Built to fly: How the radical Gitana 18 racing trimaran was engineered to fly across the ocean

With radically redesigned foils, adjustable spreaders and an AI-assisted development process, Gitana Team has taken everything it learned from Gitana 17 to create a faster, more stable flying machine. Sam Fortescue explores the technology behind the 32-metre Maxi Edmond de Rothschild...

High stakes and even higher risks have long made offshore racing the battleground for some of sailing’s greatest names. Gritty, dogged skippers endure months alone at sea in boats operating right on the margins of their capabilities. Into this heady mix of extraordinary stamina and high technology comes Gitana Team with its latest thoroughbred racing trimaran: Gitana 18.

Measuring 32 metres from razor-sharp bows to transoms and a staggering 23 metres across the beam, the new Maxi Edmond de Rothschild undoubtedly has presence. As one of the most impressive feats of marine engineering out there, the trimaran is designed to sail well clear of the water at speeds of up to 50 knots, crossing oceans in mere days, all with just skipper Charles Caudrelier at the helm.

Gitana Team is bankrolled by the French branch of the Rothschild family, spearheaded by Baroness Ariane de Rothschild. Speaking at the launch event in December, she said that she could have stopped with Gitana 17 as proof of the foiling concept, having won nearly every major offshore race on the planet, “but, discussing with the team at length, it was exciting to see all the knowledge, data and testing that we had done over the past eight years. We saw how we could really convert it all into another boat.”

The scale is hard to fathom. At the trimaran’s  big reveal inside Gitana Team headquarters in Lorient, France, the fabric walls and ceiling of a large temporary briefing room were dramatically pulled back to the sound of several hundred jaws falling open in unison. We discovered that we had all been unwittingly seated beneath the span of a single, gleaming outrigger arm.

This ability to surprise should not be taken for granted. In the highly competitive world of offshore racing, teams keep a close eye on their peers. Gitana Team is one of the biggest and best-funded outfits, so there has naturally been heightened scrutiny over the three years it’s taken to develop the yacht. And yet, the secrets of the boat’s design remained totally unknown beyond a narrow group of contractors and designers.

That is more than mere luck, as the “top secret – restricted access” signs on the doors around the giant hangar attest. The same thinking is in evidence with the construction blog, drily entitled “NDA”. “This time, the idea was to push it again to another level and try to keep it three, four, maybe even five years in front of technology,” says design director Sébastien Sainson. “Even now we’ve unveiled the foils  and the rudders, there’s still years of thinking behind those parts.”

First and foremost, the team has fully redesigned the main foils that support each outrigger hull. Where previous designs used C-shaped foils that slid up and down like a centreboard, Gitana 18 has massive Y-shaped foils that pivot under the influence of five custom hydraulic rams from Harken. 

Their position can be minutely controlled, swinging as far outboard as the Ultim class rules allow for maximum righting moment. They also carry flaps on the trailing edge of their horizontal planes, which can be independently trimmed to balance lift to windward and lift upwards.

The aim is to get the boat flying on its foils at sustained speeds above 19 knots and avoid the fitful flying and falling of previous generations. Overall, she is expected to perform 10 to 15 per cent better than her groundbreaking forebear, Gitana 17. 

“Thanks to the flaps, we can take off much earlier,” says naval architect Guillaume Verdier, who led the naval architecture and technical design of the yacht. “We have invested a lot of mass, including in the hydraulics, to allow us to go faster. Our gamble is that the extra weight will pay off.”

The boat also has two other types of foil up  its sleeve. The first is the “skate’s wing” foil positioned close to the mast under the main hull. It’s a heavy appendage machined out of a single block of titanium, yet it earns its keep by providing more stable lift because the rigidity  of the metal resists torsion and bending better than carbon fibre.

What’s more, exhaustive modelling identified that the risks of cavitation (when water flows over a foil so fast that it vaporises on the low-pressure side of the foil causing catastrophic loss of lift and control, known as “crashing” or “nosing off”) could be reduced by offsetting the vertical and horizontal sections as far as possible. In this way, Gitana Team has managed to largely mitigate cavitation by pushing the speed at which it occurs from 42 knots to above 50 knots.

The second type of foil is the three U-shaped rudders on the transom. These still provide the third and fourth points of lift necessary to keep the boat stable at high speeds, but with their two distinctive vertical elements they are a departure from what has gone before. The theory is that the U-shape will provide more rigidity than all but the beefiest of T-sections could manage – for less weight.

The two rudders on the outriggers can also be retracted along a four-metre track. This vertical range should keep them performing even in large three-metre-plus swells. Such is the sensitivity of the boat at speed that these rudders no longer need to rotate; small hydraulic flaps on the trailing edge provide all the necessary deflection.

Above the waterline, there has been just as much blue-sky thinking from Verdier and Gitana’s in-house design team. The high-aspect square-top mainsail is trimmed using a technique scaled up from dinghies, but which remains untested at this level. Instead of trimming the mainsheet and traveller to shape the main, hydraulic spreaders can be pumped back or forth to adjust mast bend. 

The traditional rope controls can require 18 to 19 tonnes of tension upwind, consuming a lot of time and energy to trim. By contrast, the spreaders exert just one to two tonnes of force, allowing for 15 to 20 times faster trimming.

“It’s super quick,” says Sainson. “So, for Caudrelier, a few turns on the pedestal and the pump and he’s going to be able to pass from a fully flat sail to fully deep in less than 10 seconds.”

Instead of struggling with a costly reef or avoiding the reef altogether by setting less sail, the crew can now trim whenever they run into a gust by using the spreaders. “Now, you just stay with your full main, because you know  that the weather front is not too windy,” he adds. “When you get [to the gust], you make the sail flat, and when it’s finished, you open it  up again. On the course, it gives an advantage  of 30 or 40 miles.”

If Gitana 17 was the first offshore racer designed to foil, her successor is fully optimised for flight; no concessions have been made to low-wind displacement sailing. You can see this from the arms that brace the three hulls where taut fabric extends the structure aft in a lightweight aerofoil not unlike the wings of early aeroplanes. This alone creates a lift surface of 73 square metres.

The design has also removed drag. The central hull has a flat bottom to take off at lower speeds, and the mainsheet traveller has been “hidden” behind the aft beam. In another first, the bold yellow doghouse where the crew will spend most of their time has been made integral to the structure of the yacht. Almost nothing protrudes from the deck to induce drag.

It is a lot to take in during a single evening. The development arc covers at least three years, with the millimetre-precision build in high-modulus carbon fibre at CDK Technologies, a few kilometres west of Lorient, taking just a year. De Rothschild confirms the Gitana 18 is in line with the previous model’s reported €15 million (£12.8m) build budget, but he waves away the notion that this was a money-no-object project.

“I have a deep conviction from experience that when you work under pressure, you work best,” says de Rothschild. “It is important to set budget caps that are reasonable, because I don’t believe in an unbridled creative force. The stress of racing, the stress between engineers is, in the widest sense, a positive thing. The no-limits approach? It very quickly doesn’t work.”

With a six-strong in-house design team, Gitana Team has also invested heavily in the planning phase of the project, enabling designers and technicians to test every idea before the boat was cast in carbon fibre and resin, titanium and stainless steel. They drew on the billions of data points gathered from Gitana 17 as she sailed in every imaginable condition, creating a sandbox environment in which to simulate the new boat.

America’s Cup campaigns have also used this approach, though they only apply to the very stable conditions of the windward-leeward race course. “The first thing we had to do was design a realistic sea state and then see if the behaviour of the boat was accurate to what we know offshore,” says Caudrelier.

Once they were satisfied with the simulator, the team harnessed the speed of AI to write snippets of computer code that represented each small design variation. In this virtual ocean, they could test 50 different foil shapes for the rudders instead of just one or two. 

“Then we follow exactly what we do when testing offshore,” he continues. “We do a phase of sailing and analyse all the numbers: what is the average trim, the balance, the difference between the maximum and the minimum. We don’t have the feeling of the boat, but we can understand if it’s stable or not.”

It meant that when Gitana 18 finally hit the water early this spring, Caudrelier didn’t need to waste time familiarising himself with the boat. Following hundreds of hours on the simulator using the same wheel to helm and hydraulic controls, he may have found the living space to be his biggest unknown. 

The navigation area has been slashed by one-third to a mere nine square metres, while the living quarters, comprising a simple cot, a single-burner stove and a toilet, is also down to a space little more than two metres by two metres.

When we touch on the idea of legacy, it is as if he knows that he’s preparing the ground for his successor. “I think it would be very difficult to do better than Gitana 17 as I am stopping my career as a single-hander within the next four years,” he says. “But, I have the opportunity to win the Route du Rhum for a second time, which will be tough, because it’s very soon [this November].” He also has his sights set on a fourth race around the globe. And as for the Jules Verne Trophy in three years’ time? “We will be ready.”

Time – and sea trials – will tell, but it certainly looks as though the “five arrows” racing stable has produced another champion stallion. If the technology proves robust enough, it will be down to Caudrelier to ride to glory.

First published in the September 2026 issue of BOAT International's Life Under Sail. Get this magazine sent straight to your door, or subscribe and never miss an issue.