Van Oossanen’s holy grail of fuel efficiency and a smoother ride

WAGENINGEN – In yacht building, “innovation” is a grossly overused word. But never in describing the work of Van Oossanen Naval Architects that Piet van Oossanen founded in 1992. By then, he was already famous for his ‘winged’ keel _ a common sight on sailboats today _ that gave Australia II the 1983 America’s Cup ending 132 years of US dominance.

By now, Van Oossanen is a leader in hull efficiency design. Its patented Fast Displacement Hull Form makes motor yachts more fuel efficient, quieter, more comfortable. That revolution continues. Last year, Van Oossanen introduced the Fast Displacement XL. More FDHF evolutions are pending.

Currently, 2 head-turning boats in build are the 45m Project Adur (Hakvoort Shipyard, Netherlands) and the 41m GTT-135 (Dynamiq Yachts, Monaco). Both have an FDHF plus a Hull Vane (right), another Van Oossanen innovation. The underwater foil beneath the transom gives a yacht additional lift improving seakeeping, speed and range.

Hakvoort says Project Adur’s fuel use and motions will be reduced by 20 to 25%. The yacht will be faster than most yachts of its size with a top speed of 26.5 knots, a 12kn. cruising speed and a range of 3800 nautical miles.

On the 42.4m Alive, left, an FDHF motor yacht Heesen Yachts launched in 2014, resistance reduction from the Hull Vane makes the yacht as fast with 2 12V engines as it would go with 2 16V ones without a Hull Vane.

“Traditionally, yachts that had to go fast were given hard chine hulls,” says Perry van Oossanen, who now helms the naval architects studio his father founded. “Those hulls run efficiently in terms of fuel use at high speeds. But they have a terrible fuel efficiency at cruising speed.”

His FDHF guarantees optimal performance at all speeds, not just in a narrow band near top speed. Heesen Yachts’ 65m Galactica Star, launched in 2013, was calculated to have a 25kn. top speed with a hard chine hull. An FDHF raised it to 29 knots with 30% less resistance. In 2022, Heesen will launch an aluminum 80m FDHF yacht with a top speed of 29 knots.

Van Oossanen’s fuel efficiency work benefits commercial vessels and yachts from 15m and up. The Fast Displacement XL design targets large yachts. If the maximum length of a 500GT aluminum yacht is 45 to 50m, an aluminum Fast DisplacementXL yacht can be 62 meters long and not exceed the 500GT limit.

The Hull Vane is marketed through Van Oossanen Naval Architects unit Hull Vane BV.