Study On The Resistance Performance Of Semi-planing Boat

In this paper the effects of variable wetted areas on the two resistance translation methods of semi-planing boat is studied through tests.And the effects of interceptor on the resistance reduction of semi-planing boat is studied through model tests in the same way. The results show that a well-designed interceptor can reduce the running trim and the resistance of the semi-planing hull.The structure of this paper are arranged as following:Firstly, this paper introduced the current situation of the development and research methods of the semi-planing ship and the current status. Confirmed the research method and emphasis of the semi-planing ship. In the second chapter two model ships will be introduce, and the test equipment and measuring instrument also introduce.There are two methods that are the Froude and three-dimensional for extraplating model to ship resistance, but it is no verdict about the conversion method on semi-planing boat, it is usully consider the wetted areas as the constant but it will be increased with the speed of model ship and it cannot ignore. In the third chapter there will be introduce the two method and consider the variation of wetted areas and compared each other.In the fourth chapter introduces the test of 46m crewboat model ship in calm water. First, the model ship's resistance, trim and heave are determine on three typical loaded condition without interceptor. Then add the interceptor on the sterm of model ship and compared the resistance and posture with the former. The height of interceptor is experimentally found to be dependent on ship speed. The results show that a well-designed interceptor can reduce the running trim and the resistance of the semi-planing hull. It also shows that the resistance reduction effect of the interceptor is also dependent on loading condition. The resistance reduction effect is most obvious on the fully loaded condtion and it can be attain 6%.In the fifth chapter introduces some basic concepts of regular wave and the test of two model ships in regular waves. The resistance is also reduce in regular wave through add the interceptor on the sterm of 46m model ship, and improving posture of model ship.