Advancing Interceptor Design: Analyzing the Impact of Extended Stern Form on Deep-V Planing Hulls

Abstract

The deep-v planing hull is designed to operate at high speeds because most of the hull’s weight is supported by the hydrodynamic lift acting on the hull base. Planing hull form characteristics such as deadrise angle, chines, and extended stern significantly affect the ship’s hydrodynamic performance. The addition of the interceptor is an innovation to reduce the total resistance of the ship by controlling the trim angle. However, the form of the ship’s stern is not always the same; thus, it needs to be studied based on the form of the ship’s stern. The extended stern form refers to modifying the hull geometry at the rear, particularly the stern extension beyond its conventional length. This research aimed to analyze the hydrodynamic performance of the interceptor at the extended stern angle. Furthermore, Computational Fluid Dynamics (CFD) simulations were performed to analyze the effect of the extended stern form. A numerical model of the deep-V planing hull with variations of the stern extension was developed, and the flow behavior around the hull was analyzed using CFD techniques. Simulations were conducted under various operating conditions, including different speeds and interceptor strokes. The results indicated that the extended stern's different forms could affect the ship's resistance, trim, and heave. The reduction in resistance was seen at moderate speeds, thereby reducing steep trim angles. The greater the extended stern angle, the more significant the reduction in ship resistance at Fr 0.58 by 26%. Likewise, the combination of interceptor and extended stern experienced a decrease in resistance in the semi-displacement phase with a percentage of 33% resistance, 66% trim, and 47% heave. The interceptor stroke (d) depended on the boundary layer (h). The extended stern with angles of 10°, 20°, and 30° were found to have d/h ratios of 0.38, 0.37, and 0.34. However, it should be noted that extending the stern without interceptors and with interceptors at high speeds could result in a dangerous increase in resistance on high-speed vessel.