A six-Dof motion solver based on unit quaternions and an actuator disk model are implemented for ship hydrodynamics predictions. The six-Dof module is tested using the water entry phenomenon of a free falling sphere. The displacement history and impacting forces are analyzed. A KCS (KRISO container ship) model with the allowances of sinkage and trim is then simulated and validated. The actuator disk model is used to replace a real propeller. The open-water test of a KP458 propeller is first carried out to obtain the thrust and torque coefficients, using both the multi-run and single-run approaches. Oblique Towing Tank (OTT) tests using the actuator disk are conducted at last and the results agree well with the experiments. These models can be used for simulating six-Dof motions and captive model tests of ships.