Flying over water

"If you don't want to stand in a pleasure craft, you need pillows: any lake, no matter how smooth as glass, turns into a mogul slope as soon as the throttle is fully depressed. If the bow shoots over the crests of waves and falls back with spray fountains, it is too late to search for the fluffy bodies. The rodeo ride, which often has three-digit horsepower figures, is not environmentally friendly anyway.

 

At Candela Seven everything should be completely different. At first glance, however, the 7.7-meter yacht hardly differs from other speedsters for lakes and inland seas. 

 

The carbon hull, teak deck and seats with the thinnest damper pads seem rather puristic for a boat that costs around 250,000 euros. 

 

Noticeable are at most two vertical bars behind the front seats in bright warning orange. They do not make the layman think of wings; the racing machine doesn't look much more spectacular than an electric tummy tuck in a boat rental. But that changes as soon as 16 knots (about 30 km / h) are reached. The beams in the hull had already disappeared before that. The passengers only feel that they are carrying the front wing and steering it every millisecond when the Candela rises majestically above the surface of the water.

 

Without flight controls, the boat would crash - as the developers have often seen

 

Hydrofoils that cut through the water with almost no waves: there is something virtual about the exit over Lake Starnberg, the electric boat lies so calmly in the water. Even at the maximum permitted speed of 40 km / h one could drink tea from flat cups, the Candela fluctuates so little. The hopper also passes the large stern waves of the sea steamer without flinching. It is child's play to take turns without heeling because the boat has a flat bottom. 

 

But you shouldn't be mistaken: it is anything but easy to hold a 1.3 ton hull stable while dancing over the cross waves. Without a special flight control with 92,000 program lines, the Candela Seven with its stubby wings (under water) would be as unstable as a modern combat aircraft. 

 

"The first attempts in 2017 regularly ended with splashing on the water," recalls Candela spokesman Mikael Mahlberg: "Especially cornering has to be precisely balanced because of the weight shift at the front and rear. Data processing almost in real time was still space technology. 

 

Smartphones with a multitude of mini-sensors and small high-performance computers made the Candela possible. The 20 developers at the Swedish start-up are also making use of the advances in the control of drones and the lightweight carbon construction of modern helicopters. 

 

Batteries and electric motors come from the Starnberg specialist Torqueedo, who gets the energy storage devices for BMW. Since 2017, Dingolfinger Batteriemontage has been supplying batteries with the highest energy density available for boat drives - at low costs per watt hour, as the Starnbergers emphasize.

 

Nevertheless, the battery is not light at 273 kilograms. That's why Candela had to starve down the excess pounds (and more) with the elaborate carbon lightweight construction. The battery lasts for several hours in foiling flight mode because it reduces driving resistance by around 60 percent. 

 

"We had a seven-meter-long boat with a V8 engine," says Candela founder Gustav Hasselskog, who lives on one of the small islands off Stockholm. "Every trip into the city cost around 50 euros for gasoline. That's why we looked for a more efficient alternative." Because there was no electric boat in this performance class with a range of around 100 kilometers, he started the Candela project in 2014. It quickly became clear that it wouldn't work without hydrofoils. Even classic hydrofoils that glide over the water like skis generate too much drag. "We are currently discussing with those responsible for local public transport in Stockholm whether a larger Candela could not be used in ferry traffic - electrically powered and autonomous," reveals Hasselskog.

 

Fast ferry traffic without noise, diesel exhaust fumes and waves - that could revolutionize transport on the waterways of many cities. But there is still a long way to go before then. So far it has only been Tesla drivers who have achieved the dream of an extremely efficient electric boat. The Candela Seven only consumes around 16 kilowatt hours at 19 knots. The comparatively lean 75 hp engine is far from over. It could accelerate the sport flounder to more than 50 km / h. Which makes the supple "Candela suspension", as the employees laughingly call it, a little tighter. Even when cozy at a travel speed of the equivalent of 35 km / h, the other boats on the lake seem to be frozen solid, especially the sailors look after the apparently floating and silent ghost ship in disbelief. Like all those seeking peace and quiet, they are happy that there are only 255 private licenses for conventional motor boats on Lake Starnberg. However, electric boats are exempt from this rule. If you can afford it, you can go out on the water with the carbon planks without having to wait ten years. And it doesn't need a license either. "