Abstract
When a ship bends in still water, the distribution pattern of bouyancy will change. This change causes to reduce the loads acting on the hull girder. The effects of this change upon the longitudinal strength of a ship will be small so far as the ship bends slightly. But, the larger is becoming the deflection of hull girder, the larger is becoming the effects of this change. In this paper, the authors idealize a ship in still water as a beam set on the elastic foundations. And we try to estimate the effects regarding a tank ship of Floating Oil Storage Barge System. And also, we investigate the effects of thermal deformation of hull girder due to temperature differences in a cross section. As the results of this study, we obtained the following items; (1) The change in distribution pattern of buoyancy due to deflection of hull girder reduces the value of the maximum bending moment about 26%, in this case. (2) Taking into consideration of thermal deformation, this reduction will become larger assuming that the temperature of deck side is higher than that of the bottom side.
