Will the future of motorboats pass through foils? That's SEAir's bet.

By launching a Zodiac 5.50 equipped with foils to sail over the water, SEAir wants to strike the spirits and show its know-how. Report of the first sea trip with the prototype.

On July 12, 2017, SEAir launched a slightly modified Zodiac 5.50: a semi-rigid boat that integrates foils and sails over the water! This is not the first motorboat sailing like this. Foils have long been used, even on commercial passenger vessels.

By equipping a Zodiac 5.50, SEAir wants to show that it is possible to sustain a motor boat of"Monsieur tout le monde". Back from the first tests, Richard Forest, president of SEAir, explains the objective of this assembly and the first sensations gathered during this sea trip.

Tell us about this semi-rigid foils project

To equip this semi-rigid, we respected a simple specification. The boat must keep all its semi-rigid characteristics. It has to be able to look good, it has to be able to be paired against a dock or a pontoon, and it has to be able to be pulled out of the water on a trailer. We did not want to change the functions of the boat while adding the possibility to fly it.

A foil is installed under the hull. It has the shape of the V and integrates perfectly under the step and the puddings. "This form of foil has been an additional constraint, but it flies! The foil goes up and down into a well in the centre of the hull. Its angle of attack is adjustable.

Motorization is standard. Voluntarily, we chose a market engine (NDLR: a 115 HP Yamaha). We just opted for an ultra long shaft bolted in the classic way to the transom. On this engine, we have added load-bearing plans

How did the first tests go?

The first tests took place at the beginning on a totally flat river. The first flight went off without a hitch. Then we came into the bay of Lorient to sail with a little chop. There, the boat behaved perfectly without even typing. To have a point of comparison, we have a second identical semi-rigid, but without the foils. He began to shake the crew as the prototype flew comfortably. Finally we went out to sea. There was 1 m of swell. In this situation, the two vessels behaved identically. We had to slow down. But it's normal with this sea on a 5.5-meter boat!

We did some measurements during our first outing yesterday, but we have not yet analyzed the results. By sailing with both boats simultaneously, we will be able to compare speeds and consumption with precision. But the first results are very encouraging: less fuel consumption, more engine speed..

In the future?

This Zodiac 5.50 is a prototype, but we are currently working on the industrialized manufacture of foils. For a robot to do the draping in the mold. This will be the next step with new tests at the end of the summer

How do you imagine the first customers?

The first sales will probably be to racing teams who are aware of foils. But sailing schools that sail a lot might also be interested. We think that at the beginning, we will make refits of existing boats, adaptations of our system.

But already major building sites have approached us to integrate this system into their series production. I can't give you a brand, but why not a motor boat specially designed for the foil from 2018?

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