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.

18.11.2009

All tucked up for winter!.

par Gitana

The first series of tests on Gitana 11, which began in mid September, were completed yesterday when the ocean-going maxi-trimaran was lifted out onto the hard. Key to fine tuning the new craft fitted out by Baron Benjamin de Rothschild with a view to her participation in the next Route du Rhum, these past few weeks sailing offshore of La Trinité-sur-Mer in SW Brittany have been highly instructive. Indeed this session on the water has proven particularly useful to Gitana Team’s shore crew, who now know exactly which improvements are required during the 77 foot multihull’s winter refit.

At this time of year, the tip of Brittany is regularly swept by the passage of lows. As such, for Yann Guichard and his team, the focus has been on finding the right weather window to lift Gitana 11 out of the water. Yesterday, Tuesday, coloured by a light, W’ly breeze and predominantly blue skies, was the perfect opportunity. In this way, in the space of three hours, the maxi-trimaran was able to be lifted out and placed inside the shed, which had played host to her revamping less than three months ago.

For the experts within Gitana Team, the jobs’ list has been drafted and part of the next three months will be devoted to this. On the programme are a fair bit of big structural upheaval as well as some slight adjustments necessary for optimum performance. Yann Guichard, the skipper of the maxi-multihulll, explains what the winter refit will entail:

– Modification of the appendages:“One of the big projects during this refit will consist of moving the foil cases forward in order to improve the overall balance of the platform. In the same way, some new float rudders will be manufactured as we’re hoping to increase their surface and hence improve the way the boat can be controlled at the helm. Finally, a retractable propeller shaft will be installed to reduce the hydrodynamic drag.”

– Improvement of the sail plan:“For the launch last September, we didn’t order any new sails. However, this winter, Jean-Baptiste Levaillant – from the Incidences sail loft in La Rochelle – will be working on an updated sail wardrobe, with the aim of optimising the shapes and surfaces of this new set of sails.”

– Research into the onboard systems, with the focus on the automatic pilots and the means at their disposal for shooting video: “Benoît Piquemal and Pierre Bourcier are working together on the boat’s nerve centre, which is based around the automatic pilots. The reasoning behind this is that without a pilot, you can’t sail single-handed, especially on a multihull. The research is going to centre as much on the performance modes as those associated with safety. Finally, the shore crew will take advantage of the winter refit to improve the means available for filming aboard Gitana 11. Such products are constantly evolving in this domain and you have to stay on the ball as regards technological progress, ensuring that the most developed and practical products on the market are aboard.”

Gitana 13 home and almost dry

The stable’s maxi-catamaran made it back to her home port of La Trinité-sur-Mer midway through last week. After two months of sailing around the Mediterranean, most of which was devoted to playing host to colleagues and clients, the men of Gitana 13 have returned to base camp. Like Gitana 11, the giant of the seas will soon be lifted out of the water for a classic winter service.

Of note is the fact that her campaign in the Mediterranean has enabled the crew of Gitana 13 to set a new reference time between Gibraltar and Tel Aviv, just one of the stopovers during her recent voyage: 7 days 42 minutes 57 seconds.

Retourner aux articles

Heritage