Extraordinary boats: the new radical PRB IMOCA 60

The new PRB IMOCA 60 is one of the latest to launch in a flurry of new launches. Originally designed for The Ocean Race, it will be Kevin Escoffier’s boat for the next Vendée Globe

As if the new PRB IMOCA 60 were not eye-catching enough, the story behind it is truly remarkable. The reason Kevin Escoffier needed a new IMOCA in a hurry is well documented: in early December 2020 Escoffier was racing in the Vendée Globe around the world race, 800 miles south of Cape Town, when his previous PRB suddenly and catastrophically broke up.

The previous PRB IMOCA 60, a 2009 Verdier-VPLP design that had been retrofitted with foils, sank without trace, leaving Escoffier not only without a boat, but also without answers as to why his yacht had broken up.

One thing not in doubt, however, was his determination to start the 2024 Vendée Globe. His sponsors were quick to affirm their support – pledging new backing even before Escoffier had landed ashore after his rescue.

Immediately after the 2020/21 Vendée Globe, however, the IMOCA 60 market was white-hot, thanks partly to the strong performance of previous generation designs driving a rush to buy competitive existing boats. Meanwhile a number of skippers preparing a 2024 campaign had already secured build slots for new IMOCAs.

However, there was one boat which was available – a Verdier-design that had originally been created as a fully crewed boat for The Ocean Race. It was in build at Carrington Boats in the UK, before a change of circumstances saw the project paused. Escoffier’s team bought the hull, finishing the build in the UK before shipping it to Lorient for final fit out and launching.

PRB has the latest evolution Verdier foils for improved stability at speed. Photo: Yann Riou/polaRYSE

Rebirth of a new PRB IMOCA 60

Perhaps surprisingly given the fate of his previous boat, the first change Escoffier made to the partially-built PRB was to saw off around 4.5m of bow. But this was a pure performance decision, Escoffier explains: “The hull was designed for The Ocean Race. [Originally] in The Ocean Race a few legs were going north up to China, so it was quite a deep bow in order to also be efficient upwind. Whereas for me most of the races – like the Route du Rhum, Vendée Globe – are more downwind races and single-handed.”

The bow was cut 50cm forward of the bulkhead where the J3 furler is fitted, and replaced with a new, shallower section that is designed for more downwind and all-round performance.

“It will be a bit slower upwind in light winds, but much better for downwind, and much better also for reaching because as soon as the foil is working the bow won’t be touching the water as often. So we were looking for more average speed instead of top speeds.

Racing these boats single-handed, you’ve already got top speed much more often than you want it.”

Buying an existing competitive IMOCA would have cost €4-4.5m, with another €1-1.5m in modifications and new foils

The team also changed the angle of the forward chine, making it more pronounced, and moving the forefoot aft. “That’s in order to build some lift on the bow and not to nose dive again, the idea is definitely to stay above the waves. So the hull is not the latest design, but the bow is.”

The foils were designed especially for Escoffier’s boat. “We changed their position a bit, and we used the last six sections designed by Verdier,” says Escoffier, who says they are an evolution of the foils on the 11th Hour Racing IMOCA 60 Malãma. “The idea of these foils was, again, for more average speed. Since we don’t have any T-rudders at the back, these boats are quite complicated to keep (from) pitching or flying too high.

“The idea of having a foil that is a bit more curved was to have something that was ‘auto stable’. Same thing for the shaft – to have a short radius on the shaft to be able to adjust the stability and the depth of the foil whether you want to fly high or not, to go above the waves or be in skimming mode.”

Flying high for the cameras, but PRB is designed for high average speeds and stability rather than outright top speed

Another distinctive feature of the new PRB IMOCA 60 is its scooped foredeck. This achieves two aims, Escoffier explains: it reduces weight by reducing the amount of material in the bulkheads, and it helps lower the boat’s centre of gravity.

“The idea is to have the mast as low down as possible to lower the centre of gravity. On these new boats, since we’ve got foils, we need less sail area. But if you’ve got the centre of gravity and the centre of pressure of the sails lower, you heel less, and you go faster.”

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In a bubble

As the mast is one-design within the IMOCA class, there is no option to lower the gooseneck fitting, but by lowering the foredeck and mast position the boom sweeps close to the coachroof. Escoffier may use soft panels to create an end-plate effect here, but he says extra mods are only added after they’ve thoroughly tested the boat and know how many kilos of weight they have to work with.

The coachroof itself tapers down rapidly towards the transom – you have to crouch when climbing aboard over the rudders. Inside the mostly enclosed space Escoffier has dual helming positions with custom-fit windows to create full-height working zones. “We’ve got bubbles over the pedestals,” he explains, “for me to be able to see around for safety, to trim the sails and also to stand up because everywhere else, you don’t have the height.”

The concave foredeck is evident here as crew move around the deck. Photo: Photos: Yann Riou/polaRYSE

There are three reasons for the closed cockpit: aerodynamic performance; reducing the amount of water on deck – and in the boat in general; and to protect the skipper from wind and waves.

The revised PRB IMOCA 60 has kept the twin pedestals that were originally specified for The Ocean Race, but the result is that solo skipper Escoffier can trim with a clear view of the sails on either tack. He will add cameras, particularly to view furlers and the bowsprit, but says he doesn’t want to have to rely on them for general visibility.

“You can see everywhere. I will have my autopilot here. I can ease or trim and I have the helm. It was very important for me to be able to do everything from here – on other boats they need to move to see, then go back to the helm. You’ve seen the issue with SVR-Lazartigue, the Ultime [François Gabart’s maxi trimaran is currently in a legal dispute about whether it meets class rules due to lookout visibility]. We have to be careful I think, not to open the class to mistakes where we could be criticised. Not to do anything that might make people say stop single-handed racing, as that would be very sad.”

On a training sail with Pascal Bidégorry. Line tails run from the mast base through carbon tunnels to exit at the pedestal positions on each side. Photo: Kevin Escoffier/PRB

Cockpit seats will be added later – along with a beanbag for sleeping below – and canting instrument screens. Escoffier says he always carries an iPad onboard as a back up. “So that if you’ve got nothing at all – you can charge an iPad with the solar panel and then you’ve got maps, GPS, you can do routing, you can go back home even if you’ve got a full blackout on the boat.”

The cockpit has also been designed to allow Escoffier to stack sails as far outboard as possible, and to move internal weight depending on which ‘flight’ mode he is sailing in. “I think that the centre of gravity is a big fight we’ve got on these boats. We want everything forward upwind, because with the foil we are flying, then downwind we want to delay the moment you put the [water] ballast in. The idea is to be able to move everything inside the boat first, to delay the moment you put in the ballast because then you’ve made the boat heavier.

Additional solar panels will be added to the hard cockpit top as Escoffier plans to race without carrying diesel. Photos: Yann Riou/polaRYSE

“By the rule we can only have four [ballast] tanks. Before it was two at the back, two in the middle. Now with the foils, it’s more like one at the back, one in the front, two in the middle. We use the ones in the middle upwind and reaching, at the back for downwind, and in the front for close reaching.”

Clever structures

Down below the build quality is evident – the boat is a web of perfect carbon and clean edges. Escoffier’s engineering background shows in a centralised systems housing that includes electronics, keel and hydraulic control boxes.

Out of the water, designer Verdier’s latest thinking in bow shape shows pronounced chines, designed for lift and fast average speeds offwind. Photos: Yann Riou/polaRYSE

“Instead of having single parts everywhere, it’s all here. Also it’s low down for a low centre of gravity, and you can access everything. Usually this is all right at the back – but here I don’t need hatches so that means that it’s lighter and if I have to work on something I can see directly which connection is not working – I don’t have to follow a wire around the boat. Everything is here, so it’s very easy.”

However, much of the engineering is hidden, such as the anti-collision system for the foils. Besides hydraulic rams to push and pull the foils to adjust their angle of attack, there is a large diameter hydraulic ram designed as a shock absorber. “It’s like a vang, very quick. You have to have a big cylinder of oil to absorb all the energy of the impact. Then at the back of the foil I’ve got a bumper, and on the forward part of the upper bearing I’ve got a 200mm titanium plate.”

The ‘bubbles’ over each helm/pedestal position allow Escoffier to trim facing forward and look directly at the sails with standing headroom. Photo: Kevin Escoffier/PRB

Overall, Escoffier seems delighted with his new boat. There were a few supply chain delays – and Brexit added extra complications – but from the worst possible situation he has found himself with a unique new IMOCA, ahead of many of his rivals awaiting next generation launches. He estimates using a pre-existing hull saved around €1.5 million compared to buying a new boat.

“Also nowadays we’re working on sustainability,” he adds, “So for me it would have been crazy to have a hull sitting there not being used. This was a perfect opportunity, so I’m very happy. I think we’ve got a beautiful boat.”

PRB IMOCA 60 specifications

LOA: 20.12m / 66ft 1in
LWL: 18.28m / 60ft 0in
Beam: 5.50m / 18ft 0in
Draught: 4.50m / 14ft 9in
Sail area (max): 565m2 / 6,081ft2
Displacement: 8.2 tonnes


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Source: https://www.yachtingworld.com/extraordinary-boats/extraordinary-boats-the-new-radical-prb-imoca-60-139829