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.

14.11.2013

In the thick of the Doldrums.

par Gitana

Since yesterday afternoon, the two 70’ trimarans have been in the clutches of the Doldrums, the direct consequence of which has been a fairly significant drop in their average speed. Forecast to be very extensive, the Inter-Tropical Convergence Zone seems to be living up to expectations. After a lively and particularly stressful night for the men, the Josse Caudrelier duo and its adversaries still weren’t through to the other side. At the 0700 GMT ranking, Oman Air Musandam’s easterly separation appeared to be giving her crew a slight edge in terms of speed, but the trimaran fitted out by Baron Benjamin de Rothschild was holding onto her lead of over 65 miles.

“The Doldrums are synonymous with managing randomness,” points out Antoine Koch, one of the onshore routers for the trimaran fitted out by Baron Benjamin de Rothschild. “It’s complicated to reach a verdict with any degree of certainty in this zone. The satellite photos certainly provide us with some indication, but things evolve so quickly that you virtually need to deal with the situation in real time.”

There is radio silence aboard Edmond de Rothschild this Thursday morning… Totally absorbed by the zone they’re currently traversing, Sébastien Josse and Charles Caudrelier are focused solely on getting their steed making headway and the only communication on the boat comprises calls to their onshore routers. In this way, Antoine Koch has some fresh news for us from the night’s proceedings: “The first part of the night went rather well with an easterly breeze (beam wind) of around twenty knots or so, which enabled them to make headway along the route at a fast pace. After that, the plot thickened somewhat; Sébastien and Charles experienced a very lively period in the early hours, with some huge storms and big squalls along their course. They had a bit of everything in the squalls: violent winds picking up to 30 knots in a matter of seconds, as well as total lack of wind at other times. The atmosphere was truly electric with lightning everywhere!”

According to the latest forecasts, Edmond de Rothschild should see the light at the end of the tunnel early afternoon this Thursday. However, in all likelihood it won’t be until the end of the day that Sébastien Josse and Charles Caudrelier hit some more established winds with which to make headway towards the equator.

Ranking on Wednesday 14 November at 0700 GMT:

Edmond de Rothschild (Josse-Caudrelier) 2,245.4 miles to go /9.9kt average over 2 hours
Oman Air-Musandam (Gavignet-Foxall) 65.8 miles behind the leader /14.6kt average over 2 hours

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