Application of Wave Devouring Propulsion System for Ocean Engineering

A Wave Devouring Propulsion System (WDPS) generates thrust directly from wave power while simultaneously generating a strong damping force. A simple WDPS design consists of hydrofoils mounted below the bow of a vessel. If a WDPS is integrated with the hull of a vessel, then it can power the vessel forward, even against the wave direction itself. One example of a successful WDPS was installed on the vessel named Mermaid II, which completed a trans-Pacific voyage in 2008, traveling approximately 7,800 km from Hawaii to Japan using wave power alone. This success indicates that the WDPS has potential for use in the field of ocean engineering. As described in this paper, we intend to apply the WDPS to the small autonomous boat and to conduct sea trials. We designed and built an autonomous WDPS boat, developed a data acquisition system, and experimentally investigated its performance in Orida Bay. The experimentally obtained results indicate that the autonomous navigation of the WDPS boat is possible when the wave height is greater than 5–10 cm.