Exclusive / Bénéteau reveals the secrets of his flying boat

Bénéteau Foiler

Finally, after 9 months of working in the shadows, Groupe Bénéteau released the first images of its hydrofoil motor boat. This 9.70 m flying boat is a concept boat that will be used during the race starts. The ultimate objective is to validate foil technology for yachting. Patrick Tableau, one of the two project managers, answers questions from Bateaux.com.

What is the origin of projet??

It is a Bénéteau Group project. We have been following the technological evolutions of foils in motor boats for a few years. To hope to see this technology arrive in the yachting industry, we have developed a hydrofoil boat concept that will be used on race starts. The racing yachts are getting faster and faster, they announce an America's Cup with monohulls racing at 40 n?uds?!

The objective is to follow the racing boats (bring VIPs or journalists) in a better comfort. Currently, motorboats are far too unpleasant at high speeds in the chop.

How was projet? set up?

We worked in a closed cell with 3 partners. Sarrazin Design - DEMS Group, a design and conception agency, SEAir for the design and manufacture of flight systems and Noval, for the design and manufacture of electric lifting and locking systems for foils and hydraulic motor chair.

Internally, Olivier Fougère and I are managing this project together. In total, there are about 20 people who, for 9 months, worked in the greatest discretion.

This boat still has a design particulier??

Indeed, the study project is a racing boat. Therefore, the cockpit is at the rear so that passengers can be installed in the front, without visual disturbance while sailing comfortably at between 25 and 30 knots. And for the monitoring of the water body, it is largely elevated.

This is an experimental phase. Like all flying boats, safety is the top priority. We sail in bucket seats, with seat belts, impact-resistant vests and helmets.

Can you tell us about the behaviour of the foils??

The design office decided to put 4 foils, two at the front and two at the back. The in-flight operating range is 15 to 40 knots. To enter the world of yachting, we are trying to eliminate electronic foil adjustments (rake...) and we are working on the versatility and simplicity of the latter. The idea is to make a comfortable and flexible boat to take people safely.

The objective is to be able to sail through the chop. Today, the tests validate a comfortable navigation at high speed under foil up to a sea of 1 m to 1.50 m.

For democratisation and cost reduction, we have worked on the accessibility of pilotage, by simplifying electronic foil settings as much as possible and automating navigation settings.

Is this hull particulière??

This boat is an opportunity to develop new concepts: new hull, new materials and new manufacturing processes. For the occasion, the boat was made of fibreglass infused around a high-density PVC foam core. We have achieved a 30% weight saving compared to standard manufacturing.

Contrary to appearances, it is not a semi-rigid. The foam flange that surrounds the rigid hull is a protection for approaching racing boats.

It is a brand new generation of 2 V hull. It incorporates new parameters such as the position of the foils or the rise and fall of the motors. The first V has a fairly high step up. We played on 2 floors to improve buoyancy and to lower the engines.

What are the constraints of homologation??

There is no provision for foils in terms of approval. Thus we have designed a hull equipped with "accessories" such as foils. Moreover, the boat will sail as well with or without. For the current application for approval, we are targeting category B with 8 or 10 people.

While the boat is flying, why such a strong motorisation??

The objective is to go at 40 knots, with or without foils. 400 horses are needed for the 5 tons of this boat. At an average speed of 25 to 28 knots, we can already see a reduction in consumption of at least 20%.

How do we use these foils??

First of all, this concept to be viable must be simple and easy. At the port, the foils are fully raised above the boat. So no problems of dirt, scale, or risk of breakage. We wanted to play it safe, all the mechanisms are also out of the water.

We have automated as many systems as possible around the foils, such as a locking system when they are ready to be used. To switch to "flight" mode, you don't have to stop, because they can be operated in slow motion.

As far as piloting is concerned, how is it done at passe??

The ascent on foils is done gently. The navigation just becomes much more comfortable. After trying, you don't want to go back to Archimedean mode. Concerning the turns, the foiler behaves like a normal boat, it takes an angle when cornering. Thanks to the 4 foils, you can turn at 25 knots in complete safety. However, no attempt will be made to turn at 40 knots.

Although there are still studies to be conducted, we are already very satisfied with the results obtained. With this conceptboat, we validate the flight up to 40 knots.

At low speed, you sail without the foils and when you want to follow fast boats, you switch to steering mode. Boats that go at 30 knots, we follow them without any problem. Especially since the races we want to follow take place in a bay relatively sheltered from the swell. It is an ideal playground.

And the suite??

After an initial phase of 3 weeks of sea tests and technical validations, the boat was returned to the yard for a general inspection, before optimization and new test phases.

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