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.

31.03.2008

In the throes of a passing front.

par Gitana

Clearly, any action has happened under cover of darkness since our departure. Like yesterday, here we are again with 30 knots of breeze in our sails, or what’s left of them at least: 2 reefs and ORC. However, this time the seas aren’t as big, which means less water on deck. To compensate for this and keep us occupied, the rain has joined in on the act, in a dense curtain of driving rain. It lashes at your face more solidly than the waves… It has to be said that we’re in the process of negotiating the warm front of the low and, in a few hours time, we’ll have to negotiate the cold front. It is 1300 hours UT and in these uncomfortable conditions, sailing close to the wind with a change of tack on the cards, we’ll be kept busy for the rest of the day.

Fortunately yesterday enabled us to get back on our feet. The galley was going flat out and everyone settled back into the route, or discovered it in the case of the five newcomers. Although the first night was a bit difficult then, this second ink black night couldn’t have gone better, despite the rotten weather. At the end of this little lot, the promise of tradewinds is certainly a big incentive. What has been most pleasing of all though is knowing that time is on our side and that the chaotic course we’re currently adopting will only serve to increase our lead over the previous record. A few little waves on the nose and the taking in of the odd reef are certainly proving to be worthwhile.

Until tomorrow

Nicolas Raynaud

Retourner aux articles

Heritage