Roll response of a ship under the action of a sudden excitation

Abstract

This paper examines the importance of roll damping on the gust response of a ship. As a mathematical model an ad hoc roll equation is used and the action of the wind gust is represented by means of a step function. A solution of the equation of motion is developed by using the asymptotic method of Bogoliubov and Mitropolsky [3]. Computational results on the influence of roll damping, initial conditions and the gust magnitude are given for a stern trawler. Results clearly indicate the importance of roll damping. In the light of this investigation it is suggested that in determining the gust response of a ship in a weather criterion the effect of roll damping should be taken into account.