Three Speed Stage Amphibious Boat

It's not a new science.

The Amphfoil uniquely combines 3 time tested and proven existing technologies (catamaran, hydrofoil and surface effect craft/"WIG") but leaves the trade-offs behind. The Amphfoil is the only water vessel that is able to travel in the water smoothly at 0-25mph, skim along the surface on hydrofoils between 25 and 50 mph and travel in surface effect between 50 and 100 mph or more.

The multi-hull, or catamaran (stage one speed)

A catamaran is a multi-hulled watercraft featuring two parallel hulls of equal size. Today's fast ferries are using catamaran hulls because they are among the fastest vessels on the seas (up to 35 mph) and receive their stability from their wide beam.


What's wrong with power catamarans

The basic design of these narrow dual hulls requires incredibly inefficient “jet” engines (read: water pump propulsion). In order to reach “high” speeds, a conventional power catamaran has very high fuel consumption of a half-mile/gallon and a terrible carbon footprint. Also, a major negative side effect of water propulsion is massive wake turbulence affecting shoreline areas and eco systems forcing these vessels used for water transportation, or fast ferries, to operate at reduced speeds, which significantly increases the time between departure and destination. In addition, they are constantly at the mercy of sea state or wave conditions. Sustaining speeds in excess of 25 mph in any seas above flat water can result in extreme discomfort to the passengers.


The Amphfoil solution

The Amphfoil uses a proprietary patent-protected hull design (SRD) on the catamaran hulls that, at Stage One speeds between 0-25 mph, provides a soft ride, more lift, while using less power. Proven and patented SRD technology provides high lift/low drag catamaran hulls that greatly reduces horsepower requirements by 50%, lowering engine weight, fuel burn, wake turbulence and pollution.




The hydrofoil (stage two speed)

Hydrofoil technology has been around since 1898. The purpose of the foils is to lift the boat out of the water. As the boat's speed increases, the hydrofoils create lift equal to the sum of the boat and cargo weights. There are high speed ferries using hydrofoil technology in limited protected waters primarily in Russia and Europe that achieve speeds of 50 mph in very moderate sea conditions.



What's wrong with hydrofoils

After almost 100 years of effort and money, no one has been able to overcome  hydrofoil physics of sonic cavitation (read: massive  vibration) at speeds in excess of 60 miles an hour. In addition, the depth of the hydrofoils determines the height of the hull above the water. This design geometry issue limits operational ability due to sea state conditions. Hydrofoils require expensive and high maintenance propulsion systems and make very inefficient boats when not operating at hydrofoil lift speeds.


The Amphfoil solution

The Amphfoil uses hydrofoil technology at Stage Two speeds, 25mph – 50mph, using less engine power through the use of tilting air propellers that both propel the Amphfoil and also help maintain constant lift on the foils.  The result is foils that skim near the surface between 25 and 50 mph, softening the ride between the troughs in wave and sea conditions. No hydrofoil craft before the Amphfoil, has effectively used, tilting, quiet, liquid-cooled engines and air propellers to dampen motion.



The Surface Effect Craft, or Wing-in-Ground Effect (stage three speed)

Ever since the beginning of manned flight pilots have experienced something unique when landing an aircraft. Just before touchdown it suddenly feels like the aircraft just doesn’t want to go lower. It just wants to go on and on due to the air that is trapped between the wing and the runway. This phenomenon or air cushion is called (aerodynamic) “surface effect”. Craft in surface effect experience a 250% molecular efficiency increase significantly reducing horsepower/weight ratios by over 75%. The Wright brothers flew in surface effect in their early flights close to the ground and benefited from surface effect without even knowing it existed.  A conventional surface effect craft or “WIG” is a craft that cruises above the water’s surface at heights of 50% of their wingspan (approx. 20-30 feet), utilizing the amazing efficiency of this smooth cushion of surface effect air achieving speeds in excess of 150 mph.


What's wrong with WIGs

WIGs fly 20 to 30 feet off the water at very high speeds, which make them unsafe in congested waterways, crowded harbors and even coastal waters. WIGs have no effective or usable intermediate speed between 0 mph and 50-60 mph. They need large engines and long stretches of water “runways” totally free of boat traffic to overcome fuselage water drag to obtain lift off speeds of approx. 40-50 mph. WIGs use airplane technology  to bank, or turn, by tilting their wings, which can be extremely dangerous if done too close to the surface of the water, or too close to other vessels. In addition, due to emergency maneuvering accidents, they are in danger of being classified as “low flying airplanes rather than a marine craft” and coming under FAA and EASA agency jurisdiction with complex regulations and insurance requirements.


The Amphfoil solution

 The AMPHFOIL uses surface effect physics when traveling over 50 mph on a smooth cushion of 250% efficient air. Unlike WIGs, the Amphfoil uses marine technology to turn and maneuver, allowing the craft to operate safely only a foot or so above the water surface. The use of the patented “ATA” (Articulating Trim Arm) means the Amphfoil is always in contact with the water, therefore will always be classified as a boat or marine craft by regulatory agencies. The speed necessary to obtain full surface effect lift physics is obtained on the Amphfoil by usable and flexible Stage One catamaran speeds (0- 25mph) and Stage Two speeds (25-50mph) hydrofoil technology, totally precluding the need for water “runways.”





Amphfoil. More speed. More safety. More comfort. More flexibility.

Less fuel. Less pollution.  Less maintenance.  Less restrictions.



CAD ASSISTANCE  Joseph P. Bolduc

MODEL RENDERS Noah Acosta, Justin  DeSilva and Alex Strongwater

ANIMATIONS   Aroha Media Pvt., and  Noah Acosta

VIDEOS Inshop Videos

LEGAL  McInnes & McLane LLP


Contact Us:

Shannon Boat Company

19 Broad Common Rd

Bristol, RI 02809 U.S.A.

+1 401-253-2441