Marine

Foiled again: Candela's C7 "flying boat" blows electric range figures out of the water

Foiled again: Candela's C7 "fl...
The hydrofoil system cuts drag by up to 80 percent, helping the C-7 squeeze out three times more range than other electric boats
The hydrofoil system cuts drag by up to 80 percent, helping the C-7 squeeze out three times more range than other electric boats
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The hydrofoil system cuts drag by up to 80 percent, helping the C-7 squeeze out three times more range than other electric boats
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The hydrofoil system cuts drag by up to 80 percent, helping the C-7 squeeze out three times more range than other electric boats
The Candela C-7 hydrofoiling electric boat squeezes impressive range out of a lithium battery pack from a BMW i3
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The Candela C-7 hydrofoiling electric boat squeezes impressive range out of a lithium battery pack from a BMW i3
Hydrofoiling boat pulling a hydrofoiling board rider... there's a flex for ya!
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Hydrofoiling boat pulling a hydrofoiling board rider... there's a flex for ya!
That propulsion unit hangs way down under the surface; hence, it needs to tilt way up in shallow water
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That propulsion unit hangs way down under the surface; hence, it needs to tilt way up in shallow water
The Candela C-7: top view
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The Candela C-7: top view
Top speed is 30 knots
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Top speed is 30 knots
Even at high speed, the C-7's minimal contact with the water leaves only a couple of inches of wake
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Even at high speed, the C-7's minimal contact with the water leaves only a couple of inches of wake
The entire foil system fully retracts automatically
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The entire foil system fully retracts automatically
View gallery - 8 images

Batteries are taking their sweet time to improve, but Sweden's Candela isn't waiting around. This company has built a clever, low-drag hydrofoiling boat that barely touches the water, giving it a super-smooth, efficient ride and three times the range of other electric boats. The C-7 is already in production, having passed Swiss certification tests the company describes as the world's toughest. With its automatically actuating hydrofoils and electric propulsion system, it's a unique and seriously practical configuration that's much more than an eye-popping novelty.

Hydrofoils, of course, are primarily designed for efficiency. As they rise up out of the water, they reduce hydrodynamic drag to a fraction of what the hull normally causes. That's handy on a gasoline-powered boat, but an absolute game-changer for an electric; gasoline carries so much more energy per kilogram than lithium batteries, and boats use so much more energy than cars to drag themselves through the water, that electric boats have been seriously range-restricted as a result.

By incorporating hydrofoils, the Candela C-7 achieves a top speed of 30 knots (35 mph, 56 km/h), and a range of 50 nautical miles (57 miles, 93 km) at 22 knots (25 mph, 41 km/h) on a single charge of its 40-kWh battery. That might not sound like a ton, but Candela says it's about three times the range that other electrics on the market can offer. There are others that go further – the Sarvo 37, for example, can go 100 nautical miles (114 miles, 186 km) for twice the range. But it uses a colossal 350-kWh battery, nearly nine times the size of the C-7's, to get there.

The Candela C-7 hydrofoiling electric boat squeezes impressive range out of a lithium battery pack from a BMW i3
The Candela C-7 hydrofoiling electric boat squeezes impressive range out of a lithium battery pack from a BMW i3

Efficiency is not the only benefit here; the C-7 is virtually silent in operation, and even at speed it leaves a tiny 5-cm (2-in) wake compared to a regular boat; both of these factors will be appreciated by wildlife and other water users alike.

And its ability to rise above the water level makes it a much smoother ride in choppy conditions than a regular boat; the hull won't get a smack from a wave less than 1.1 m (3.6 ft) high, so you can glide along in silent serenity as your buddies in a standard boat get thumped and bumped all over the place. This will be an amazing machine for taking video footage from.

The system is not simple, though. The boat has to fit on a trailer, and also needs to operate in shallow water, so Candela had to make the carbon-composite foil system fully retractable. The front foil is simple enough, pulling back into the body of the boat on electric actuators. The rear foil is more of a challenge; the custom-designed propulsion unit hangs beneath it, and the whole thing is connected back up to the outboard motor – well, what would be the outboard motor if that's where the motor actually sits.

The entire foil system fully retracts automatically
The entire foil system fully retracts automatically

Either way, that big outboard unit has to tilt up a long way to get the prop out of harm's way in the shallows, so the whole thing is mounted on a big hydraulic arm as well as a tilting system.

Hydrofoils are also tricky to fly, and in order to make the C-7 simple to pilot, Candela has had to design its own in-house "flight control" system. Using ultrasonic sensors, gyroscopes, accelerometers and GPS, the C-7's digital flight controller automatically adjusts the angle of the foils 100 times per second to keep things smooth, safe and pointed in the right direction.

It ain't cheap; Candela sells these things for around US$240,000. But the experience will be pretty amazing, it's a very clever way to pull vastly more range out of a battery, and all eyes will certainly be on the C-7 the second it rises up out of the water. Candela is offering test drives now, including in Venice, where Candela says its boats can significantly reduce the wake pollution that is responsible for damage to the city's buildings.

Check out a video below.

Meet the Candela C-7 | The world's first hydrofoiling electric boat

Source: Candela

View gallery - 8 images
14 comments
14 comments
SteveMc
A great leisure boat! I think my first question would be “How much is a new hydrofoil set going to cost me after I hit a semi-submerged log or similar object”. I hope the sensor system also halts the boat if it ‘sees’ a sandbank. I’d love one of these but I’m not sure I would be able to relax for fear of constantly scanning the water for obstacles.
Primecordial
Looks like mostly straight-line boating. What about the fun stuff, such as tight turns?
Nobody
I'm afraid a hydrofoil would be severely limited where I boat. Shallow water, submerged rocks, floating logs, ropes and nets would be a constant hazard. What voltage does this boat operate on? High enough to be a hazard if the boat where to sink or be damaged? What hazard does it pose to swimmers or people in the water? I could buy a really nice boat for the cost of this one.
jerryd
I'm sure the waterlife is thrilled having these knives slicing through the water! s
While interesting the water has too much c-rp in it to clog or break the foils and faceplanting the boat.
Nor is the performance all that as not hard to design, build a cat or tri to match it.
Bruce H. Anderson
I realize i am probably speaking sacrilege, but perhaps a petrol unit (providing a significant range increase) would be an effective tool for the Coast Guard, Border Patrol, Fish & Game, or the local police. Logs and such would be a problem, but there are probably ways to make these easily repairable after you limp back to the dock.
imboox2
What does it take to get one of these up on the foils? I see in the video they are really moving along.
Allen
Like Bruce. H. Anderson I would prefer a hyrbrid or gasoline model as an option for the range. Around here, Savannah Georgia, the best fishing is almost 80 miles out on the Continental shelf.
michael_dowling
Why do they almost always have loud music in EV boat videos? As it is electric,I want to hear what the damn thing sounds like!
rdp
A question about this statement: "Candela says its boats can significantly reduce the wake pollution". A boat must displace its weight in order to stay afloat. My rudimentary understanding of hydrodynamics says that the volume of the wake displaced by a hydrofoil must be the same as the displacement of a convention hull, but perhaps "short and wide" versus "tall and narrow"; ultimately there's the same amount of energy behind it. Is wake pollution actually reduced?
Aermaco
@rdp there is huge difference between passive buoyancy and active dynamic lift. Think of the hot air balloon and the turbojet aircraft that stay aloft. The same holds for fast power boats and sail boats that can transition from floating to planing being designed with planing hulls only, and so a hydro foil is planing at its best with minimal surface drag thus they move with much more efficiency.