Theoretical Calculations on the Motions, Hull Surface Pressures and Transverse Strength of a Ship in Waves

Abstract

The authors tried the theoretical analysis on the motions, hull surface pressures and transverse strength of a gigantic oil tanker in regular waves.In the first place, the ship motions in regular waves from different directions were analysed by assuming the coupled equations of heaving and pitching motions and those of swaying, yawing and rolling motions based upon the modified strip theory. The non-linear roll damping was introduced into the latter coupled equations of motion.In the second place, the hydrodynamic pressures induced on the hull surface were evaluated theoretically by using the solutions of ship motions.Finally, the transverse strength calculations were performed for several cases of the ship in waves by using the obtained hull surface pressures and the estimated cargo oil pressures.The large hydrodynamic pressures were found in beam and quartering waves, which produced the large bending moments at the deck corner, bilge and bottom of longitudinal bulkhead in the transverse ring.