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.

06.02.2008

Back on track!.

par Gitana

Today, at 16:38 UT, we will wrap up our third week of sailing, with Cape Horn still in front of us. Our time has gone from good to so-so. But what’s important today is that the southern tip of the Americas is back on the calendar. At the end of the night tonight—i.e., Thursday bright and early—a secondary cold front is expected to sweep across the area around Lemaire Channel, right where we plan to end our stand-by period. The westerly wind will be blowing at 40-45 knots, but we’re used to it—that’s been the average wind speed over the past three days! As soon as the front has passed, we’ll take off in its wake, in seas that we hope won’t be too high and in a wind that should lose strength over the following hours. We have 110 miles of tacking to look forward to, from the start of the channel to Cabo de Hornos island.

It’s going to be really rough going at first, then the strong wind will quickly weaken—too much in fact—once we’re past Cape Horn. The area will be calm, before a new low-pressure system arrives on the scene. But the wind will come from the south-southeast, finally giving us the opportunity to reach. Then we’ll have another squeeze play coming: when we start our turn northward, we’ll have to move fast to stay ahead of the new low-pressure system. If we tangle with this new system, we’ll be in for another good one, with a further loss of time. Two factors will be decisive: the difference of a few knots of wind, plus the speed of the low-pressure system. If it decides to move faster than forecast, the door to the north will be locked.

For now, until we can put our plan into action, we’ll spend our last day (we hope!) near Tierra del Fuego. This hostile landscape—comprising desert and sandy cliffs—has protected us from the worst of the seas. But it also prevented us from heading toward the Strait of Magellan on Tuesday. Too short, too abrupt, we had to give up. So, sailing along slowly, we again checked Gitana 13 and then got some rest. For the past three days, we have been enjoying six hours straight of sleep, as the stand-by watch hasn’t been necessary. So we’re well rested and ready to pick up where we left off tomorrow…San Francisco here we come!

Goodnight

Nicolas Raynaud

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