VTT and partners testing paraffinic e-fuel in diesel tractor
Scout Motors awards €450M contract to Magna to develop electric SUV and pickup

Cranfield team investigates wave-induced flapping foils; wave devouring propulsion (WDP)

Researchers from Cranfield University have designed a method of achieving greater thrust from the power of the waves by harnessing a vessel’s submerged flapping foils (wave-induced flapping foils) in an innovative way. An open-access paper on their work is published in Renewable and Sustainable Energy Reviews.

The ocean waves have a tremendous amount of energy. The flapping foil, as a wave propulsion device, can use the kinetic energy of the waves to achieve self-propulsion without fuel. This green propulsion technique converts wave energy into thrust using submerged flapping foils called Wave Devouring Propulsion (WDP). The human-crewed and uncrewed ships can be powered with WDP and achieve higher propulsion efficiency. The main purpose of this paper is to provide a comprehensive summary of the research on wave-induced flapping foils.

Flapping foils has been of great interest for a long time. The ability to generate thrust from surrounding flows was discovered and demonstrated as early as 1909. … Flapping foils can also enhance traditional propulsion methods, which leads to the development of the wave devouring propulsion system (WDPS). It often utilizes a spring-loaded foil mounted under the bow or stern of the vessel.

In addition, WDPS operate at a lower frequency compared to traditional marine propellers, which can reduce the generation of underwater noise and its adverse effects on sea life, particularly marine mammals.

—Xing and Yang


The flapping foils used in WDPSs have three modes of motion: (a) pitching motion, (b) heaving motion and (c) flapping motion. Xing and Yang.

Taking inspiration from the power of a whale’s fins, the team studied the structure and movement of the tail fin to unravel how it effectively uses wave energy for propulsion. Through simulations and experiments, they developed and integrated a simplified version of the whale’s tail fin action into a ship’s power system.


Ship with retractable flapping foils. Xing and Yang.

WDP technology offers a range of benefits, making it an attractive solution for the marine industry. Not only does it reduce fuel costs, it also significantly enhances marine craft propulsion. This green technology can find applications in small, unmanned vessels and can be seamlessly integrated into hybrid propulsion systems, including those powered by electricity, hydrogen, or fossil fuels. It also has the potential to achieve carbon reduction targets and contribute to the sustainable development goals of the shipping industry, the researchers said.

The funding for the project was delivered as part of the Transport Research and Innovation Grants (TRIG) from the Department for Transport.


  • Jingru Xing, Liang Yang (2023) “Wave devouring propulsion: An overview of flapping foil propulsion technology,” Renewable and Sustainable Energy Reviews, Volume 184, doi: 10.1016/j.rser.2023.113589



Nice open access pdf paper really demonstrates the double digit efficiency potential of this technology, which should have practical applications but the vessel size and operating area and weather will be a big factor for ROI.

The comments to this entry are closed.