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.

13.02.2008

Route selection.

This afternoon, Lionel Lemonchois and his nine-man crew will celebrate the end of their fourth week at sea. They left New York on Wednesday 16 January. As of this morning, the team still has 4,688 miles to go out of the 14,000-mile total distance.

par Gitana

The pace has picked up onboard Gitana 13, as can be seen in the 400 nm sailed in the past 24 hours. However, with boat speeds again exceeding 20 knots, the 10 sailors on the 33-meter catamaran are being kept busy. The watches execute the necessary maneuvers on deck in order to take the fastest route to the northern hemisphere. To stay in a fresh southeasterly wind of around 15 knots, the maxi-catamaran fitted out by Baron Benjamin de Rothschild will have to carry out a series of jibes as it works its way to the equator. These changes in tack have already begun: “We jibed a few times yesterday in order to stay in the flow of stronger trade winds. Our trajectory isn’t exactly rectilinear, but we’ve been able to sail in a stronger breeze while keeping the wind at a favorable angle. The full main is up, along with the genoa staysail and the big gennaker: this sail configuration shouldn’t change for a while,” said Dominic Vittet.

Gitana 13’s strategy trio is already planning ahead. The boat is sailing this morning at 28°50 S, but the trio is already thinking about the equator crossing and the second Intertropical Convergence Zone that they will encounter along their record attempt between New York and San Francisco. “Lionel, Sylvain and I are thinking out the best route to take to the northern hemisphere. This decision will determine the point at which we cross the Doldrums. It will also set the stage for the last part of our trip to San Francisco,” said the onboard navigator.

Lemonchois and his crew have two options. They can decide to push farther northwest in order to cross the narrowest part of the Intertropical Convergence Zone. In this case, on the other side of the Zone they will have to deal with headwinds—not ideal for the maxi-catamaran. The second alternative is a route farther east. Negotiating the Doldrums will take longer and be more difficult, but the team won’t have to sail close-hauled for very long before reaching the city of the Golden Gate Bridge.

Gitana 13’s skipper will have to decide between these two options very soon…

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