A new CFD simulation method has been developed for simulating unsteady motions of a vehicle with movable wings. The coordinate system used in this simulation method is fixed to the moving body and inertia forces such as Corioli's force and the centrifugal force are treated as body forces in the incompressible Navier-Stokes equation. A multi-block grid scheme is introduced for the body having a number of wings and the motion of movable wings is treated in a moving grid scheme. The method of simulation is explained and some results of the simulation applied to the keel of a racing yacht are presented.