John Shuttleworth Yacht Designs (JSYD) has launched a new lightweight and fuel efficient trimaran known as the Adastra. Described by Boat International as “one of the world’s most amazing super yachts, that could spell the future for efficient long range cruising”, the 42.5m vessel was revealed in China for two Hong Kong clients.
An article on Manufacturing.net describes how the company sees weight as a primary design consideration when developing the vessel.
According to Orion Shuttleworth, one of Adastras design team, keeping the weight of the vessel to a minimum meant several features which he had hoped to incorporate were not included in the final design, including a sliding sunroof in the bimini over the aft deck (the guest area closest to the back of the boat on the main level) and “pirate proof” automatic step covers on the wings that would’ve increased security.
Other features that didn’t make the final design included an articulating outrigger, part of a boat’s rigging which extends beyond the side of a boat to stabilise the main hull.
“During the preliminary design stage, we built a tank test and remote-controlled model of the boat with outriggers that articulated up and down,” says Shuttleworth. “The idea was that one could lift the outriggers out of the water while at sea so they would be skimming the water, thus reducing drag, and then submerge them while at anchor or port to reduce the roll and make the vessel more comfortable.” It was decided that that the additional weight required to build the articulating mechanism would increase the drag more than the potential energy savings from lifting the outriggers out of the water.
Monitoring the weight played a huge role in the project, as the vessel is incredibly weight sensitive. About 18 months prior to the launch, JSYD and McConaghy Boats made the decision to place load cells under the hull so that the weight could be continuously monitored. “This gave us a good idea of the center of gravity, so we were confident that she would float correctly,” Shuttleworth adds.
The superstructure is carbon fiber with Nomex honeycomb core, the hull is glass/kevlar foam sandwich and the interior is light weight oak cabinetry using honeycomb panels. To help reduce weight, virtually every aspect of the boat is custom built. This includes carbon fibre hatches, portlights, ladders and even hinges, which are all built specifically for the vessel.
The Adastra’s top speed comes in at 26 miles per hour (22.5 knots) with a maximum range of 4,000 miles when cruising at 17 knots.