Silent Hunter 4
Real Fleet Boat
User Manual
v1.52
Table of Contents
Part I: An Introduction to RFB _______________ 1
Introduction _________________________________________ 2
A Real Fleet Boat Patrol _______________________________ 4
Installation Instructions _______________________________ 6
Mod Compatibility ____________________________________ 6
Part II: Gameplay In RFB ____________________ 7
Crew Management____________________________________ 8
Crew Rosters _______________________________________________ 8
Rosters Used for Real Fleet Boat _______________________________ 9
Crew Size Limits ____________________________________________ 9
Crew Skills ________________________________________________ 10
Crew Ratings ______________________________________________ 12
Crew Injuries ______________________________________________ 13
NYGM Ship Damage Mod _____________________________ 14
Stock SH4: An Exercise in Certainty___________________________ 15
Implementing the SDM ______________________________________ 16
Causing Ships to Sink by Flooding – Creating Realistic Ship Sinking __ 16
Compartment Flooding ________________________________________________ 17
Critical Chance ______________________________________________________ 19
Introducing Uncertainty and Variability in the Way Ships Sink ________ 19
Ship Damage Model __________________________________________________ 19
Ship Damage Model __________________________________________________ 20
Weapons Damage____________________________________________________ 20
The Player __________________________________________________________ 21
Creating Realistic Ship Sinking Times __________________________ 21
Delaying the “Ship Sunk” message for as long as possible __________ 22
Eliminating the Ability to Split Ships in Two ______________________ 23
Using the Deck Gun in a More Realistic Fashion __________________ 23
NYGM Fleet Boat Damage Mod ________________________ 25
Stock SH4: The Tiger Tank™ Submarine Damage Model __________ 26
Design Decisions in the FBDM: It’s all Relative __________________ 27
Implementing the FBDM _____________________________________ 28
Making the Player’s Submarine Vulnerable to Large Caliber Naval Gunfire
________________________________________________________ 29
The Player’s Perspective ______________________________________________ 29
Redesigning the Fleet Boat Propulsion System within the Limits of the
SH4 Engine ______________________________________________ 30
The Player’s Perspective ______________________________________________ 30
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Making the Exposed Crew and Equipment Vulnerable to Small Caliber
Gunfire __________________________________________________ 31
The Player’s Perspective ______________________________________________ 31
Losing the Submarine by Exceeding Crush Depth_________________ 31
The Player’s Perspective ______________________________________________ 31
Avoiding Death and/or Injury During Depth Charge Attacks for Crew
Members Stationed in External Compartments ___________________ 32
Background: External vs. Internal _______________________________________ 32
The Player’s Perspective ______________________________________________ 33
Equipment Repair and Crew Injury ____________________________ 34
The Player’s Perspective: Equipment Damage _____________________________ 34
The Player’s Perspective: Crew Injury ____________________________________ 34
NYGM AI Visual Sensor Mod And Submarine Visual Sensor
Mod _______________________________________________ 36
The Player’s Perspective_____________________________________ 36
Distance Measurement, Draft, and Tonnage Mod _________ 38
Stock Silent Hunter 4: Clear Skies Ahead _______________________ 38
Introducing the Fog of War to Ship Targeting____________________ 38
Bringing it All Together ______________________________________ 39
Determining the Correct Distance Measure Reference Point _______ 39
Submarine Upgrades & Availability_____________________ 40
S-Boat Upgrades ___________________________________________ 40
S-18 Equipment Upgrades & Availability ________________________ 40
S-42 Equipment Upgrade & Availability _________________________ 40
Fleet Boat Upgrades ________________________________________ 41
Equipment Upgrade & Availability _____________________________ 41
Conning Tower Upgrade & Availability __________________________ 42
U-boat Upgrades & Availability _______________________________ 43
Torpedo Availability & Malfunctions ____________________ 44
U.S. Torpedo Availability_____________________________________ 44
U.S. Torpedo Malfunction Data________________________________ 44
German Torpedo Availability _________________________________ 45
German Torpedo Malfunction Data ____________________________ 45
Japanese Sensor Data _______________________________ 46
Surface Search Radar Availability _____________________________ 46
Sonar ____________________________________________________ 46
Airborne Radar_____________________________________________ 46
Part III: Submarine Details__________________ 47
American Submarines _______________________________ 48
S-18 Class_________________________________________________ 48
History __________________________________________________ 48
Performance______________________________________________ 48
S-42 Class_________________________________________________ 49
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History __________________________________________________ 49
Performance______________________________________________ 49
Porpoise Class_____________________________________________ 50
History __________________________________________________ 50
Performance______________________________________________ 50
Salmon Class ______________________________________________ 51
History __________________________________________________ 51
Performance______________________________________________ 51
Sargo Class _______________________________________________ 52
History __________________________________________________ 52
Performance______________________________________________ 52
Tambor Class ______________________________________________ 53
History __________________________________________________ 53
Performance______________________________________________ 53
Gar Class _________________________________________________ 54
History __________________________________________________ 54
Performance______________________________________________ 54
Gato Class ________________________________________________ 55
History __________________________________________________ 55
Performance______________________________________________ 55
Balao Class _______________________________________________ 56
History __________________________________________________ 56
Performance______________________________________________ 56
Tench Class _______________________________________________ 57
History __________________________________________________ 57
Performance______________________________________________ 57
German Submarines _________________________________ 58
Type IXD2 Class: ___________________________________________ 58
History __________________________________________________ 58
Performance______________________________________________ 58
Part IV: Bibliography and Credits____________ 59
Research Resources_________________________________ 60
Books ____________________________________________________ 60
CD-ROMS _________________________________________________ 60
WEBSITES ________________________________________________ 62
CREDITS___________________________________________ 64
Developers: _______________________________________________ 64
Testers:___________________________________________________ 64
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Part I: An Introduction to RFB
-1-
Introduction
The Real Fleet Boat (RFB) modification project originated to address
shortcomings in realism many players felt were present in the WWII submarine
simulation Silent Hunter 4 (SH4). The original RFB started modestly enough
addressing just a few areas in the early versions of the mod and SH4. Since
then, RFB has evolved to include more scope and has expanded into many more
areas of the game, quickly becoming what is commonly referred to as a
“SuperMod”. The latest version of the RFB “SuperMod”, discussed in further
detail in this manual, is based on the latest version of SH4 (v1.5) included as a
part of the U-boat expansion. Due to the extent of the changes with SH4 v1.5
and the additional changes incorporated in this version of RFB, it is not
backwards compatible with earlier versions of SH4.
As RFB has evolved into its current form, the team has remained dedicated to
bring the player the most realistic experience possible – hence the “Real” in Real
Fleet Boat. Webster’s Revised Unabridged Dictionary defines realism as:
Realism:
(Art & Lit.) Fidelity to nature or to real life; representation
without idealization, and making no appeal to the imagination; adherence
to the actual fact.
In essence, RFB attempts to make art imitate life. Clearly this is difficult to
accomplish and presents a rather slippery slope because one person’s (or
group’s) vision of realism may not match that of another, especially for a game
that is primarily an offline, single person experience. In the end, this means the
RFB developers must carefully balance every design decision to ensure that art
does imitate life to the maximum extent practicable.
Similar to the way the scope of RFB has evolved, the definition of “realism” in
RFB has evolved. In early versions of RFB “realism” was a rather mechanical
goal based on matching statistical averages from Pacific Theater patrol reports to
actual game play. While this may sound good in theory, it has the potential to
result in rather unrealistic results, and more importantly unrealistic behavior from
the player. These limitations have been addressed such that the focus was
shifted from strictly matching statistical averages to trying to get the player to
behave as a WWII submarine commander would have behaved. Specifically,
“realism” has been “redefined” to ensure that the player experiences the same
fear, exhilaration, tension, and joy as a WWII submarine commander. In this
respect, the player experience is paramount. The player should be rewarded for
using the proper strategy and tactics, and punished for the wrong strategy or
tactics. And of course luck is always a factor in the player’s success or failure.
How well the RFB team has done at making art imitate life can only be judged by
the players who use this mod. There will likely be some areas where individuals
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may disagree with our design decisions. This is unavoidable in a mod with the
breadth of scope in RFB. On the balance though, we hope you – the player - feel
we’ve done a respectable job to bring our brand of “realism” to SH4. Remember,
the RFB team is not dictating how anyone should play SH4, we are only
providing our vision, for other similarly minded individuals, to enjoy.
Good Luck and Good Hunting!
The RFB Team
-3-
A Real Fleet Boat Patrol
…Somewhere in the Pacific, December 1941…
27 December 1941
Arrived assigned station, Makassar Strait, 2 deg 7 min south, 120 deg 34 min
east. Course NNE, Speed 7. Trim dives and sonar search every three hours.
17:32
Sonar reports convoy containing at least one merchant, 2 or 3 escorts
bearing 86 deg. Long range. Surfaced and ran toward for one hour.
18:43
Periscope depth. Sonar reports contacts bearing 355, Long range.
Single ping shows range 22500 yards. Estimated course 265. Est speed
7 knots. Switched to normal intercept course on surface, Ahead
emergency — 10 knots in this S-Boat.
19:15
Convoy sighted, bearing 90, range estimated 7000 yd. Identified
merchant as Chitose Seaplane Tender, not a merchant at all! Vital we
not be spotted as he can make at least 15 knots. Submerged for
approach. Escorts not reacting so believe we are not sighted.
-4-
19:25
Range 2200, Target speed 5 kt. AoB 60 deg port. Fired four torpedoes,
Dick O’Kane technique, longitudinal 80% spread, depth set at 5’feet.
Estimate torpedo run 1 min 50 sec. Sonar report all torps hot and on
track. 1 hit just aft of the beam. 2 pass under. 1 dud. Target listing 20
deg to port. Turns away and accelerates. Ordered to follow submerged
while reloading.
19:35
Escorts searching active sonar. We are ahead emergency to catch up to
Chitose to finish it off. Ordered battle stations to speed up reload.
19:45
Tube 1 reloaded. Making 9 kt but not making up much distance on
Chitose. Escorts definitely hear us but can’t locate. We must continue
ahead emergency if we are to finish off our target. Last four torpedoes
are loading.
19:55
Range to Chitose 1800 yards. Own speed 9 kt. Target speed about 7.
Course 5 deg. Two escorts behind searching, one ahead of target
pinging. Safe for now. Batteries down to half charge. We will start losing
speed very soon.
20:04
Range decreased to 1000 yards. Decide to try stern 180 deg Aob shot.
Fired #1, depth 5 feet, AoB 0 deg, Bearing zero. One minute 10 sec after
firing, Chitose turned 10 deg left. Torp missed. Did not appear to be
spotted by target or escorts. Will take another shot at 700 yd range.
20:10
Own speed down to 8 kt. Range 700 yd. Fired #2 depth 5 feet AoB 0
deg, bearing 0. Fired #3 same parameters, bearing 2. Torp 1 normal run,
Torp 2 started norm run but motor shut down at 15 sec. Torp 2 sank.
Torp 1 missed to port. One torpedo left.
20:19
Own speed to 7 knots. Target at 5 kt. Apparently didn’t see either torp
from last attack. Last torpedo fired from parallel course, submarine to left
of target, Target bearing 55 deg, range 900 yards, we are no longer
gaining. Must shoot. Target bearing 55 deg, range 900 yd, AoB 120 deg
port. Fired shot to hit broadside—what I should have done with the
misses. Torp run hot and normal. Run 45 seconds. Sonar reports impact
on target. Torpedo is a dud. Damn it, we’re going home.
-5-
Installation Instructions
Real Fleet Boat (RFB) is designed to be installed with the JoneSoft Generic Mod
Enabler Program (JSGME). Simply extract the contents of the compressed file to
your MODS directory and enable the mod via the Mod Enabler’s interface. As
RFB is a very large program, it can take up to 30 seconds or more for the mod to
be enabled, depending on the user’s computer specifications.
You will find two extra folders in your downloaded RFB file: (1) Alternate
Nomographs, and (2) German Audio Files. The first folder contains nomographs
calibrated to the metric system and can be seen on the in game nautical chart.
The second file overwrites certain standard audio files in order that one has a
proper in game experience when playing a German campaign or mission. Like
the main RFB install file, these folders are enabled and disabled with JSGME.
Mod Compatibility
Great efforts have been made to make RFB compatible with other popular Silent
Hunter 4 mods. However, certain mods by design will not work with RFB. Among
them are the following:
•
•
•
•
Trigger Maru
Environmental Mod
Natural Sinking Mechanics
Manual Targeting Ship Centered Accuracy Fix
For those players wishing to run the Run Silent, Run Deep (RSRDC) and
Operation Monsun (OM) campaigns, please enable these mods after enabling
RFB, and ensure you have downloaded the RFB compatible version of each
mod. For those wishing to run RSRDC and OM simultaneously, enable RSRDC
before OM.
Any other mods not listed here may or may not work properly with RFB, and as
such the end user uses these mods at their own risk.
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Part II: Gameplay In RFB
-7-
Crew Management
The aim of the crew management model in Silent Hunter 4 is to attain a level of
crew management as realistic as the game allows. In Real Fleet Boat, thus, any
deviations from reality are a result of a limitation in the game engine. The realm
of realistic crew management in Real Fleet Boat covers the following areas:
•
•
•
•
•
Crew Rosters
Crew Size Limits
Crew Skills
Crew Ratings
Crew Injuries
Crew Rosters
All of the crew rosters in RFB reflect real world crew rosters for each type of
submarine modeled, within the limitations of the SH4 engine. These limitations
are described below:
•
Crew Sizes: unlike Silent Hunter 3, the starting crew for each boat
remains the same throughout the war. Because of this, we have chosen
real world rosters (listed below) that, in general, reflect the “final,” typical
crew complement for each particular boat.
•
Planesmen: The biggest limitation you will notice is that one planesman is
always present in the control room. In reality, the dive plane controls were
manned by the bridge watch only when the boat was submerged. Thus, to
maintain a semblance of reality we have elected to keep one man
stationed at the dive planes controls at all times.
•
German Watch Rotations: The “three watch” system is hard coded to
apply to both American and German submarines in SH4. In reality,
German U-boats had two watches: Port and Starboard. From 0800 to
2000 hours, the watches rotated every four hours. From 2000 to 0800
hours, the watch rotated every six hours. Because of the way the game is
coded, we cannot implement the German two watch system without
running into problems with game play. Thus, some concessions have
been made to the Type IXD2 crew roster in order for this boat to function
correctly.
-8-
•
Damage Control Team: In reality, every crewman on a sub was expected
to be skilled in damage repair. While large surface ships certainly had
dedicated damage repair crews, the reality of crewing a submarine means
every man on board had to know how to repair damage to the boat,
whether big or small. Hence, the men you see in the Damage Control slots
represent those crewmen who worked in compartments other than those
modeled in SH4. Historically, these were the cooks, stewards, and
yeomen. When General Quarters was called these men were used as
extra manpower to help repair any damage the boat might suffer.
Rosters Used for Real Fleet Boat
The crew rosters in Real Fleet Boat are all drawn from real world crew lists and
reflect the assignments given to each crewman, within the above stated limits of
the game’s mechanics. These assignments will be discussed further below:
•
•
•
•
•
•
•
•
S-18 and S-42 Classes: USS S-26, January 1942
Porpoise Class: USS Pickerel, April 1943
Salmon and Sargo Classes: USS Seawolf, October 1944
Gar, Tambor, and Gato Classes: USS Herring, May 1944
Balao Class: USS Archerfish, December 1943
Tench Class: USS Kete, March 1945
Type IXD2: U-873, May 1945
Type XVIII: U-2502, May 1945
Crew Size Limits
Silent Hunter 4 v.1.5 introduced crew limits for each playable submarine. These
limits are broken down as follows:
•
•
Petty Officers: sailors with a rank from level 4 to 6.
Chief Petty Officers and Officers: sailors with a rank from level 7 to 12.
Simply put, if you want to add one of these types of sailors to your boat, you will
need to drop a sailor from the corresponding classification, or else the game will
tell you the boat is already at its maximum number of sailors for that type. The
starting crew rosters are at their maximum numbers for both of the above listed
classifications. There are no limits on the number of Seaman/Matrosen a player
may add to their boat.
Do note that while Chief Petty Officers and Officers are lumped together into the
same category, it is not possible to promote CPOs to the Officer ranks with RFB.
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While it was true that CPOs could become officers, the time needed to do so took
far longer than the “instantaneous” promotions Silent Hunter 4 allows.
Crew Skills
Every sailor in RFB has a unique set of skills. These skills are the sailor’s natural
abilities and are broken down as follows:
•
Leadership: the higher the value here, the greater the compartment’s
efficiency will be when the sailor is in a leadership slot.
•
Mechanical: this skill applies to a myriad of duties on board a submarine,
from engines and motors to torpedoes and detection equipment.
•
Electrical: again, this skill applies to a variety of compartments, from the
propulsion compartments and equipment in the control room to the
sensors mounted in the conning tower.
•
Gunnery: as the name implies, this skill applies to the ability to spot,
engage, and destroy enemy targets with the deck mounted weapons. It is
also a skill related to torpedo maintenance.
•
Visual: skilled lookouts will consistently and efficiently spot targets while
assigned to the bridge watch on the surface. This skill also has an effect
on the efficiency of deck mounted weapons.
Enlisted crew skills gradually increase in value. Once an enlisted sailor reaches
rank level 6, however, his skill progression stops. At rank levels 7-9, only the
leadership skills will increase. It is at this point that, as in the real world, enlisted
sailors become “hands-off” leaders. That is, they lead by tasking the men below
him with the duties that need to be accomplished, and thus the enlisted men
below him will carry out those tasks. In other words, his job is “to make sure the
job gets done, not to do it himself.”
Officer skills start off at a midlevel (roughly level 4) petty officer skill set and
gradually progress upwards. The major difference between them and the enlisted
men, though, is that the leadership skills of the officers will be somewhat higher.
Thus, a rank level 12 officer will have roughly the same skills as a level 7 chief
petty officer, but he will have slightly higher leadership skills, in general.
The skills of each sailor will depend on the particular compartment to which the
sailor is assigned. Each sailor has what is known as a “primary” skill and a
“secondary” skill; these are his highest rated skills and those which are relevant
to his assigned compartment. Likewise, each compartment has a primary and
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secondary skill that is needed to run that compartment efficiently. These skill sets
are detailed as follows:
•
Bridge Watch: sailors here need to spot and identify targets quickly.
Hence, the primary skill here is Visual, followed by the secondary skill of
Gunnery.
•
Torpedo Rooms: loading torpedoes quickly and safely is critical to
maintaining the boat’s offensive readiness. As such, Mechanical and
Gunnery are the primary and secondary skills here, respectively.
•
Conning Tower (Radio and Listening Rooms in U-boats): home to the
boat’s sonar and radar systems, these pieces of equipment require an
operator skilled in electrical components and mechanical know how.
Hence, Electrical and Mechanical skills are the primary and secondary
skills, respectively.
•
Control Room: home to a myriad of devices that make the boat work, this
compartment has a primary skill of Mechanical and a secondary skill of
Electrical.
•
Main Propulsion Plant (Machinery Rooms in U-boats): home to the
boat’s diesel engines and electric motors, this compartment also has a
primary skill of Mechanical and a secondary skill of Electrical.
•
Deck Guns and AA Guns: naturally, men here need to be skilled
primarily in Gunnery, though the Mechanical skill also has an effect here
on compartment efficiency.
•
Damage Control: crewmen skilled primarily in Mechanical and
secondarily in Electrical will help repair damaged compartments and
components more quickly.
•
Hogan’s Alley: nicknamed after the after battery crew quarters, this is
where the enlisted men from the bridge watch need to be placed when the
boat is submerged, in order to protect them from depth charge damage
(this will be described in detail later). Since this compartment functions as
an off duty section of the boat, it has no skill modifiers.
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Crew Ratings
Like their real world counterparts, each sailor (above the junior enlisted ranks)
has a rating (or Laufbahn in German). This rating shows that a sailor has been
trained to be a specialist in a particular military job. In RFB, these ratings improve
the sailor’s relevant primary and secondary skill sets. These skills and their
relevant compartment are described below:
•
Machinist: these are the men that keep the boat’s propulsion systems
running. As such, men here are skilled primarily and secondarily in
Mechanical and Electrical, respectively, and assigned to the diesel and
motor compartments. Their skill set also makes them good crewmen to
man your submarine’s guns.
•
Radioman: the radiomen man the sonar and radar equipment. Thus, their
primary skill is Electrical and their secondary skill that of Mechanical.
•
Torpedoman: obviously, these men should be assigned to the torpedo
compartments. Their primary skill is Mechanical, and Gunnery is their
secondary skill. Because of this, torpedomen make good crewmen for the
deck and antiaircraft guns.
•
Command: these men manned the control room systems and typically
came from either the machinery or electrical ratings. Hence, their primary
skill is Mechanical and secondary that of Electrical.
•
Gunner: as the name implies, these men are experts at handling the
boat’s deck-mounted weapons. Their primary skill is Gunnery and
secondary that of Mechanical. Gunners also are handy at reloading
torpedoes.
•
Lookout: these are the men that man your bridge watch. As such, their
primary skill is Visual, and Gunner is their secondary skill.
You will notice another “rating” on your boat that is not in this list: Pharmacist’s
Mate (Sani for the U-boats). Introduced as a special skill with the 1.5 add on, this
skill has been modified so that only particular crewman can have this skill. This
crewman will help to reduce the crew’s recovery time from injuries and slightly
reduce their fatigue recovery time.
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Crew Injuries
You will notice a large number of crew slots in Hogan’s Alley and three additional
leader slots in the conning tower. These slots have been introduced as part of
the new submarine damage model system introduced to RFB and as a
workaround to the way SH4 models crew damage. In essence, when a bridge
watch crewman is off-duty, he does not “leave” the bridge; rather, the game just
treats him as an inactive crewman still physically located on the bridge. This
applies to both surfaced and submerged travel. Thus, to avoid exposing the
bridge watch to injuries caused by depth charge explosions, you need to move
your enlisted bridge crewmen to Hogan’s Alley and the officers to the conning
tower. Historically, as the Officer of the Deck, the bridge watch officer would
move to the conning tower when the boat submerged. The radarmen and
sonarmen will thus gain a small efficiency bonus when these officers are moved
to the conning tower. This subject is covered in more detail in the Fleet Boat
Damage Mod section of the manual.
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NYGM Ship Damage Mod
“One of the stupidest things in game design is the lack of uncertainty given
to the player”
The NYGM Ship Damage Mod for Silent Hunter 4 (henceforth referred to simply
as the SDM), developed in collaboration with the RFB team and included in the
Real Fleet Boat mod package, is based upon the same guiding principles as the
original NYGM Ship Damage Mod developed for Silent Hunter 3.
The SDM seeks to achieve several important goals:
•
•
•
•
•
•
•
Cause ships to sink by flooding rather than by having them run out of hit
points;
Cause ships to sink in a realistic manner;
Introduce uncertainty and variability in the way ships sink;
Introduce more realistic ship sinking times based upon both the amount of
damage and the size of the ship;
Delay the “Ship Sunk” message for as long as possible, and no earlier
than with significant flooding at or above the main deck level;
Eliminate the stock behavior where certain torpedo hits would result in the
ship splitting in two;
Require the player to use the deck gun in a more realistic fashion.
While these design goals may make sinking ships more challenging, they are not
intended to make sinking ships “harder,” or to make the ships sink in an
unrealistic manner.
The current version of this mod includes the following types of ships:
•
•
•
All merchants ships;
All AI submarines;
All small coastal vessels.
Warships will be completed in groups in the future starting with those most
important from the player’s perspective.
It is important to note that the design decisions, changes, and alterations for this
modification are all original and are not based on any other previous attempts to
modify ship sinking physics for SH4. These changes have resulted in extensive
modifications to the core SH4 files. In many respects the changes introduced in
the SDM are even more extensive than those introduced by the original SH3
NYGM Ship Damage Mod. Because of the extensive changes to core SH4 files,
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this mod is not compatible with any other total conversion mod (e.g. Trigger
Maru), although a standalone version is planned for the future.
Stock SH4: An Exercise in Certainty
Silent Hunter 4 (v1.5) is arguably the best submarine in the world today. While
Silent Hunter 3 may have extensive user support and modifications, SH4
introduces a number of significant graphical and other code related changes that
help make it a much superior platform over the previous version. One common
area for both SH3 and SH4 is a very sophisticated damage model. While this
may not be apparent in the stock version of either game, with a little effort and
massaging, the SH4 damage model can be coaxed into some very realistic,
unique and unpredictable behavior.
Perhaps one of the best improvements of SH4 over SH3 is in the area of ship
sinking. In SH3 when the ship ran out of hit points (HP) it would explode with a
mighty BOOM! This has been dramatically improved in SH4 so that when the
ships run out of HP they sink instead of exploding. While this may sound good
on the surface, there are two problems with this model.
First, every ship of the same class has exactly the same number of HP. For
example, the stock large composite freighter has 300 HP, and will take 2 or 3
MK14 torpedoes to sink - every time without fail. It also means that the hit
location is not important to sinking the ship. If all 3 torpedoes hit exactly the
same location, the ship will still sink – every time without fail. This is also true for
the deck gun in that the player can target the very tip of the bow and hit the exact
same spot with enough shells to reduce the HP to zero thus sinking the ship.
Clearly this is unrealistic behavior.
The second problem with this model is that these ships almost never actually
sink by flooding, and they sink in a very short period of time – several minutes in
most cases. While very quick sinkings did actually happen, they were the
exception and not the rule. The quick sinkings in SH4 fails to force the player to
make tactical decisions similar to those the actual commanders had to make. By
making ships actually sink by flooding compartments and by slowing the time it
takes to sink a ship, the player will be forced to decide if another torpedo (or the
deck gun) will be required to finish sinking the ship. This in turn spawns a
separate decision tree for this seemingly “simple” decision. These are the
problems real commanders had to face.
Finally, by slowing down the sinking time and making a ship sink by flooding, it
also makes it possible to introduce situations where ships will look “sunk”, but will
not actually sink. While it is not possible to eliminate the “Ship Sunk” message –
the message is integral to the code of SH4 and the recording of sinkings – they
have been significantly delayed over stock SH4 (v1.5).
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Implementing the SDM
This section will provide additional detail on how each of the design goals was
implemented in the SDM.
Causing Ships to Sink by Flooding – Creating Realistic Ship
Sinking
In order to get ships to sink by flooding rather than through the loss of HPs, the
first task was to raise the ship HP to 4000. This represents over 22 max HP
torpedoes, or nearly an entire torpedo load for a U.S. fleet boat. This value
should represent a sufficient number of HP to prevent the player for firing
torpedoes until the ship finally sinks. In essence, the player will have to plan the
location of torpedo impacts rather than “spray and pray” as in the stock
implementation.
The next step was to create a model for the ships that replicated the actual
design of the ship and the advantages of compartmentalization. For the
merchant ships, this is represented primarily as a combination of cargo and
machinery compartments. These compartments are located where they would
logically be expected. For example, the machinery compartment is logically
located where one would expect the engine room to be for a given ship (typically
near the funnel). In addition to the main compartments, there are several special
compartments such as fuel bunkers, and the engine room represented in each
ship model. Finally, each model has a series of special effects that visually
represent the level of damage to the player. This will include effects such as fire,
smoke, and explosions.
As mentioned earlier, the SH4 damage model is simple, yet surprisingly
sophisticated.
The combination of the main compartments, special
compartments and effects completes the ship damage model. A typical example
of the compartmentalization present in each model is shown in the graphic
below:
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It is important to note that the extent of compartmentalization is dependant on the
size and type of ship. Some ships will have more compartmentalization, while
others will have less. It is also important to note that damaging a compartment is
the only way to sink a ship, just as in real life. Finally, depending on the ship and
the size of the ship, damaging one compartment is not likely to cause the ship to
sink.
Despite the sophistication of the SH4 damage model, one weakness is that
bulkheads are not modeled, or easy to model. Instead, the SDM uses a gap, or
a space, between each compartment. The various random characteristics of the
torpedo are then used to affect damage to the compartment as they would if a
bulkhead were present. The main drawback to the lack of a bulkhead is the
inability to model catastrophic failures. This has instead been handled through
“critical chance” covered in more detail below.
When a compartment is damaged to a sufficient level, it will start to flood. As the
compartment floods, the mass of water entering the compartment will negatively
affect the ship’s buoyancy. In SH4, this negative effect on buoyancy is known as
“floatability”. The higher the floatability of the compartment, the higher the
negative effect on the ship’s buoyancy, and the quicker it will sink. When the
sum of the “floatability” exceeds the ships buoyancy, the ship will sink. The
interesting (and subsequently difficult) part about this is that every ship in SH4 is
unique and as a consequence has unique sinking characteristics. This means
that the compartment structure and compartment floatability has to be uniquely
tailored to each individual compartment on each individual ship in order to
achieve optimal sinking characteristics. This individualization of ships is not
present in the stock SH4 ship damage model to the detail and extent present in
the SDM.
Compartment Flooding
Critical to understanding how to sink ships is an understanding of how
compartments flood. Flooding in compartments is governed by two parameters.
The first is the compartment HPs and the second is called critic floatation. The
compartment HP defines how much damage, in HP, the compartment can
sustain before being destroyed. Critic floatation defines how much damage, as a
percentage of the compartment’s HP, the compartment must take before flooding
starts. For example, if a compartment has 200 HP and critic floatation is set for
0.70 (70%) a compartment must sustain at least 140 HP of damage before it will
start to flood. Assuming the damage is caused by a MK14 torpedo with 120 –
180 HP, a minimum strength torpedo will not cause flooding in the compartment.
Torpedo, shell and bomb damage HPs are randomly picked between the
minimum and maximum HP values for the applicable weapon.
- 17 -
Once a compartment has been damaged to be point that flooding starts, the
compartment will flood until 100% flooded – every time. Unlike the player
submarine, there is no stopping a compartment from fully flooding once damaged
beyond the critic floatation. Flooding time is based on the extent of the damage.
The more damage to the compartment, the faster it will flood. Flooding time is
represented for each compartment by a parameter called “FloodingTime”. This
parameter represents the amount of time it takes, in seconds, to fully fill a
compartment if it is 100% damaged. Clearly the extent of damage and the critic
floatation will both impact how quickly a compartment floods.
It is important to keep in mind that causing more damage to the same
compartment will not cause more flooding effect (floatability), and thus will not
cause more negative buoyancy.
The only effect will be to cause the
compartment to flood faster. If for example, the player damages a compartment
with a torpedo such that it starts to flood, the floatability of the compartment will
be subtracted from the ships buoyancy (as a sliding scale of how flooded the
compartment is). Shooting a second torpedo at the same compartment will
only cause the compartment to flood faster, and will not increase the
“sinking effect”. This same principle holds true regardless of the weapon
employed by the player.
One of the particularly sophisticated aspects of the SH4 damage model is that
when optimally modeled the location of the hole makes a significant difference on
how ships sink. If the player uses an impact torpedo in SH4 Ship Damage Mod,
the ship will list to the side of the impact. As with all things in SH4, the extent
and degree of list varies from ship to ship, with some ships exhibiting more list
than others.
The depth of the hole in the ship also effects compartment flooding. This is
primarily reflected in two different ways. First, the deeper the hole in the ship’s
hull the faster the compartment will flood. Second, if a torpedo detonates near
the very bottom on the ship’s hull, there is a possibility for extra sinking effect.
The extra flooding is mostly applicable to magnetic detonation (under hull)
torpedoes rather than impact torpedoes, but it may be possible.
Finally, if damage to another location of the ship causes a previous hole to be
raised out of the water, the flooding in that compartment will stop assuming there
are no other holes in the hull still below water.
- 18 -
Critical Chance
Critical chance is a special setting for each compartment that represents the idea
that a single torpedo hit may cause catastrophic damage resulting in the sinking
of the ship. Critical chance represents a sort of “golden BB”. It is possible to get
a critical hit any time a compartment takes damage. Critical chance is an
important characteristic of the ship damage mod since it represents the intangible
factors that could cause a ship to suddenly sink such as coal dust or fuel vapors,
an old, weak ship, a weak spot, etc. All cargo and machinery compartments
have the potential for a critical hit, though the possibility is small.
Introducing Uncertainty and Variability in the Way Ships Sink
The previous section described in detail how the stock SH4 damage model has
been modified, including a review of the effects of key parameters that control
compartment flooding and subsequent ship sinking. This section will be divided
into the three major aspects that help introduce uncertainty and variability into the
way ships sink in the SDM.
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Ship Damage Model
The primary attribute used to introduce uncertainty in the physical ship damage
model is space, or the distance between compartments, and the size of the
compartments. In the case of spacing between compartments, they are spaced
such that the location of the hit matters. If the hit is in the correct location, it is
possible to damage up to two compartments and cause flooding. If the location
is not correct, only one of the compartments may be damaged and flood.
Compartment spacing primarily applies to torpedoes. It is not difficult to damage
multiple compartments during a torpedo attack, but it does require careful
planning, solution development and aim to accomplish successfully. Spacing is
also used to add some variability to the possibility for the player to damage the
fuel bunker, or cause flooding in the engine room that will cause the ship to slow
or stop.
Compartment size is used to help control the way damage is applied to the ship,
specifically as it relates to use of the deck gun. For best results, the player
should aim for the waterline with the deck gun because this will have the greatest
chance of causing enough damage to each compartment for them to start
flooding. While the ship may take damage above the waterline in the form of
fires, masts destroyed, or external cargo destroyed, this will probably not result in
the ship sinking.
Weapons Damage
The weapons parameters allow for the greatest variability in how damage is
applied to the ship damage model. All weapons, regardless or type, have the
same parameters. These parameters will be discussed in general, but have
been tuned to achieve the desired effects with the ship damage models.
Every weapon has three basic parameters: min and max HP damage, armor
penetration setting, and the min and max damage radius. Each will be discussed
individually in more detail below.
HP Damage – this is the amount of damage the weapon or ammunition inflicts to
the ship and/or compartment. Each has a minimum value (MinEF) and a
maximum value (MaxEF). The MinEF is the smallest amount of HP damage that
will be inflicted, while the MaxEF is the largest HP damage the weapon can
cause. The actual damage is a random number between MinEF and MaxEF.
Armor Penetration (AP) – this is the basic setting for the armor thickness the
ammo will penetrate in centimeters (cm). The actual calculation of armor
penetration is a very complex formula that takes into effect the HP damage and
several other factors. If the weapon or ammo does not penetrate the armor, then
no damage HP is applied.
- 20 -
Damage Radius – this is the range in meters (m) in which the ammunition will
cause damage. This parameter consists of a minimum radius (MinRadius) and a
maximum radius (MaxRadius). Originally it was believed that the damage radius
was a random number between the MinRadius and MaxRadius similar to the HP
damage above. In reality the damage radius is always at the MaxRadius with
the only variability in the number of HP applied between MinRadius and
MaxRadius. In essence, this means that if a compartment is inside of MinRadius
it will receive the full damage HP. If the compartment is between MinRadius and
MaxRadius, it will receive a portion of the damage HP depending on how far it is
from MinRadius (HP drop off at a rate proportional to the inverse of the square of
radius). If a compartment is outside of the MaxRadius, it will not receive any
damage HP. This is a critical concept that has huge impacts on compartment
sizing and spacing as discussed above.
The Player
With all of the previous discussion on compartment design, compartment
parameters, and random ammunition damage effects, the player may well be the
most significant contributor to uncertainty and variability in ship sinking. Now the
quality of the solution is now much more significant. Now the type of weapon
and location of hits/impacts suddenly matter. Now the player must carefully plan
attacks to ensure he is at the optimal range and geometry, and that the proper
tactics are employed for each individual ship prior to attack. While the player can
help reduce these factors, random chance will still play a role and there will be
instances of frustratingly awful “bad luck”, but then this is exactly the same thing
experienced by most WWII submarine commanders at some point in the war.
Creating Realistic Ship Sinking Times
The previous sections have focused on the mechanics of making ships sink by
flooding compartments. That will not be repeated in this section. By comparison,
this section will only point out two factors related to ship sinking times.
First, as mentioned earlier, each ship class is unique. As such, the sinking time
for each class has been individually tuned. In general, the player should expect
a ship that has been torpedoed to sink in about 10 minutes per 1000 tons. Some
ships will sink slower, and some faster, but this will depend on the location,
quality and quantity of damage inflicted to the ship.
Second, the player should not expect that using the deck gun on a ship will result
in the same sinking time as a torpedo. The holes created from deck gun shells
are much smaller than the hole caused by a torpedo, therefore the deck gun will
- 21 -
result in a much slower flooding rate, and thus a longer sinking time, than a
torpedo.
The tactical situation may cause the player to use another torpedo to speed the
sinking. Remember to target another compartment since, as discussed above,
an additional torpedoes to the same compartment will only change the flooding
rate, and will not cause a change on the ship’s buoyancy.
Delaying the “Ship Sunk” message for as long as possible
One of the major difficulties with this modification is the infamous “Ship Sunk”
message. When the ship is considered “sunk” by the SH4 engine, based upon
an unknown set of criteria, the player receives the “Ship Sunk” message. While
this system may have advantages from a game play perspective, the reality is
that real commanders never had this sort of message to validate a sinking.
Reality to the side, the real disadvantage from a game play perspective is that it
provides the player with too much, and too accurate of information. If the
message is displayed too early, the player will not expend extra ordinance (either
torpedoes or deck gun shells) to sink the ship. Based on the mechanics of the
engine, if the message were removed, the player would never get any credit for
sinking any ship thus rendering the renown system useless. For the fans of the
renown based system, rest assured that it’s not possible to remove the “Ship
Sunk” message, a fact that has been confirmed by the developer. Instead, the
best that can be accomplished is to delay the message for as long as possible.
At a minimum, the message should not be displayed until major portions of the
ship, such as the main deck and/or superstructure, are physically underwater.
The actual implementation of this design goal is very difficult to achieve. First,
the exact criterion the game engine uses is not know, and has not yet been
explicitly determined through testing or any other empirical method. The only
useable method to date has been time consuming and extensive testing and
tweaking. In many respects this is easier on the SH4 engine than it was on the
SH3 engine because of what seems to be some additional “flexibility” in some of
the major criteria currently believed to be used by the SH4 engine for the
message. These criteria include such attributes as flooding time and total
floatability. In other cases it can be frustrating due to the extreme uniqueness of
each ship, and some individual quirks in the SH4 engine.
In the end, the SDM has attempted to delay the “Ship Sunk” message for as long
as possible, therefore the player must use his judgment to determine if and when
the ship will actually sink. The player may choose several different methods to
evaluate the “sinking potential” for each ship. Some of these are as simple as
just waiting longer if possible. Where not possible, the player may choose to
damage previously undamaged compartments in order to speed the sinking. In
- 22 -
either case, the delay should force the player to make these critical decisions
without the aid of unrealistic additional information.
Eliminating the Ability to Split Ships in Two
Many of the stock ships in SH4 have been designed such that when hit in a
special location by an impact torpedo, the ship will split into two pieces and sink.
While the intent of this section is not to debate the realism of this design decision
– there have been many discussions on this topic on various forums – the SDM
has removed this design feature. Specifically, the ship DAT and ZON files have
been totally restructured such that ships will not split in two when hit by an
impact torpedo.
There are a couple of technical reasons why this behavior has been removed.
First, ships will only split in two when struck by an impact torpedo. The ship will
never split into two parts from a magnetic torpedo. Second, the frequency of
ships splitting in two far exceeds the reality of such events ever happening.
Once the player learns the “magic spot” this can be repeated every time with a
100% success rate. Clearly this goes against the design goal to create variability
and uncertainty.
Due to the above mentioned distinct differences between the impact and
magnetic torpedo behavior in SH4, the keel has been removed and modeled in a
different way. As mentioned above, the depth of the torpedo does matter, and
with torpedo damage deeper on the ships hull, flooding will be both faster and will
have the potential to result in a larger sinking effect. Additionally, the SDM has
been designed such that magnetic torpedoes will have the potential to cause an
even bigger impact on negative buoyancy than an impact torpedo. This
represents the impact of very large holes in the deepest part of the hull.
Using the Deck Gun in a More Realistic Fashion
In stock SH4, the player was not required to use the deck gun in a particularly
realistic manner. For starters it was possible to aim the deck gun at the very tip
of the bow and repeatedly hit the same spot resulting in the ship sinking.
Secondly, the deck gun only required a few shells to actually sink a very large
merchant.
With the changes made in the SDM, the player will find that the deck gun is not a
very effective primary weapon for sinking ships. The deck gun is quite effective
when used to finish off crippled or damaged ships, and it may be effective when
used against small merchants or coastal vessels, but it will take a long time and
maybe even dozens of shells to sink a large merchant alone. Additionally, the
shots must actually cause flooding to be helpful in sinking the ship. For best
- 23 -
results, the player should aim shots at or below the waterline. Also keep in mind
that the deck gun causes a significantly smaller hole than a torpedo, therefore
the flooding rate will be slower.
The shells have also been modified so that the size of the shell matters. For
example, deck gun shells should be effective against all merchants and small
coastal vessels (or similar) with the 5” shell being the most damaging and the
3”/88mm shell being the least damaging. The 40mm, 37 mm, 20mm and 50 cal
shells may be effective against small coastal vessels – as they were historically but do not expect them to be effective against anything larger. For small coastal
vessels, the 40mm and 37mm are the most effective, while the 20mm and 50 cal
rounds are just marginally effective.
NOTE: When using the deck gun or the AA guns manually in RFB, the
player must click on the shell icon to load the first shell, otherwise nothing
will happen when the player tires to fire the gun.
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NYGM Fleet Boat Damage Mod
The NYGM Fleet Boat Damage Mod (FBDM) for Silent Hunter 4, developed in
collaboration with the RFB team and included in the Real Fleet Boat mod
package, is based upon achieving the following major design goals:
•
•
•
•
•
•
•
Make the submarine vulnerable to large caliber surface gunfire;
Redesign the Fleet Boat propulsion system within the limits of the SH4
engine;
Make the exposed crew and equipment on the player’s submarine
vulnerable to small caliber gunfire;
Redefine the damage model for the player’s submarine so that it will be
lost by exceeding crush depth rather than through the loss of hit points;
Make the exposed crew on the player’s submarine less vulnerable to
depth charge attacks;
Extend the duration of equipment repair times and redesign the equipment
so that it will not work when damaged beyond a certain point or when it is
destroyed. Badly damaged equipment should not be able to be repaired
at sea;
Dramatically extend the duration of crew healing times..
The current version of this mod includes the revised damage models for the
following fleet boats:
•
•
•
•
•
•
•
•
•
•
Balao
Gar
Gato
Porpoise
S18
S42
Salmon
Sargo
Tambor
Tench
The Narwhal and German U-boats will be completed in a future version of this
mod.
As with the SDM, all design decisions, changes, and alterations for this
modification are all original and are not based on any other attempts to modify
the player’s submarine damage model. These changes have resulted in
extensive modifications to the core SH4 files. Because of the extensive changes
to core SH4 files, this mod is not compatible with any other total conversion mod
(e.g. Trigger Maru), although a standalone version is planned for the future. With
- 25 -
regards to a standalone mod, file overlap makes compatibility very challenging,
therefore while a standalone version of the FBDM would be compatible with the
SDM, and vice verse, the SDM and FBDM will likely be released as a combined
package rather than as separate packages for simplicity sake.
Stock SH4: The Tiger Tank™ Submarine Damage Model
Silent Hunter 4 (v1.5) shares much in common with its older brother SH3 with
respect to the submarine damage and physics - the player’s submarine is nearly
indestructible. When SH4 was first released, and even after 4 patches and an
add-on, it is not uncommon to see screen shots of submarines motoring around
with huge damage textures on the hull caused by damage received from large
caliber naval gunfire or circle running torpedoes. The boats in these screen
shots were still able to submerge without any adverse effects (in some cases
before the damage was even “repaired”) and were still able to return to port,
many without even a single casualty. While the damage textures are mere
window dressing, they point to a severe underlying problem: no submarine
should ever be able to submerge (let alone survive and return to port with no
casualties) after being hit by armor piercing naval gunfire or a circle running
torpedo. The ability to survive (and still fight!) following what should catastrophic
damage beggars the imagination.
Other problems with the submarine damage model are intrinsic to the nature of
the SH4 engine. One of the biggest problems with SH4 turns out to be a carry
over from the SH3 engine effectively negating one of the biggest advantages the
U.S. Fleet Submarine over its German counterpart: submarine propulsion. The
U.S. Fleet Submarine used a diesel electric propulsion train based on the
propulsion system used in diesel electric locomotives in use in the U.S. at the
time. In this propulsion train, the diesel engines drive generators that in turn
provide power to DC motors. These DC motors turn the reduction gear driven
shaft. Further enhancing this system, designed to be highly reliable for very long
range boats, was the built in redundancy of four diesel engines and four electric
motors, plus an auxiliary diesel and generator. This system virtually ensured that
battle damage or propulsion failures would not strand the submarine. Not so with
SH4. The SH4 propulsion model, based on the SH3 model, uses the German Uboat system of two direct drive diesel engines and an associated generator. This
model, unfortunately, cannot be changed. While the equipment screen for a
Gato class submarine, for example, may show four diesel engines and four
electric motors, in reality, there are only two; the other two diesel engines and
electric motors are merely window dressing. If the two main diesel engines are
destroyed, all four will in turn be “destroyed” and the ship will be stranded. Even
if the other two diesel engines are not destroyed, the ship will still remain
stranded.
- 26 -
Providing reasonable solutions for these two problems, within the limitations of
the SH4 engine, created the impetus for this modification. The other features
and design goals listed above were added as work progressed.
Design Decisions in the FBDM: It’s all Relative
Making the player’s submarine vulnerable to large caliber naval gunfire required
a new way of looking at the current damage model. The first step was to define
the desired damage model response to large caliber naval gunfire, namely: large
caliber naval gunfire (3” or larger) striking the hull of a submarine should, in
nearly all cases, penetrate the hull causing damage such that the submarine
cannot submerge without risk of flooding and the subsequent loss of the boat.
The 3” round was selected because it was the most conservative approach and
would cause the least amount of damage, therefore it the proper characteristics
were achieved with a 3” round then those characteristics would be maintained for
all other rounds.
With the basic design criteria established, it was then also important to recognize
the different types of interactions present in the SH4 world. Specifically these
are:
1. AI to Player – this interaction is where the AI attacks the player’s
submarine with gunfire, bombs, or depth charges.
2. Player to AI – this interaction is where the player attacks the AI naval
vessels or aircraft with guns or torpedoes.
3. AI to AI – this interaction is where the different AI factions attack each
other with guns, bombs or torpedoes.
Most of the player’s experiences in SH4 will involve only two of the interactions
listed above: (1) AI to Player and, (2) Player to AI. The AI to AI interaction is
limited at best, and present in only a few specific instances that the player will
seldom see and will seldom participate. For this reason, interaction was not
considered to be important to the players experience and was excluded from
design consideration in the FBDM. Instead, the focus was placed on the AI to
Player and Player to AI interactions to ensure they provide as rich an experience
as possible for the player in the SH4 world. The focus on these two interactions
has an additional advantage in that it dramatically simplifies design of the FBDM.
For the purpose of the FBDM, all remaining discussion will relate to the AI to
Player interaction, however it is important to note that the SDM must account for
both the Player to AI and AI to Player interactions, and it must also consider
changes made in the FBDM. This a critical, but unappreciated are of mod
overlap.
Another important principle for the FBDM is the recognition that everything in the
SH4 world is relative. For example, the amount of damage inflicted to a
- 27 -
compartment by a 3” shell is relative to the number of hit points in the
compartment, the armor rating of the compartment and the number of damage hit
points inflicted by the shell. Changing the balance of these attributes changes
the damage. If for example, the HP damage from the shell were raised, it would
be relatively more damaging to the compartment. Unfortunately, it’s possible for
this to get out of control, if for example the 3” shell HPs get too large, so it’s best
to rebalance the all of the important attributes. This can quickly results in an
unconstrained engineering problem with too many degrees of freedom. That’s
why selecting an optimal baseline is so important, and as mentioned above the
3” shell serves this purpose.
Once the compartment and shell HPs are rebalanced, it becomes necessary to
rebalance the other ammunitions used in the AI to Player interaction, namely the
bomb and depth charge. This serves to make the player’s submarine more
vulnerable to all damage and helps establish another constraint on the problem.
In the end, much of the work on the FBDM is a simple rebalance of all AI used
shells, bombs and depth charges and to the submarine damage model and vice
verse – simple in theory, complex in practice.
Finally, in order for this rebalancing to work properly, the ammunition used by the
AI must be unique and cannot be used by the player. This is because it is
designed specifically for the AI to Player interaction. By contrast, the ammunition
used by the player cannot be used by the AI because it is designed specifically
for the Player to AI interaction. It is important to remember this very fundamental
concept for others who may wish to modify or change the FBDM and/or SDM at a
later date. It is not worth worrying about any perceived relative differences
between ammunition since they have been designed for a specific application
and have had the settings modified to work on this interaction only. Practically,
this means that shells specifically assigned to AI only guns (e.g. 4.7” AP shell)
should never be assigned to the submarine deck gun (or vice verse) as this will
destroy the premise of the FBDM and SDM.
Implementing the FBDM
This section will provide additional detail on how each of the design goals listed
above was implemented into, and the characteristics the player can expect to
see in the FBDM.
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Making the Player’s Submarine Vulnerable to Large Caliber
Naval Gunfire
The Player’s Perspective
With the changes to the submarine damage model, the player should expect to
experience the following with respect to large caliber naval gunfire:
• A hit by a single 3” shell (or larger) to a compartment will cause major
damage, though it may not destroy the pressure hull;
• Depending on the hit location (above or below the waterline), the player
may experience flooding;
• Hits by larger caliber shells, or additional hits by smaller caliber shells (e.g.
3”), stand a very significant chance of destroying the pressure hull in the
affected compartment. When this happens the ship will be lost by
flooding;
• It is possible, but unlikely, to be hit by naval gunfire and not have
compartment damage;
• Because of basic changes in the damage system, the player should not
see gunfire cause an increase in “hull damage” nor will be damage texture
appear. These effects are unavoidable (the first desirable the second
not).
- 29 -
Redesigning the Fleet Boat Propulsion System within the Limits
of the SH4 Engine
The Player’s Perspective
With the changes to the submarine damage model, the player should expect to
experience the following with respect to the Fleet Boat Propulsion System:
• Diesel and electric engine equipment entries have been combined into a
single entry for the port (#2 and #4) engines and starboard (#1 and #3)
engines. This is consistent within the limitations of the SH4 engine.
• The diesel and electric engine equipment damages have been redesigned
such that the following rules apply:
o Damage to one group of engines <50% (e.g. #1 and #3 diesel engines)
represents damage to a single engine of the group. Ship speed will be
reduced by an amount proportional to the amount of damage the
damaged engine has received.
o Damage to one group of engines >=50% (e.g. #1 and #3 diesel
engines) represents one diesel engine destroyed and the other diesel
engine damaged.
Ship speed will be reduced by an amount
proportional to that of one destroyed engine plus the loss in speed
proportional to the amount of damage the other engine has received.
o If one engine in a group is destroyed (e.g. >= 50% damage) the group
damage will not be reduced less than 50% while at sea. The player
must return to port for the engine to be repaired.
o The diesel engines have been modeled, in both location and damage
resistance, to make it less likely to suffer a situation where both groups
of engines will be destroyed. This outcome is not impossible, but it is
less likely especially given the general rebalancing of the submarine
and shell damage.
o The auxiliary diesel engine and generator has been conceptually
modeled in the port and/or starboard diesel engine groups. This
simply means that extra HP are present making it that much more
difficult to destroy the diesel engines.
• Port and starboard propeller shafts have been modified to make it less
likely that they will be destroyed during certain types of attacks.
• Damage to the port and starboard propeller shafts will result in a reduction
in speed proportional to the level of damage to the shafts.
• Due to limitations in the SH4 engine if a group of engines is completely
destroyed (e.g. the port diesel engine group) the associated shaft will not
turn. This behavior is based on the U-boat propulsion model adopted from
the SH3 engine.
• The rudder has been modified to make it less likely that it will be destroyed
during certain types of attacks.
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Making the Exposed Crew and Equipment Vulnerable to Small
Caliber Gunfire
The Player’s Perspective
With the changes to the submarine damage model, the player should expect to
experience the following with respect to exposed crew injury from small caliber
gunfire:
• Crew in exposed areas will be extremely vulnerable to small caliber
gunfire (e.g. 40mm or less). This will result in serious crew member injury
or even death. Exposed areas are considered to be the anti-aircraft gun
stations, the deck gun station and the bridge watch stations.
• External equipment will be vulnerable to, and could be damaged or
destroyed by, small caliber gunfire. Equipment that could be damaged or
destroyed by small caliber gunfire includes, but is not limited to the antiaircraft guns, the deck gun, TBT, SJ and SD radar antennas, and the
periscope heads.
Losing the Submarine by Exceeding Crush Depth
The Player’s Perspective
With the changes to the submarine damage model, the player should expect to
experience the following with respect to the submarine damage model:
• The player’s submarine will no longer receive “hull damage” in most cases
when damaged by depth charges, bombs, naval gunfire, or when rammed
by other ships.
o “Hull damage” represents the percentage of HPs lost from the
submarine object’s total HP, and establishes the percentage loss in
the submarine’s “crash depth” (crash depth is the same as the
submarine’s crush depth) due to this damage.
o Example: Assume the submarine object has 100 HP and has a
crash depth of 100 feet. If the submarine object takes 1 HP
damage, it will have 99 HP remaining (when HP = 0 the object is
destroyed), and the crash depth will be reduced to 99 feet. If the
submarine exceeds the crash depth, HP will be removed from the
total, at a defined rate, until either the object is destroyed, or the
depth no longer exceeds crash depth (for submarines, crash depth
is dynamic as explained above).
• When the player’s submarine is damaged by depth charges, bombs,
gunfire, or when rammed by another ship, damage will be applied to the
submarine’s compartments, which if damaged severely enough, will start
- 31 -
•
•
to flood. Flooding reduces the submarines positive buoyancy and may
cause the submarine to sink. If the compartment starts to flood, the
submarine may experience the following effects (remember, these effects
will be more severe if multiple compartments are flooding):
o While Submerged: The submarine will tend to sink off of the
ordered depth. The player may have to increase speed, order a
new, shallower, depth, or if the flooding is severe enough order a
main ballast tank blow.
o While Surfaced: A fully flooded compartment will not likely cause
the submarine to submerge because of the excess surfaced
buoyancy. Therefore, if the submarine has taken enough damage
such that flooding makes it difficult or impossible to maintain depth
submerged, the best course of action is to surface the boat.
o Pressure Hull Destroyed: If a compartment on the submarine
takes too much damage before the crew can repair it, the pressure
hull in that compartment may be destroyed. When this happens,
the submarine will almost certainly sink uncontrollably regardless of
whether surfaced or submerged.
Collision with land will cause the submarine to receive “hull damage”. This
effect is necessary for a couple of reasons (for example ship sunk in
shallow water with destroyed bulkheads), so it is advisable that the player
not attempt to “ground” the submarine in shallow water.
If the submarine exceeds crash depth, it will very rapidly receive “hull
damage” and the ship will be lost. This will happen so quickly that
the player will not be able to react fast enough to save the ship.
Avoiding Death and/or Injury During Depth Charge Attacks for
Crew Members Stationed in External Compartments
Background: External vs. Internal
Because of behavior unique to the SH4 engine it is not possible to have an
external crew be vulnerable to small caliber gunfire and resistant to depth charge
attacks. This is because of the way the SH4 engine treats compartments and
also because the engine does not distinguish between the various types of
ammunition causing damage to the compartment (e.g. bombs, guns or depth
charges). One other unique “feature” of the SH4 engine is that for the “external”
compartments, the submarine state (e.g. surfaced or submerged) only changes
the state of the compartment (e.g. active or inactive). When submerged, the
main deck watch “compartment” is inactive, but the crew members are not
actually removed from the compartment. Making the main deck watch crew
vulnerable to small caliber gunfire also makes the main deck watch crew
extremely vulnerable to depth charge attacks. In reality, the main deck watch
crew would be stationed inside of the submarine hull while submerged and would
- 32 -
only be as vulnerable as any other crew member in the same “internal”
compartment. This mod incorporates a couple of key changes necessary to
make external crew less vulnerable during depth charge attacks.
The Player’s Perspective
For the fleet boats, the following compartments are considered to be external to
the submarine pressure hull:
• Main Deck Watch
• Deck Gun
• AA Guns
For the fleet boats, the following compartments are considered to be internal to
the submarine pressure hull:
• After Torpedo Room
• Main Propulsion Plant
• Control Room
• Conning Tower
• Forward Torpedo Room
• Hogan’s Alley
• Damage Control Team/Room
The following guidelines should be followed in order to avoid unnecessary crew
injury and/or death in external compartments during depth charge attacks:
• Never permanently station crew members in the Deck Gun or AA Gun
compartment crew slots. Only man these stations when necessary, and
be sure to use crew members from internal compartments.
• Never fill the last, empty, crew member slot in the conning tower (one per
watch section). If these slots are filled, the player will not be able to Rig
Ship for Depth Charge.
• Prior to any attack on the submerged (or submerging) submarine, the
player must manually Rig Ship for Depth Charge! Rigging Ship for
Depth Charge involves the following player actions:
1. Move the OOD from each Deck Watch watch section to the empty
crew slot in the conning tower. For example, the 1st watch section
OOD should move to the 1st watch section slot in the conning tower.
2. Move the remaining deck watch crew members to Hogan’s Alley. It is
highly recommended to move then in a logical fashion, such as by
watch section, in order to make it easier to move them back to the
deck watch stations. Note: it is most important to move the men
quickly and keep them alive. Proper watch sections can always be
sorted out later.
3. Check the deck gun and AA gun stations for any other crew members
and move them back to their original compartment.
- 33 -
•
Note: Rig Ship for Depth Charge! is a manual player action and cannot
be automated.
Sometimes the AA gun slots can be difficult to move crew to because of
different screen resolutions. If there is difficulty placing crew members in
the AA gun slots, use the “Hide Interface” command to access these crew
slots.
Equipment Repair and Crew Injury
The Player’s Perspective: Equipment Damage
In addition to all of the other changes in this mod, the equipment repair times
have been dramatically extended over the stock SH4 repair times. The player
can expect that repair times may take from several minutes to several days
depending on the extent of the damage. During this time, the equipment will
operate at a reduced level to the maximum extent allowed by the SH4 engine. In
addition to taking longer to repair, badly damaged equipment will require a higher
“repair skill” in order to repair while at sea. If the equipment is damaged beyond
a certain point (usually about 50% damage) the crew will not be able to repair the
equipment while at sea, and it will be considered “Out of Commission”. The
equipment can be repaired once the ship returns to port from patrol.
Some equipment affected by these changes include: Diesel and electric engines
(as explained above), torpedo tubes, AA guns and the deck gun, the radar (to a
more limited degree), hydrophones, periscopes and the TBT.
The Player’s Perspective: Crew Injury
As with the equipment repair times above, the extent and effects of crew injury,
and the amount of time that it takes for crew members to recover from an injury
has been dramatically changed over those present in stock SH4. When the
submarine takes damage, the player should expect the crew to be injured. The
extent of the injury will depend on a number of factors such as compartment
location and the type of damage. As explained above, crew in external
compartments will likely receive the most severe injuries because there is little or
no protection. Even during depth charge attacks, the crew can be injured if a
compartment is damaged. The severity of injury will depend on the severity of
damage to the compartment. For light damage, crew injury will mostly be limited
to bumps and scratches. These will heal relatively quickly in a matter of a few
hours. More severe injuries such as broken bones, large lacerations, head
injuries, etc. could take days or even weeks to heal, and the most severe injuries
may not heal until the player returns to port.
- 34 -
It is important to keep in mind that as crew members are injured, their watch
standing effectiveness will decrease. So to will their repair effectiveness. This
can result in a double impact in that severely injured crew members may be
unable to repair only moderately damaged equipment because of their reduced
effectiveness and the need for increasing crew repair skill due to increased
equipment damage. The player should pay attention to these potential types of
situations and make the necessary adjustments in crew configuration in order to
ensure that critical equipment is repaired. Hogan’s Alley may serve as a useful
location to place severely injured crew members so that they can heal. It’s not
advisable to place injured crew members in the empty deck or AA gun slots
because they could potentially be killed as outlined above, although the deck and
AA gun slots may serve as useful locations for crew members who have been
killed in action.
- 35 -
NYGM AI Visual Sensor Mod And Submarine
Visual Sensor Mod
During testing of RFB 1.52 and operational game play of Operation Monsun
Patch 3 and above, a visual detection issue with stock Silent Hunter 4 was
discovered. Under a defined set of conditions, the game will consistently fail to
report certain ships within visual range even though the player can see these
ships. There may be cases where the player’s submarine is within 1000 yards /
meters of a contact without the game generating a visual contact report. The
causes of this issue are as follows:
1. The values used in the “Visual” section of Sensors.cfg
2. The true position of the ship from the Sub
3. The date of the mission
4. The latitude and longitude of the player’s submarine
The Player’s Perspective
If you are in the Northern Hemisphere (Latitude 25 degrees north or above) in the
winter (November, December, and January), the game may not generate the
ship/s location on the navigation and attack maps. The periscope’s ability to stay
locked on a ship that is located clockwise from approximately bearing 280 true to
bearing 050 true from the sub will be reduced to short periods of around 20
seconds before disconnecting. Once the ship in question moves south of the
sub’s position the game will then allow unaffected auto TDC lock. It should be
noted that the further north you go, the larger the non-detection area becomes.
However, if you are in the same location in the summer (May, June, and July)
you may not see this issue at all.
If you are on the equator you will see all contacts no matter what the date is.
If you are in the Southern Hemisphere, the reverse of the effect in the Northern
Hemisphere applies in the winter (latitude 25 degrees south or below). From
June to August the game may not generate a ship’s given location on the
navigation and attack maps. The periscope’s ability to stay locked on a ship that
is located clockwise from bearing 110 true to bearing 250 true from the sub will
be reduced to the above mentioned period of approximately 20 seconds. Once
the ship in question moves north of the sub’s position the system will then allow
unaffected auto TDC lock. It should be noted that the further south you go the
larger the non-detection area becomes. In addition, as with the Northern
Hemisphere if you are in the same location in the summer (November,
December, and January) you may not see this issue at all.
- 36 -
With the addition of the NYGM AI Visual Sensor Mod and Submarine Visual
Sensor Mod, this issue has been significantly magnified. Therefore, the player
will have to act like a real captain and actually look through the periscope and
conduct 360-degree scans to confirm the location and/or number of the ships
instead of having all ships instantly and magically appear in real time. The NYGM
Submarine Visual Sensor Mod's unintended result of reducing the real time
satellite ability of the submarine AI to display the ships on your navigation map
down to the meter/yard and the degree of ships the player doesn't even know are
there adds to the “realistic uncertainty” of RFB’s game play. When using Silent
Hunter 4’s “automatic targeting” option, the player will still have to work for every
sinking, which is another selling point for those who want the auto TDC but
disliked its 1000% accuracy.
- 37 -
Distance Measurement, Draft, and Tonnage
Mod
RFB’s new distance measurement, draft, and tonnage mod aims to make the
distance measurement method used with either periscope more in line with the
historical reality, thus adding to the “fog of war.” This fog of war is further
enhanced by modifying the tonnage and draft values presented to each player.
Stock Silent Hunter 4: Clear Skies Ahead
In stock SH4, the game uses the exactly correct mast height of every individual
AI ship as the reference point used to determine the distance to a target. While in
theory this is a valid way to determine the distance to a target, it removes any
uncertainty about the ship’s true mast height, and the reality is that there were
many different reference points on a ship used to measure the distance to a
target (funnels, deckhouses, decks, forecastles, etc.). Relying on the mast height
only was generally considered to be impractical, since steps were taken to
conceal a ship’s true mast height, such as using camouflage and modifying the
height of the masts.
Furthermore, the tonnage and draft values presented in the recognition manual in
stock Silent Hunter 4 largely take out any guesswork on the part of the player.
The ship’s listed tonnage and draft values reflect their exact, in-game values.
With a torpedo running at its proper depth, for instance, a player targeting a ship
in stock Silent Hunter 4 will know for certain whether or not a torpedo will run
underneath the keel of a ship. Players can thus “snipe” a ship, firing a torpedo at
just the right depth so as to ensure a magnetic detonation.
Introducing the Fog of War to Ship Targeting
Throughout WWII, the U.S. Navy’s Office of Naval Intelligence (ONI) produced
an extensive series of recognition manuals designed to help commanders
identify and target enemy shipping. These manuals included a variety of data,
including the estimated height of various points on each ship, the ship’s
estimated tonnage value, the ship’s draft when fully loaded vs. empty, armor,
weapons, etc. Notes were included in these entries to let the commander know
how accurate the data was believed to be. For instance, in the 1944 manual on
Japanese merchant shipping, each ship entry had an intelligence value from A to
C. These ratings were described as follows:
- 38 -
•
•
•
A: “Excellent. Source material has been available and drawing believed
to be correct in detail.”
B: “Source material limited, some details may be inaccurate.”
C: “Source material very limited, profile believed to be generally correct
but proportions and details doubtful.”
Bringing it All Together
Armed with this material from the ONI manuals, extensive changes were made to
the way target data is presented to the player in Real Fleet Boat. These changes
are detailed below:
1. Distance Measurement Reference Point: the reference point used for
each ship uses the exact values extracted from ONI manuals. Depending
on the intelligence information surrounding a given ship, this value may or
may not be very accurate.
2. Tonnage: again, this value is taken from each respective entry in the ONI
manuals. The tonnage values credited to each ship reflect those known to
the U.S. Navy at the time each respective manual was distributed to the
fleet.
3. Draft: like tonnage values, the draft value of each ship represents the
value known to ONI. Where both empty and loaded draft values are
presented for a particular ship’s entry, the latter value is used, since Silent
Hunter 4 treats each ship as sailing fully loaded. It is important to note
here that these draft values do NOT necessarily reflect the ship’s true ingame draft. With the depth-keeping problems present with both German
and American torpedoes, it is thus generally a good idea to not fire one’s
torpedoes too deep and thus risk having the torpedo run harmlessly
beneath the keel of a ship.
Determining the Correct Distance Measure Reference
Point
In order to reduce confusion while remaining true to the data presented in the
ONI manuals, the following reference points are used for each class of ship. Note
that one can also find this data when moving the mouse cursor over the check
box in the recognition manual:
•
•
•
Merchant Ships: top of the tallest mast.
Aircraft Carriers and Aircraft Transports: flight deck.
All Other Warships: top of the tallest funnel.
- 39 -
Submarine Upgrades & Availability
S-Boat Upgrades
S-18 Equipment Upgrades & Availability
1942
Radar Upgrades
SJ Surface Search Radar
SJ-1 Surface Search Radar
1943
1944
1945
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
1
1
1942
1943
1944
1945
AA Gun Upgrades
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
Single-barrel 20mm AA Gun
1
1942
Deck Gun Upgrades
4 Inch Deck Gun
3 Inch Deck Gun
1942
Misc Upgrades
Conning Tower Upgrade
1943
1944
1945
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
1
1
1943
1944
1945
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
1
=Upgrade Available
S-42 Equipment Upgrade & Availability
1942
Radar Upgrades
SJ Surface Search Radar
SJ-1 Surface Search Radar
SD-1 Air Search Radar
1943
1944
1945
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
1
1
1
1942
1943
1944
1945
AA Gun Upgrades
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
Single-barrel 20mm AA Gun
1
1942
Deck Gun Upgrades
4 Inch Deck Gun
3 Inch Deck Gun
1942
Misc Upgrades
Conning Tower Upgrade
1943
1944
1945
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
1
1
1943
1944
1945
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
1
=Upgrade Available
- 40 -
Fleet Boat Upgrades
Equipment Upgrade & Availability
1942
Radar Upgrades
SD Air Search Radar
SD-1 Air Search Radar
SV Air Search Radar
SJ Surface Search Radar
SJ-1 Surface Search Radar
1942
Sound Equip. Upgrades
WCA Sonar
JP-1 Sonar
1943
1944
1945
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
1
1
1
1
1
1943
1944
1945
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
1
1
1942
1943
1944
1945
AA Gun Upgrades
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
Single-barrel 20mm AA Gun 1
Twin-barrel 20mm AA Gun
1
40mm AA Gun
1
1942
Deck Gun Upgrades
3 Inch Deck Gun (Fore)
3 Inch Deck Gun (Aft)
4 Inch Deck Gun (Fore)
4 Inch Deck Gun (Aft)
5 Inch Deck Gun (Fore)
5 Inch Deck Gun (Aft)
Twin 5 Inch Deck Guns
1942
Misc Upgrades
Decoy Launcher
1943
1944
1945
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
1
1
1
1
1
1
1
1943
1944
1945
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
1
=Upgrade Available
- 41 -
Conning Tower Upgrade & Availability
1942
Balao
Late War
1942
Gar
Mid War
Late War
Mid War
Late War Variant #1
Late War Variant #2
Mid War
Late War
Mid War
Late War
Mid War
Late War
Mid War
Late War
1945
1943
1944
1945
1943
1944
1945
1943
1944
1945
1943
1944
1945
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
1
1
1942
Tambor
1944
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
1
1
1942
Sargo
1943
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
1
1
1942
Salmon
1945
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
1
1
1
1942
Porpoise
1944
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
1
1
1942
Gato
1943
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
1
1943
1944
1945
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
1
1
=Upgrade Available
- 42 -
U-boat Upgrades & Availability
1939
Radar Upgrades
FuMO29 Radar
FuMO30 Radar
FuMO61 Radar
1939
Sonar Upgrades
GHG Sonar
KDB Sonar
Balkon Gerät Sonar
FuMB1 RWR
FuMB7 RWR
FuMB10 RWR
FuMB26 RWR
20mm C/30 AA Gun (x1)
20mm C/38 AA Gun (x1)
20mm C/38 AA Gun (x2)
20mm C/38 Gun (x4)
37mm C/30U AA Gun
37mm M/42U AA Gun (x1)
37mm M/42U AA Gun (x2)
105mm Deck Gun
Bold 1 Decoy Launcher
Bold 2 Decoy Launcher
Bold 3 Decoy Launcher
Bold 4 Decoy Launcher
1944
1945
1940
1941
1942
1943
1944
1945
1940
1941
1942
1943
1944
1945
1940
1941
1942
1943
1944
1945
1940
1941
1942
1943
1944
1945
S OND J FMAM J J A S ON D J FMAM J J A S ON D J FMAM J J A S ON D J FMAM J J AS ON D J FMAM J J AS ON D J FMA
1
1939
Misc Upgrades
1943
S OND J FMAM J J A S ON D J FMAM J J A S ON D J FMAM J J A S ON D J FMAM J J AS ON D J FMAM J J AS ON D J FMA
1
1
1
1
1
1
1
1939
Deck Gun Upgrades
1942
S OND J FMAM J J A S ON D J FMAM J J A S ON D J FMAM J J A S ON D J FMAM J J AS ON D J FMAM J J AS ON D J FMA
1
1
1
1
1939
AA Gun Upgrades
1941
S OND J FMAM J J A S ON D J FMAM J J A S ON D J FMAM J J A S ON D J FMAM J J AS ON D J FMAM J J AS ON D J FMA
1
1
1
1939
RWR Upgrades
1940
S OND J FMAM J J A S ON D J FMAM J J A S ON D J FMAM J J A S ON D J FMAM J J AS ON D J FMAM J J AS ON D J FMA
1
1
1
1940
1941
1942
1943
1944
1945
S OND J FMAM J J A S ON D J FMAM J J A S ON D J FMAM J J A S ON D J FMAM J J AS ON D J FMAM J J AS ON D J FMA
1
1
1
1
=Upgrade Available
- 43 -
Torpedo Availability & Malfunctions
U.S. Torpedo Availability
1942
Torpedo Upgrades
Mark 10
Mark 14
Mark 18
Mark 23
Mark 27
1943
1944
1945
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
1
1
1
1
1
=Upgrade Available
U.S. Torpedo Malfunction Data
Premature
Detonations
Duds
Up to 12 Feet
(August 1942)
Large Chance
(Until June 1943)
Large Chance
(Until Sept. 1943)
Up to 12 Feet
(August 1942)
Large Chance
(Until June 1943)
Large Chance
(Until Sept. 1943)
Type
Deep Runner
Mark 10
Up to 10 Feet
(All War)
Mark 14
Mark 18
Mark 23
Mark 27
- 44 -
German Torpedo Availability
1939
Torpedo Upgrades
T1
T2
T3
T1 FAT1
T1 LUT1
T3 FAT2
T4
T5
T11
1940
1941
1942
1943
1944
1945
S OND J FMAM J J A S ON D J FMAM J J A S ON D J FMAM J J A S ON D J FMAM J J AS ON D J FMAM J J AS ON D J FMA
1
1
1
1
1
1
1
1
1
=Upgrade Available
German Torpedo Malfunction Data
Deep Runner
Premature
Detonations
Duds
T I Types
Through
Feb. 1942
Through
Nov. 1942
Through
Nov. 1942
T II Types
Through
Feb. 1942
TIII Types
Through
Feb. 1942
Type
Through
Nov. 1942
Through
Nov. 1942
T IV
TV
T XI
- 45 -
Through
Nov. 1942
Japanese Sensor Data
Surface Search Radar Availability
1942
1943
1944
1945
TYPE 22 Radar
D J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND J FMAM J J AS OND
Kongo Class Battleship
1
Fuso Class Battleship
1
Ise Class Battleship
1
Ise Class Battleship (Convert)
1
Yamato Class Battleship
1
Takao Class / Maya Cruisers
1
Furutaka Class Cruiser
1
Mogami Class Cruiser
1
Kuma Class Cruiser
1
Agano Class Cruiser
1
Taiho Class Carrier
1
Okinoshima Minelayer
1
Subchaser
1
Kagero Class Destroyer
1
Yugumo Class Destroyer
1
Other DD Classes
1 1 1 1
=Upgrade Available
Note: This is the only surface search radar available to Japanese surface ships,
and has a maximum range of about 5 km against submarines.
Sonar
Warships: Gradually improve over the war and are at their peak by late 1944.
Merchants: Start using sonar in late 1944.
Airborne Radar
Airborne radar starts being fitted in limited numbers to aircraft in the fall of 1942.
By the end of 1944, most aircraft have been fully equipped with airborne radar.
- 46 -
Part III: Submarine Details
- 47 -
American Submarines
S-18 Class
History
The S-18 class of submarines evolved from Electric Boat’s prototype S-1 (Fiscal
Year 1917) for the new class of S-boat submarines. Although many of these
boats would eventually be discarded under the terms of the 1930 London Naval
Treaty, a number survived to serve in a variety of roles during World War II. Six
S-18 class submarines were in service with the Asiatic Fleet at the outbreak of
the war, and they were later joined by other S-18s in the Aleutians and the North
Pacific. S-18s continued to serve in combat roles until early 1944, when they
were finally retired and relegated entirely to training duties.
Performance
Speed: 13 knots surfaced; 9 knots submerged
Range: 8,950 miles at 9.5 knots surfaced; 100 miles at 5 knots submerged
USS S-36 (SS-141) at Bethlehem Shipbuilding Corp., San Francisco, CA
March 29, 1923
- 48 -
S-42 Class
History
The S-42 class was a small group of six Electric Boat S-boats authorized under
the 1 July 1918 Appropriation Act and Emergency Fund (24 new S-boats had
been ordered by the U.S. Navy, but only these six were built). S-42s incorporated
a variety of improvements over the older S-18s, such as increased surfaced
range, changes to the ballast system and a gun access hatch under the breech
of the deck gun. S-42 boats served in both the South Pacific and the Alaskan
waters into 1944, at which point they were withdrawn from combat service.
Performance
Speed: 12.5 knots surfaced; 9.5 knots submerged
Range: 10,000 miles at 8.1 knots surfaced; 100 miles at 5 knots submerged
USS S-44 (SS-155)
- 49 -
Porpoise Class
History
Authorized as part of Fiscal Year 1934 funding, the Porpoise class was the
precursor of the fleet submarines of the Gato and Balao classes. This class
incorporated features that would become standard in follow on classes, such as
an all electric drive with four diesel engine generators, high surface speed and an
endurance of 75 days. However, the forward torpedo room was too cramped,
and the reserve battery capacity was too low. These deficiencies would ultimately
be corrected in later classes. Submarines of this class served in combat from the
war’s beginning until the end of 1944, when the surviving boats were reassigned
to training duties.
Performance
Speed: 19.25 knots surfaced; 8.75 knots submerged
Range: 11,000 miles at 10 knots surfaced; 62 miles at 4 knots submerged
USS Pike (SS-173) Underway off New London, CT
May 5, 1944
- 50 -
Salmon Class
History
A class of six submarines built with Fiscal Year 1936 funding, these boats were
an improvement on the earlier Porpoise boats. The forward torpedo room was
enlarged, and the diesel compartment was split into two equal parts. More
torpedoes could now be carried, including 4 in external storage for the aft tubes,
plus two more tubes were added to the stern compartment. The battery capacity
was increased so that these boats could stay underwater for up to 48 hours at
2.5 knots. Boats of this class served from the war’s first days until the cessation
of hostilities.
Performance
Speed: 21 knots surfaced; 9 knots submerged
Range: 11,000 miles at 10 knots surfaced; 84 miles at 4 knots submerged
USS Snapper (SS-185) off Mare Island Naval Yard
February 24, 1945
- 51 -
Sargo Class
History
Fiscal Year 1937 submarines, boats were generally repeats of the Salmon class.
The standard battery fitted to this class, produced by the Navy’s Bureau of
Engineering, replaced the earlier commercial type bought from Exide and Gould.
It was henceforth known as the “Sargo battery” and was fitted in all follow on fleet
boat classes. A faulty main induction valve (as the Squalus found out) and a
badly overweight design were the main faults of this class. Even so, Sargo boats
served with distinction during World War II, sinking some 73 ships, including a
Japanese submarine.
Performance
Speed: 21 knots surfaced; 8.75 knots submerged
Range: 11,000 miles at 10 knots surfaced; 84 miles at 4 knots submerged
USS Sailfish (SS-192), off Mare Island Navy Yard
April 13, 1943
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Tambor Class
History
Authorized with Fiscal Year 1939 appropriations, these were the first fleet
submarines with six bow torpedo tubes. The four externally stored torpedoes of
the Salmon and Sargo classes were now moved inside the hull. The Bureau of
Engineering re-rated the main diesel engines so the boats could now make their
required speed at their rated power. Boats of this class could exceed 18 knots
while one engine charged batteries or was repaired. Boats of this class served
with distinction throughout the war, with the Tautog holding the record of most
ships sunk by a single U.S. submarine.
Performance
Speed: 20.4 knots surfaced; 8.75 knots submerged
Range: 11,000 miles at 10 knots surfaced; 84 miles at 4 knots submerged
USS Triton (SS-201) Underway
Circa 1940
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Gar Class
History
The Fiscal Year 1940 program consisted of six fleet submarines and two 800 ton
coastal boats. In late December 1938, Navy Secretary Claude Swanson decided
that the fleet submarines would be repeats of the Tambor class, thus the boats of
the Gar class performed to the same specs of its immediate predecessor. Gar
class boats served in combat from the war’s first days until the end of 1944.
Performance
Speed: 20.4 knots surfaced; 8.75 knots submerged
Range: 11,000 miles at 10 knots surfaced; 84 miles at 4 knots submerged
USS Gudgeon (SS-211) off Mare Island Naval Yard
July 7, 1941
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Gato Class
History
Initially authorized under Fiscal Year 1941, the Gato class was an improvement
over the preceding Tambor and Gar boats. The maximum diving depth was
increased, a pressure proof bulkhead now divided the engine room in half, and
the auxiliary ballast tanks were finally enlarged to compensate for the weight of
24 torpedoes or 40 mines. The first Gato class boats were commissioned in late
1941, and from early 1942 until war’s end they formed the backbone of the U.S.
Navy Submarine Force along with the follow on Balao class. Surviving boats of
the Gato class would continue to serve well into the postwar years with both the
U.S. Navy and various foreign fleets.
Performance
Speed: 21 knots surfaced; 9 knots submerged
Range: 11,000 miles at 10 knots surfaced; 84 knots at 4 knots submerged
USS Gato (SS-212) off Mare Island Naval Yard
November 29, 1944
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Balao Class
History
Fiscal Year 1942 boats, the Balao class was designed to take advantage of a
stronger type of metal known as high tensile steel. The change to this type of
material allowed boats of this class to dive deeper than the preceding Gato class
boats. Entering combat in mid 1943, the Balao class boats came alongside the
Gatos to form the bulk of the late war American submarine force in the Pacific.
Like the Gato class, Balao class boats also served in the postwar U.S. Navy and
various foreign navies.
Performance
Speed: 20.25 knots surfaced; 8.75 knots submerged
Range: 11,000 miles at 10 knots surfaced; 84 miles at 4 knots submerged
USS Balao (SS-285)
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Tench Class
History
In 1943, the Portsmouth shipyard conducted a redesign of the Balao class to
address some of the weaknesses of this class. The tank layout was revised to
eliminate weak points in the torpedo rooms, and fuel capacity was increased by
installing a “variable fuel tank.” In addition to this, the installation of double
armature motors reduced gear whine, which was a major source of noise. Lastly,
the addition of 4 reload torpedoes brought the torpedo capacity to 28. Serving in
the Pacific from early 1945, a number of Tench class submarines were canceled
when it was realized they would not be needed to help win the war. It was a
Tench class boat – the Torsk – that sank the last Japanese warship of World War
II.
Performance
Speed: 20.25 knots surfaced; 8.75 knots submerged
Range: 16,000 miles at 10 knots surfaced; 84 knots at 4 knots submerged
USS Torsk (SS-423) Underway off the U.S. East Coast
February 16, 1945
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German Submarines
Type IXD2 Class:
History
The Type IXD class originated from Karl Dönitz’s request for the further
development of a long range and Fleet style U-boat but without the heavy artillery
armament of the Type XI class. As a completely new design based on the Type
XII class was deemed impractical, it was decided to enlarge the Type IXC class
into a U-boat with a higher surface speed and an increased range. While the
Type IXD1 experienced problems with its six torpedo boat diesels, the IXD2
boats were quite successful with the standard Type IX propulsion unit, which was
augmented with a diesel electric addition for increased range. Serving from 1942
until the war’s end, Type IXD2 boats conducted extremely long patrols, with a
handful of boats serving in the Far East as part of Operation Monsoon.
Performance
Speed: 19.2 knots surfaced; 6.9 knots submerged
Range: 23,700 miles at 12 knots surfaced; 57 miles at 4 knots submerged
U-848 under attack by PB4Y-1s and B-25s near Ascension Island
November 5, 1943
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Part IV: Bibliography and Credits
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Research Resources
Books
Bauer, K. Jack and Roberts, Stephen S. Register of Ships of the U.S. Navy,
1775-1990: Major Combatants. New York: Greenwood Press, 1991.
Friedman, Norman. U.S. Submarines Through 1945: An Illustrated Design
History. Annapolis, Maryland: Naval Institute Press, 1995.
Gannon, Robert. Hellions of the Deep: The Development of American Torpedoes
in World War II. University Park, Pennsylvania: The Pennsylvania University
Press, 1996.
Köhl, Fritz and Rössler, Eberhard. The Type XXI U-Boat. Annapolis, Maryland:
Naval Institute Press, 1991.
Möller, Eberhard and Brack, Werner. The Encyclopedia of U-Boats: From 1904
to the Present. London: Greenhill Books, 2004.
Rössler, Eberhard. The U-Boat: The Evolution and Technical History of German
Submarines. London: Cassell & Co, 1981.
Williamson, Gordon and Pavlovic, Darko. U-boat Crews 1914-45. London:
Osprey, 1995.
Wiper, Steve. Warship Pictorial #27: Kriegsmarine Type VII U-Boats. Tucson,
AZ: Classic Warships Publishing, 2004.
CD-ROMS
Navy Department – Bureau of Naval Personnel. NavPers 16160: The Fleet Type
Submarine. June 1946. History on CD-ROM.
Navy Department – Division of Naval Intelligence. ONI 41-42: Japanese Naval
Vessels. November 1942 – with supplements through August 1943. History on
CD-ROM.
Navy Department – Division of Naval Intelligence. ONI 54-R: U.S. Naval Ships
and Aircraft. June 9, 1942. History on CD-ROM.
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Navy Department – Division of Naval Intelligence. ONI 54 Series: U.S. Naval
Vessels. November 1943 – with supplements through December 1943. History
on CD-ROM.
Navy Department – Division of Naval Intelligence. ONI 201 (1943-44): Warships
of the British Commonwealth. July 1, 1943. History on CD-ROM.
Navy Department – Division of Naval Intelligence. ONI 204: German Naval
Vessels. August 13, 1942 – with supplements through October 1942. History on
CD-ROM.
Navy Department – Division of Naval Intelligence. ONI 208-J: Japanese
Merchant Ships. August 24, 1942. History on CD-ROM.
Navy Department – Division of Naval Intelligence. ONI 208-J (Revised):
Japanese Merchant Ships. May 1944. History on CD-ROM.
Navy Department – Division of Naval Intelligence. ONI 208-J Supplement No. 2:
Far Eastern Small Craft and ONI 208-J Supplement No. 3: Standard Classes of
Japanese Merchant Ships. January/March 1945. History on CD-ROM.
Navy Department – Division of Naval Intelligence. ONI 220-G: German
Submarines. April 13, 1944. History on CD-ROM.
Navy Department – Division of Naval Intelligence. ONI 222-J: A Statistical
Summary of the Japanese Navy. July 20, 1944. History on CD-ROM.
Navy Department – Division of Naval Intelligence. ONI 222-J: The Japanese
Navy. June 1945. History on CD-ROM.
Uboataces. U-995 German Type VIIC U-Boat. August 15, 2007. Aardvark Global
Publishing Company.
Walkowiak, Thomas F. Gato and Balao Class Submarine of World War Two Plan
eBook. August 27, 2008. The Floating Drydock.
War Department – Military Intelligence. FM 30-58: Identification of Japanese
Naval Vessels. December 29, 1941. History on CD-ROM.
War Department – Navy Department. FM 30-50/NAVAER 00-80V-57:
Recognition Pictorial Manual of Naval Vessels. September 1, 1944. History on
CD-ROM.
Wittmer, Paul. United States Submarine Men Lost During World War II. May
2007. Paul W. Wittmer.
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WEBSITES
“American Military Patches, Other Insignia and Decorations of World War Two.”
http://www.angelfire.com/md2/patches/index.html
“Dictionary of American Naval Fighting Ships.”
http://www.history.navy.mil/danfs/index.html
“Dud Torpedoes, WW2 Pacific.” http://www.ww2pacific.com/torpedo.html
“Early CPO Rate Abbreviations.”
http://www.goatlocker.org/resources/cpo/history/abbrev.htm
“Enlisted Ratings and Jobs in the U.S. Navy.”
http://www.history.navy.mil/faqs/faq78-1.htm
“Feldgrau.com - The German Armed Forces 1919-1945.”
http://www.feldgrau.com/
“The Fleet Type Submarine Online.”
http://www.maritime.org/fleetsub/index.htm
“FleetSubmarine.com is your source on World War II American submarines.”
http://www.fleetsubmarine.com/
“German U-Boats and Battle of the Atlantic.” http://www.uboataces.com/
“Historic Naval Ships Association.” http://www.hnsa.org/index.htm
“Home Page of Paul W. Wittmer.” http://www.subvetpaul.com/
“HyperWar: Current Doctrine, Submarines (United States Navy: 1944—USF-25).”
http://www.ibiblio.org/hyperwar/USN/ref/SS-Doct/index.html
“HyperWar: US Navy Bureau of Ordnance in World War II.”
http://www.ibiblio.org/hyperwar/USN/Admin-Hist/BuOrd/index.html
“Imperial Japanese Navy Page.”
http://www.combinedfleet.com/kaigun.htm
“Japanese Radar of World War II.” http://www.stargames.com/exhibits/japaneseradar/japaneseradar.html
“Kriegsmarine and U-Boat History.” http://www.ubootwaffe.net/index.html
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“Naval-Reference.Net: Illustrated Naval History Reference.” http://navalreference.net/index.html
“Naval History via Flix.”
http://navalhistory.flixco.info/H/93745x263540/259869/a0.htm
“NavSource Naval History.” http://www.navsource.org/
“NavWeaps – Naval Weapons, Naval Technology, and Naval Reunions.”
http://www.navweaps.com/
“The Official USS Batfish (SS 310) Website.”
http://www.ussbatfish.com/index.html
“On Eternal Patrol.” http://www.oneternalpatrol.com/
“Online Reading Room: Publications, Documents, and Subject Presentations.”
http://www.history.navy.mil/library/online/readingroom.htm
“The Pacific War Online Encyclopedia.”
http://pwencycl.kgbudge.com/Table_Of_Contents.htm
“PigBoats.com” http://www.pigboats.com/
“Reports of the U.S. Naval Technical Mission to Japan.” http://www.fischertropsch.org/primary_documents/gvt_reports/USNAVY/USNTMJ%20Rep
orts/USNTMJ_toc.htm
“The Ship Camouflage Website.” http://www.shipcamouflage.com/
“Submarine Research Center.”
http://www.submarineresearch.com/index.html
“U-boat Archive.” http://www.uboatarchive.net/
“uboat.net – The U-boat War 1939-1945.” http://www.uboat.net/
“USS Bergall.” http://www.bergall.org/
“Valor at Sea.” http://www.valoratsea.com/main.htm
“World War II Day by Day.” http://www.wwiidaybyday.com/
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CREDITS
The task of creating a mod like Real Fleet Boat is a large one, and as such many
members of the Silent Hunter 4 community, past and present, have contributed
to its success. Without their help and input, Real Fleet Boat would not be the
mod it is today. In no particular order of importance, the following persons have
contributed to the development of the mod:
Developers:
9th Flotilla
AkbarGulag
Ailantd
AntEater
Beery
Capnscurvy
Captain Cox
Carotio
Castorp345
CCIP
Cdrake66
Chomu
Der Teddy Bär
Ducimus
Egan
FullMetalEdges
Galanti
GouldJG
Gunfighter
GunMod
Hildofr
Iceberg
Jace11
JimBob
JimiMadrid
Jungman
kriller2
LukeFF
Lurker_hlb3
Mikhayl
Nisgeis
NVDrifter
Observer
Redwine
Schlageter-JG26
Scoochy
Shad43
skwasjer
swdw
Timetraveller
Xantrokoles
Donner
jrex53
Nuc
r6751
Rockin Robbins
Testers:
399nkov
AVGWarhawk
DeepIron
Deviance
Dieselglock
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