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.

10.08.2002

Reinforce crossbeam butts….

The engineers have announced their verdict. The new generation all-carbon curved foils (surface skates on the floats) exert greater loads on the trimaran's structure than the hypotheses applied during the design process. So the butts of the crossbeams have to be reinforced, a long-winded job requiring painstaking attention to detail and lots of dif…

par Gitana

The engineers have announced their verdict. The new generation all-carbon curved foils (surface skates on the floats) exert greater loads on the trimaran’s structure than the hypotheses applied during the design process. So the butts of the crossbeams have to be reinforced, a long-winded job requiring painstaking attention to detail and lots of different stages.

A brief summary. These foils (surface skates) are absolutely essential in order to attain higher levels of speed. Gitana X’s designers spent vast amounts of time poring over the mobile appendages, allowing for large safety factors. But a prototype remains a prototype and once out on the water, it was discovered that the foils solicit the structure much more than the highest figures upon which the hypotheses were based. Gitana Team’s engineers put their computers back to work once again and have come up with new curves for the loads generated by these convex foils.

After the whole boat had been checked over by engineers specialising in the resistance of materials, only the crossbeam butts (point where the beams are fixed onto the floats) have been identified as needing reinforcement.

Painstaking attention to detail

Getting at the inside of the butt (shaped like the arc of a circle), is a fiddly job requiring precision. Once accessed, then the damage sustained to the carbon on the forward starboard beam (right-hand side) can be repaired, and the 4 butts reinforced.

Multiplast’s prototype team will add layers of carbon on the four inner and outer faces of the butts, using the wet lay-up technique, which involves using a brush and/or roller to impregnate the carbon cloth with resin. Next stage is to vacuum-bag the whole so that the cloth adheres correctly to the structure, before a final step, post-curing at 60° C so that the resin attains maximum resistance.
Reinforcement work is currently underway and Gitana X should be back on the water at the end of August.

A studious summer

The Gitana Team is close-knit and everyone has stayed close to the roost this summer making the most of this set-back to enhance the boat’s preparation.
Some of the team members have managed to get some successful racing in over the summer: Nicolas Berthoud won the European 6M IC Championship in Helsinki (Finland). On the same course in the 8M IC Worlds a few weeks earlier, Nicolas Engel finished 6th and Philippe Durr 10th overall and 1st of the old boats. Marc Guessard won the Tour de France à la Voile, Olivier Staub finished 16th out of 50 in the Muscadet Nationals and Jean-Baptiste Epron is back on the maxi catamaran Orange for the Round Britain record attempt.

As for Benjamin de Rothschild, chairman of the LCF Rothschild Group , owner and himself a sailor, he has set sail on another voyage of sorts to welcome his fourth daughter into the world.

So Gitana X’s skipper Lionel Lemonchois will be back in gear at the end of August with a highly-motivated team in tip-top condition ready to get down to new training sessions before the Grand Prix de Fécamp and his qualifying sail for the Route du Rhum.

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