0n the Measurement of Wave Induced Vibration on Board

Abstract

Wave induced vibration (springing) has been studied both theoretically and experimentally. The excellent researches have been reported in each field. But only theoretical and experimental studies are not enough to investigate springing. It is necessary to carry out the measurement of springing on board. Especially the measurement on board is very important to get the relation between springing and sea condition. The new type of ship cultivated in Mitsubishi Heavy Industries, Ltd. which is the shallow draft tanker (L/B=5) is a suitable ship to measure springing. Then the long-term measurement from October in 1974 to February in 1975 was carried out. According to the result of measurement, the sea condition which the ship encountered was Beaufault Scale 8 at the most. The upper limit of springing stress (RMS) was about 0.6 kg/mm^2. The average frequency of the hull nodal vibration for the ballast condition was about 36.O cpm. Through the long-term measurement of springing this time, the basic data to investigate springing in relation to sea condition were gained to a certain extent.