Dutch naval architecture firm Vripack has announced two new construction projects that will use its patented Slide Hull design. The hull design – which offers a high level of efficiency at medium planing speeds combined with good seakeeping qualities – was the result of several years of work following investigations into how another Vripack client had managed to achieve high levels of efficiency through DIY modifications to the hull of his own 17.5m boat.
“It’s been my unicorn for some time,” Peter Bouma, Vripack naval architect, tells SuperyachtNews.com. “It first came into my field of vision in 2008. Another client kept talking about this boat called Blue Whale, which was used for sportfishing and diving trips, so we spoke to the boat’s owner.” That owner/captain was called Jaap de Brujin, and he had continually optimised his boat over the course of a decade. “He was claiming fuel use of seven litres per hour at 24 to 25 knots,” Bouma continues, “but we couldn’t figure it out – the numbers didn’t make sense.”
Through close cooperation between de Brujin and Vripack, the mystery was gradually solved. “We made a scan of his boat,” Bouma explains, “and from that were able to see the various ratios [that his modifications had created] between things like deadrise and chine slats. They were not what you’d usually design.”
From that, and working with de Brujin’s friend Ruud Lievaart, the trio further optimised the design, increasing efficiency by a further 15 per cent and enabling the new hull to press on through a seaway of 2-3m significant wave heights while maintaining speeds in excess of 20 knots. The result was SC Amethyst (above) – the first hull to use the refined Slide Hull design. Vripack filed to patent key aspects of the design early in 2015, with the patent being granted in June 2015.
With two more similar vessels under construction, both destined for commercial use and with LOAs at 17 metres, the obvious question is whether the Slide Hull has applications for yachts. “For a 20 metre yacht at 20 to 25 knots, the Slide Hull is a great choice,” says Bouma, “and the design scales up really well - especially for bigger boats that are quite heavily laden. Moreover, one of the side benefits of the foreship design is more volume forward, which obviously means more space down below.”
Look out for more on the Slide Hull design in Issue 27 of SuperyachtDesign.