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.

23.01.2024

Slaloming across the Indian.

par Gitana

The sixteenth day at sea for the solo sailors competing in the Arkea Ultim Challenge Brest began early afternoon this Tuesday. For Charles Caudrelier, the firm leader of this round the world, the atmosphere is studious on the deck of the Maxi Edmond de Rothschild. Now navigating the stormy tail of a depression, the sailor is having to contend with 20-25-knot WSWly wind and 3-4-metre waves as he links together a series of gybes just shy of the Antarctic Exclusion Zone. In the wake of the five-arrow giant, another solo sailor has entered the Indian Ocean. Indeed, since midday Armel Le Cléac’h has joined the club of 3 with Thomas Coville and Charles Caudrelier. Despite damage to his port foil, Anthony Marchand is set to join them very soon. The progress of the skipper of Actual Ultim 3 has slowed and one can imagine that his maxi-trimaran is no longer able to exploit her true potential, but no pit stop is envisaged at this stage.

Betwixt the AEZ and the high pressure

AEZ is the acronym for the Antarctic Exclusion Zone. This virtual line has been put in place by Race Management in the Arkea Ultim Challenge – Brest for safety reasons and to prevent the competitors from venturing too far south into the ice zone. It is a barrier where heavy penalties will be incurred if crossed. The AEZ is a major part of the race strategy then, since its boundary is currently forcing Charles Caudrelier to slalom his way across the Indian Ocean. “48 hours ago, the depression we were managing to stay ahead of in the South Atlantic, passed to the south of us. It made good its escape and we weren’t able to follow it due to the AEZ. That’s the name of the game. For the past two days, we’ve switched to a different wind system – from a N’ly breeze ahead of a front to a WSW’ly breeze with more difficult seas – and our trajectory has curved round under an anticyclone to our north. That is forcing Charles to put in quite a few manoeuvres, but within the next thirty hours or so, it will change again with the arrival of another depression. The NW’ly breeze associated with that will carry us along with it for a bit, giving us a nice ride eastwards to the next passage point of Cape Leeuwin,”explains Julien Villion, one of the Maxi Edmond de Rothschild’s three weather routers.

Charles Caudrelier, on 23 January

“We’re in the Indian good and proper now! The sea is unpleasant without too much breeze. We’re dead downwind, so we’re having to slalom along the edge of the Antarctic Exclusion Zone with a series of gybes! I don’t have a huge amount of breeze – between 20 and 25 knots – but there is still more than forecast on the grib files. As a result, I’m always on the limit of two sails, between 1 reef or no reef, so it’s busy on deck. It’s been that way for 24 hours. It’s not so nice… It’s a rocky ride. I still have 36 hours where conditions are a bit heavy-going and then things should get better.

It’s a studious atmosphere aboard. I’m trying to rest between what are pretty tiring manoeuvres and get the boat making headway without her suffering too much. That’s the major challenge of leading as you try to maintain a good speed to stay in the same weather system, but without going too fast either, so I’m constantly trying to balance out the brake and the accelerator: that’s what my days involve… I’m also taking a lot of care with the Maxi Edmond de Rothschild. Giving her an overhaul, checking 2 or 3 things when I get the chance. The shore team sent me a detailed list after the passage of Good Hope and each day I set myself a little mission to go and check a part of the boat. All’s well for now, which is pretty good. We’ve found some minor issues, that I’ve repaired, small details like tightening certain elements, but nothing serious so far.”

Ranking at the 18:00 UTC position report

1) Maxi Edmond de Rothschild – Charles Caudrelier

2) Sodebo Ultim 3 – Thomas Coville – 1,500.9 behind the leader

3) Maxi Banque Populaire XI – Armel Le Cleac’h – miles 2,632.3 behind the leader

4) Actual Ultim 3 – Anthony Marchand – 2,857.8 miles behind the leader

5) SVR Lazartigue – Tom Laperche – 3,149.1 miles behind the leader (victim of serious damage, on a pit stop in Cape Town)

6) Ultim Adagio – Eric Peron – 4,437 miles behind the leader

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