Increasingly, yacht owners are requesting more fuel-efficient projects. With more shipyards making claims to delivering these desires, it’s important to know specifics. For example, what was the fuel burn during sea trials? And, how do the figures stack up against those of most yachts around the same size and type? The team behind the new Feadship Najiba is providing these numbers, which shape up to be pretty impressive.
The owners of the 190-foot (58-meter) Najiba first sought naval architecture by Vitruvius Yachts, established by famed designer Philippe Briand. They wanted not just a sleek profile, but also a smooth performer. “The owners understood very well that a perfect yacht requires a strong scientific and architectural approach to support the exterior design,” Briand explained when Najiba launched in January. All Vitruvius Yachts projects emphasize fuel savings, drawing largely on Briand’s extensive fast-sailing-yacht experience. During construction, his calculations anticipated that the megayacht would consume as little as 3 gallons (11 liters) per nautical mile at a 12-knot cruise.
With further input from De Voogt Naval Architects, Briand’s team and the shipyard team felt confident in these numbers. Come February, not only were they all happy, but also happily surprised. In fact, the Feadship Najiba reportedly achieved a best fuel burn of 3 gallons (11.4 liters) per nautical mile at the above-mentioned speed. Feadship says this is 20 to 25 percent lower than most motoryachts of her size. In addition, the yacht hit a max speed of 17 knots, 1 knot more than expected. Even better, however, her calculated best range is reportedly upwards of 6,000 nautical miles. This represents an increase of more than 1,000 nautical miles compared to what the parties expected.
“It was a real ‘wow’ moment for everyone involved to see this level of efficiency during the sea trials,” says Roderick de Vries, technical director for Feadship’s Aalsmeer yard, where Najiba saw construction. The project marked the first time that Feadship and Vitruvius Yachts collaborated. “It was a fascinating challenge at times,” de Vries adds. The team needed to think far more about every component in the water, like prop shafts and thrusters. Specifically, Vitruvius Yachts strives to minimize resistance everywhere, not just with the hull itself. Resistance means drag, which of course impacts speed and fuel efficiency.
Even the hull design was educational. “Najiba has a different hull shape from any previous Feadships, showing curvature in all degrees,” says Annemarie Steenbergen of De Voogt. In sum, multiple differences amounted to lower resistance without impacting maneuverability. Of course, “the hull design was very much Philippe’s, but we ensured it could be built according to Feadship procedures and standards,” Steenbergen says. Better yet, the Feadship Najiba showed the naval-architecture and construction teams new ways to approach efficient projects. They even see how they might approach projects with electric propulsion. “Who knows what the future may hold!” Steenbergen asserts.
De Voogt Naval Architects feadship.nl/family/de-voogt-naval-architects
Vitruvius Yachts vitruviusyachts.com