Behind the scenes of the design of Gitana 18

During the technical conferences at the Défi Azimut 2026, Sébastien Sainson, head of the Gitana team’s design office, looked back at the design of Gitana 18. The decision to start from scratch, the collaboration between the defending champions of the Route du Rhum – Destination Guadeloupe and the architectural firm Guillaume Verdier – take a look behind the scenes of this new adventure.

A blank page with constraints

After eight years of loyal service covering more than 200,000 nautical miles, crowned with a list of achievements as long as its floats, Gitana 17 – the first maxi-trimaran designed to sail round the world – officially passed the baton in 2025, becoming Actual Ultim 4.

Within Charles Caudrelier’s team, plans for its successor had been in the pipeline since 2023. Writer’s block? Not a thing in the Gitana team when it came to planning the development of Gitana 18, launched in February 2026. “As Gitana 17’s years in service progressed and with the volume of data accumulated, the team felt it was better to start from scratch rather than develop the existing boat,” explains Sébastien Sainson, design director at Gitana France.

Subject to the Ultim class rules and World Sailing’s OSR regulations, “anything is possible; everything is open for six months, whilst ensuring that everyone in their working group can explore ideas as far as possible whilst remaining within this framework. At a certain stage in the preliminary design phase, the question arises as to whether the concepts developed by the design office and Guillaume Verdier’s firm are consistent. We pool our ideas and run simulations to assess the potential benefits of each option.”

Alignment and complementarity between Team Gitana and Guillaume Verdier

The partnership between Team Gitana and Guillaume Verdier’s office is a long-standing one, underpinned by a spirit of openness and a desire to push the boundaries of innovation. “If we hold ourselves back from the outset, we may inevitably fail to explore such diverse avenues.” .Gitana 18 has also benefited from a certain synergy between the two organisations: “Both teams draw inspiration from what they see in the wider world. At Gitana, we tend to focus on a single project and are probably more specialised in what we do and in certain areas. At Guillaume Verdier’s firm, they work on multiple projects and therefore bring a different set of expertise to the table.”

In the end, an analogy with the handling of a small catamaran or a windsurfing board was chosen. “The chosen innovation: the addition of spreaders to pre-tension the mast (35 metres high, with a carbon cross-section of approximately 1 m²) with less effort than the Cunningham system alone, allowing for rapid and active control of the mast’s camber in a matter of seconds, whilst remaining manageable when sailing solo.”

A three-line sketch for the double-bladed rudders

As regards the rudders, Gitana’s aim was to get the boat to plane a little higher. “On the previous boat, the rudders often came out of the water. There were a few instances of the boat veering off course at high speed, above 40 knots.”

Guillaume Verdier’s experience in the America’s Cup proved invaluable. In practical terms, the concept began with a simple sketch: “It started with three lines on a scrap of paper. We sent Guillaume a long way down this path, accompanied by two of our own people.”

Sébastien Sainson’s team found themselves faced with a tooling challenge and had to design the design tools before drawing up such parts.

Another major challenge was a structural issue. “The idea behind this rudder is that when it deforms laterally, rather than the rudder deforming and the lifting surface tilting, the whole structure deforms a bit like a parallelogram: the lifting surface remains horizontal, and it also deforms much less.”

The ‘design loops’ theory

Faced with the major challenge of designing a worthy successor to Gitana 17, Sébastien Sainson and his team drew on ‘design loops’. The central idea is that, for every component or vessel, one must start with ideas and ‘go round in circles until arriving at the final product’. This involves accepting the risk that the specifications agreed with the shipyards may arrive late, or that one might hit a snag because a component does not exist or will arrive too late in relation to the deadlines set.

This risk of ‘tripping over one’s own feet’ enables a genuine level of creativity and boldness to be achieved: a team that fixed its constraints too early would automatically limit the range of solutions explored.

The Gitana Team’s advantage in staying on course with these iterations lies in the small size of its design office. “With around twenty people in total, compared to around a hundred for an America’s Cup programme, the Gitana team can move back and forth between working groups without coordination becoming a hindrance.”

Manufacturing challenges

These deliberate risks gave rise to manufacturing challenges.

Take the foils, for example. Designed to tilt inside the float with the arm at the front – a technological breakthrough – they required the simulation and structural analysis tools to be completely reworked (the existing simulator was not designed for this type of component).

Greater coordination between the various trades was required, as the integration of numerous systems (hydraulics, electronics, sensors, metal) within the appendages further increased the complexity.

There were some delays: the design phase took longer than anticipated, and manufacturing faults were found in the ‘wings’ (5–6-metre composite parts), meaning that certain parts had to be remade.

The construction of certain components (e.g. titanium or carbon fibre blocks requiring up to 10 months’ lead time) sometimes had to begin before the design phase was complete, illustrating the risks taken by the team.

The team’s design office rose to all these challenges with flying colours. Now, all that remains is to see Gitana 18 take to the stage on the world’s greatest theatre: the Atlantic Ocean.