If you want to make a yacht go fast, there is one relatively simple way of doing it: throw as much horsepower at it as possible. But while this sounds easy on paper, in reality the challenges are far greater. Not only are you likely to push the cost of fitting out and running the vessel to the extreme, you also face the problem of diminishing returns.
As you reach the limits of your hull's hydrodynamic efficiency, each additional horsepower has less and less impact on the speed particularly for a large yacht where a planing hull becomes impractical. You will end up at a point where all you are doing is pushing a wall of water, burning more and more fuel to no effect. So how do you create a fast, 65m yacht while keeping your propulsion package and your fuel bill within sensible bounds? An innovative 65m under construction at Dutch yard Heesen may have the answer.
New, high-efficient hull
The yacht is being built on the revolutionary 'fast displacement hull form' (FDHF), a concept developed by Dutch naval architect Van Oossanen Associates. This hull design went through extensive tank testing at the Wolfson Unit in Southampton early in 2010, and a patent has been applied for it.
'The FDHF hull offers a solution to the problem of having to have different hulls for displacement and semi-displacement modes of operation,' explains Peter van Oossanen. 'This one hull is efficient in both speed ranges and thus offers great flexibility when designing a semi-custom series; the naval architecture and engineering do not need changing according to the speed requirements, as long as the engine room can take both large and small engines.
'Moreover, the FDHF hull has often as much as 15 per cent less resistance in the semi-displacement speed range compared to a hard-chine hull, which translates to a lower power requirement for the same speed.'