Vibration of Container Ship

Abstract

The vibration of a container ship has been studied with a chief attention to the horizontal and the torsional vibrations. Some checks on the problems of structural behaviour and of the added virtual mass of water have been made. Centre of virtual mass of water is calculatedfor the Lewis form sections. The model experiment has been carried out to check the behaviour of coupled vibration. At the last the experiments in a full scale container ship have been made, using the vibration generator and in the sea trials. It is found that the problem is pretty complicatedand many investigations are necessary in order to clarify the mechanism of coupled vibration and therigidities in the torsional vibration. Horizontal vibration, though it is complicated due to the coupling with torsional vibration, is more accessible. The characteristics of the vertical vibration of the container ship are qualitatively the same as those of conventional types of ships. The bottom vibration is significant in the vertical vibration of higher modes which is likely to reduce the natural frequencyof the vertical vibration.