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.

12.02.2008

Proper use of the bunk.

par Gitana

Wind! More than expected, and that’s fine with us. It built up gradually throughout the day yesterday, reaching 35 knots by the end of the day. As I type these lines this Tuesday morning (8:00 UT), the wind from the east/southeast continues to drive us with only the genoa staysail and one reef in the main. This acceleration is due to a local effect, very similar to the one occurring near Cape Finisterre, except that here it’s due to a point of land on the Chilean coast south of the city of Tome. In the morning, the wind should again weaken, which means the big gennaker will go back up. We’ll continue on our way toward the equator, jibing as necessary to stay in the strongest part of the wind generated along the edge of the Easter Island high-pressure system. That’s our plan for the next few days. With 392 miles covered (although only 350 miles closer to our destination), the past 24 hours were, according to our weather team (Lemonchois/Vittet/Mondon), pretty indicative of the days to come. We expect to cross the equator next Monday, 19 February.

Now that we’re able to sail on a reach again, we can sleep “feet forward.” Let me explain. If you’re ever lucky enough to sleep onboard a multihull like our maxi-catamaran, be aware that you need to sleep in the right direction. When the bows crash brutally into the waves, this produces a powerful forward force on your body. It’s a good idea for your feet and legs to absorb this shock rather than your head, for reasons that don’t need explaining. There is one exception however. When sailing close-hauled in rough seas, it’s not always obvious which direction is best to sleep in. The hull, especially the leeward one, is constantly subject to powerful forward/backward movements as the boat goes over the waves. So you’re propelled forward and then immediately backward, in a perpetual tug-of-war…it would be interesting to know how many G’s of gravity are at play! The force of the boat surging forward is stronger, so it’s a better idea to sleep “head forward.”

To complete this primer on bunk usage, I would add that to get some sleep, you have to relax and become part of your bunk, and ignore the forward/backward movements as well as the up-and-down ones—which are just as frequent and brutal. In the well-being section of magazines, they call this “letting go.” On deck, this is not an option, but in our bunks, we are masters of “letting go.”

Goodbye

Nicolas Raynaud

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