Amphfoil marries Air Props and Hydrofoils


A rendering of Shannon Boat Company’s Amphfoil 28′ (8.5m), a foil-borne commuter that uses a 400-hp (295-kw) hybrid-electric propulsion system with air propellers.

In the wake of the Miami International Boat Show in February, longtime builder of quality cruising sailboats Shannon Boat Company of Bristol, Rhode Island, announced the rollout of the Amphfoil Offshore Foil Boat, a foil-borne multihull available in a range of shapes and sizes, from 28 to 160 (8.5m to 18m). “Leveraging surface effect/ground effect lift, the vessel requires 75% less energy, resulting in unprecedented speed, range, and efficiency,” the press release claims. “The Amphfoil introduces tilting air propellers for dual-purpose propulsion and lift, complemented by custom-designed quad hydrofoils for enhanced maneuverability and comfort, thus combining catamaran stability, surface effect and hydrofoil lift, and electric tilting air propellers that are tasked with producing most of the lift and all propulsive power to create a totally new type of efficient offshore foil boat [that] eliminates the common sea travel nuisances like bouncing, fatigue, and seasickness.”

The press release touts speeds of 70 mph/60.8 kts/112.6 kmh and a range of 350 nm (648 km) for a boat powered by a hybrid-electric drivetrain. The company claims that this technology overcomes shortfalls of traditional hydrofoils, such as inadequate lift in waves and limited adaptability, and “represents a paradigm shift in maritime travel, seamlessly integrating hydrodynamic and aerodynamic technologies to redefine the hydrofoil experience.” The patented design supposedly “enhances maneuverability without complex electronics,” and protects marine life with retractable foils that prevent groundings in shallow water.

To learn more about the advances in the Amphfoil, we contacted Shannon president and cofounder Walt Schultz, a naval architect, engineer, boatbuilder, private pilot, and holder of several marine-related patents.

“Shannon Boat Company has been working on this project for almost 10 years, and now that the international patents have been awarded, we are ready to talk publicly about [it],” Schultz said. “Besides patents and COVID, we were delayed by the lack of suitable electric motors for the air propellers. We have been talking to e-Motion in Italy for a hybrid-electric system, and I think we are almost there with the propulsion package for the 28 [8.5m] Amphfoil prototype, which is an eight-passenger plus two-crew boat. There is no size limitation on our patents, but everything depends on the hybrid-electric propulsion systems. My hope is hydrogen-fuel-cell technology will be a game changer someday in the future for all marine craft.” In a later note, Schultz put that plan into perspective, calling “the electric-hybrid propulsion system…somewhat fluid. We still have a way to go to solidify our plans.” Therefore, he’ll build a 16 (5m) prototype for bollard testing and gathering dragline information, and data for energy requirements. He expects to exhibit that craft at the Fort Lauderdale boat show next fall.

Explaining the hydrofoils (which he calls “Seafoils”), he said they account for only 30% of total lift, with surface effect and the tilting air propellers of the propulsion system providing the rest. On the 28 model, two small, submerged propellers on [electric] 7.5-kW pods mounted on the rear foils will assist docking and in-port maneuvering.

Typical applications for these vessels, Schultz added, could be crew transfer boats for offshore wind farms; upscale ferries for places like the Hamptons and Nantucket; government agencies like the Coast Guard, DEA drug interdiction, and the U.S. Navy; and perhaps megayacht tenders and private vessels. Building these boats will require technicians who are conversant in carbon fiber (foils), and Kevlar (hulls and superstructures). “Shannon Boat Company will build the Amphfoil in the USA, and we are also talking to companies in Europe and Indonesia,” Schultz said. “All models are designed and engineered for ocean freight in standard-sized shipping containers and assembled at final delivery by low-skilled workers using hand tools.”

Shannon Boat Company Inc., 19 Broad Common Rd., Bristol, RI 02809, USA., tel. 401–253–2441, www.shannon

—Dieter Loibner