From the change of speed of the wind current along a wave surface, it is expected that the inclining moment due to wind pressure acting on a ship increases on a wave crest and decreases on a wave trough. But the wind moment on a ship, especially on a small vessel, may be influenced not by the wind speed but by other factors. Two dimensional wind tunnel tests, for example, prove that wind pressure distributions on the surface of a box-shaped model on a wavy surface, and the characteristics of the wind moment and the drag on the model, unexpectedly change with the location of the ship-model relative to a wave trough. In this paper, these factors are discussed based on the experimental results.
