Some Tests on Spray of a Prismatic Planing Hull

This study was carried out for understanding the characteristics of the spray around high speed vessels. Prismatic planing hull made of an acrylate board was used to the tests. The distribution of local spray velocity were estimated from the analysis of the spray visualization. A new test system for measuring the spray thickness is proposed, and was used to estimate the local spray thickness in the model. The pressure distributions on the bottom of the hull are measured and integrated to estimate the pressure drag of the model in the towing tests. Finally. the spray drag/lift component is separated from the total drag/lift on the prismatic hull. These test results show that the spray drag component on high speed vessels is relatively large and important in total drag.