The movement of a floating body and the forces acting upon its mooring facilities can be estimated by a hydraulic model test or a numerical simulation. The latter, however, is a recently developped new method. Accordingly, its applicability and accuracy has not been sufficiently investgated.
　In order to verify the numerical simulation, hydraulic model tests on the movement of a floating rectangular body and forces acting on it are carried out in the irregular wave tank. The model scale is determined to be 1/50 by imaging the floating oil storage tank of 390m long, 97m wide, and 26m high as a prototype floating body. In the experiments, regular and irregular waves are exerted upon the body in their approaching angle of 60°and 90°.
　In the comparison of the experimental results to the simulated ones, it is clearified that the simulation overestimates the movements and the forces without modifying the theoretically obtained added mass and damping coefficient. Then, the coefficints are modiffied as the simulation reproduce the experimental movements in the case of the normal approaching angle.
　In the result of the modification, the simulation shows relatively good agreement to the experiments except the surging and its related force.