STEADY STATE EQUILIBRIUM OF SHIPS MANEUVERING UNDER COMBINED ACTION OF WIND AND WAVE

Abstract

Maneuverability is important in ship design stage not only for ship performance but also for safety reason regarding the collision and stability especially in quartering following waves. The International Maritime Organization (IMO) therefore developed maneuvering criteria and collision regulation to ensure the ship safety against collision. This paper discusses maneuvering performance of ship under combined action of wind and wave. The steady state equations of ship maneuvering were numerically solved using the Newton-Rhapson method in order to obtain the drift angle, the rudder angle and the ship forward speed. Results of numerical simulations show that the combined action of wind and wave has significant effect on the drift angle and the rudder angle in the range of wind and wave direction between 20.0 degrees and 120.0 degrees. The ship forward speed significantly changes due to alteration of wind velocity in the wind and wave direction smaller than 40.0 degrees or in the wind and wave direction larger than 140.0 degrees. The wave height has significant effect on the ship forward speed in the wind and wave direction between 20.0 degrees and 80.0 degrees.