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.

05.04.2008

After the midway mark… the International Date Line.

With the midway mark of the course in their wake, Gitana 13 is continuing its ride to Yokohama. Six and a half days after leaving San Francisco, Lionel Lemonchois and his ten crew are maintaining a brisk pace across the North Pacific and had racked up a lead of over 540 miles on the reference time at 0830 hours. However, the second half of the cour…

par Gitana

“Our night (during the day on Friday GMT) was not very amusing as we had shifty winds both in terms of strength and direction. This forced us to make a few sail changes and meant that the men on watch on deck had to be extremely vigilant. Conditions have become steadier now though and Gitana 13 is flying along at over 20 knots under full mainsail and large gennaker” detailed Léopold Lucet last night.
A few hours prior to that the crew of the maxi-catamaran in the colours of LCF Rothschild Group had proceeded with a gybe, after which they repositioned themselves slightly to the north and gybed again overnight. This morning, Gitana 13 is sailing downwind on port tack, benefiting from a fine Pacific swell to slip along the edge of a ridge of high pressure: “It’s like the Russian mountains behind us! It’s the first time that the sea has been so well organised and this long swell is quite a sight” recounted Léo.

Making the most of this temporary stability, the standby watch spontaneously got down to a little shaving session, knowing full well that the wind is set to pick up again as the weekend draws to a close. Indeed, the crew of Gitana 13 have a rendez-vous with another cold front, which they’re likely to hit on Sunday evening. The S’ly wind will then clock round to the south-west, filling in slightly at the rear of the front. Following on from this, they will encounter 20 to 25 knots of N’ly wind, with gusts possibly reaching 30 knots, so conditions will be rather feisty for the eleven sailors.

A leap in time at the passage of the International Date Line
In a few hours time Gitana 13 should cross what we refer to as the International Date Line (the opposing meridian to that of Greenwich). The crossing of this imaginary line indicated by the 180th meridian, will mark the maxi-catamaran’s passage from the western longitudes to those of the east. However, in addition to the change in longitudes, the international date line will also disrupt the onboard clock, as Sylvain Mondon explains in this email sent to the crew of Gitana 13: “The 5th April will be a very short day for you. Indeed, if you take into account the local time, when you cross 180° you’ll lose a day in relation to the local calendar. As a result the end of day will be that of 4th April amongst the Hawaiians, but already that of 5th April amongst the Fijians. Those of you who have already crossed the line in the other direction have experienced the same date twice so it’s good to reset the clock from time to time…” concluded the router from Météo France somewhat humorously.

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