Transverse Stability of a Ship in Following Sea.

Abstract

Transverse stability of small fishing boats in following sea are investigated both theoretically and experimentally. A ship model is towed with the same velocity as the celarity of a wave train generated by means of a wave-generating screen board that is attached beneath the towing carriage. The relative position of ship model to wave is fixed at several different positions. The ship model has a given angle of heel and is free with sinkage and trim. The righting moment, ship resistance, lateral force and moment acting on the model are measured with a 4-component dynamometer. On the other hand, a calculation based on Froude-Krylov Hypothesis are made to compare the experimental results. The calculation is carried out for both cases in which the effect of wave orbital velocity is taken into account and neglected.