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.

07.04.2008

Off again !.

par Gitana

The passage of the cold front was already shaping up to be a little tricky for Lionel Lemonchois and his ten men to negotiate, but storms then stepped in to further complicate matters for Gitana 13. In fact, a temporary breathlessness on the part of the wind gods has already set the nerves of the eleven sailors on edge. Since this time though, the wind has kicked back in again and the maxi-catamaran in the colours of LCF Rothschild Group is making up for lost time by snatching back some precious miles on the reference time.

Yesterday evening gave Gitana 13 a rather nasty surprise. Finding themselves up against a real barrage of squalls, which appeared very late on in the satellite images, Lionel Lemonchois and his ten crew had to battle hard to extract themselves from the capricious storms. Sylvain Mondon, weather expert from Gitana Team, provided us with a few explanations about this stormy zone: “The storms were buried within the mass of the cold front. The front piled one on top of the other and reactivated each of them, creating a vast zone of storms which didn’t even exist on the satellite images just a few hours prior to Gitana 13’s passage” commented the router of the maxi-catamaran.

“The wind doesn’t want to come!” said a slightly irritated Lionel Lemonchois at the start of the conversation yesterday evening. “There is no breeze, or the little there is, is turning every which way. The upshot of this is that we have covered just 30 miles in 4 hours and we’re under some awful squalls so it’s raining too… We’re going to get across this zone in the end though. The main concern is that this situation doesn’t last long.” Perturbed to see the time ticking by without racking up the miles at this precise moment, Lionel Lemonchois is not concerned about the overall record but rather the timing which Sylvain Mondon has given them, in order to join up with a very deep low, which will likely be the most difficult obstacle on this North Pacific crossing: “We should manage to pass to the north of the large depression which is lying in wait for us. Our rendez-vous with this fine zone of low pressure is scheduled for tomorrow lunchtime and given that it’s extremely active and that there’s a lot of wind forecast, we really can’t be late.”

Shortly before midnight (UT), after over four hours at a reduced pace, the maxi-catamaran being flashed at 3.2 knots at the 2030 position report, the skipper’s wishes were granted and Gitana 13 has progressively picked up speed again. Hard on the nerves, this situation was also tiring for the crew, who were constantly on deck trying to trim the sail area as best they could according to the variations in the wind, in order to get Gitana 13 making good headway again.

At the 0830 position report, the maxi-catamaran equipped by Baron Benjamin de Rothschild was making over 25 knots of boat speed, downwind on starboard tack, on a course of 250°. Gitana 13 is making good speed again then, which is enabling Lionel Lemonchois and his men to increase their lead over Olivier de Kersauson and his crew; a differential that has now stretched to over 600 miles.

Retourner aux articles

Heritage