Design and development of high speed craft includes general design, intact damage and hydrodynamic stability, performance prediction and simulation, hull development, structural design and analysis and seakeeping performance.
Military Patrol Craft
65 ft Navy Prototype Patrol Craft developed by Safeboats International
Coast Guard CB-OTH MKIV
US Coast Guard Over-the-Horizon patrol craft developed by Safeboats International
Full Load Condition
Hydrostatic model floating in the full load condition
9.2M Rib for the Singapore Navy - Twin Diesel Sterndrives
Structural Layout of High Speed Patrol Boat
Sea State 5
30 ft Patrol Boat operating in Sea State 5
Static Stability Limits
Down Flooding Points and Static Stability Limits
Full Load Waterline
Propulsion System Integration
Propulsion System Integration is to ensure that the installed system meets or exceeds the expectations of the builder and customer. The system is run through a simulation to determine fuel economy, acceleration, dynamic stability, etc.
44 knot RIB Sterndrive Installation
Twin 275 bhp Diesel Sterndrives
Pod Drive Installation
Structural Arrangement for Pod Drive in composite production motoryacht.
Structural Layout 43 ft Motoryacht
Completed support structure in prototype installation.
Typical Inboard Installation
Conventional inboard installation with tunnel. Integrated shaft, strut, propeller and rudder.
Comparison of two pod drive installations to evaluate weight and center of gravity shift.
Typical Engineroom Arrangement
3D Propeller model integrated into design to ensure adequate clearance and sizing of propulsion components.
Finite Element Model
Finite Element model of the shaftline for a 50M motoryacht. Check all modes of vibration: longitudinal, lateral and torsional.
Product Develop can take many forms. The projects to date have been primarily marine related.
Exhaust System Design
Integration and design of wet exhaust system with underwater discharge and integral bybass.
Detail Design of Muffler
Noise remediation to existing muffler designs.
Small Controllable Pitch Propeller
Finite Element Analysis of Propeller Blade Assembly
Layout of gun mounts and tow post for high speed patrol craft.
Wave break arrangement for high speed patrol operating in breaking surf.
Fireboat Push Knees
Integrated push knees for high speed fireboat
Propeller Design includes a wide range of vessel types including high speed counter-rotating propellers, tandem propellers and custom propellers for large yachts and commercial vessels.
I can offer a full range of propeller designs from small counter-rotating propellers to propellers over three meters in diameter. The propellers are custom manufactured in Japan by Nakashima.
156 inch 5-Blade Propeller Design
5-Blade Propeller for 16,000 bhp double ended ferrry
156 inch 5-Blade Propeller
156 inch Propellers at final dye-penetrant inspection.
68 inch Propeller
3D Model of a 68 inch propeller on a 179 ft Motoryacht. Propeller is fitted with a hydraulic hub and is class to Lloyds Registry.
68 inch Propeller
68 inch Propeller installed on the boat.
60 inch 7-Blade Propeller
7-Blade Propeller for 92 foot Sportfisherman.
Counter-Rotating Propeller Design
Propeller design for Unmanned Autonomous Vehicle.
Performance simulation includes the prediction of planning craft in calm seas over the full speed range of the application. The simulation is capable of predicting the performance of the boat taking into account the engine and drive system including a standard inboard, pod drive, outboard, surface drive or waterjet from single to quad installations. The program will pick a propeller for the application and estimate top speed, cruise speed and idle speed. The waterjet simulation uses affinity rules for determining the thrust versus engine RPM. The outboard simulation uses the Newton-Radar Series and the counter-rotating propellers for pod drives are modeled using an equivalent single propeller. The fuel map is based on typical high speed engines adjusted for the fuel consumption at rated RPM.
The program can integrate tank test results into the program instead of the standard modified Savitsky's Long Form. The program calculates appendage drag, whisker spray and windage under separate routines. The whisker spray resistance is neglected above 40 knots.
The program provides the added resistance and response spectrum heave, pitch and acceleration for Sea States 1 through 4 in head seas.
Intrepid 370 at 60 knots
Intrepid 370 Performance Comparison
Intrepid 370 Acceleration Comparison
USCG 47 ft Motorlifeboat
47 ft Motorlife Running through Surf
47 Motorlifeboat Hull Model
47 ft MLB added Resistance Seastate 3
47 ft MLB Pitch Response Seastate 3
Heave Response Seastate 3 at 25 knots
Heave & Pitch Response Seastate 3
47 ft MLB Acceleration Response in Seastate 3 at 25 knots
47 ft MLB Acceleration in Seastate 3
The following are some of the results of a wide range of analysis problems that have been completed over the last couple of years. The problems include a high performance muffler which discharged underwater with a bypass leg above the waterline to the development of the water surface in a sea state 5.
Ultra-quiet Muffler with Underwater Exhaust
Engine Data Results to determine Exhaust Flow & Water Injection requirements.
Surface Representation of Sea State 5
As part of a simulation running in head seas the irregular sea surface can be developed to show the wave heights in relation to the vessel or multiple vessels.
Four Quadrant Propeller Curve for Double Ended Ferries and Dynamic Positioning Vessels
Speed Trial Results
Alternating Torque Estimate Comparing 4B to 5B Propellers.
Computational Fluid Dynamics
Cotty Fay Marine Design is excited to announce the addition of Computational Fluid Dynamics (CFD) to our tool box.We can offer very competitive pricing for external hydrodynamics including resistance estimates using multiphase dynamic mesh with RANS turbulence models.The package is OpenFoam and templates have been developed to accelerate the modeling and development of the domain and boundary conditions.The modeling for running resistance estimates can be developed and run very quickly. The computer time is 24-36 hours per speed point depending on speed. The hull model can include spray rails, tunnels and chine details which the designer may want to investigate.
The second level of complexity would be to add the appendages to determine their drag and wake.An optimization could be run or a range of parametric designs.The superstructure and pilothouse can be added to investigate flow and forces due to wind forces.The appendages would be modeled on a full hull using an LTS solver (Local Time Stepping).
42M Yacht Support vessel at 11.5 knots showing running wake elevation in meters.
110M Double Ended Ferry
110M Ferry at 16.5 knots streamlines over hull and rudder.
Stepped Hull at 50k
49 ft Interceptor Hull at 50 knots wake elevation
4M Diameter Propeller
Highly loaded propeller during acceleration. The propeller is 4M in diameter producing 1298 kN with a torque of 795 kN-M.
Propeller Velocity Profile
Propeller Wash Velocity during acceleration
83M Ferry Wave Profile
Wave Elevation with bilge keels
Streamlines over Bilge Keel
Flow over bilge keel at 13.5 knots
Finite Element Analysis
The following are the latest finite element analysis projects that have been completed. The analysis includes the dynamic response of a planing hull at speeds up to 54 knots. The next application is a modal analysis and alignment procedure for a 54m patrol boat and the last application is a pedestal crane foundation on a 31m Fireboat.
Structural Arrangement of an Interceptor Hull
Structural Model with Hull Skin removed
Finite Element Model of a Interceptor Hull
von Mises Stresses in Heavy Seas
Maximum Displacement (inches)
Finite Element Model of Shaft, Gear & Engine
Gap & Sag Calculation for Alignment
First Lateral Mode including Strut
Crane Pedestal Structural Model
Under Deck Structure
von Mises Stresses in Deck
von Mises Stresses in Structure under Deck
Heavy Lift & Transport
The following cradle has been developed to be modular to provide the shipyard with the most flexibility in transporting docked vessels from an 1800 ton floating drydock to a terminal area. The cradles allow the weight of the vessel to be safely transferred from the drydock blocks to the dollies and rolled off the floating drydock to land where the cradles are landed on a series of transfer blocks where the dollies are removed to be available for the next docking.
Type II Cradle Assembly
Cradle can be assembled in three (3) configurations to use (9), (7) or (5) Dollies.
Cradle on Dry Dock
Cradle being assembled on dry dock with wheels and transfer blocks in position.
Overall Block and Cradle Arrangement
Cradle assembly for a 600 ton vessel
Transfer Block Arrangement
Cradle Assembly after the dollies have been removed.
Wing in Ground Effect Craft - WIG
The craft is an aircraft - boat hybrid. The propulsion system is a 160 BHP driving a sixty inch air propeller. Take-off speed is 64 knots with a top speed of 96 knots. The payload is 1000 lbs with a maximum flight weight of 2500 lbs.
Wing in Ground Effect Craft
Two Person craft: LOA = 8M
Speed = 90 knots
Power = 120 kW
Wig Craft at Takeoff
Speed = 64 knots
Height off Water = 24 inches
Wig Craft at 64 knots
Streamlines at 64 knots running 24 inches above the surface.