Wajer 38 with Foil Assist

NUDE – Van Oossanen Naval Architects of the Netherlands has become the leading fluid dynamics innovator, making yachts and commercial craft go faster and more comfortably and using less fuel.

In the past decade, it has successfully marketed it’s the Fast Displacement Hull Form and Fast Displacement XL for large yachts. It has topped that with the Hull Vane, a patented hydrofoil just behind the transom of yachts and commercial and naval vessels.

The latest Van Oossanen patent is that of the Foil Assist, a passive, stainless steel hydrofoil placed amidships on planing hulls. It recently premiered on a 38ft luxury dayboat from Wajer Yachts of the Netherlands, but it can also go on fast yachts of, say, 20m or more.

“The goal of the Foil Assist,” Managing Director Niels Moerke, tells IBI, “is not to go into an all-out ‘flying mode,’ but to carry part of the boat’s weight on the foil, not the bottom. The Foil Assist is widely applicable. Boat length is not an issue. The main requirement is that the boat is a full-planing craft.”

As the name implies, the foil offers an ‘assist’ meaning “a small part of the transom stays in the water,” says Moerke. “The foil raises most of the boat from the water improving speed, generating fuel savings of 10 to 20% and, above all, generating more comfort.”

From the outset, Van Oossanen, which employs about 2 dozen naval architects, looked for a combo of benefits that generates better performance. Dries Wajer, managing director of Wajer Yachts says his company is always keen to try new technologies “to improve our fleet. Next to aesthetics, like materials and practical enhancements, we wanted to take a serious step in upgrading the performance of our 38 models. By adding the foil assist, I believe we have.”

To introduce the Foil Assist to the market, Moerke opted for a muted, bunting-free launch. “Even so, we are already in negotiations with 3 interested parties in the Netherlands,” he says. Moerke says over time, the Foil Assist will be folded into the Van Oossanen Hull Vane unit.

Van Oossanen’s Winged Keel

His company has a solid international reputation in improving yacht performance. Founder Peter van Oossanen drew the ‘winged keel’ under Australia II, the 1983 America’s Cup winner. A common sight today, the design caused lawsuits in the AC community in the early 1980s. It gave Australia II a big advantage in maneuverability and heeling moment.