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.

31.10.2006

Behind the front.

The pace has picked up considerably since last night with the passing of a front heralding a propulsive north to north-easterly breeze: the Orma trimarans are now sailing at an average speed in excess of 20 knots and the two Gitanas have both taken up trajectories among the southernmost in the fleet.

par Gitana

The gloves are off! Since last night, speeds have been well and truly ratcheted up so that the averages are now oscillating between 16 and 26 knots as the trimarans head straight for the Azores archipelago. The reason for the change is a front from the north-west which is leaving a nice anticyclone in its wake: temperatures are going to drop significantly, but the wind will gradually rotate towards an easterly direction. What’s more, this turbo-charged situation looks set to last until Thursday and beyond! Consequently, there are no real strategic or tactical options on the cards until the archipelago is passed around Wednesday evening, but there are important positioning issues in terms of negotiating the low-pressure front which will take hold over the Azores in the coming days. The soloists need to take up a sufficiently northerly course to benefit from a stronger downwind flow, but stay far enough south to touch on the low-pressure front in order to slip more easily along the Azores anticyclone swelling up behind, to the south of Newfoundland… It amounts to a delicate balancing act that suggests the current positions of the solo sailors are far from set in stone!

Indeed, this Tuesday morning sees differences in latitude of over sixty miles between the new leader, Michel Desjoyeaux, who has opted for a very northerly trajectory, and Lionel Lemonchois (Gitana 11), who has stayed closer to the direct (orthodromic) route, as has Thierry Duprey du Vorsent (Gitana 12). In fact, the fleet of trimarans remains highly bunched and the difficulty for the competitors now is coping with the stress generated by the unrelenting speed. According to the weather info, the wind will remain abeam (north-easterly) while reaching twenty knots and more amidst the squalls, which means sailing with one reef (or two) in the mainsail and gennaker up for hours… not to say days! This is precisely where the difficulty lies, as all the single-handed trimarans go at the same speed in these conditions, but the skipper has to remain watchful round the clock. The leaders should cover over 500 miles on this second day of the race and the Azores archipelago should be rounded to the north from Thursday morning… Consequently, the problem facing the solo sailors is keeping up a mounting rhythm (gradual acceleration up to more than 30 knots) over several days’ racing, since strong leading winds are forecast… all the way to the finish in Guadeloupe !

Thierry Duprey du Vorsent (Gitana 12):

“01 :45: everything’s going well, even if Monday was a bit testing due to the highly unstable wind force and direction, which meant that a lot of time had to be spent on the bridge. I’d expected the front to be a bit more powerful and I slowed down a bit too quickly… But at least it allowed me to have a siesta, which did me the world of good: now, I’m on the other side of the front and the wind should grow as the hours pass, allowing me to quickly slip onto the direct route towards the Azores!”

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