This paper presents a numerical method for predicting the hydrodynamic and cavitation performance of a submerged hydrofoil. The numerical model of a hydrofoil is constructed with a hydrofoil and center and side struts. It is also taken account of the effect of the controll of flaps. The method represents a hydrofoil and struts by discrete vortices and line sources located on the camber surface of the hydrofoil and strut. The effect of the water surface is considered approximately by the image system in the present method. A three-dimensional theoretical procedure is used to calculate partial-and super-cavitation occurring on the hydrofoil surface. In order to verify the validity of the method, the lift and drag acting on the hydrofoil and the extent of the cavity occurring on the back or face surface of the hydrofoil were calculated and compared with the test results which was carried out in the cavitation tunnel of Akishima Laboratories (MITSUI ZOSEN) Inc. The comparisons show that the present method becomes a very useful tool for designing the hydrofoils of a high speed craft.
