Auxiliary Propulsion Based on Wave Energy Converters

This study presents a proof of concept for novel auxiliary propulsion. The intent is to minimize the additional power needed when ships sail in a seaway. The proposed new design includes open-to-sea ship compartments. Seawater oscillates inside the specially shaped compartments due to the relative ship motions in waves. The curved profile of these compartments deflects the water backwards from its natural vertical flow, and the water inertia pushes the vessel forward. The new wave energy converter has no parts that move or protrude outside the hull. The converter can operate entirely underwater, but CFD and model tests show that efficiency increases when it crosses the water surface. In the latter case, different water levels inside and outside the compartment act as a non-return valve that enhances the flow in the backward direction. The new auxiliary propulsion can produce thrust comparable to the added resistance of a ship in waves. It can reduce the carbon footprint of marine vessels and increase the operability range of battery-powered ships.