Effects of Forward Speed and Wave Height on the Seakeeping Performance of a Small Fishing Vessel

Abstract

The effects of wave height and forward speed on the seakeeping performance of a small fishing vessel in irregular waves are evaluated using computational fluid dynamics (CFD). The wave height effect changed linearly for a forward speed in the head sea and beam sea. In the stationary state, the heave and roll motions attributed to the wave height appear nonlinearly. The effect of the speed showed a non-linear shape wherein the heave motion became larger with an increase in the forward speed in beam sea. The seakeeping performance of pitch motion is greatly improved at forward speed rather than in a stationary state. The seakeeping performance of the roll motion is more dangerous than the pitch motion, regardless of wave height and vessel speed. The mean roll period in irregular waves is obtained through this study, and it is longer than the natural roll period in still water. It is necessary to be careful as the probability of exceeding the limit is high and GM is decreased in transverse waves.