A numerical simulation method has been developed for predicting the maneuvering motion of blunt ships by solving the equations of motion with the Navier-Stokes equations. Since coordinate system is fixed to an arbitrarily moving ship, inertia forces must be incorporated into the NS equation as body forces. The hydrodynamic forces acting on the hull of the ship are obtained by solving the incompressible and time-dependent NS equations numerically. The hydrodynamic forces caused by rudder and propeller and their interactions with the hull are calculated by the mathematical model. This method was applied to the simulations of the 10-degree Z maneuvering motion of two VLCC models with the same principal dimensions and different aft-part frame lines, that is, one is so-called V-shaped and the other is U-shaped. The results of the simulations agreed well with those of model tests and revealed the typical difference in maneuverability between the two ships.