Retractable Y-shaped foils, adjustable in three dimensions

Inspired by the appendages of the America's Cup foiling monohulls, these Y-shaped foils have a wingspan of over 5 metres. They are designed to generate powerful lift, increase power and offer a wide range of adjustments to optimise flight at every point of sail and in all conditions. Beyond their impressive size, these foils feature many unique innovations.

Revolutionary U-shaped rudders

These are probably the most visually striking innovations on the new Maxi Edmond de Rothschild. To fly high above rough seas while maintaining control, the team wanted very long rudders that would remain in contact with the water. The challenge is that longer rudders tend to flex under load, severely affecting steering and the efficiency of their lifting surfaces. A new geometry was needed to give these appendages maximum stiffness, resist cavitation and ultimately improve control of the boat and make better use of its power. The result is a set of U-shaped rudders over 4 metres long, a metre longer than those on Gitana 17. Their shape, reminiscent of a tripod or an inverted π, is only the visible part of what makes them so distinctive.

A daggerboard optimised to stabilise the boat and limit cavitation

With its wide span, the daggerboard resembles an aircraft tail assembly, with two adjustable flaps: one on the vertical section and the other on the horizontal section, the distinctive “manta-ray wing”. On Gitana 18, the innovation is to position this wing behind the vertical part of the appendage, rather than directly beneath it, to minimise flow disturbance and cavitation.

Rig: adjustable spreaders to control mainsail power while sailing

Gitana 18’s mast is 1.50 metres taller than its predecessor’s. The boom is also shorter, creating a more slender sail plan. The major innovation is a set of spreaders that can be adjusted while sailing to bend the mast fore and aft. Actuated by hydraulic rams, these spreaders can pivot through 35 degrees to adjust the bend in the middle of the mast. This unprecedented system allows the sailor to control mainsail power: adding depth in light winds to take off sooner, or flattening the sail to reduce power at high speed or in strong winds. Adjusting the depth, and therefore the power, of the mainsail can also save a solo sailor time and energy by reducing the need for risky manoeuvres or headsail changes.

Central hull:
an integrated, structural coachroof

The naval architects and Gitana design team wanted an exceptionally stiff, structurally robust platform. This applies both to the floats, which must withstand heavy loads from the foils and rudders, and to the central hull, which is subject to torsion. The enclosed coachroof is integrated into the hull and contributes to its structural strength. Inside, the cockpit brings all sail-handling controls together, with ergonomics shaped by many hours of design and development. The coachroof also stands out for the number and size of its windows. This configuration meets the visibility requirements of the Ultim class rules and gives sailors the best possible view to keep a visual watch.

12.11.2013

A magical night in the tradewinds.

par Gitana

Yesterday the Canaries, today Cape Verde the 70’ trimarans leading the Transat Jacques Vabre fleet are ticking off the islands as well as the miles. Some 600 miles have been covered over the past 24 hours, equating to an average speed of over 25 knots to sum up the day’s first figures. It has to be said that since yesterday, the one-design skippers have finally been able to enjoy optimum gliding conditions on settled seas swept by a well-established tradewind. Despite this hellish pace, life is gently becoming more comfortable aboard the trimaran fitted out by Baron Benjamin de Rothschild. Indeed, after four days at sea characterised by a disjointed rhythm and conditions not conducive to physical recovery, Sébastien Josse and Charles Caudrelier have been able to recharge their batteries.

The seas have flattened out and the north-easterly winds are firmly in position, a configuration which is enabling the leading trimarans to rack up some fine average speeds on the way to Itajaí: “It was a night coloured by a straight course through the tradewinds,”Antoine Koch explains, “though they still had to cope with some slight oscillations in the intensity of the breeze”.

At the 0700 GMT ranking, the trimaran fitted out by Baron Benjamin de Rothschild was still holding onto the lead she acquired over her adversary along the Iberian Peninsula. And even though her pursuer’s deficit has greatly reduced in comparison with yesterday evening, over 70 miles still separate Gitana XV from Oman Air-Musandam.“Oman has made up ground in terms of miles, but in relation to the ground gained to windward Edmond de Rothschild managed to slip along nicely overnight,” explains the onshore router for the Edmond de Rothschild duo, who is clearly entirely satisfied with the trajectory traced by Sébastien Josse and Charles Caudrelier last night.

Positioned some 150 miles from Cape Verde shortly before 0800 GMT this Tuesday, Edmond de Rothschild is likely to leave the Portuguese archipelago abeam of her late this afternoon or early this evening. As was the case when they passed Madeira and the Canaries, the sailors will be keeping an eye out for the wind shadow created by the islands which, if poorly negotiated, could be synonymous with less wind in the sails and a subsequent loss of ground in relation to their adversary.

Night message from Charles Caudrelier: “ A magical night: 20 knots of breeze, the first night without a fleece and the first calm night, albeit it at 30 knots! We’re making the most of the conditions to get some decent sleep. After three years on the Volvo Ocean Race with ten crew aboard, I’d forgotten my many years of solo and double-handed sailing, where you suffer from lack of sleep… I’m also discovering how wearing it is sailing multihulls shorthanded and in race mode, as we’re having to live with the constant stress of capsizing. That element doesn’t exist when you’re sailing a monohull and I’d underestimated it; in fact you’re helming all the time as the boat performs a lot better and it’s more reassuring. That’s another significant difference with monohulls. It requires concentration, so it causes fatigue. All that to tell you that I’m off to get some sleep because in 90 minutes I’ll be getting right back into that and I love it… And yes, I complain, but I wouldn’t give up by seat aboard the MOD 70 Edmond de Rothschild for all the world, as these boats are simply magical!”

Ranking on Tuesday 12 November at 0700 GMT:

Edmond de Rothschild (Josse-Caudrelier) 3,168.5 miles to go /25.7kt average over 2 hours
Oman Air-Musandam (Gavignet-Foxall) 72.7 miles behind the leader /25.7kt average over 2 hours

Retourner aux articles

Heritage