New Ground Effect Boats
A yard in La Rochelle, France, is building a range of wing-shaped catamarans that use aerodynamics as well as hydrodynamics to improve the boat’s overall efficiency. The boats are known as Advanced Aerodynamic Vessels or A2Vs and they’re capable of speeds exceeding 50 knots with improved fuel economy.
Wing-Ground Effect
The manufacturer says that an A2V takes advantage of what’s called wing-in-ground effect. Conventional airplane wings are shaped to generate low pressure on the top side and high pressure on the low side as the vessel moves through the air. The closer the wing is to the surface of the water, the more efficient it becomes. In the case of a catamaran, the focus is on the area between the hulls and the trick is to reduce drag and balance the lift so the vessel doesn’t flip when running at speed.
What separates the A2Vs from other catamarans is that the whole boat is shaped like a wing, not just the deck between the hulls. By placing the center of gravity forward, the designer says there is no danger of the boat taking off. One way that the manufacturer keeps the weight properly positioned is by locating the passenger compartment at the front of the vessel. Passengers sit inside the wing just aft of the leading edge. The helmsman sits above in an aircraft-style glass bubble cockpit.
Proving the Concept
Designers reportedly spent more than seven years developing the prototype that was built in 2015 and has allegedly completed more than 5000 nautical miles of testing in waves up to approximately 6’ and wind speeds up to 30 knots. Two 39’ (12 meter) fast ferries were developed and the most recent has entered service in the Port of Monaco.
For pleasure boaters, the company has released details of an outboard-powered fast cruiser. It has an articulating roof and drop-down side panels that let the teardrop-shaped aft section open when the yacht is at rest. It reveals a sheltered cockpit with sunpads, dinettes and side bathing platforms. Companionways lead to a master suite and smaller guest cabins.
Power for the pleasure version is a pair of 300-hp engines that reportedly push the boat to 50 knots and a range of 150 nautical miles. The builder says the boat will burn less fuel at 45 knots than she will at 30.