[RESEARCH] Fatigue in composite materials

Every two years sees the hosting of the Journées Nationales sur les Composites (National Days on Composites), which is the perfect venue for meeting researchers, engineers and manufacturers, who come along to exchange ideas about the latest scientific and technological advances. GSea Design was inevitably in attendance this year…

It was Adrien Launay, in the 2nd year of his doctorate, who is doing his thesis at the Lorient-based company, in partnership with the UBS and the IRDL in Lorient, who made the journey to Bordeaux from 1 to 3 July. His work is focusing on the influence of defects on compression resistance within the scope of the dimensional analysis of the lifespan of high-performance composite structures such as racing yachts.
The problem with the resistance of composite materials and their ability to withstand the test of time, lies at the heart of GSea Design’s business, which involves the dimensional analysis of race boats. Material fatigue can potentially lead to a loss of resistance, which means that parts can break at a lower load threshold compared with their initial capacity. However, to what extent can the presence of flaws in the materials have an impact on the strength of the composite over time?


“These are specialised subjects to which we don’t yet have all the answers. Here we’re referring to high-quality materials. At the JNC, I met researchers and engineers who are working on this subject with whom I was able to exchange ideas. The majority of them work in aeronautics and the space industry, in sectors which are a lot more heavily funded than in boating. They’ve fine-tuned some methods for analysing the materials they’re interested in, which we should take inspiration from within the context of high-performance material analysis.”
In addition to his doctorate thesis, Adrien sees an opportunity for GSea Design within his research. “The idea is to quickly fine-tune the digital tooling enabling us to estimate the lifespans of the parts we’re designing within the context of dimensional analysis.”

[The Journées Nationales sur les Composites (JNC) are held every two years. They were hosted in Bordeaux from 1 to 3 July 2019 and constitute a special venue for pooling the knowledge of scientific and manufacturing communities.]

Le Bourget - GSea Design explores new horizons

GSea Design is attending the Salon du Bourget (Bourget Air Show) this week. It’s a first for the Lorient-based company, which sees it as a great opportunity to develop its business in the domain of aeronautics.

GSea Design has already had the opportunity to put its expertise to good use in several aerial projects, most notably in a mission for Airbus and for the landing gear structure on Nijal, a prototype plane made from composite materials.

“We’re not novices in this field. Indeed, there are parallels between aeronautics and race boats, particularly so since they have been using foils. Aeronautics may enable some interesting technology transfer and we might be able to work with the R&D departments of some large companies from this sector”, explains Benjamin Madec, Business Engineer. “We’re among the first to have worked on fixed wings for boats and on foils, which enable them to fly. We’ve had a lot fewer constraints in terms of certification on race boats than on planes, though things are tending to get a bit tighter today. This has enabled us to have complete freedom to explore, to carry out a huge number of tests and to make very quick progress”.

Expertise and responsiveness

Today, GSea Design’s expertise and responsiveness are two key assets capable of attracting the R&D departments of some of the flagships of aeronautics: “When you fine-tune a boat, between the point where you make the decision to do it and the launch, there’s a very short amount of time; it’s much tighter a timeframe than in aeronautics. As such, we know how to respond to problems quickly and that’s an important factor in terms of the research and innovation in aeronautics. We’ve developed some fast, high-performance tools to ensure we respond quickly. This tooling, which has been fine-tuned for the structural calculations on foils for example, can be rapidly adapted to the calculations on wings.”
Benjamin Madec is heading to Le Bourget to explore a whole new world then, which might well become a great showcase for GSea Design. The Lorient-based company is in a position to work with aviation companies directly or as a subcontractor for the yards.

[The Salon du Bourget runs through to Sunday 23 June. GSea Design is exhibiting there with four other companies from the Eurolage network, which has been invited to attend by the Breton Region.]

[SAILING] Extreme load cases: cruising expertise

GSea Design is developing its expertise in the cruising sector. A logical transfer of skills from racing boats to pleasure craft? Not really. Though the two categories share similarities in images, the comparison ends once it comes down to structural calculations. Maeg, an engineer, spent eight years working for a pleasure craft certification body, before bringing her expertise into play at the service of GSea Design.

On the water, two parallel worlds combine but the links between offshore race boats and cruisers tend to be in short supply. The former, largely prototypes, make wide use of carbon and are starting to fly, whilst constantly striving for improved performance, even if it means totally sacrificing comfort. The latter, production boats, are built of glass sandwich and now favour all that offshore racing delivers on: extreme stability, ‘better than home’ equipment and increasingly wide openings in all the bulkheads to offer a greater sense of space and visibility.
“We’re working on all types of cruising platforms, monohulls and most notably catamarans. The specifications favour ergonomics and the structure is designed to be adapted. They’re evolving towards more openings with portholes everywhere and glazed windows. These boats are kitted out with fully equipped kitchens and bathrooms and the load cases studied are extreme. We’re essentially working on the “distortion”, which is significant on multihulls. When the hulls work, the glazed windows should continue to close properly! The stiffness of the structure is vital.

GSea Design complies with all the regulations published by certification bodies like ICNN or Bureau Véritas, with which the engineers from Lorient regularly collaborate to refine these texts.

At the same time as the ‘classic’ monohulls and multihulls, a new category of so-called ‘cruising’ boats has been created. GSea Design has notably got involved in the studies into fast foiling boats like the “Foiler” built by the ENATA yard, as well as the famous Seabubbles!


Every year, the Yacht Racing Forum is the place to be to decipher the future of offshore racing, both in terms of economic and technological development. On this last point, GSea Design is a key interlocutor and two of its engineers have been invited to express themselves. For the first time, GSea Design plays at home, in the Sailing Valley ... Lorient.

 “Appendages and foils in particular are no longer the future of offshore racing. They are the present.” Maël, the first to take the floor, sets the scene. “The future will be about making gains in terms of performance and hence understanding. It’ll be important to develop and analyse embedded data and then we’ll be able to design boats able to remain stable on their own

GSea Design is already working on data collected via sensors that cover the whole foil. The Recala software, which has been developed by the team in Lorient, is capable of making a three-dimensional analysis of the foil’s distortion and measuring the stress it has undergone in terms of load. Soon, this data could be accessible as a live stream by the crews themselves, whilst sailing.

Maël will also speak about Sofia, the software developed by GSea Design to optimise the appendages. “This software is linked to an important research on foils and the aim is to optimize the appendage in order to obtain the final sought-after distortion.”

 Higher, faster…

Joseph will be speaking about a more general-interest topic which, despite well knowned in the Sailing Valley, is a lot less common on the international scene: the development of the Ultims Class. How far will they go? “In geographical terms, these multihulls are already going very far as they are circumnavigating the globe. We don’t know their limits yet in sailing terms. Today, our focus is on safety. Safer boats are a prerequisite for any new gains in performance. Servo control enabling better management of the foil will lead to boats going higher, faster”, Joseph assures us.

[The Yacht Racing Forum, which will be held in Lorient for the first time (following Denmark, Malta and Geneva), is a major gathering for competitive sailing protagonists. As such, each year discussions are split into two main areas debated by the world’s top specialists: business and marketing on the one hand; design and technology on the other.
At the Palais des Congrès and the Cité de la Voile, in Lorient, on 22 and 23 October.]

[Data] The challenges of digital transformation: KIRIKO, the Quick Rig Computation

This year, between digital transformation and GDPR, technology forms an integral part of GSea Design’s daily life. Digital tools, historically designed for the company’s core activity, are becoming a central factor in communication with our clients. Following a few months of development, KIRIKO is the first tool we’re unveiling today.

KIRIKO, which stands for QUIck RIg COmputation, is a proportioning tool, which enables us to respond as promptly as possible to your requests for a mast weight estimate.

This application is available online here >>

Upon acceptance of your registration request, you’ll have access to the following interface:

This web page, will enable you to select the features of your request: mast type (spreader, wing, diamond…), boat type, construction details and the various data necessary for processing the request.

The data at your disposal will be as follows:

  • Estimated mass of the tube with reinforcement
  • Cable features (Class EA and load)
  • Conceivable mould geometry