Study on the compound effects of interceptor with stern flap for two fast monohulls

The effect of trim mechanisms (including stern flap, interceptor and integrated interceptor with stern flap) on resistance reduction were examined in this study. Two planning crafts were used for the resistance test. The first one is a 20-meter patrol boat and the test was conducted at the towing tank of National Taiwan University(NTU), Taiwan, ROC. The second one is 29.5-meter patrol boat tested at HSVA towing tank, The Hamburg Ship Model Basin, Germany. The results show that a well-designed trim mechanism can reduce the running trim and the resistance of the planning craft. It also show that the trim mechanisms have a best resistance reduction effect at the volume Froude number between 2.0 and 2.5. The drag reduction of integrated interceptor with stern flap is better than that of interceptor alone and stern flap alone.