 1957, for
the establishment of a new land-based ASW and maritime reconnaissance aircraft to
replace both the P-2V and P-5M aircraft.110
In May of 1958, the Navy announced the winner of the design competition. The
Lockheed Aeronautical Systems Company of Burbank California won the competition
with a design based on their Electra commercial airline.111 The Bureau of Aeronautics
issued a contract for the P-3V-1 to the Lockheed Company on 2 February 1959.
Ultimately, Lockheed delivered 610 aircraft to the Navy and an additional 36 for use by
other organizations or countries with VP-8 receiving the first of these aircraft on 22
August 1962.112 The Navy plans to replace the Orion with the Boeing 737-800 multimission maritime patrol aircraft beginning in 2013.113
While the Lockheed engineers used many of the Electra basic features in the
design of the Orion and though the appearance of the two aircraft is similar, the P-3V-1 is
not a modified Electra, rather a completely new aircraft. Shortened by seven feet, with
the overall structure substantially strengthened compared to that of the Electra as this
additional strength was needed due to stress of low altitude flying. The deleted seven feet
110
David Reade, The Age of Orion, the Lockheed P-3 Story (Atglen: Schiffer Military / Aviation History,
1998), 8.
111
Reade, 8.
112
Roberts, 654.
113
United States Navy Fact File http://www.navy.mil/navydata/fact_display.asp?cid=1100&tid=1300&ct=1
178
provided a significant weight savings and improved the aerodynamic flying qualities of
the aircraft.
The P-3V-1 represented a quantum leap in technology and capabilities over the
Neptune and Marlin. Possessing a spacious pressurized fuselage with an air-conditioned
controlled environment, the new aircraft had all the necessary attributes of a modern ASW
aircraft. With its four Allison T56-A-10W turboprop engines, with Hamilton Standard
constant-speed propellers, the Orion was capable of a top speed of 380 knots at 15,000
feet.114
The P-3V-1 had an overall length of 116 feet, 10 inches, and a wingspan of 99
feet, 8 inches. With a ceiling of 28,300 feet and a maximum range of 4,700 nautical
miles, the Orion incorporated all the requirements shout in a maritime patrol aircraft.
With a bomb bay capable of carrying 7,250 pounds of weapons and ten under-wing pylon
stations capable of carrying another 16,000 pounds of ordnance, the Orion was
formidable opponent.115
The Orion was built in three basic configurations, the P-3A, P-3B, and the P3C.116 Unlike the Marlin and Neptune, the majority of the changes made to the Orion
were to its avionic systems and not to the aircraft. As previously mentioned the Allison
T56-A-10W provided power for the P-3A. The -10W produced approximately 4,200
equivalent shaft horsepower (ESHP).117 Water-methanol injection provided an 11%
114
Reade, 164. 380 knots is the equivalent of 437 miles-per-hour.
Ibid.
116
In September 1962, the military instituted a new tri-service classification / designation policy. For a
detailed description of the policy, see the instruction Designation, Redesgination, and Naming Military
Aircraft, issued on 18 September 1962. This instruction implemented DOD Directive 4505.6, issued 6 July
1962 and superseded the individual service instructions AFR 66-11, AR 700-26, BUWEPS Instruction
13100.7 which were used by the various services to designated aircraft..
117
Reade, 16.
115
179
increase in power over the T56-A-1 engine used by the Electra.118 The introduction of
the P-3B on 1 January 1966 saw the first and last modification to the Orion’s engines.
The new engine, the Allison T-56-A-14 engine produced 4,500 ESHP without the watermethanol injection system of the -10W.119
Other changes made to the P-3A included the installation of an auxiliary power
unit (APU) that provided electrical power for air-conditioning and engine starts. With the
increase weight of the new model, the P-3B saw an increase of its maximum weight from
126,000 pounds, to 135,000 pounds. This increase in weight necessitated the installation
of new land gear system that was capable of handling the additional weight.120
Additionally changes included the installation of the Martin ARW-77 Bull-pup guided
missile system, giving the Orion an air-to-surface capability against surface vessels or
ground targets.121
The first P-3C entered the fleet on 12 June 1969. From an airframe and power
plant perspective there was little difference between the “Charlie” and the “Bravo.”
Internally the crew seating arrangement changed the ladder used to embark and
disembark was different. The “Charlie” underwent five major modifications with the
addition of as new avionics systems.122
There are, however, two significant changes made to the P-3C that did not
involved the aircraft‟s avionics systems. The Update II saw the incorporation of the
AWG-19(v) 1 Harpoon aircraft command-launched control system (HACLCS). This
118
Ibid., 15.
Ibid., 24. All subsequent models of the Orion utilize the T-56-A-14.
120
Ibid.
121
Roberts, 654.
122
The P-3C Update I entered service on 1 May 1974, the Update II on 5 March 1977, the Update II.5 May
1981, the Update III in January 1985.
119
180
system provided the crew with the capability to launch and control the AGM-84A
Harpoon anti-ship missile.123 The other change was in the area of self-defense, which
saw the incorporation of foam self-sealing fuel tanks in the early 1990s in order to
provide a degree of security from small arms fire and shrapnel.124
The P-3A was equipped with the finest avionics of the day. Along with the APN122 Doppler an APN-70 LORAN navigation systems, the P-3A was the Navy‟s first
patrol aircraft to be equipped with the ASN-42 Inertial Navigation System (INS). Its
ASW sensors included the APS-80 surface search radar, the ALD-2 electronic countermeasures (ECM) direction finding system, the ASQ-10 MAD detector, the ASR-3 diesel
exhaust detector, the AQA-3 passive acoustic signal, and the ASA-20 active echo
locating system.125 In 1965, in a major advancement to its passive acoustic capability,
the AQA-5 passive acoustic processor replaced the AQA-3 and ASA-20 systems.
The initial “Bravo” models, while incorporating new engines, retained most of the
avionics installed on the “Alpha.” Beginning in 1970 existing models of the P-3B
underwent a tactical navigation modification (TACNAVMOD) which digitized the older
analog navigation systems, additionally the AQA-7(v)-5 acoustic processor replaced the
older acoustic processor. Later improvements in the 1980s included the installation of
the AQA-7(v)-7 acoustic processor, the AAS-36 infrared detection set (IRDS), LTN-72
inertial, the ARN-99 OMEGA navigation systems, and a new ESM system, the AN/.ALR66(v)-1/2126
123
Reade, 30.
Ibid., 46.
125
Ibid., 17-19. It should be noted that various avionic systems were retrofitted into older models of the
Orion. An example of this retrofitting was the installation of the Bull-pup missile system in the “Alpha”
models.
126
Omega was a very low frequency (VLF 10-14 kHz) radio navigation system with a total of eight
worldwide stations transmitting phase-synchronized signals at five frequencies in a time-multiplexed
124
181
The final model of the Orion was the P-3C. Built in four basic configurations, the
“Charlie” was the first ASW aircraft to be equipped with a centralized computer. The
UNIVAC CP-901 / ASQ-114 computer linked the crew and sensors together. This
assisted in the decision making process. Other improvements to the initial “Charlie”
models included the APS-115 surface search radar, the ALQ-78 electronic support
measures system (ESM), the ASQ-81(v) MAD system, the AXR-13TV low-light-level
television system (LLLTV), and two of the AQA-7(v)-1 acoustic processor systems,
doubling the capability of earlier aircraft.127
Throughout the 1970s and 1980s, the “Charlie” underwent continual
improvements and modifications. The Update I saw the introduction of the AQA-7(v)-4
and ASA-66 tactical display, and the incorporation of a fourth computer logic unit with a
393,000 word magnetic drum.128 Of the various updates, the Update II aircraft saw the
greatest number of changes with regards ASW equipment. Earlier AQA-7 system were
replaced with the AQA-(v)-6/7, a much more capable system, and the AQH-4(v)-2 sonorecorder to record mission data. A critical upgrade to the ASA-76A, signal generator /
transmitter group, permitted the processing of the new DICASS sonobuoy.129 Other
changes included the replacement of the LLLTV system with AN/AAS-36 IRDS and the
installation of the AN/ARS-2 sonobuoy reference system, which provided continuous
format. Designed to provide all weather position fixing with 2-4 mile accuracy, the system was terminated
on 30 September 1997.
127
Reade, 27-28.
128
Ibid., 216. The ASA-66 tactical display was located between the two acoustic operators, provided
sonobuoy location data, and other tactical information such as target‟s estimated position.
129
DICASS is the acronym for “directional command activated sonobuoy system.” This system will be
discussed in detail in a later section.
182
update of all sonobuoy positions.130 In addition, the Update II was the first of the
“Charlie” models that was capable of firing the Harpoon anti-ship missile.
The Update II.5 continued the trend in upgrading existing systems, with the
installation of the AQA-7(v)-10/11 acoustic processors. A new capability was add with
the installation of the OV-78A integrated acoustic communications system (IACS) which
permit the aircraft to communicate with a submerged submarine.131
The last major upgrade to the Orion during the Cold War was the Update III
modification. This modification was a major upgrade to the acoustic processor of the P-3.
Throughout the Cold War, the Navy had operated the AQA-7 and its derivates. The
system had performed well but with the increased capability of the newer Soviet
submarines, the need for a more capable acoustic processor was at hand. The AN/UYS-1
advanced signal processor provided this needed capability.
Other changes to the Update III included the AN/ALR-66A/B-(V) 3 ESM system,
the AN/ARS-5 Sonobuoy Reference System, and the AN/ARR-78 Advanced Sonobuoy
Communications Link (ASCL) sonobuoy receiver systems.132 The final Cold War
improvement occurred in 1988, with the channel expansion (CHEX) program. This
program resulted in doubling the number of sonobuoys that the crew could monitor at one
time.133
Throughout the Cold War, the Navy continually upgraded and improved the
sensors needed to counter the Soviet submarine force. With the development of the P-3
130
Standard Aircraft Characteristics, P-3C Update II, NAVAIR 00-110 AP3-4, May 1984.
Reade, 33.
132
Ibid., 34-35.
133
Ibid., 35.
131
183
Orion, the Navy had found the ideal ASW airframe. With its suite of acoustic and nonacoustic sensors, it proved a match for the submarines of the Soviet Union.
The Cold War saw the introduction of new sensors and the improvement of existing ones.
The need to confront both diesel-powered and nuclear-powered submarines required a
variety of tools if the maritime patrol aircraft was to be successful in its attempt to
counter the Soviet submarine threat. Many of the sensors that proved to highly
successful against the diesel submarine, had little effect upon the deep diving, high-speed
nuclear powered submarine. The sensors used by the various models of aircraft came in
two basic categories, acoustic and non-acoustic sensors. The Navy classified those
systems that utilized sound to detect or track the submarine as acoustic sensors while
non-acoustic systems were those that utilizing other means, such as electromagnetic
energy, to counter the submarine threat.
Non-acoustic systems include the various radars, electronic counter-measure and
support measure systems, magnetic anomaly detecting equipment, visual and infrared
systems, and systems capable of detecting the exhaust fumes of diesel engines. During
the years of the Cold War, these systems saw continued improvements in the areas of
reliability, sensitivity, size reduction, and over time, more automated with the
development of computer technology.
The Navy ended World War II with numerous radar systems, most were bulky,
and difficult to maintain. In addition, these early systems were work intensive, requiring
great care if the operator was to detect the submarine. Throughout the Cold War, the
Navy‟s maritime patrol aircraft utilized one of three surface-search radars, the APS-20,
APS-80, or the APS-115.
184
In the later stages of World War II, the APS-20 began to enter service with the
first models of the radar installed on the Grumman TBM Avenger.134 The APS-20 was a
large system with the antenna assembly weighing 210 pounds and with a huge antenna
measuring 43 5/8, by 57 5/8 by 94 13/16 inches. This forced the external mounting of the
antenna causing excessive drag on the aircraft. With a range maximum detection range
of 200 nautical miles, the APS-20 represented a quantum leap in performance over earlier
radar set, however, it was an analog system and required considerable skill to operate this
system.135
The introduction of the P-3 Orion also saw the introduction of the APS-80
surface-search radar. Unlike the previous APS-20, which had a single large antenna, the
APS-80 had two smaller antennas. One of which was located in the nose of the aircraft,
with the other located in the tail section thereby providing 360˚ coverage.136 While an
improvement over its predecessor, the APS-20, the APS-80 still required considerable
manual manipulation by the operator. In the high-speed cat and mouse game of ASW,
reaction time was a critical component to success.
The APS-115 eliminated many of the problems associated with the earlier radars.
A frequency agile system, it operates within the “I” band.137 The new radar added the
ability to interface with the crew via the central computer that contributed greatly to the
ASW mission. The system displayed the radar contacts on a multi-purpose display. From
this display the operator could determine the range and bearing to the contact by placing
This was the Navy‟s first attempt at creating an AWACS aircraft with the PPI imagery transmitted to the
ship‟s command information center (CIC).
135
APS-20 @ Integrated Publishing, http://www.tpub.com/content/radar/TM-11-487C-105851.htm
136
Reade, 167.
137
Chris Johnson, ed. Jane’s Avionics, 7th Edition, 1998-99. (Alexander: Jane‟s Information Group Inc,
1999), 185. The “I” band are the frequencies from 8-10 GHz.
134
185
a cursor on the contact. This action would display the range, in nautical miles, and
bearing of the contact to the operator. To enhance the flow of information, the radar
operator could then transfer the position of the contact to the tactical coordinator
(TACCO). No longer was it necessary to plot such information on a chart, as it was
automatically available to the crew with the new technology.
As the radar systems came to rely upon computer technology, the electronic
support systems underwent a similar evolutionary change. A quick examination of the
early ECM / ESM suites, show that in order to detect, classify, and provide locating data,
a series of systems were needed. In order for the crew of the P-2V-5FS to detect and
exploit the submarine‟s radar, three distinctive systems, the AN/APA-9B auxiliary radar
assembly, the AN/APA-11 pulse analyzer, and the AN/APA-69 direction finding radar
set. The operator was required to manually analyze the target‟s signal and determine the
location of the target with no computer assistance. It was only with the introduction of
the AN/ALQ-78 ESM system that these procedures were to undergo a radical change.
The ALQ-78 is an automatic system that uses a high-speed rotating antenna and a
scanning, super-heterodyned receiver for acquisition. The system searches in specific
frequency bands for signals of interest. Operating in an omni-directional mode, it scans
360˚ around the aircraft. The detection of a signal of interested automatically initiates a
directional finding sub-routine generating a line-of-bearing on the operator‟s multipurpose display along with all the parametric data associated with the signal.138 This
138
Johnson, 340.
186
allows rapid classification the type and function of the signal by the operator.139 As with
the APS-115, the operator would then transfer the information to the TACCO.
Further refinement to the ESM/ECM systems came about with the introduction of
the AN/ALR-66(v)-3. The ALR-66 combines a high degree of sensitivity, with increased
accuracy. Operating in the “C” through “J” bands, the system is capable of detecting
most signals of interest.140 In the continuing pursuit of automation, the ALR-66
incorporated a removable emitter library. Utilizing EEPROM technology, mission
planners could reprogram the library to meet developing threats and tactical situation.141
The use of this ESM library is critical when operating near populated landmasses,
because it is only by using this type of technology, is possible to detect a single signal of
interest out of many signals that fill the airwaves.142
From the earliest days of combating the submarine, crews have relied upon the
“mark-1 eyeball” to detect the presence of a submarine.143 Visual detection has remained
a critical and viable means of countering the submarine into the 21st century and while a
viable means of detection during daylight hours, the night became an ally of the
submarine. The first systems used turned the dark into light by the use of powerful
searchlights, such as the AN/AVQ-2. These searchlights were descendents of the British
Leigh developed during World War II and the AN/AVQ-2 produced 70,000,000-candle
The information displayed includes the signal‟s radio frequency (RF), pulse width (PW), and pulse
repetition frequency (PRF).
140
This permits coverage from 500 MHz to 20 GHz.
141
EEPROM is a special type of programmable read-only memory chip (PROM). It is similar to the
erasable programmable read-only memory chip with the difference being the method used to erase the date.
An EPROM uses ultraviolet light, while the EEPROM requires only electricity to erase it.
142
Johnson, 334.
143
“Mark-1 eyeball” is a phrase frequently used to indicate visual means of search and detection without
the use of any technology.
139
187
power.144 While these searchlights were capable of illuminating the submarine in many
instances, in inclement weather they were severely limited. Additionally, the use a
searchlight by an aircraft, gave the submarine a target to shoot at.
To remedy this problem, the Navy looked to new technologies. The first of these
new technologies to be developed was low-light-level television system (LLLTV). While
the technology to create a low-level light television system is complex, the theory is
somewhat simple. The basic concept of a LLLTV system is its ability to display a
television picture with very little visible light.145 Though this was a passive system and
did disclose the location of the aircraft, it had limitations and liabilities. As with any
system that relies upon visible light, fog, rain, and snow seriously hampered its ability to
detect the target. To overcome these issues, engineers designed the system in such a
manner to make it extremely sensitive to light. So sensitive was the ARS-13 system that
it was possible to “blind” it with a bright light. An additional limitation to the AXR-13
TV system was its inability to track a target. Mounted in a fixed pod under the port wing,
inboard the number two engine, the camera could not swivel and track a target. Once
past the target the crew had no way of observing its actions, a serious tactical limitation.
The latest visual detection system installed on the P-3C is the AN/AAS-36 IRDS.
Utilizing the infrared spectrum, the system is capable of detecting targets day or night
and in any weather condition.146 Similar to the AAS-33 detection-and-ranging set on the
Navy‟s A-6E attack bomber, to provide greater tactical flexibility the detector unit,
designers mounted the detector unit in small turret under the nose of the aircraft. The
144
Edward M. Brittingham, Sub Chaser, the Story of a Navy VP NFO (Richmond, ASW Press, 2004), 50.
See P. Gardner, “Application of Low-Light Television,” Physics in Technology, Volume 9, 1978, p. 4753, for a detailed discretion of the works of low-level light systems.
146
The infrared spectrum is from 5.5-1000 microns.
145
188
turret is capable of rotating 360˚; it was now possible to track the target regardless of the
aircraft‟s relative position to the target. With its auto-track function, it was possible for
the operator to slew the turret to the target and allow the computer to maintain the
track.147
The last of the non-acoustic sensors used during the Cold War, was the magnetic
anomaly system. The AN/ASQ-8, the first of the post-war MAD systems, as with all
early MAD systems had detection ranges of 500 yards or less and in the desire to increase
its detection range, the Navy developed the highly successful AN/ASQ-10.148 The ASQ10 uses a magnetometer, which is a saturable inductor. The magnetometer is a coil of
wire wound on some high permeability core. To balance out the earth‟s magnetic field, it
is necessary to pass a dc current through the coil with results in the core being in a zero
magnetic field. A gimbal mounting was use to achieve stabilization and orientation of
the “MAD head.”149 This improved the diction range of the AN/ASQ-10 to approximately
1000 yards.150 All of the early MAD systems utilized mechanical means to stabilize the
“MAD head” the AN/ASQ-81 introduced a new and improved method of stabilization
and detection. Through the elimination of the mechanical gimbals by utilizing optically
pumped metastable helium, the AQS-81 had an effective range of 3000 feet.151
In an attempt to counter the diesel submarine, the Navy developed an exhaust gas
detector. Two models were installed in the Navy‟s patrol aircraft the AN/ASH-2 and the
147
Norman Friedman, The Naval Institute Guide to World Naval Weapons Systems, 1991/92 (Annapolis:
Naval Institute Press, 1991), 144-145
148
Alfred Prince, Aircraft versus Submarine, the Evolution of the anti-submarine aircraft, 1912-1972
(Annapolis: Naval Institute Press, 1973), 104.
149
A gimbal mounting permits a body to incline freely in any direction or suspends it so that it will remain
level when its support is tipped.
150
Friedman, 686.
151
Ibid. Metasble helium atoms are produced by an electric discharge in a small volume of helium gas in
its ground state.
189
AN/ASR-3. Both had the capability to detect the exhaust fumes from the snorkeling
submarine. Flying a zigzag pattern, the aircraft was able to localize the target. Of limited
range, the Navy soon abandoned the “sniffer” in favor of more capable sensors, such as
the sonobuoy.152
Of the various sensors developed during the Cold War, the acoustic systems
proved most successful. Classified as either passive or active, depending upon how the
system utilized sound energy, acoustic systems proved capable of countering the
submarine threat. Passive systems detecting sounds generated by the submarine and
transmitted the information to the aircraft. Active systems generated sound energy,
which reflected off the submarine and return to the sensor. Each had its strengths and
weaknesses and employment depended upon the tactical situation. In addition, these
acoustic systems were composed of two parts, the dry end, which was the processor in
the aircraft, and the wet end, which was the sonobuoy.
The first active system developed by the Navy for airborne use was codenamed
“Julie.”153 “Julie” worked with the CODAR processor, the AN/SSQ-2B sonobuoy, and
explosive signals. To generate the necessary broadband sound wave, the crew dropped
an explosive charge, a practice depth bomb (PDC), on top of one of the sonobuoys. The
purpose of the PDC was to generate a broadband sound wave that would strike the
submarine and reflect back to the sonobuoy. The operator would then measure the
difference in the time arrival of the signal on the CODAR processor, resulting in a line-of-
While the “sniffer” worked relatively well in areas such as the mid-Atlantic, in coastal waters air
population would saturate the sensor
153
It has been reported that the engineers in honor of a stripper selected the code name “Julie” at a local
nightclub.
152
190
bearing.154 To resolve the ambiguity, it was necessary to deploy another set of buoys and
drop another explosive charge. “Julie” was a time consuming process and the Navy
replaced it in 1957 with the AN/SSQ-15, B-size sonobuoy.155 The SSQ-15 was the first
active sonobuoy to go into production. It projected an omni-directional continuous wave
(CW) signal instead of the broadband explosive pulse used in Julie. A vast improvement
over the earlier system, the SSQ-15 allowed the crew to determine the range to the
target.156
Improvements to the SSQ-15 followed with the introduction of the SSQ-47, an “A”
size buoy that produced a free-running CW pulse every ten seconds on one of six sonic
frequencies. As with the SSQ-15, the SSQ-47 provided only range data. The next
evolutionary step in the development of active sensors was the introduction of the SSQ50, part of the command activated sonobuoy system (CASS).157 The SSQ-50 had the
advantage of being control by the operator. The operator had the ability to control when
the buoy would ping and had the capable of sending the transducer to deeper depths. As
with the SSQ-47, the only tactical data provided was the range to the target. This
changed with the introduction of the AN/SSQ-62 directional command activated
sonobuoy system (DICASS). The SSQ-62 had all the capabilities of the SSQ-50 plus the
154
Friedman, 665.
The letters, A, B, C etc, designate buoy size. Most current buoys are “A” size, which have a diameter of
4.875 inches and a length of 36.00 inches. The larger “B” size buoy is 6.875 inches in diameter and a
length of 60.00 inches.
156
Roger Holler, “Not Ready Retirement: The Sonobuoy Approaches Age 65,” Sea Technology, November
2006. http://findaricles.com/p/articles/mi_qa5367/is_200611/ai_n21403257
157
The SSQ-50 and SSQ-62 were part of the P-3s active system. Modifications to the AN/ASA-76 signal
generator / transmitter group were necessary in order to use either of these buoys.
155
191
ability to provide a bearing to the submarines. This allowed the operator to “fix” the
target with a single ping.158
While there were considerable improvements to active sonobuoys, MAD,
ESM/ECM, and radar systems, it was the development of low frequency analysis and
recording that proved decisive in the struggle to contain the Soviet submarine fleet.
The Navy experimented with two types of acoustic processing in the 1950s, low
frequency, and recording (LOFAR) and correlation-display analyzing recorder (CODAR).
LOFAR uses narrow band acoustic signals from the submarine‟s machinery and
propellers to detect and track the target, while CODAR correlated broadband acoustic
signals from a pair of sonobuoys yielding bearing data to the target.159 Of the two
methods, LOFAR proved the most successful and the Navy abandoned CODAR
processing early 1960s.
CODAR used two precisely spaced SSQ-23s, introduced in 1956, to detect and
correlate broadband LF signals using the time difference of arrival method. When
successful, the first CODAR pair gave an ambiguous bearing, and at least one other pair
of buoys was necessary to resolve the bearing ambiguity. The fundamental weakness of
the CODAR was that the broadband signal was speed dependent and when the submarine
decreased speed, the signal would be lost.160
LOFAR processing differed from other passive means of detection in that it uses a
narrow frequency range; code named “Jezebel,” LOFAR processing was to be the
primary means of detection and tracking of Soviet submarines in the Cold War. Specific
158
For additional information concerning various sonobuoys see Navy Training System Plan Navy
Consolidated Sonobuoys, N88-NTSP-A-50-8910 B/A, September 1998.
159
Narrow-band and broadband refer to the bandwidth of the acoustic source.
160
Owen R. Cote, Jr., “The Third Battle: Innovation in the U.S. Navy‟s Silent Cold War Struggle with
Soviet Submarines” Naval War College, Newport Papers, Paper Number Sixteen, (2003), 32.
192
pieces of rotating machinery within the submarine create narrow band sources, while a
submarine‟s broadband signature resembles background noise in that it contains a
continuous spectrum of frequencies within which the source levels at particular
frequencies rise and fall in a random fashion around a mean over time. Narrow band
sources in contrast, generates sound at several specific frequencies continuously. When
compared to the background noise generated at these specific frequencies, which will
average out over time to x, the signal plus noise received at the tonal frequency will
average out over time to x + y, with y being the source level of the signal. In order to
detect these specific frequencies, a passive sonar system uses a spectrum analyzer that
passes the incoming broadband signal through a set of narrowband filters tuned to the
frequencies of interest. Narrowband processing will detect signal y as long as it remains
high enough to be reliably distinguished from the background noise.161 Some form of
time compression was needed for the exploitation the LOFAR spectra.
The early LOFAR systems, such as the AQA-3 and AQA-4, were the first to
accomplish this time compression in a practical fashion. Engineers were able to achieve
the necessary time compression by recording the incoming signal on to a magnetic tape
and then transferring it to a secondary analog memory. In the AQA-3 system, the
secondary memory was a round five-inch in diameter magnetic tape that slowly passed
over an erase head and then a recording head on the outside of the tape. The pickup
heads for analysis rotated rapidly on the inside of the tape.162
Building upon the success of the AQA-3/4 systems, the next step in the
evolutionary development of LOFAR systems, was to go from a mechanical to a solid-
161
162
Cote, 21.
Friedman, 680.
193
state system. The AQA-5 system saw the introduction of a solid-state delay-line time
compressor (Deltic). Unlike earlier attempts at time compression, the Deltic contained a
digital memory and a delay line. Incoming acoustic data is digitized in the analyzer It is
then circulated back through the system were the oldest bit of data is dropped and a new
on each pass back through the system the oldest bit of data is dropped and new data is
added. The product of the clock rate and the delay-line is a multiplication factor. This
factor could then be applied both to multi-buoy operations and to better the resolution.
When compared to the older systems the AQA-5 had an increased compression factor of
seventeen.163 The AQA-5, when compared to the AQA-3/4, improved the operator‟s
ability to classify the submarine by using a narrower effective bandwidth, a wider display,
and better frequency resolution. While the Deltic was a vast improvement over earlier
systems, it was still fundamentally an analog device. It was only by using digital analysis
techniques (FFT), that a truly digital processor was developed and the first such
processor, the AQA-7(V)-1, was introduced with the P-3C.164
The AQA-7 acoustic processor underwent continual improvements, with the
incorporation of five major changes. When compared to the AQA-5, the frequency of the
AQA-7 was greater and was more sensitive. First introduced in 1969, the AQA-7(V)-1
also saw the introduction of directional LOFAR processing (DIFAR).165 DIFAR
processing combined the advantages of LOFAR, with the additional capability of
providing a bearing to the target. Additional capabilities included incorporating
automatic line integration (ALI) which permitted automatic detection of a strong and
consistent source. The introduction of the AQA-7(V)-8/9 saw the introduction of
163
Friedman, 680.
Ibid.
165
DIFAR processing uses the SSQ-53 sonobuoy.
164
194
DICASS processing and the AQA-7(V)-10/11 provided a passive tracking algorithm (PTA)
to the operator.166
The last acoustic processor developed for the maritime patrol aircraft during the
Cold War, was the UYS-1. Installed in the P-3C Update III, it is a programmable
acoustic processor. First introduced in 1981, by October 1984, the Navy had procured
250 units. Recognizing the need to match the rapid improvements to Soviet technology,
the Navy sought a programmable system. The advantage of a programmable processor
allows for rapid changes to the system to meet the changing capabilities of Soviet
submarines.
As the acoustic processors continued to evolve and improve, the need for more
sensitive sonobuoys also grew. In 1960, the Navy introduced the AN/SSQ-28 passive
omni-directional LOFAR sonobuoy. With the capability to operate down to 10 Hz, it was
the first true LOFAR sonobuoy. As with other sensors, the Navy developed a variety of
sonobuoys. In 1964, in an attempt to develop a long life search sonobuoy, the Navy
introduced the AN/SSQ-38, used by the crews to search large areas for extended
periods.167 Introduced in the same year, the AN/SSQ-41, an improved LOFAR sonobuoy,
replaced the AN/SSQ-28. The AN/SSQ-41 was an omni-directional sonobuoy with an
operating frequency of 10 Hz to 20 KHz, and could be set to operate at either 60 or 300
feet. With an operating lifetime of 1, 3 or 8 hours the SSQ-41 and its successors became
the most widely used sonobuoy. Replaced by the AN/SSQ-41B, the new buoy had a
maximum operating depth of 1000 feet.168
166
PTA is a computer program that automatically tracks the submarine with little input from the operator.
The AN/SSQ-38 had a 72-hour life.
168
Friedman, 675.
167
195
While the SSQ-41 was a highly flexible buoy, its inability to provide bearing
information to the target was a great hindrance to the crew. This need resulted in the
development of the AN/SSQ-53, DIFAR sonobuoy. While in most respects, the SSQ-53
was similar to the SSQ-41B, with an operating life of 1 or 8 hours and operating depths
of 90 or 1000 feet, there were two critical differences. One was the frequency response
of the sonobuoy and the second was its ability to provide bearing information to the
target.169 The SSQ-53 sonobuoy had a frequency range of 10 Hz to 2,400 Hz and while
considerable less than the SSQ-41, proved adequate for all normal tactical evolutions.170
The SSQ-53, upon water entry, converts the sound waves into amplified electronic
signals and provides a magnetic reference for each signal through utilization of a flux
gate compass.171
The SSQ-53 underwent a series of changes during the Cold War. Because the
SSQ-53 was very sensitive to motion and vibration, numerous changes were made to
minimize these problems. The SSQ-53D incorporated changes that decoupled the
hydrophone from the rest of the sonobuoy assembly. Engineers accomplished this in part
with elastic-compliant suspensions, damper disk, drogues, and flow shields.172 Other
changes included additional depth and operating setting.173
In the quest for greater sensitivity and detection range, the Navy introduced the
AN/SSQ-77, vertical-line array DIFAR sonobuoy (VLAD). Unlike the DIFAR sonobuoy
The AN/SSQ-53 had a frequency response that was limited to 10 Hz – 2.4 KHZ. Later versions had
operating limits of 1, 3, o4 8 hours and a frequency response of 5 Hz – 2.4 KHz.
170
Global Security, http://www.globalsecurity.org/military/systems/ship/systems/an-ssq-53.htm. Most
submarine generated narrow-band sounds occur less than 1,000 Hz.
171
Navy Training System Plan Navy Consolidated Sonobuoys, N88-NTSP-A-50-8910 B/A, September
1998, page: I-7.
172
Holler.
173
The SSQ-53B had 3 depth settings, 100, 400, and 1,000 feet. The operating life of the sonobuoy could
beset to 1, 3, or 8 hours.
169
196
that had a single hydrophone, the VLAD buoy uses nine omni-directional hydrophones, in
conjunction with a conventional DIFAR hydrophone for bearing computations.174 The
initial SSQ-77 buoys had the frequency response of the SSQ-53, with two operating lives,
one or eight hours. To increase the sensitive and detection capability of the new buoy,
engineers turned to beam forming technology. Beam forming provides enhanced
detection of the desired threat signals while attenuating the reception of unwanted
noise.175 Designed from the outset as a search sensor, the SSQ-77 had an operating depth
setting of 100 feet in order to exploit bottom bounce signals.176
Equipped with these complex and highly capable sensors, crews had the ability to
detect, track, and, if need be, attack and hostile submarine. Additionally the aircraft had
come of age, no longer were crews hindered by the technical limitations of their aircraft.
With these issues resolved, the only remaining concern was to develop a weapon capable
of destroying these fast, deep diving submarines.
During the Cold War, it became readily apparent that the Navy needed
sophisticated, homing torpedoes, or special weapons to destroy modern submarines.177
Conventional depth bombs, rockets, cannon were weapons of a bygone era. Modern
submarines spent little time on or near the surface unlike the U-boats of World War II.
Though American crews conducted no attacks against Soviet submarines during the Cold
War, the Navy expended considerable time and money developing weapons capable of
sinking the largest Soviet submarine.
174
Friedman, 677.
Navy Training System Plan Navy Consolidated Sonobuoys, N88-NTSP-A-50-8910 B/A, September
1998, page: I-2.
176
Sound transmission paths will be discussed in a later section.
177
“Special weapon” is euphemism for nuclear weapon.
175
197
At the end of World War II, the Navy had seven torpedoes in service use. Of the
seven weapons, the Mk-13 and Mk-24 were ASW torpedoes used by the various ASW
aircraft employed by the Navy. The Navy soon removed the Mk-13 from its inventory
and introduced the Mk-34 an improved Mk-24. The Mk-34 was a large weapon,
weighing 1,164 pounds, with a diameter of 19 inches, and an overall length of 124 inches.
Electrically powered, it had a search speed of 12 knots and once acquired by its passive
homing sensor the torpedo would increase speed to 17 knots.178 Entering service in 1948,
over 4,000 produced in the 1950s and was the primary airborne ASW weapon on the
era.179
While the Mk-34 was a considerable improvement over earlier torpedoes, it
possessed serious limitations. Due in part to its weight, only a limited number of
weapons could be carried and its relatively slow speed proved to be a great handicap
when confronting a high-speed nuclear powered submarine. What the Navy desired was
a lightweight weapon with greater speed. Setting a maximum weight limit at 350 pounds,
engineers began the development of the Mk-43 in 1950.180
The Mk-43 was the archetype for all future anti-submarine torpedoes. Entering
service in 1952, the Navy purchased approximately 5,000 Mk-43s. Electrically propelled
and weighing only 260 pounds, its size and length made it readily adaptable to the bombs
bays of all naval aircraft. While the introduction of the Mk-43 solved the size issue with
its top speed of only 14 knots, it was incapable of countering the new high-speed
178
E.W. Jolie, A Brief History of U.S. Navy Torpedo Development, NUSC Technical Document 5436
(Newport: Newport Laboratory, Naval Underwater, 1978), 48.
179
Ibid.
180
Ibid., 49.
198
submarines that were entering service.181 This led to the development of the Mk-43 Mod
3, which achieved a maximum speed of 21 knots and had a run time of six minutes. Even
these improvements proved inadequate with the advent of the nuclear powered
submarine.182
This requirement led to the development of the Mk-44. With a speed of 30 knots,
the MPA was finally equipped with a torpedo capable of countering the speed, deep
diving nuclear submarine. A second-generation ASW torpedo, the Mk-44 entered service
in 1956 and embodied all of the requirements of a modern ASW torpedo. With a 73pound warhead, it provided the necessary force to disable the larger nuclear submarines
entering service and while a potent weapon, improvements needed to be made to keep
pace with the submarine‟s development.183
This need to improve performance necessitated a new torpedo. Developed by the
Naval Ordnance Test Station at Pasadena California, and Aerojet General, the Mk-46, a
third generation torpedo, entered service in 1963. A 500-pound class weapon, a solidfuel turbine engine provides the necessary power to propel the Mk-46 Mod 0 at speeds of
45 knots. The torpedo consists of four subsystems, which allows for rapid repair of a
defective subsystem. Throughout its years of service, the Mk-46 underwent of series of
incremental improvements to its performance. The Mod 1 saw the replacement of the
original turbine engine, with a 2-stroke swash-plate engine, driven by a news high-energy
181
Post-World War II Acoustic ASW Torpedo Development A brief history of the MK-35, MK-41, MK-43
and MK-44 By James V. Shannon Updated 14 June 2002
http://www.navweaps.com/index_tech/tech-082.htm
182
Jolie, 115. Unlike anti-surface torpedoes which used range and speed to measure performance, antisubmarine torpedoes used speed and run time to measure a weapon‟s effectiveness
183
Duncan Lennox, ed. Jane’s Air-launched Weapons, 35th Issue (Alexandria: Jane‟s Information Group,
2000), 744.
199
liquid monopropellant fuel.184 Mod 2 saw the introduction of improved computer logic
and a new autopilot that permitted the torpedo to re-attack if the first attempt failed. By
1984, the Navy determined that there was a need to improve the weapon‟s shallow water
and slow speed attack capability. As with any weapon, the Soviet Navy had discovered a
potential weakness to the Mk-46. The various models of the Mk-46 all used the Doppler
Effect to determine the target‟s position and a shallow, slow speed target could be lost
against the backdrop of the water‟s surface.185
The other weapon employed by the Navy‟s ASW forces, in the event of a
confrontation between the two great superpowers, was the B-57. The B-57 was a
lightweight, multipurpose nuclear depth charge and bomb. Development started at Los
Alamos National Laboratory (LANL) in 1960, with initial tests conducted in 1962 during
Operation Dominic Phase 1. A very versatile weapon capable of air, surface, and
underwater bursts, a host of American aircraft and helicopters employed it.186
The B-57 entered service in 1964 and after a production run totaling
approximately 3,100 weapons, ceased in May 1967. By 1975, the Navy began reducing
the size of the inventory and by 1983; only 1,000 bombs remained in the Navy‟s arsenal.
A low-yield, low-drag weapon, the B-57 weighed 3,060 pounds (230 kilograms), was
approximately 10 feet long and had a diameter of 15 inches. With a nuclear yield of 5-10
kilotons, the detonation of the B-57, would create shock waves sever enough to destroy
the target.187
The fuel was called “Otto fuel.”
Lennox, 745.
186
Along with the P-3 Orion, the B-52H, Stratofortress, S-3 Viking, A-6 Intruder, A-7 Corsair, F-4
Phantom, F/A-18 Hornet, F-111 Raven, British Tornado and the SH-3 Sea King, SH-60F Seahawk
helicopters were all capable of employing the B-57.
187
Duncan Lennox, ed. Jane’s Air-launched Weapons, 35th Issue (Alexandria: Jane‟s Information Group,
2000), 467.
184
185
200
Armed with modern aircraft, avionics systems, and highly effective weapons, the
maritime patrol forces of the United States Navy was to conduct a relentless campaign
against the submarine forces of the Soviet Union.
The key to successful anti-submarine warfare is the ability to detect the submarine
and strip away its invisibility. In World War II the development of radar forced the
diesel submarine to submerge where due in part to its slow speed and poor endurance
proved incapable of intercepting Allied convoys. Radar striped the submarine of its
invisibility, allowing the maritime patrol aircraft to control large segments of the ocean.
With the development of nuclear power, this dominance by the aircraft quickly
changed. The nuclear powered submarine, with its unlimited endurance, and highsubmerged speed, was capable of defeating the ASW systems of World War II. With
radar proved to be of little use against the nuclear submarine forcing the Navy to develop
new ways of stripping the submarine of its invisibility. Sound became the primary means
of detection however at its core, anti-submarine warfare is a problem of organization, and
to be successful it is necessary to bring together a variety of disciplines.188 The Cold War
saw the use of land, sea, and air assets in the struggle to contain the Soviet submarine
fleet.
For airborne assets to be effective, they needed some sort of queuing data to a
submarines approximate location. In War II, HF/DF stations provided this datum.189
Intercepting radio communications from U-boats, the Allies were able to triangulate their
position, thereby providing ASW forces with a position in which to begin their search.
Leland C. Allen, “The Role of Undersea Warfare in U.S. Strategic Doctrine,” Military Affairs, vol. 23,
no. 3 (Autumn, 1959), 156.
189
German radio signals would be intercepted and the signals and through triangulation a position would be
obtained.
188
201
While this method provided successful in World War II Soviet submarines seldom
communicated with their headquarters in such an overt manner. To provide their ASW
forces this datum, the Navy turned to sound and the development of the sound
surveillance system (SOSUS).
SOSUS grew out of work performed by Professor Maurice Ewing of Lehigh
University in 1937. During seismic refraction experiments preformed with explosive
charges, Ewing noted that a chain of echoes, generated by repeated reflections between
the ocean bottom and the surface could be detected onboard the research vessel. From
these observations, Ewing postulated that if there were horizontal sound propagation
paths in the deep ocean that avoided the surface and bottom reflections the acoustic signal
could travel hundreds of miles.190 Know as the “deep sound channel,” it provided the
means to detect Soviet submarines as great distances and provided a datum for the
maritime patrol aircraft to search.
Initial development of SOSUS began under the code name CAESAR and in
January 1952, the Navy laid the first prototype, a 1,000-foot long array of forty
hydrophone elements, in 240 fathoms of water, off the coast of Eleuthera Harbor in the
Bahamas.191 The system proved to be highly effective and the Navy decided to install
arrays along the entire eastern seaboard of the United States. In 1954, the west coast
received a similar system, with an additional array installed off Argentia Newfoundland
Edward C. Whitman, “SOSUS, the “Secret Weapon” of Undersea Surveillance,” Undersea Warfare, the
Official Magazine of the U.S. Submarine Force, Winter 2005, vol. 7, no. 2.
191
Whitman.
190
202
in 1959.192 The arrays were connected by cables to shore stations called Naval Facilities
(NAVFACS) were naval personnel analyzed the signals.193
Following its success in the Atlantic, the Navy established similar lines of arrays
throughout the world. The system installed on the Pacific coast was code named
Colossus while the arrays linking Norway with Bear Island and those linking Scotland,
Greenland, and Iceland together were code named Barrier. In the western Pacific, the
Navy strung the array, code named Bronco, from the southeastern tip of Hokkaido along
the Kurile Islands to a point off the Aleutian Islands. The Navy also laid arrays on the
Atlantic side of the Straits of Gibraltar, throughout the Mediterranean Sea, in the waters
around Hawaii, and in the Indian Ocean. Anywhere the oceanographic conditions
permitted the use of the deep sound channel, the Navy installed SOSUS.194
The introduction of narrowband signal processing permitted SOSUS arrays
detection ranges that could extend for thousands of miles. In the Pacific, SOSUS arrays
were capable of tracking Soviet Yankee class submarines at ranges of between 400 and
1,000 miles.195 Sources commonly detected from these submarines were those produced
by the propeller at the rate at which its blades turned and those associated with particular
items of rotating machinery. The sounds produced by these sources were aspect and
speed dependent and when taken together gave SOSUS the ability to detect and classify
Soviet submarines and given time the ability to track them. If two or more arrays held
192
Cote, Jr., 25.
Tom Stefanick, Strategic Antisubmarine Warfare, and Naval Strategy (Lexington: Lexington Books,
1987), 39.
194
Michael T. Isenberg, Shield of the Republic, the United States Navy in the Era of Cold War and Violent
Peace, Volume 1 (New York: St. Martin‟s Press, 1993), 366.
195
Stefanick, 40.
193
203
contact an area of probability could be generated in, which patrol aircraft would search in
an attempt to localize the target‟s position.
With the introduction and success of SOSUS, the Navy developed an ASW
doctrine based upon the concept of placing barriers between Soviet ports and open-ocean
patrol areas. The Navy established barriers in deep water in such a way as to cover a
geographical choke point. The waters between Greenland, Iceland, and the United
Kingdom form one such choke point. The SOSUS stations provided long-range acoustic
detections of Soviet submarines as they attempted to transit the choke point thereby
providing cueing data for the maritime patrol aircraft. By 1974, there were twenty-two
such stations and by 1981, the Navy had established thirty-six NAVFACs throughout the
world.196
The change to passive acoustic was the result of the need of the nuclear submarine
continuously operate reactor coolant pumps when under-way. Additionally Soviet
nuclear submarines used reduction gears to reduce the speed of the steam turbine to a
useable level and the American ASW forces could detect the noise produced by the
impact of these gears.197 It was through the analysis of underwater sound recording
obtained from various sources that the Navy developed the processes known as hull-toemitter correlation (HULTEC).198 By collecting and analyzing these recordings, the Navy
soon had the capability of acoustically identifying individual Soviet submarines. Began
196
Cote, 41.
Turbines revolved at 3,000 RPM and more, while propellers need to operate at speeds less than 500
RPM.
198
Christopher Ford and David Rosenberg, The Admirals’ Advantage, U.S. Navy Operational Intelligence
in World War II and the Cold War (Annapolis, 2005), 82. The radars carried by submarines and warships
provided another way in which to HULTEC a vessel.
197
204
in June 1951, by August 1959, the Navy‟s acoustic analysis effort was processing 700
tape recordings a month.199
The acoustic intelligence collected from these recordings provided critical
information used by mission planners in the execution of ASW mission performed by the
maritime patrol squadrons. Of the items obtained from these recordings, the most critical
component to the execution of the ASW mission was the sound pressure level (SPL) of
the target of interest. SPL is the determination of the noise level generated by various
systems on board submarines measured in decibels and Project Beartrap, specially
equipped aircraft and manned by highly trained crews, provided this critical information
to the mission planners.200
Only by knowing the sound pressure levels generated by a submarine was it
possible to determine the oceanographic transmission path to the sound. The type of
sound transmission path was a critical component to the localization of a submarine‟s
position.201 Mission planners used a formula called the Figure of Merit (FOM), which
gave a 50% probability of detection, to determine which transmission paths and their
range would be available to the crews.
To determine the FOM, the mission planner would use the following formula:
FOM = LS – (LN – NDI) – NRD.202 Using the result derived from this equation with a
propagation loss curve, the range of the various oceanographic transmission paths would
199
Wyman H, Packard, A Century of U.S. Naval Intelligence (Washington D.C.: Department of the Navy,
1996), 190.
200
CNO Project K-0416 is the official designation of this project.
201
The three transmission paths used by the crews were convergent zone, bottom bounce, and direct path.
For a detailed explanation of these transmission paths see Appendix 6 of Strategic Antisubmarine Warfare
and Naval Strategy.
202
LS is the radiated noise level of the submarine. LN is the Omni-directional background noise. NDI is the
directivity index and NRD is the recognition differential (the operators ability to recognize the target). Both
NDI and NRD are represented by a negative value. All values are measured in decibels.
205
be determined.203 Crews and mission planners would use these ranges to determine the
proper spacing of the sonobuoy patterns.204 By the late 1950s, the Navy had established
an Antisubmarine Warfare Environmental Prediction System (ASWEPS) whose mission
was to collect daily information from around the world in order to predict oceanographic
conditions in order to support the American ASW forces.205
During the Cold War, ASW missions began with a detailed brief. In the early
years of the Cold War, crews received their brief at an Anti-Submarine Classification and
Analysis Center (ASCSC). In 1972, the ASCSCs underwent a series of upgrades that
permitted real-time mission planning and evaluation. The Navy classified these new
upgraded facilities Tactical Support Centers (TSC).206 The TSC was able to coordinate
the contact p obtained from the NAVFAC with critical oceanographic data from the
ASWEPS to develop an effective search plan, which proved critical in the battle against
the Soviet submarine force.207
The key items of an ASW brief were the oceanographic conditions, the type of
submarine and its mission. The oceanographic conditions dictated the type of sonobuoy
pattern used and the type of submarine and mission aided the crew in recognizing the
contact. At locations such as the Greenland-UK Gap, the entrance to the Mediterranean
Sea, and the waters south of the Aleutian Islands, crews normally employed barriers
tactics as the submarine was transiting to its patrol area. With SOSUS providing a course
and speed, to be successful it was only a matter of placing the sonobuoy in front to the
203
A propagation loss curve represents the attenuation of a frequency a function of range and signal
strength. A standard curve is a graph with the x-axis representing range, measured in miles and the y-axis,
204
Operations Analysis Study Group United States Naval Academy, Naval Operational Analysis
(Annapolis: Naval Institute Press, 1972), 181.
205
Tactical and Strategic Antisubmarine Warfare, a SIPIR Monograph (Cambridge: MIT Press, 1974), 15.
206
Edward M Brittingham, Sub Chaser, the Story of a Navy VP NFO (Richmond, ASW Press, 2004), 241.
207
In typical Navy, fashion in the late 1980s the TSC was renamed Anti-submarine Operations Center
(ASWOC). This designation lasted until 1993 when ASWOC was replace in favor of TSC.
206
submarine.208 Once detected the crews began the process of localization and tracking by
dropping three or four sonobuoys in various geometrical shapes.209 Tracking a submarine
for days, crews were able to collect value ACINT data.
While barriers worked well when the submarine was transiting, once on patrol, it
became a much more difficult problem. With the introduction of the submarine launch
missile, the Soviet Navy deployed their SSB / SSBN submarines in the waters off the
coast of the United States. Golf SSB and Hotel SSBN submarines with their short range
SSN4 / 5 missiles patrolled the eastern seaboard from Florida to Maine, while in the
Pacific Ocean; Soviet submarines patrolled the waters off the coast of Mexico to
Canada.210 By 1969, the Yankee class replaced the Golf and Hotel class greatly
expanding their patrol area thereby making detection much more difficult.211
To find these quiet patrolling ballistic submarines, the Navy developed an entirely
new method of search. While barriers worked well against the transiting submarine, once
a submarine reached its patrol area, the course of the submarine was completely random
and while two or more SOSUS arrays could provide a datum, due to the tremendous
ranges and inherent bearing error, the resultant fix was hundreds of miles in size.212 To
search these large areas, the Navy deployed large search patterns that exploited the
convergent zone (CZ) transmission path.213
208
Brittingham, 137
Sonobuoy tracking patterns consisted of squares, triangles, circles, and lines. The distance between
sonobuoys was based upon the FOM.
210
The Nuclear Information Project, http://www.nukestrat.com.index.htm, Russian Nuclear Submarine
Patrols @ http://nukestrat.com/russia/subpatrols.htm
211
Ibid.
212
Stefanick, 40. In the eastern Pacific, the Navy has achieved contact on Yankee class at ranges between
400 – 1,000 nautical miles.
213
Fleet Oceanographic and Acoustic Reference Manual, RP-33 (Stennis Space Reference Publication
Center, 1986), 89-90.
209
207
When searching these large areas, crews would drop large numbers of sonobuoys,
spaced at ranges determined from the FOM. Once the crew deployed the search pattern,
the acoustic operators would monitor the sonobuoys in hopes of detecting the submarine.
Tedious and boring, the acoustic operators would spend hours monitoring the sonobuoys
in their search for the submarine. For the mission to be successful, two events had to
occur. One the submarine had to enter the CZ annulus and two, the acoustic operators
recognizing the submarine as it entered the annulus.214 Once the crew had gained this
initial contact, it would then proceed to refine the target‟s position by dropping additional
sonobuoys.
During the Cold War, the Navy maintained crews on an alert status, ready to
launch with one hour.215 Speed was a critical component to the success or failure of an
ASW mission. Cueing data, provided to the MPA had to be acted upon quickly as the
estimated position of the submarine was not a fixed point, rather an expanding circle,
getting ever larger with the passage of time. It was common to fly several missions in
rapid succession, this ensured complete coverage of the search area or the gathering of
critical ACINT.
Throughout the Cold War, American maritime patrol aircraft, working with
various other sensors and intelligence sources, continually hunted the submarines of the
Soviet Navy. The acoustic advantage held by the American forces permitted detections
at extended ranges, and the collection of hull specific acoustic data ensured properly
trained acoustic operators. While the Soviet Union was to close this gab with the
214
Fleet Oceanographic and Acoustic Reference Manual, RP-33 (Stennis Space Reference Publication
Center, 1986), 92.
215
This alert status was maintained both in the continental United States and at over-seas bases.
208
introduction of the Victor III in the late 1970s, the improvements proved too little and too
late as the Soviet empire slowly collapsed in the 1980s.216
216
Cote, 70-71.
209
Conclusion
Conclusion
Unlike earlier conflicts in which the maritime patrol aircraft, the Cold War, rather
ending abruptly, came to a gradual end in the late 1908s during the administration of
Soviet leader Mikhail S. Gorbachev. Due in part to Gorbachev’s internal reforms,
political power shift from the Communist Party to the various republics of the Soviet
Union and in late 1991, the Soviet Union collapsed bringing to an end the Cold War.
Through three conflicts, the American maritime patrol aircraft confront the
submarines of its opponent. At the beginning of each conflict, the submarine held a
technological advantage and through the early years of the conflict dominated the
battlefield. World War I saw the introduction of the submarine, a warship with the
capability to submerge and strike from beneath waves. A new concept that found the
Allies ill prepared to meet. The submarine held this advantage during the early years of
the war but by 1917, the development of the long-range seaplane helped deny the
submarine the ability to operate on the surface. The maritime patrol aircraft forced the
submarine to submerge where with its slow submerged speed, it proved incapable of
intercepting the convoys.
World War II saw the United States confronting a highly professional and
technological advanced foe, in the U-boats of Nazi Germany. The American Navy found
itself unprepared to meet the challenge of the German submarine force as Germany
attempted to force a strategic decision by destroying the Allies shipping capacity.1
Initially the Germans achieved a great deal of success however, the anti-submarine
warfare effort of the Allies demonstrated that the concept of submarine operations where
Werner Rahan, “German Naval Power in the First and Second World Wars,” in Naval Power in the
Twentieth Century, ed. N.A.M. Rodger (Annapolis: Naval Institute Press, 1996), 97.
1
210
the submarine operated on the surface whilst remaining mainly stationary while
submerged was a failure.2
Driven from the surface by the radar equipped long-range maritime patrol aircraft
the U-boats where forced to operate submerge. Unable to escape the Allied surveillance
the Type VII and IX submarines proved incapable of defeating the Allied ASW forces.
While Germany was developing submarines capable of defeating the World War II
generation of maritime patrol aircraft, the effort proved to be too little and too late to
have an significance in the battle.
The postwar saw the introduction of nuclear power. As the submarine’s primary
means of propulsion, no longer was the submarine forced to operate on the surface to
close with its target. With its high speed and unlimited endurance, the nuclear powered
submarine was a true submergible. No longer required to operate on the surface, tactics
that had proven so successful in the final years of World War II were unable to counter
the new threat. Technology that had proven its worth in 1945 was suddenly obsolete and
to counter the emerging threat, the United States Navy needed find new technologies that
would render the submarine visible once again.
The initial breakthrough occurred with the exploitation of passive acoustics to
search, localize, track, and classify submerged submarines by using the sounds generated
as a signature. Passive acoustics provided the means to search large areas of ocean and
when combined with the speed and endurance of the modern maritime patrol aircraft the
American forces possessed the means to counter the Soviet submarine threat.
Throughout the 1960s and 70s the Americans held a significant acoustic advantage over
the vast majority of Soviet submarine fleet. Able to detect and track Soviet submarines at
2
Rahan, 97.
211
great distances and for extended periods, the ASW forces of the United States Navy
dominated the battlefield.
As with all military advantages, this acoustic advantage could not last
indefinitely. The introduction of the Akula class saw this acoustic advantage evaporate
and if the Cold War had continued, the pendulum would have swung back over in favor
of t the submarine. However, just as the German electric-boats arrived too late to
influence the outcome of the Battle of the Atlantic, the technical advancements made by
the Soviet Navy had no impact upon the outcome of the Cold War.
In 1991, the Navy operated 24 patrol squadrons by 2008 this number has been
reduced to twelve.3 No longer did the Navy find it necessary to deploy squadrons to
Iceland or Alaska. Many though, that with the demise of the Soviet Union, there was
little need for the maritime patrol aircraft whose primary function was ASW as there was
no longer an opponent. Maritime patrol aircraft are now patrolling the skies of Iraq and
Afghanistan searching no for submarines but for improvised explosive devices (IEDs).
While the use of these crews in new and innovative ways is exciting, it may be
premature to announce the demise of airborne ASW. On 26 October 2006, the
Washington Time reported that according to Pentagon sources a Chinese Song-class
diesel submarine surfaced within five miles of the U.S.S. Kitty Hawk.4 Equipped with
the YJ-8-2 radar homing cruise missile and YU-4 and YU-1 torpedoes, the Song had the
potential to seriously damage, if not sink, the American carrier if the need had arose.5
3
U.S. Navy Fact Sheet, P-3C Orion Long Range ASW Aircraft.
http://www.navy.mil/navydata/fact_print.asp?
4
Bill Gertz, “Chinese Sub Stalked U.S. Fleet,” Washington Times, 13 November 2006.
55
Richard Sharpe, Jane’s Fighting Ships 1998-1999, ed. (Alexandria: Jane’s Information Group, 1998),
118.
212
While this may prove to have been an isolated incident, it does demonstrate the inherent
capability of the submarine.
Submarine technologies continue to evolve and improve. Development of air
independent propulsion systems allow diesel submarines to remain submerged for as long
as fourteen days at a fraction of the cost of one powered by nuclear energy.6 Countries
such as Iran and China operate submarines that have the potential of disrupting the flow
of goods across the seas of the world. Only the long-range maritime patrol aircraft is
capable of responding to this fleeting submerged threat. Based in key locations
throughout the world, the need for the ASW capable maritime patrol aircraft is as great as
ever.7
Edward C. Whitman, “Air Independent Propulsion: AIP Technology Creates a New Undersea Threat,”
Undersea Warfare, vol. 4, no. 1 (Fall 2001).
7
Owen R. Cote, The Future of Naval Aviation (Cambridge: Center for International Studies, Massachusetts
Institute of Technology, 2006), 10.
6
213
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