Numerical investigation and its application on the falling motion of freefall lifeboat

Abstract

In order to improve the simulation accuracy for free-fall lifeboat in ship life-saving training system, this paper analyzes and models the motion of boat’s launching from the skid. The whole launching is divided into four phases, namely: sliding down, rotation, free fall and water entry. According to the theory of momentum and strip theory, hydrodynamic forces of the boat at water entry are calculated under the effect of waves. The method of interpolation is used for calculating the half width and added mass of cross-sections at water entry. The model is used for numerical investigation about the boat launching from skid under different conditions and applied to ship life-saving simulation training system. The following conclusions are finally obtained: (1) When the initial inclination angle is 30[Formula: see text], the horizontal distance between the point of water entry of the boat and the lower end of the slide is about 7.2[Formula: see text]m. The horizontal distance will be smaller, when the initial inclination angle increases. There is no obvious law between forward distance and waves. (2) When the initial inclination angle is 45[Formula: see text], the setback may occur after the boat entering the wave. When the initial angle is 60[Formula: see text], the setback occurs after the boat entering the water. (3) When the center of gravity is 1.5[Formula: see text]m in front of the midship of the boat, the boat will turn over.