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.

11.11.2013

Tradewind gliding.

par Gitana

Having covered 564 miles in 24 hours, at an average speed of 24.4 knots, it’s safe to say that the trimaran fitted out by Baron Benjamin de Rothschild isn’t hanging around. Leaving Madeira abeam of them early yesterday evening, Sébastien Josse and Charles Caudrelier are continuing on their way to Brazil at a fair old lick and were passing offshore of the Canary Islands this morning. Still leading, the Edmond de Rothschild duo boasts a sizeable lead of around 80 miles over its rival, Oman Air Musandam.

“I didn’t have any contact with the boat last night. That’s the first time that’s happened since the start, but it’s a good sign!” Antoine Koch explained this morning. “The speeds and the headings are tallying up with what we’d forecast so all’s well. Sébastien and Charles must make the most of the tradewind conditions to slip along nicely and recharge their batteries a little.”

In a well-established north-easterly tradewind of around 20 to 22 knots, the trimaran Edmond de Rothschild has already switched to oceanic mode and Sébastien and Charles have transformed into top-flight pilots so as to get the very best from their steed. The sailing conditions remain technical but more favourable to their watch system and life aboard in general. Indeed the two Multi70s are pounding along the tradewind expressway, but there are a number of pitfalls to be avoided. This is particularly true among the islands that are dotted along the Transat Jacques Vabre course and need to be taken into consideration and negotiated with the utmost care. “Madeira culminates at an altitude of 2,000 metres and it can generate wind shadows that extend up to 100 miles offshore. With a stable wind like we have right now, the satellite photos show us that there is no breeze at all up to 50 miles downwind of the island. It’s pretty much the same set-up for the Canaries,” Antoine Koch tells us.

For now the duel between Edmond de Rothschild and Oman Air is turning to the advantage of the men from Gitana Team. Since rounding Cape Finisterre, Sébastien Josse and Charles Caudrelier have managed to outpace the Gavignet – Foxall duo and currently boast a lead of nearly 80 miles over the Omani crew. It’s certainly a substantial lead, but as those in the know continue to explain, on multihulls, where speeds are very high, any gains can grow or shrink very quickly. Aside from these handy miles in the bank, Jean-Yves Bernot and Antoine Koch, the onshore routers for the Josse-Caudrelier pairing, were satisfied with the position of their ‘protégés’ this morning: “The separation between them and Oman Air remains virtually unchanged in terms of VMG, but Edmond de Rothschild’s controlling position is more appealing today. Yesterday, Oman was to their west, whilst this morning she’s in their wake. That means that Sébastien and Charles have managed to reduce the lateral separation, whilst holding onto their lead: a rather smooth operation all in all.”

Ranking on Monday 11 November at 0700 GMT:

Edmond de Rothschild (Josse-Caudrelier) 3,768.6 miles from the goal / an average speed of 26.2kts over 2 hours
Oman Air-Musandam (Gavignet-Foxall) 81.9 miles behind the leader / an average speed of 23.7kts over 2 hours

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