In our previous study, investigations on property of ship motions was conducted through a numerical simulation and a field observation of ship motions and mooring loads. From the investigations, it was concluded that low-frequency motions such as sway, surge and yaw were induced significantly by resonant effects with the long-period wave, and resonant roll motion also occurred at the berth due to the swell component of the wave. It is important for the investigations on property of the ship motions to estimate the natural periods of each ship motion and damping effects precisely as possible. In this study, we have conducted a physical model test on free oscillations of the model ship for a large vessel moored along dolphin to obtain the property of the natural periods and the damping effects.
