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While most people who travel aboard boats worth £1m or more might be mainly concerned with the size of the sundeck, the quality of the refreshments and the comfort of the cabins, the designers of such vessels are becoming ever more focused on making them lighter and more efficient.
In many ways, however, their task is thankless because ever greater demands for luxury mean more on-board equipment and greater weight, which in turn usually means increasing engine sizes — and therefore fuel consumption and emissions — in order to maintain performance.
To solve the puzzle, some designers and builders are thinking laterally in an attempt to introduce innovative — and not always obvious — solutions to make their boats better, both in terms of the way they move and the comfort that they offer.
One such person is the celebrated naval architect Nigel Irens, who is noted for creating the trimaran used by Ellen MacArthur to break the record for a solo circumnavigation of the world back in 2005.
“Our particular approach in recent years has taken us away from planing hulls because, while they provide the obvious means of going fast, we feel that there is an exciting opportunity to explore the ‘mid-ground’ speeds between those offered by alternative displacement hulls,” says Mr Irens.
“The vessels we have developed are quite slender for their length, so that their weight is carried on a longer-than-usual waterline length. Low displacement/length ratio — or LDL — is the term we use to describe these hulls, and their objective is radically to reduce resistance in the chosen speed range for which they are designed,” he says.
As an example, a 60-foot vessel with a planing hull would typically have a cruising speed of 20 knots, whereas a boat of the same length with a conventional displacement hull would be restricted to little more than 10 knots.
A 60ft LDL hull, however, will allow a speed of 15 knots, with the added benefits of increased fuel economy, greater range, reduced noise and vibration, and a more comfortable ride.
“The yachts of this type produced so far have lived up to our expectations in combining low energy use with smooth and comfortable operation at speeds that could be described as swift rather than fast,” he adds.
“Another benefit of low power consumption is that long-range cruising under power becomes feasible — especially as levels of noise and vibration are so low.”
Indeed, the twin problems of noise and vibration are considered so undermining of the feeling of “luxury” that is central to the success of a high-end boat that Princess Yachts, based in Devon in south-west England, recently completed a three-year, government-funded research and development programme to find ways of suppressing these annoyances.
One of the results is an “actively damped” generator platform that Princess will demonstrate for the first time at January’s London Boat Show.
“The location and installation of the generator plant is really important, especially during the night when you want as near to total silence as possible,” says Julian Spooner, who joined Princess 10 years ago as head of composites.
He explains: “The system we have developed uses little shakers — rather like you would see in an audio speaker — which sense the vibration input and produce an anti-vibration movement to cancel it out. The reduction in noise and movement is remarkable, making the yacht considerably more comfortable.”
Mr Spooner’s main role at the company, however, is to develop new, more efficient methods of hull construction, the latest of which is known as “resin infusion”. Rather than create a traditional thick, heavy skin made from glass fibre reinforced with ribs, resin infusion takes the form of a “sandwich” construction, in which layers of laminate are held apart by a foam core. “The result is that you have a very solid structure, but without the space-consuming ribs that are required in traditional open-moulding techniques,” says Mr Spooner.
That means a larger interior volume for the same external hull size. That, in turn, means living areas can be larger, as can space for the engines.
“There is also a weight reduction of up to 25 per cent, which leads to fuel savings and improvements in performance,” says Mr Spooner.
“One of our key aims at Princess is always to enhance efficiency, and the resin infusion technique has proved to be a real leap forward, so much so that it is now used across the range, from the 39ft V39 model right up to our 40m, £15m flagship.”
A toy for the fast and furiously wealthy
Niche automotive firm BAC has joined forces with broker Camper & Nicholsons to create an on-board toy for the fast and furiously wealthy: a 170mph, single-seat sports car, supplied with a carbon fibre crane to lift it on and off ship, and a deck-mounted, temperature-controlled storage unit to keep it in while at sea.
The Mono Marine features corrosion-resistant components and bespoke finishes to match the livery of its host vessel. The car (pictured) is a featherweight 580kg propelled by a 305hp engine, but costs a heavyweight £500,000. A standard Mono — offering the same performance — costs £80,000.