Spoiler: I dont buy it…
The concept looks good to me. It looks cheaper to construct, smaller, lighter, and have less drag above and below the water than a catamaran. They also have some funding, a number of employees, and past innovations: https://syro.co/en/news/e2f-syrocos-innovative-foil-be-deployed-hynova-40-hydrogen-tender/
But now maybe the kite wants to pull the thing out of the water and is a big source of drag? Maybe a fundamental question is, how quickly can a soft kite go through the air?
According to the French website below, a paraglider (soft kite) can fly up to a maximum of 15 m/s; 28 m/s for a hang glider; 42 m/s (150 km/h, as for the targeted speed record on the video) for a rigid wing.
I think the values can be much higher for soft or semi-rigid kites, but a rigid kite will be needed to reach alone more than the targeted value of 150 km/h (42 m/s) for the foil boat.
Good concept for reducing drag and parasitic forces.
For an AWE use perhaps a flexible wing will have a reasonable speed if we want to avoid the cavitation of a hydro turbine placed at the bottom of the foil, and even the cavitation of the foil itself. From the foil boat only the foil is required, its mast and the tether being aligned.
My issues with the design as shown is that pull of the kite is not always constant. Perhaps you can have semi constant for a few seconds, but other times that hull is going to be oscillating like hell. Its going to be a super bumpy ride. And the size of that tail control surface is not enough to stabilize the hull.
Id have more faith in the idea if the hull had its own wings like an aeroplane.
Perhaps with a few more revisions of the design? But why start so difficult, instead of first making, say, a sailboat with an existing hull and a kite, or even a sailboat on three foils and with a kite.
Im not saying it will never set a speed record. I am saying I thing it will not be usable for anything other…
Maybe if the single foil is pitch controlled
But by my guesswork…
They won’t start with a single foil in the water like that.
They’ll want the pitch authority of a 2nd trailing foil to keep the main foil in the water.
I was envisioning this way back in the 1980’s when I was taking my first Autocad course. My first primitive drawing was a boat pulled by a parafoil kite. The question in my mind, for this version of the general kite-sailing concept, was how high should the fuselage be suspended? In other words, would this be more of a watercraft, or an aircraft?
Like an airplane, with a tail featuring an elevator (horizontal stabilizer). “Flying wings” do work, but with swept wings and the pitch-control located near the wingtips, which are to the rear due to the sweep of the wings. I tend to agree that a proper tail is a more reliable method for pitch control. Hang-gliders these days incorporate a reflex bridle that raises the trailing edge to prevent getting stuck in a dive, after too many pilots were lost to unrecoverable dives.