Numerical investigation of transom and double interceptor systems on a high-speed planing craft in regular waves with experimental validation

High-speed planing craft (HSPC) operating in waves can experience severe vertical motions and impact accelerations, potentially affecting operational performance and occupant safety. This study investigates the effects of a transom interceptor system (TIS) and a double interceptor system (DIS) on the seakeeping performance of an HSPC in regular head waves at a constant beam Froude number of Fr B = 3.0. A CFD model was validated against towing tank measurements of heave, pitch, and vertical acceleration for three configurations: the bare hull, TIS-equipped hull, and DIS-equipped hull. The validated model was then applied to a range of regular wave conditions with different wavelengths and wave steepnesses. HSPC responses were evaluated using Response amplitude operators (RAOs), pressure distribution, and hull-motion characteristics to identify the hydrodynamic mechanisms governing interceptor performance. While both systems have limited influence under mild and moderate waves, their differences become more significant under severe conditions. The TIS maintains a more favorable pressure distribution, reducing fly-over severity and water re-entry impact acceleration. Within the investigated wave conditions, the TIS reduced peak vertical acceleration by up to 28.9% compared with the bare hull. In contrast, the DIS produces longer airborne phases and higher impact acceleration.