The naval architecture is by Berret Racoupeau, the La Rochelle firm behind Royal Huisman’s latest 35m/118ft sailing and power catamaran concepts.

The multihull market is the fastest growing marine sector, but only series production options or full custom boats have so far been available. The SWCAT90 targets the segment in between by offering a versatile platform whereby the design and engineering is in place, but a good degree of customisation is still offered to the customer.

The Cape Town shipyard is known for its go-anywhere 80-110ft semi-custom monohulls. The SWCAT90 concept, developed with Southern Wind’s long-term partner Nauta Yachts, has been designed to share these monohulls’ renowned qualities of performance, comfort and reliability.

The space and speed potential of this carbon catamaran is particularly appealing. Olivier Racoupeau says it was a challenge to try to match the performance of a 100ft monohull, but in fact this cat should exceed it on all angles but at just 5º of heel.

The polars he showed us indicate it’s capable of 22-24 knots’ boat speed in 20 knots of wind (depending on mast type). Two sail plan options are available including a tall rotating mast, and the spec includes curved asymmetrical daggerboards and T-rudders.

Meanwhile, Nauta’s Massimo Gino compared the space and volume to a 39m/128ft monohull (Nauta was behind the 40m/130ft My Song project). Gino says the SWCAT90 presents 50% more interior space than an equivalent SW96 monohull (171m² compared with 113m²).

In terms of accommodation, there are four guest cabins, including an owner’s cabin with opening platform to the sea. These double ensuite cabins are orientated around the centre of the boat where there is the least amount of pitching, and the two or three crew cabins are separated from the guest areas. The distribution of systems has also been carefully considered, to keep weight as central as possible.

Southern Wind thinks the SWCAT90 will also appeal to motoryacht owners seeking a greener alternative, thanks to its reduced dependence on fossil fuels. The yard’s chief naval architect Yann Dabbadie explains that the boat is offered with the choice of diesel propulsion or an electric hybrid system.

“It also allows the two main engines to be independent from the shaft line, resulting in a greater efficiency as generators,” he adds. “This will bring savings of both weight and space and the centring of machinery will realise better seakeeping and reduce pitching motion.”

Although the cat(s) will initially be built in infused carbon, the yard is also conducting its own tests on sustainable materials and resins, with a particular focus on reliability. Southern Wind has capacity in its Cape Town facility to build the cat alongside its monohulls, but the SWCAT90 is a three-year project as the yard wants to design it with the client.

Dimensions

LOA: 88ft 10in (27.07m)
LWL: 88ft 5in (26.96m)
Beam: 36ft 8in (11.17m)
Displacement (light): 56.27 tonnes (124,050 lbs)