Propulsive Performance of a Container Ship in Waves (5th Report)

Abstract

With a ship model of single screw high speed container ship, self-propulsion tests in regular head waves are carried out. In order to investigate the effect of propeller diameter on the powering characteristics and the propeller load fluctuations in waves, two propellers of different diameter are used. The effects of wave height on the mean increases of thrust, torque and number of revolutions and the load fluctuations of propeller are also investigated. With the same model, self-propulsion tests in regular following waves are carried out, and the experimental results of ship motions are compared with the calculated results. At the same time the mean increases of thrust, torque and number of revolutions and the propeller load fluctuations are measured. Calculation method of surging motion in regular following waves and spectral analysis of encounter waves and ship motions in irregular following waves are discussed. Power predictions in a seaway for a container ship of 175 m length are performed using the results of model experiments by four different methods, that is direct power method, torque and rate of rotation method, thrust method and thrust identity method.