Analysis of Wave Parameters on the Uprighting Process of a Grounded and Capsized Ship

Abstract

It is a complicated task to right a capsized ship on the sea bottom because of wave load. Based on the influence of waves on stability and mechanical action, this paper constructs a wave force calculation model by the airy wave theory, and the stability and righting force models of righting a grounded and capsized ship are obtained. The uprighting process of a grounded and capsized ship is simulated by GHS software. In the process, stability and righting force are solved, and the effect of wave parameters on stability and mechanical action is studied. The result shows that when the wave phase is at its origin, the stability and the righting force can be effectively reduced. The wavelength has a significant effect on the hull stability, righting force and ground force in the range of 25 m–35 m. The change of wave height has significant influence on the stability and ground force, but the maximum ground force does not always change regularly with the wave height. Variation of the angle between the hull and the direction of the wave could significantly affect the stability, righting force, and ground force. When the encounter angle is 90°, the righting force is smaller than in other cases, and the maximum negative-going stability, the maximum righting force, and the maximum ground force values are 7.1%, 7.57%, and 3.83%, respectively, 11.7% smaller than those of still water. It is found by comparing several groups of wave parameters that a transverse wave could significantly reduce the difficulty of righting a grounded and capsized ship.

Keywords

• capsized ship
• ground force
• righting force
• stability