Drifting of a dead ship in wind

ABSTRACT The drift characteristics in wind of a dead ship that cannot sail on its own are investigated experimentally and theoretically. First, a free-drift test of a bulk carrier model in wind is conducted. Next, a time-domain simulation method is developed for predicting the drift motion of the dead ship in wind. Tank tests and motion simulations show that the dead ship drifts with a large hull drift angle over in wind, and the converged drift angle is independent of wind speed and initial ship heading angle. To explain why the dead ship drifts with a large drift angle in wind, a theoretical formula is derived for investigating the motion stability of the dead ship in wind. It is theoretically confirmed that the ship drifts stably with a large drift angle over in wind, whereas drift angles of and result in unstable motion. Thus the reason for the drift behaviour of the dead ship is clarified.