Wind Moment Acting on a Ship among Regular Waves

We usually assume a constant wind moment or a cos2-ly varing one. But these are not wellfounded.Wind force and its centre of application were ever experimented by Mr. okada and the centre of water pressure which resisted to steady drifting on a still water by one of the present anthors. With these results the wind moment on a ship is most stong at nearly upright position and decreases somewhat rapidly with her list, wind-wards or lee-wards. Work done by the wind moment during one swing of the ship is considerably less than that by an assumed constant moment.This suggests that effects of shipping sea, shifting of goods and so on upon a ship in a confused sea, which were not ostensibly taken in usual calculations related to the dynamic stability, for example, in the stability standards, stand comparison with wind and waves.These data, especially the centre of water pressure, however, may be affected by encountered waves and associated rolling. Experiments were conducted with model-ships, for this time, under actions of wind and regular waves in the experimental tank, and it was cleared that the wind moment among waves also was computable approximately with above data modified suitably.