FIFTY YEARS & MORE OF
HOVERCRAFT DEVELOPMENT
SNAME and IHS Dinner Meeting
11 MAY 2011
DAVID R. LAVIS
BAND LAVIS DIVISION OF CDI MARINE
CONTENTS OF PRESENTATION
 EARLY ENDEAVORS
 RAPID EXPANSION
 MAJOR CHALLENGES
 MOST SIGNIFICANT CONTRIBUTIONS
 MANY ACV & SES PHOTOS & VIDEOS
 RECENT DEVELOPMENTS




CUSHION SEALS
PROPULSION
MANEUVERING CONTROL
DESIGN SOFTWARE
 SUMMARY, CONCLUSIONS & THE WAY AHEAD
EARLY ENDEAVORS
1936 – Grandpa Lavis stumbles onto
the idea of Amphibious Assault
WELL, MY GRANDPA DID RUN A BOAT BUILDING BUSINESS
EARLY ENDEAVORS
SR-N1 in 1959
 RINA PAPER LISTS 30
INVENTORS WITH PATENTS
PRIOR TO 1953.
 AT LEAST 12 OTHERS DID
NOT FILE PATENTS.
 8 PATENTS FEATURED FLEXIBLE SKIRTS
BEFORE SR-N1 CROSSED THE ENGLISH
CHANNEL WITHOUT A SKIRT IN 1959.
Date of
Patent
1716
1876
1877
1880
1882
1888
1889
1897
1902
1906
1907
1908
1908
1909
1912
1913
1916
1921
1922
1922
1925
1927
1928
1928
1935
1935
Name and Location
Swedenborg, E., Sweden
Ward, J., San Francisco,
USA
Sir John Thornycroft, UK
Girard, L., France
De Laval, G., Sweden
Walker, J., Texas, USA
Barre, M.C.A., France
Culbertson, USA
Therye, C., France
Schroeder, F.W., Germany
(British Patent)
Clark, J., USA
Worthington, C., USA
Porter, J.R., UK
Wunderlich, A., Germany
Alcock, A.U., Perth,
Australia
Eells, A.F., USA
Von Thomamhul, D.M.,
Austria
Gambin, M.A., France
Breguet, L., Paris, France
Trask, F.G., North Dakota,
USA
Casey, V.F., Minneapolis,
USA
Tsiolkovski, K.E., Russia
Nicin, V., Dresden,
Germany
Warner, D.K., Sarasota,
USA
Birrard, J., France
Kaario, T.J., Finland
Subject
Plenum Craft Illustration
Plenum Machine Idea
Air Lubricated Hull
Rail Car
Air Lubricated Hull
Air Lubricated Hull Idea
Rail Car
Sidewall Craft Idea
Rail Car
Air Lubricated Hull Design
Craft With Annular Ducts
Rail Car With Flexible Seals
Annular Jet Craft With Flexible Skirt
Plenum Craft
Levapad Craft
Rail Car
Air Lubricated Torpedo Boat
Date of
Patent
1939
1942
1944
1952
1954
1955
1955
1955
1957
1957
1957
1958
1958
1958
Sidewall Craft
Plenum Craft With Flexible Seals
Rail Car
1959
Air Lubricated Hull With Air
Recirculation
Rail Car
Plenum Car Giving Reduced Wheel Load
1960
1960
Sidewall Craft with Spring-Loaded Rigid
Seals
Sidewall Craft Design
Plenum/Ram Wing Craft
1960
1959
1960
1962
1962
Name and Location
Courant, France
Cristadoro, C.C., Venice,
CA, USA
Brian, W.S. & Birk, F.J.,
Owensboro, KY, USA
Bondat, A.J., France
Seck, W.G., Canton, Ohio,
USA
De Lima, R.A., Brazil
Cockerell, C., UK
Roe, A.V., Canada
Beardsley, M.W., Severna
Park, MD, USA
Weiland, C., Switzerland
Bertin, M., France
Jay, D.J. & Pelthman,
H.W., USA
Latimer, C.H., Needham,
UK
Petersen, T.K. & Smith,
P.L., Tulsa, OK, USA
Gaska, C.W., Michigan,
USA
Vaughen, J.F., Irving,
Texas, USA
Ford, A., USA
Hurley, R.T. & Agni, E.S.,
USA
Mackie, H.A. & Veryzer,
R.W., USA
McCreary, N.B., Arkansas,
USA
Lewis, N.W., USA
Bliss, D.S., of HDL, UK
Subject
Sidewall Craft with Mechanical End
Seals
Sidewall Craft With Flexible End Seals
Sidewall Craft
Snow Skis With Multi-Plenum Air
Cushions
Hovering Vacuum Cleaner by Hoover
Co.
Peripheral Jet and Aircraft Landing Gear
Peripheral Jet and Sidewall Craft
Peripheral Jet Craft
Craft With Peripheral Jet & Membrane
Sheet
Craft With Labyrinth Seal
Craft With Multi-Cell Plenum Skirt
Craft With Multi-Plenum
Craft With Flexible Skirt
Cargo Handling Conveyor
Craft With Flexible Skirt
Hover Pallet With Flexible Seals
High-Speed Sidewall SES
Sidewall Craft
Wheel Barrow With Flexible Skirt
Plenum Craft With Flexible Skirt
Craft With Finger Skirt - Vertical
Craft With Finger Skirt - Inclined
CRAFT WITH FLEXIBLE SKIRT BY
PORTER, UK, 1908
FABRIC
SKIRT
FLEXIBLE END SEALS BY
BREGUET, FRANCE, 1922
FLEXIBLE END SEALS AND CUSHION
DIVIDER BY CRISTADORO, USA, 1942
Transverse Seal
Air Supply Fans
AVRO PROJECT-Y, FLYING SAUCER
(1952 to 1962, CANADA)
Click for web source
Click for web source
CURTIS-WRIGHT MODEL 2500 AIR CAR (USA)
Operated in 1959 with 8-inch Flexible Skirt
Click for Web Source
EARLY ENDEAVORS (Contd.)
 1952 – 1960 ACV (GEM) DEVELOPMENT
 CANADA (AV ROE); UK (Cockerell), USA (CURTIS-WRIGHT, GM,
FORD, CONVAIR, MARTIN, BELL, GD, H. Chaplin, Beardsley,
Bertelsen)
 1960 – HIGH-SPEED SES DEVELOPMENT
 USA NADC (A. Ford) & UK HDL (Cockerell)
 1960 – 1970 RAPID EXPANSION
 UK, USA, CANADA, SWEDEN, NORWAY, FRANCE, JAPAN,
RUSSIA, CHINA, AUSTRALIA
TECHNOLOGY PROGRESSION
1959 UK
UK
1980 USA
1963 USA
2004 FINLAND
THE PRINCIPAL CHALLENGES






HIGH COST (LOW EFFICIENCY) PROPULSION
LOW RELIABILITY OF HIGH-POWERED SYSTEMS
NEED TO REDUCE AIRBORNE NOISE
PERFORMANCE SENSITIVE TO WEIGHT GROWTH
TWO ADDITIONAL SYSTEMS (SKIRTS + AIR SUPPLY)
SKIRT MAINTENANCE (MINIMIZED BY GOOD DESIGN)
 SPEED LOSS IN A SEAWAY
 CHALLENGING MANEUVERABILITY
 SAFETY (HIGH-SPEED NAVIGATION)
SOME OF THE MOST SIGNIFICANT DEVELOPMENTS
1962 to 1977













HDL Bag-Finger Skirt (ACV & SES) – 1962
Denny D-2 GRP Hulls (SES) – 1962
Airscrew-Weyroc Centrifugal Fans (ACV & SES) – 1962
SRN-Series Integrated Lift & Propulsion (ACV & SES) – 1962
SRN-Series Integrated Maneuvering Controls (ACV) – 1962
US Navy XR-Series of Experimental SES – 1962-85
Bell Skimmer Shrouded Propellers (ACV) – 1964
Aerojet General Application of Water Jet Propulsion (SES) – 1966
Aerojet General Ride Control (SES) – 1966
Aerojet 100A, Bell 100B and Rohr 3KSES Programs – 1967-79
Hovermarine GRP Hull Mass Production (SES) – 1968
Aerojet All-Welded Aluminum AALC JEFF(A) (ACV & SES) – 1977
Bell AALC JEFF(B) Controllable Bow Thrusters (ACV) – 1977
SOME OF THE MOST SIGNIFICANT DEVELOPMENTS
1978 to 2008
 BHC Low-Pressure Responsive Skirts (ACV) – 1978
 Bell BH-110 Medium Displacement Sidehulls (SES) – 1978
 BLA Whole-Craft Design Synthesis Tools (ACV & SES) – 1978
 BHC/HW Air-Cooled Diesel, Auto-Welded Structure for AP.1-88 (ACV) – 1982
 Griffon Hovercraft Ltd starts World’s Largest Range of ACVs – 1982
 LCAC Erosion Protected Propeller and Fan Blades (ACV) – 1984
 Brodrene Aa Cored Composite Structures (SES) – 1986
 BLA Compact Axial-Flow Water Jets (SES) – 1988
 ABS Hovercraft Ltd M-10 with Advanced Composites (ACV) – 1994
 BLA Deep Skirt (ACV) – 1995
 BLA Wake-Adapted Shrouded Airscrews (ACV) – 2003
 Japan’s Ogasawara 460-ft Techno-Superliner (SES) – 2005
 Russia’s Murena E-Class Landing Craft (ACV) – 2005
 IMAA Partial Air Cushion Catamaran, PACSCAT (SES) – 2008
VA1, 1960 (UK)
CC 1 AND 2, 1960 & 1961 (UK)
CC 2, 1961 (UK)
QuickTime™ and a
BMP decompressor
are needed to see this picture.
SR-N2, 1961 (UK)
First Integrated Lift & Propulsion & Maneuvering Control System
VICKERS VA-2, 1961 (UK)
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BMP decompressor
are needed to see this picture.
VA3, 1962 (UK)
First ACV Passenger Ferry
SR-N3, 1963 (UK)
BELL SKMR-1, 1963 (USA)
First ACV with Shrouded Props
BELL SKMR-1 (USA)
HD1, 1963 (UK)
With Inclined Finger Skirt
QuickTime™ and a
BMP decompressor
are needed to see this picture.
SR-N6 AND SR-N5, 1965 & 1964 (UK)
SR-N5, 1964 (UK)
With Peripheral Jet Skirt
QuickTime™ and a
BMP decompressor
are needed to see this picture.
BHC SR-N4, 1968 (UK)
With Bag-Finger Skirt
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BMP decompressor
are needed to see this picture.
BHC SR-N4, 1968 (UK)
QuickTime™ and a
Microsof t V ideo 1 decompressor
are needed to see this picture.
BHC BH-7, 1969 (UK)
BELL LACV-30, 1969 (USA/CANADA)
Modular Construction for Transportability
JEFF(A), 1977 (USA)
First ACV with Welded Aluminum Structure
JEFF(B), 1977 (USA)
First ACV with Rotatable Bow Thrusters
BHC AP-188, 1982 (UK)
Air-Cooled Diesel-Powered and Auto-Welded Aluminum Structure
LCAC, 1984 (USA)
GRIFFON-HOVERWORK 4000 TD (UK)
QuickTime™ and a
BMP decompressor
are needed to see this picture.
POMORNIK, 1986 (ZUBR-CLASS USSR)
Click for Web Site
ABS M-10, 1994 (UK)
QuickTime™ and a
BMP decompressor
are needed to see this picture.
DASH 400, 1998 (UK)
DENNY D1 SES, 1961 (UK)
DENNY D2 SES, 1962 (UK)
First SES Passenger Ferry and First of GRP
HD1 CONVERTED TO SES, 1963 (UK)
US NAVY XR-1 SES, 1963 (USA)
First High-Speed SES
US NAVY XR-1D SES, 1974 (USA)
US NAVY XR-3 SES, 1967 (USA)
HM2 SES, 1968 (UK)
QuickTime™ and a
BMP decompressor
are needed to see this picture.
HM2
BELL SES 100B, 1972
AEROJET SES 100A, 1972 (USA)
3KSES (USA)
US NAVY XR-5 SES, 1973 (USA)
BELL-HALTER BH-110 SES, 1978 (USA)
First Commercial SES in USA
SES-200, 1982 (USA)
CIRR 120P SES, 1987 (NORWAY)
First Cored FRP SES
QuickTime™ and a
BMP decompressor
are needed to see this picture.
DERGACH SES, 1987 (USSR)
Largest Military SES
CORSAIR SES,1989 (GERMANY)
Modular Construction including MTU Diesels
Suspended in Modules from the Overhead
AGNES 200 SES, 1990 (FRANCE)
AGNES 200 SES, 1990 (FRANCE)
QuickTime™ and a
BMP decompressor
are needed to see this picture.
SMYGE SES, 1991 (SWEDEN)
OKSOY & ALTA-CLASS, 1993 (NORWAY)
Mine Hunters and Sweepers
OKSOY SES, 1993 (NORWAY)
P960 SES, 1997 (NORWAY)
55-knot Skjold Military Patrol SES
IMAA 1/3rd -Scale FLC Manned Model (UK)
Partial Air Cushion Catamaran, PACSCAT (SES)
Operating at High Speed in Scale SS4 Head Seas
PACSCAT 2010 (UK)
Click for Web Source
JAPAN’S TSL-A140 OGASAWARA SES, 2005
Largest Fast Ferry of any kind
MORE RECENT TECHNOLOGY
DEVELOPMENTS




CUSHION SEALS
PROPULSION
MANEUVERING CONTROL
DESIGN SOFTWARE
SKIRT SYSTEMS
Cross-Section of JEFF Craft Skirts
SIDE SKIRT
BOW SKIRT
DEEP SKIRT DESIGN
DEEP SKIRT DESIGN
Subjected to Extensive Sub-Scale Test Prior to Committing to
Full-Scale Prototyping
QuickTime™ and a
decompressor
are needed to see this picture.
NOT ALL IS GOOD
Material Delamination after 100 operating hours on the
prototype skirt.
 Issue also showed up on the Canadian Coast Guard
AP.1-88/400 and the Hoverspeed SR.N4 MKIII.
 All three craft used the same natural rubber material.
Suspected that Fatigue was the Primary Failure Mode.
NOT ALL IS GOOD
FEA analysis of an inflated finger indicated Stress
Concentrations and areas of Large Deformations.
Stress Map
Deflection Map
THINGS GET BETTER
FEA analysis indicated that a modification of the Design
& Lofting Process would correct this.
Deflection Map before
Modification
Deflection Map after
Modification
SECOND & THIRD GENERATION DESIGNS
QuickTime™ and a
Microsof t V ideo 1 decompressor
are needed to see this picture.
 2nd Generation T-2000
Skirt had 440+ hours
on original bow and
side fingers.
 Stern corner and stern
fingers replaced after
approximately 300
hours.
SECOND & THIRD GENERATION DESIGNS
Head-Sea Operation in Sea-State 3
.
Believe that Additional Performance Improvements are Possible
THE OVERALL POWERING CHALLENGE
Diminishing Transport Efficiency with Speed
1,000.0
THE POWERING
CHALLENGE
WV
P
Monohull
Catamaran
SWATH
IOWA Monohull
Circle Q
100.0
Hydrofoil-Foil
RV Triton Trimaran
SES
Austal III MEF Cat
W.V
P
InCat 050 HSV-X1
ACV
Bazan B60 Cat
HydroPlane
KNM Skjold SES
10.0
Stena HSS 1500 SemiSWATH
Aker T2000 ACV
Offshore Racer Monohull
InCat Jervis
Bay
VISBY MonoHull
Jetfoil Hydrofoil
1.0
Miss Budweiser
HydroPlane
SPEED (VOLUMETRIC FROUDE NUMBER)
Circle K
JGH
0.1
0.1
1.0
10.0
100.0
TODAY’S SOLUTIONS
70-kt ACV
QuickTime™ and a
Microsof t V ideo 1 decompressor
are needed to see this picture.
1,000.0
QuickTime™ and a
Microsof t V ideo 1 decompressor
are needed to see this picture.
Monohull
WV
40-ktPSEMI-SWATH
100.0
40-kt SEMI-SWATH
70-kt ACV
Catamaran
100-ktSWATH
OFFSHORE
RACERS
Hydrofoil-Foil
IOWA Monohull
RV Triton Trimaran
SES
Austal III MEF Cat
InCat 050 HSV-X1
Bazan B60 Cat
QuickTime™ and a
Microsof t V ideo 1 decompressor
are needed to see this picture.
10.0
ACV
KNM Skjold SES
Stena HSS 1500 SemiSWATH
Aker T2000 ACV
Offshore Racer Monohull
InCat Jervis
Bay
VISBY MonoHull
1.0
55-kt
SES
Jetfoil Hydrofoil
Miss Budweiser
HydroPlane
170+-kt HYDROPLANES
QuickTime™ and a
Microsof t V ideo 1 decompressor
are needed to see this picture. JGH
QuickTime™ and a
Microsof t Video 1 decompressor
are needed to see this picture.
0.1
0.1
HydroPlane
1.0
10.0
Speed (Volumetric Froude Number)
100.0
DUCTED PROPULSORS
 Typically, designs are
developed for free-stream
conditions.
 Ignores Installation
Effects.
 Full-scale trials
experience indicates that
these designs typically
produce Significantly Less
Thrust than expected.
TOOL VERIFICATION
LCAC CFX Computational Model
 LCAC propulsor analyzed
prior to starting new design.
 Checked against known
performance.
 Results compared favorably.
CFX for LCAC at 25 knots (Midway Station 7’6”)
AIR FLOW INTO PROPULSOR
View from Bow
View from Aft
Leading Edge of Shroud
BOW THRUSTER NOZZLES
 Bow Thrusters are used on many modern ACV’s
 Enhance Maneuverability
 Augment Thrust from Main Propulsors
 Provide Some Redundancy to Main Propulsors
BOW THRUSTER NOZZLES
 Typical Bow Thruster Nozzle
 Easy to Manufacture
 Aerodynamically
Inefficient
 Easy Bend versus
Hard Bend
 Large Over-Turning
Moment on Bearing
BOW THRUSTER NOZZLES
Low-Profile Bow Thruster
 Aerodynamically
Efficient Cascade
 Significant Reduction in
“Over-Turning”
Moment on Bearing
 Reduced Visual & Radar
Signature
 Complex to Manufacture
Full-Scale Trials Verified Aerodynamic Efficiency
ACV DESIGN TOOL
Designing With Respect to Cost
SUMMARY & THE WAY AHEAD
 NEW SKIRT


Lower drag, reduced powering, more reliable, less cost.
Extra depth, improved seakeeping /overland operations.
 NEW LIFT FANS

Higher efficiency, more compact & quieter.
 NEW PROPULSORS

Higher power absorption, more efficient.
 NEW BOW THRUSTERS

More efficient, less vulnerable, reduced loading.
 NEW SES

Lower cost, more reliable PACSCAT solution.
 ACV & SES DESIGN & ASSESSMENT TOOL


Reduced cost, easier to assess technology options.
Easier to assess cost impact of operational requirements.
 WHAT’S LEFT

Lighter weight systems, better skirt material, stability, ride,
collision avoidance, less noise, improved RMA & lower cost.
Questions?