Simulation-based uprighting of a capsized ship in wave-induced environments

Abstract

AbstractThe present study aimed to find the truth about the effect of ocean waves on the process of righting a capsized ship by employing common computational methods of marine salvage engineering. Mathematical models of ship stability and uprighting were developed to quantitatively evaluate the effects of wave encounter angle on the righting forces, bending moments and torques of the hull during the uprighting process. The results indicated that during the uprighting process, the maximum righting forces of the capsized ship were almost unchanged with a maximum difference of 1kN, when the ocean was calm or when the encounter angle of the waves varied. However, the righting force moment showed significant discrepancies under all conditions, with a maximum difference of 1177.5 kN m. When the wave encounter angle is at 0°, the shear force of some parts of the ship is 2–3 times that of the still water environment, and the shear force of some parts of the ship is 3–4 times that of the wave encounter angle at 300°. Remarkably, the bending moment varied by more than 200% at some particular locations under a particular wave encounter angle. Furthermore, the negative torque variation was relatively minor at a 300° wave encounter angle, and the uprighting process still needs relatively large righting forces.