This paper deals with two-dimensional flow problem from the view point of ship manoeuvrability by applying the Finite Element Method. It is shown how to calculate horizontal two-dimensional potential flow including quasi-stationary circulation, and how to obtain hydrodynamical forces on arbitary shaped ships moving in an arbitary shaped channel. The interaction forces between two same ships in a parallel-walled watercourse are numerically computed as an example. In order to discuss the propriety of horizontal two-dimensional approximation, the experimental data are compared with the calculated forces of a ship in a restricted water, and the correction coefficients for the added mass, the added mass moment of inertia, bank suction, etc. are obtained.
