We used to understand the wind action usually in its summarized features. But, minute experiments prove that the wind acts on horizontal surfaces of a vessel in a manner different from on vertical ones. The difference has influence on the behavior of a vessel in the wind. Sometimes, the heeling angle varies according to the area or the position of a horizontal surface even in the wind with the same speed. In some cases, the wind resists less to the rolling in the wind than in no wind, moreover, a vessel goes on rolling in the wind without any periodic excitation as waves. The present paper deals with those phenomena.