This Yacht Can Walk on Water

The 40 Open Sunreef Power blends day-boat topsides, an expandable cockpit and go-fast hydrofoils.

November 5, 2017
40 Open Sunreef Power
The 40 Open Sunreef Power, with hydrofoils, is the latest entry in a flurry of futuristic, tech-focused day boats. Courtesy Sunreef Yachts

One of the coolest hydrofoil concepts should become reality in 2018, with the launch of the 40 Open Sunreef Power. The Polish builder, known for pushing the boundaries of catamaran design, incorporated four adjustable hydrofoils into a twin-hulled speedboat.

[Sunreef][] is one of several European builders (including Evo, Fjord, Wider and Wally) transforming the open ­day-boat category with creative designs. ­Beyond its hydrofoils, the boat’s cockpit has side “wings” along the aft gunwales that fold out at anchor, widening the beam from 17 feet to 22 feet 9 inches.

With inboard power, the 40 Open should make about 50 knots, according to the builder. With quad 400 hp Mercury Racing outboards, the boat is designed to soar past 60 knots. Sans foils, the planing-hulled catamaran has a reported top-end of 35 knots.


If the hydrofoils live up to their promise, the 40 Open could be the latest wunderkind in the luxury day-boat category.

Finessing the Foils

The 40 Open’s hydrofoils raise and lower hydraulically, allowing the captain independent operation of the 3-foot-6-inch-long forward foils and 4-foot-9-inch aft foils. “The system lets you set the exact angle of attack to improve the longitudinal balance of the boat for optimum performance,” notes Grzegorz Wladzinski, a Sunreef designer. Placing the foils along the centerline also increases the catamaran’s stability, Wladzinski says.


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