The owner’s brief for Ngoni would be challenging for any size of yacht: “Build me a beast. Don’t build me a sheep in wolf’s clothing. This has to be an edgy and innovative weapon; fast and furious.” When the boat in question is a giant 58m (190ft) sloop with a displacement of nearly 400 tonnes this project was always going to push hard against existing boundaries of superyacht design, deck hardware and materials technology.

“The owner wanted me to take a fresh look at large yacht design,” Dubois recalled before his untimely death four years ago. “He wanted me to go back to my roots in the late 1970s and ’80s when we were designing race boats, but he also knew we had designed a number of high performance yachts that were nevertheless seaworthy and comfortable cruisers.

“So I had to reset my internal computer, if you like, and look hard at how we could save weight and add strength. That’s how the reverse sheer came about. I was worried he might not like it. The next time we met in London I showed him the design and he loved it – in fact he gave me a big bear hug!”

‘The instruction was simple and clear yet allowed for creative interpretation: don’t design a traditional yacht interior’. All photos: Breed Media

The distinctive reverse sheer shape is a great example of top-notch design that combines both form and function. Compared with a conventional sheer using the same materials the shape increases strength and load resistance by 12 per cent. This turned out to be an important factor, given that the hull and deck both have numerous openings.

Even with an additional 35mm thick aluminium plate around the top of the hull that acts like a ring beam, without the reverse sheer, it was still a struggle to come up with the required stiffness to resist the forestay loads that were calculated to reach 60 tonnes. Further refinement led to the concave sheer aft of the superstructure, which improves visibility from the cockpit and gives the boat her distinctive style.

Dubois considered using carbon construction instead of aluminium, which would have made for a faster boat, but one that would have had a more aggressive motion at sea. It would also have been intrinsically noisier and therefore less suitable for world cruising. “Again, it all came down to balance: understanding the true purpose of the yacht and coming up with the right formula,” he said.

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This yacht had potential to end up highly complicated, but Ngoni’s owner wanted a fast global cruiser with relatively simple systems that would require minimal downtime for maintenance. A ‘less is more’ philosophy therefore informed the project, with the aim of minimising complexity. This also helped to enhance the clean and clutter-free appearance.

Technical challenge

Despite the sheer size and displacement of Ngoni, a key requirement of the brief was that the boat needed to be fun and rewarding to sail. In particular, the owner, who is a knowledgeable sailor and a veteran of multiple Rolex Fastnet and Sydney Hobart race campaigns, insisted the steering should be light, yet firm and responsive. In the initial brief he said: “I want to get off the wheel after a day of sailing feeling knackered from the excitement of hands-on fast sailing.”

These requirements called for a high aspect ratio-balanced rudder allied to a manual steering system with no power assistance. All components of the systems, including rudder area, rake and linkage friction were carefully analysed. This process led to a single, 6.95m2 (75ft2) carbon rudder made by Royal Huisman’s sister company Rondal.

The passarelle by Cramm, which extends from the bathing platform, is self-levelling

While the owner’s requirements for the steering may sound like a tall order it was not one that fazed Royal Huisman. “We were already accustomed to producing hand steering systems on big yachts, so we already knew what needed to be done,” says design manager Jan Knol. “The two most important things are to have the shortest route from the wheel to the quadrant and to have the correct balance area on the rudder.”

Once those two criteria have been met, Knol says then you focus on minimising friction. Linkages are a mix of chain and sprocket and torque tubes, all of which are supported on low-friction bearings. Similarly, the hydraulic system for the autopilot has low-friction seals to minimise interference when hand steering. The massive bottom rudder bearing, which has an inside diameter of 750mm, has stainless steel spherical roller bearings that further minimise friction, even when subjected to huge loads.

The biggest technical challenge the project faced was with the deckhouse windows that are curved in two planes. The low-profile superstructure is constructed from compound curved moulded glass, at the very limits of current technology. The gleaming black finish also disguises four large skylights. “Getting the curves right in the glass panels was very difficult,” says Knol.

The use of so much curved, tinted glass creates a remarkable deckhouse with unhindered views. Inside you can see the bar and dining area to starboard and informal saloon area to port

“After we finished and faired the deckhouse we made a mould and then asked a number of different glass suppliers to make a test panel. All of them said it would be impossible, apart from BCE in Turkey. Fortunately their test panel was good and they then also supplied the rest of the glass.”

The scale of the rig

Dubois was not restricted by Panamax constraints, so was able to draw a carbon rig a full 17m higher than the clearance under the Bridge of the Americas near the Pacific end of the Panama Canal. The towering mast, built by Rondal, is therefore one of the world’s largest one-piece carbon spars. The rig had to look aesthetically perfect, so the aft four metres of the boom is an extension beyond the clew of the mainsail that’s shaped to match the profile of Ngoni’s stern.

The enormous square top mainsail covers almost a quarter of an acre – the equivalent of four tennis courts. A neat piece of engineering means the forward end of the diagonal top batten automatically detaches and attaches to the luff car when the sail is hoisted or furled into the boom. Both raising and lowering the sail can therefore be achieved with minimal intervention from the crew.

The helm station as a ‘work of art’

As well as contributing to the minimalist styling, the elimination of as much on-deck hardware as possible has reduced weight aloft, while minimising wind resistance and improving airflow, particularly over the headsails.

The mainsail halyard lock, for instance, significantly reduces compression loads in the mast, while the continuous carbon shrouds are 70 per cent lighter than Nitronic rod rigging. Internal D-Tang connections at the top of the diagonal stays mean bottlescrews are not needed, which further reduces visual clutter. In addition, the headsail furlers are below deck and there’s no pulpit.

External styling and finish

The topside finish is a bespoke metallic topcoat applied with an electrostatic technique that uses charged particles to bond the paint to the surface. All deck hardware is bead-blasted to a uniform titanium look, while the arched carbon wheel pedestals have curved tops milled from stainless steel.

The informal guest cockpit is a few steps down from the main deck level. The aft overhang of the deckhouse roof, combined with electrically powered retractable wind breaks, provides shelter from sun, showers and spray. Sliding glass doors separate this area from the deckhouse, with a near seamless transition between the two zones.

Avoiding traditional

The interior is by Rick Baker and Paul Morgan, who have worked with the owner on a number of large projects for more than 20 years, but had never designed a complete yacht interior. The brief was simple and clear yet allowed for creative interpretation: “Don’t design a traditional yacht interior.”

“We consciously avoided giving the yacht a theme, but rather chose to make the different areas very individual,” says Morgan. “We selected some specialist finishes which would not normally be associated with a contemporary yacht. These include artisan resin panels and metalised spray and lacquered textured effects.” Other finishes include bespoke veneers, distinctive marbles and Italian onyx.

The lavish owner’s suite takes up a considerable proportion of the accommodation deck

The deckhouse has a bar and dining area to starboard and informal seating, with coffee tables and a pop-up television, to port. A curved staircase leads down from the deckhouse to the owner’s and guest accommodation. The lavish owners’ suite takes up a significant proportion of the main accommodation deck.

It includes a full-beam stateroom with a large bathroom, a study and a spacious gym with an opening port in the topsides. There are two superbly appointed guest cabins – a twin to port and a double to starboard with a Japanese theme.

The owner was very specific about the sophisticated audio-visual system on board, which was tested rigorously for a year before delivery. The custom set-up was supplied by Tijssen Elektro and has 48 terabytes of storage capacity that can be controlled via an iPad.

The owner’s gym has a large opening to port in the topsides

Forward accommodation

The quality of crew quarters on a yacht of this size are essential in recruiting and retaining the best people. A good deal of thought and investment has therefore gone into this aspect of Ngoni. The navigation station at the forward end of the deckhouse has stairs leading down to the crew accommodation and machinery spaces. There is provision for up to nine crew in six cabins, all of which have quality fit-out and full en-suite facilities. The spacious, professionally equipped galley is open to the crew mess.

From here there’s direct access to the engine control room and engineer’s office, which in turn has direct access to the engine room. “As with all of the projects that we undertake for this client, once the initial design concepts were agreed, the production work started and the client did not see the finished article until launch day,” says Baker. “Thankfully Ngoni was very well received by a happy client.”

Specifications

LOA: 58.15m (190ft 9in)
LWL: 51.20m (167ft 12in)
Beam: 9.54m (31ft 4in)
Draught (keel up): 5.30m (17ft 5in)
Draught (keel down): 8.10m (26ft 7in)
Displacement: 353 tons (778,224lb)
Hull speed: 17 knots
Upwind sail area: 1,950 m2 (20,989ft2)
Downwind sail area: 3,093 m2 (33,293ft2)
Air draught: 75m (247ft)

First published in the April 2018 issue of SuperSail World.