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.

10.07.2012

The top trio stamp the pace.

par Gitana

Like metronomes, the trimarans in the Krys Ocean Race are attacking their third day at sea. Still on the leading edge of the cold front, which has been propelling them towards Europe since the first few hours of racing, the crews of the MOD 70’s don’t appear to have decided to ease off the pace. This is particularly true given that the big seas, picked up by the proximity of the banks of Newfoundland, are now in their wake and that the wind has stabilised to between 20 and 25 knots and is still carrying them downwind. Aboard Edmond de Rothschild Group, Sébastien Josse and his five crew are keeping pace and are still in second position. They conceded a few miles on the leader, Spindrift Racing, last night, but nothing serious since they had a deficit of 42 miles at the 0700 UTC standing this Tuesday morning.

Extracts from the radio link-up between Sébastien Josse and Press HQ this Tuesday 10 July

“The dampness has been omnipresent aboard the boat since the start. We really haven’t had the time to dry out and, given the weather forecast, I don’t think we’re going to be able to do that before Brest.”

“The conditions are still just as testing for the boat and the crew! There is now a top trio and the pressure’s on to keep pace with the others. However, the worst of the bad weather is behind us now or should be soon at least.”

“It’s down to me to find the right pace so that the crew can rest and that we can maintain these high speeds safely. We’re close to the edge on these boats. We’re playing with the limits but you mustn’t go beyond them. Getting rest when we’re tired is doable must it certainly hasn’t been easy to get off to sleep since the start with the crashing halts we have to endure when the bow buries into a wave. However, though we’re not sleeping, we’re still managing to take a break and cast our minds to other things. For the past 24 hours, the freeze-dried foods have come out and we’re managing to get some food down quite normally.”

The day ahead is set to see 20-25 knots of breeze still, with a little more at times and waves of 2.50m, 140° to the wind. This will stay with us virtually all the way to the finish… Our ‘nominal’ speed is thirty knots! After that, we regulate it according to the sea state.”

Message sent from on board in the early hours

“All’s well aboard Edmond de Rothschild Group. Last night the wind eased a tad and the sea flattened out. We had to put in a fair number of manoeuvres to adapt the sail plan to the new conditions. Everyone was on deck for a few hours. The rhythm of the watch systems clicked in again after that, over the course of the night, and the wind is gradually building, which is enabling us to slip along nicely under gennaker with 25 knots of wind. The temperature is dropping gently, which is making things considerably better down below! As such I’m going to make the most of the situation and get 2 hours sleep! See you soon, Antoine.”

Standing on Tuesday 10 July at 0700 UTC

Spindrift Racing – 1,485.8 miles from the finish (44 28.44’ N – 38 52.88’ W)
Edmond de Rothschild Group – 42.7 miles astern of the leader (43 39.92’ N – 39 25.52’ W)
Foncia – 46.2 miles (43 23.85’ N – 39 19.30’ W)
Musandam – Oman Sail 165.6 miles (41 45.99’ N – 41 10.48’ W)
Race for Water – Not polled

Retourner aux articles

Heritage