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.

01.04.2008

Flat out on a reach.

par Gitana

It is the third night at sea in over 30 knots of wind, the anemometer even witnessing peaks at 35/38 knots. It is the third ink black night where the water is constantly drenching both the deck and the crew. The rewards are good for the speedo though, the latter never seeming to drop below 20/22 knots, despite the big, messy seas and a trajectory as straight as a die, which is saving us miles with each hour that passes. This trajectory was a daring option, others wouldn’t have attempted it. We could have made do with a tradewind glide towards Hawaii, but Captain Lionel, still fabulously supported by Sylvain Mondon of Météo France, chose this course which is a shade lively to say the least. Since the start, we have been making a series of “reaching de la mort” manoeuvres. So what exactly is this?

Every sport, every job has its jargon and in this one we have the word ‘reaching’, from the verb ‘to reach’. It designates a point of sail where the boat can reach its goal by adopting a direct course, without having to put in some tack changes. This point of sail is the fastest point of sail for a yacht, which is logical given that it only covers useful miles towards the goal in this instance. However, it is also highly uncomfortable at times, as is the case for us at the moment. Beam on to the wind, beam on to the waves, we hit the sea at full bore, with all the power the 25 tonne Gitana 13 has to offer; the sea as a result explodes into a thousand shards of luminosity as we power through it. As our maxi-catamaran was considerably overhauled during the stopover and after 43 days spent at sea during the previous record we fully understand the boat’s capability, so we’re willingly driving our steed onwards.

Until tomorrow

Nicolas Raynaud

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