Some readers may remember the incredible-looking biodiesel-powered Earthrace trimaran. Originally designed to circumnavigate the world, it ended up being donated to the Sea Shepherd Society, and was promptly rammed and sunk by a Japanese whaling ship. Well, while we may no longer have it to gawk at, a one-off watercraft that could almost be considered its gigantic, luxurious sibling is currently being constructed in China. Behold, the Adastra.

The 16 by 42.5-meter (52.5 by 139.5-foot) yacht was designed by John Shuttleworth Yacht Designs and is being built by McConaghy Boats, for Hong Kong residents Anto and Elaine Marden.

While Shuttleworth acknowledges the legacy of vessels like Earthrace, he considers them to have been "stripped out record breaking machines." Transforming that basic form into a luxury yacht was a process that reportedly took five years (so far), including water tank tests, and the use of a scale radio-controlled model. It is now said to be nearing completion.

Although not intended to run specifically on biofuel, the Adastra is nonetheless designed for fuel-efficiency, which mostly involves keeping it as lightweight and streamlined as possible. The superstructure, for instance, is made from carbon fiber with a honeycomb core, while the hull is composed of a glass/Kevlar foam sandwich material. The oak cabinet panels also have honeycomb cores, while the custom hatches, portlights, ladders and hinges are all carbon fiber.

The yacht is powered by a main Caterpillar C18 engine, putting out 1150 hp at 2300 rpm, and two Yanmar outrigger engines, which each manage 110 hp at 3200 rpm. Fuel economy is estimated at 90 liters (24 U.S. gallons) per hour at 13 knots, or 120 liters (32 gallons) per hour at 17 knots. It should have a top speed of 22.5 knots, and a range (at 17 knots) of 4,000 miles (6,437 km).

Up to nine passengers and six crew should be comfortable, in a full-width master cabin, guest cabins, and crew accommodations. The yacht will also feature a galley, lounge area, main dining area, navigation station, and a pilot house. Interior design is being handled by Jepsen Designs of Hong Kong.

The Mardens and their privileged friends will also be able to enjoy a foredeck sunbed, an aft deck sofa, bar area and dining area, and a diving platform that doubles as a garage door for one of two tender boats.

There's no word on its price, but other details are available on the John Shuttleworth website.

Source: Bornrich

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