Development And Optimization Of A Hydrofoil Assisted 36 Feet Power Catamaran

A hydrofoil catamaran boat is a catamaran boat which adds single or more foils between its hulls in order to take advantages from those two components.The principle of catamaran specifies significant advantages in stability,while hydrofoils principles highlight methods to reduce ship resistance,resulting;lower propulsion power.In an effort to demonstrate the advantages of hydrofoil catamaran craft,Sino Eagle Shipyard Co.Ltd.(SEY),located in Fuyang city,Hangzhou,China has based their interest in retrofitting their un-launched new products"Aquila 36(A36)" into "hydrofoil catamaran craft".Boats hydrodynamics,resistances,stabilities,motions and structural strengths need to be analyzed to obtain the most optimum design.Thus,the main objective of this thesis was set to investigate those aspects and provide the most optimum design of A36 hydrofoil assisted catamaran.This thesis begins with creating design of Aquila 36 catamaran hull and hydrofoil structures.The hull hydrostatics,stability and resistance were analyzed by using combined theoretical-computational method,Computational Fluid Dynamics(CFD)and boat trial.The hydrofoil assisted catamaran also investigated by using same methods as catamaran hull.The results of hydrofoil catamaran investigation then compared with catamaran hull to find the efficiencies.Foils positioning onto the boats hull determined by calculate balancing moment.The standard canard configuration of hydrofoil was used,and the hydrofoils were positioned at the After Perpendicular(AP)for stern foil and pairs of bow foils located 7.4 m up front stern foil.Several configurations of A36 hydrofoil catamaran have made by optimizing foil lift/drag values and implementing some variations of hydrofoil Angle of Attack(AOA).The configurations named configuration 1(AOA of stern=-0.4deg,bow=1.4deg),2(AOA of stern=-0.2deg,bow=1deg),3(AOA of stern=0.2deg,bow=1.5deg)and 4(AOA of stern=0.4deg,bow=1.5deg).ANSYS workbench used to investigate hydrofoil structural strength;the results of displacement and stress analysis were not exceeding the material yield limit.Thus,the foils have enough safety to be installed and used as boat assistance.Besides,the stability investigation was done by using computational and theoretical methods which shows that designs of A36 catamaran hull and A36 catamaran hydrofoil are passing all criteria required by classification societies.The resistance analyses were performed by using combination of theoretical and computational methods using Maxsurf resistance at first.The results of this method then plotted into the resistance graph to be compared with each configuration,catamaran hull resistance and typical hydrofoil assisted resistance.The result shows good agreement with previous experimental works by using this comparison.Moreover,configuration 2 shows the lowest resistance which can be considered as the best configuration achieved by using this method.CFD assessment performed to predict resistance and motion in head waves,limited only to the sinkage and trim.Simulation results show that configuration 2 was found as the best configuration with results in the lowest total resistance as 6.28 KN at the maximum speed 40 knot.Full scale tests or boat trial then conducted to validate theoretical-computational method and CFD results,mainly for the motions and resistances,and the results shows consistency on each other.All methods used in this study show that configuration 2 of A36 hydrofoil assisted catamaran provides better performance and efficiency.In conclusion,the main objective of this research was achieved by suggesting configuration 2 of A3 6 hydrofoil assisted catamaran as the most suitable and optimum configuration.