Brilliant Boats in Antalya, Turkey, has completed the first of a projected pair of aluminium catamarans for an Australian client specifically designed to carry a mini sub. The 21.5m power cat is equipped with LARS (Launch and Recovery Systems) for the Triton 3300 three-man submarine and displays the striking green livery borrowed from the cult TV series Thunderbirds. Built to DNV (Det Norske Veritas) certification, the cat conforms to MCA’s MGN (Marine Guidance Notes) 280 in relation to risk assessment and especially Electronic Chart Display & Information Systems (ECDIS), which means the owner can commercialise this unique package. Indeed, the second yacht in build is designed to function as a shadow vessel that can be chartered by superyacht owners who fancy exploring under the water, but do not have the onboard facilities on carry their own sub.

Built for an Australian client, Thunderbird 2 has been designed
to function as a shadow vessel that can be chartered by owners who don't have a yacht with sub-carrying facilities

The specialised brief meant that Michael Schütte, the principal designer and founder of Brilliant Boats, had to go back to the drawing board and begin working on the naval architecture from scratch. The catamaran configuration was an obvious choice because it offers a wide and stable platform for sub ops, while the Hamilton 521 water jets combined with twin 900hp (2 x 671kW) Yanmar engines provide a shallow, one-metre draught suitable for Caribbean cruising grounds. Schütte developed a hull form that generates some dynamic lift at semi-displacement speeds with the addition of horizontal spray flats to capture the energy lost to cross-flow under the hulls. The 8.5t-capacity hydraulic LARS was developed by Hardy Engineering in the UK and consists of four hydraulic rams used to activate each corner of the height-adjustable platform, along with the array of battery chargers and oxygen storage and transfer systems required to fully support the submarine.

Michael Schütte, principal designer and founder of Brilliant Boats

“The challenge was that no matter where the sub is placed on the platform, it has to operate smoothly and evenly,” says Schütte. ”The platform has to drop some three metres into the sea and we didn’t want to do that with the long, skinny legs of a single-stage system. We eventually figured out how to do it in two stages.”

The crisply modern interior design is by Miami-based Karine Rousseau and offers accommodation in two lower deck suites, combined with spacious social areas, a day head, study/office, large galley on the main deck and open-air dining areas in the forepeak of each hull with a sun lounger in between. The flexibly mounted and heavily insulated interior constructed of balsa, honeycomb and Forex, means that at a full speed of 22 knots sound levels on the lower deck are a hushed 65dB and a comfortable 72dB on the main deck.

The owner's suite, part of the interior designed by Karine Rousseau

Thunderbird 2 is due to transfer in the New Year to Florida to take delivery of her Triton mini-sub. During sea trails the yacht was running a little bow heavy, but once the sub is installed on the aft deck she will trim perfectly. Lightship she weighs just 54 tons, so the addition of the eight-ton sub will make an appreciable difference.

“This is going to be a helluva tool once the mini-sub is aboard,” concludes Schütte. “People look at it and they smile. The owner is really happy – it looks like a big toy, which is exactly what he wanted.”