Nyumba: On board Southern Wind's first hybrid sailing yacht

Just off the coast of Cape Town, South Africa, in the shadow of Table Mountain, a glinting, grey-hulled sailing yacht cuts across the water. Nyumba, the latest in Southern Wind Shipyard’s 96 series, is being put to the test before her owners take delivery. On board, the build team, eyes glued to the helm, count out loud excitedly as the numbers climb upwards. They aren’t tracking the yacht’s speed, as might be expected, but a different stat entirely.  

As the first Southern Wind yacht to employ a hybrid propulsion system, the figure that’s causing such a flurry of excitement is how many kilowatts of energy the 29-metre is generating as she hurtles along. “It’s a change from trying to get a half-knot faster (during sea trials) to trying to get more kilowatts generated,” says Yann Dabbadie, Southern Wind’s technical manager. Nyumba is the first sailing yacht of less than 30 metres LOA to implement high-voltage energy storage and be powered by a serial hybrid propulsion system.

Inside, Nyumba has the classic Southern Wind layout, which places the guest living areas forward, separated from the aft crew area. The decor is welcoming and relaxing, with classic oiled teak veneers and built-in furniture brightened up by African-print fabrics. These vivid materials come from a range of collections by local artists, curated by Dewald Prinsloo of Ebony Design. The art on board plays to the yacht’s African heritage as well, with photographs of animals, such as elephants gathered around a waterhole, by South African photographer
Marc Stanes. 

“‘Nyumba’ is a Swahili word for ‘home’ and the owners will be spending a lot of time aboard, so the interior had to be both comfortable and cosy,” says Gino. The saloon is designed to the owners’ requests – the typical SW96 layout with a long L-shaped sofa to starboard was changed into a workstation for him and a reading lounge with a daybed for her. To port, the dining area’s coffee table transforms for mealtimes. Large skylights overhead in the saloon allow light to pour in and brighten up the space, which has dark-wood floorboards. A few steps down, a lower lounge to starboard serves as a relaxation area or cinema with a large television and deep sofa.

The forward master has an unusual element in the form of a vertical carbon ladder that leads straight from the bedroom up to the deck via a hatch – specifically requested by the owner’s wife. “She likes to get up in the morning and jump straight into the sea for a swim, without having to walk through the corridors or see anyone else,” says Captain Burgess. 

The owners are very hands-on when it comes to sailing, he adds. “They are always driving the boat or trimming the sails, even more so her – she drives the boat way more than he will.”

The owners sailed for many years on a smaller full-carbon racer cruiser, so performance was of the utmost importance. They sought to push the yacht’s performance capabilities in cruising mode on a daily basis rather than compete in superyacht regattas. “But,” says Micheli, “if he does want to race one day, he wants to win.”

The hull shape of the SW96 series exhibits Farr performance DNA, with a narrow bow, fine waterline entry and an optimised transom shape. “The two key features of Nyumba’s hull that foster performance are minimal wetted surface and a wide, balanced transom shape,” says Jim Schmicker, vice president of Farr Yacht Design. “Minimal wetted surface is achieved using circular sections below the waterline and a narrow overall beam. The transom is wide, low and shaped to maximise the effective length for optimum speed in all conditions. The appendages and rig are placed on the hull to achieve a precise aerodynamic/hydrodynamic balance so handling is easy and drag is minimised.” 

The hybrid propulsion system on Nyumba is heavier than the standard configuration. To accommodate this, the hull was lengthened by a 50 centimetres to fine tune the transom immersion. “The underwater drive components are larger for the hybrid system as they are also used as water generators,” says Schmicker. “In order to offset the additional drag and achieve suitable light wind performance, 9.5 per cent more area was added to the mainsail in the form of a square-topped planform compared to the standard triangular shape.”

Nyumba is powered by customised Doyle Sails, with a high-performance sail inventory including a square-top mainsail, structured luff jib, SL staysail and SL J4, while her rigging is by Hall Spars. “Carbon and Technora fibres are used in conjunction with specific resins, which have been selected for their long-term durability and resistance to fatigue,” says Mario Giattino, superyacht sails co-ordinator for Doyle Italy. “All [of Nyumba’s] sails have been designed by senior designer Stefano Nava and Dario Motta and constructed at Doyle Sails Italy utilising the Stratis 1100 CT that provides unmatched flexibility in fibre orientation, placement accuracy and superior lamination. Custom-designed Doyle sails allow for a layout that produces stronger, lighter and faster sails that are smoother when set.”