Candela C-8 the flying boat on the water with electric propulsion
After the great success with the Candela C-7 boat in 2018, obtaining numerous awards and exceeding the sales of electric boats in Europe, the Swedish shipyard Candela Boats builder of only electric boats is about to deliver the new high-end luxury boat to its first customers. performance the Candela C-8 always powered by an electric engine.
Even if C-8 currently costs 290 thousand euros (excluding VAT), the shipyard is convinced that in the next few years it will build several thousand and will become an industrial product if it manages to conquer the taste of the people of the sea and the lake considering the numerous advantages it offers. compared to the competition of both boats powered by electric motors and internal combustion engines.
The C-8 is a long-range electric aircraft that travels silently above the water surface with zero emissions, no noise pollution and no marine life disturbance.
It is the evolution of the previous C-7 and offers wider spaces and greater driving comfort, it has been designed to bring electric boats to the wider nautical market thanks to its new C-POD engine, small, powerful and eternal that according to the company, it is none other than the most efficient and long-lasting boat powertrain ever. In addition, this engine will end up powering boats that are conceptually different from conventional ones, which will make the whole even more efficient.
In fact the C-8 instead of making its way through the waves, after reaching the expected take-off speed at 16 knots (18.41 mph) will fly silently over the surface of the water using the hydrofoil technique and can reach 30 knots (34.52 mph) of speed with a single C-POD.
Technically, the C-8 exploits the ” foils “, a particular “profile” capable of generating a force when it passes through a fluid, which stretch downwards and when a certain speed is reached they lift the hull from the surface of the water, drastically reducing the aerodynamic drag created by friction as the boat moves forward.
Pushing a conventional, planing powerboat into the water requires enormous amounts of energy, which drains even the largest lithium-ion batteries after just 30-45 minutes of sustained driving.
In fact, a typical planing hull has a lift / fatigue ratio of 4 to 1, while the Candela C-8 has a lift advantage of 20 to 1. Sailing at 20 knots (23.01 mph), the C-8 can fly for 50 nautical miles with its 44 kWh battery, 2-3 times longer than traditional electric speedboats with 300% larger batteries. A truly surprising result.
All this thanks to the new C-POD which is not the classic outboard motor, but has a “torpedo” shape, without mechanical parts external to the water, the whole engine is constantly submerged in water has been solved, so the problem that everyone electric motors face: heat. In fact, the engine has been designed to be cooled directly and efficiently by the seawater flow, thus allowing higher operating temperatures and extracting more power from the engine. In this regard Gustav Hasselskog, founder and CEO of Candela Boats has released the following statement:
“With Candela C-POD, we have almost unlimited cooling power: we just have to transfer the heat from the coils to the surrounding water flow”.
The engine has a power of 50 kW and weighs 26 kg is equipped with two counter-rotating propellers with an efficiency of 80% and promises to offer over 3 thousand hours without the need for maintenance thanks to the work carried out in recent years by Candela Boats where it has decided to increase the number of revolutions and reduce the torque to increase the power density.
In particular, the aim was to divide the necessary thrust on two propellers for which the maximum number of revolutions is limited by the tip speed of the propeller that moves in the water.The division of the load on two propellers allows for propellers with a smaller diameter and therefore a higher number of revolutions and, in turn, smaller motors. In addition, the two propellers on the engine are mounted in sequence, and counter-rotating, a technical choice that was reached after several tests and a long program of efficiency and fluid dynamics work.
The explanation is given by CEO Gustav Hasselskog:
“A big plus is the much lower propeller losses. A conventional single helix configuration has losses of more than 30%. About 20 of 30% is burned by giving the water a spin. After the propeller, the water not only flows backwards, but also makes useless movements ”. “By placing one helix behind another helix and spinning them in opposite directions of rotation, the flow after the second helix can be made to go completely straight. So you end up with about 30% losses in the main propeller and only 10% in the rear, moving the overall efficiency from 70 to 80% which translates into a 14% increase in range “
To avoid further problems due to the movement of two propellers with a single electric motor, it was then decided to use two motors, one for each propeller this allows the almost total absence of mechanical parts, making the motor sealed and free of any maintenance, so much so as to last two or three generations of owners.
Furthermore, the engine is among the quietest ever built. “The other motors, although electric, are not very quiet, let’s not talk about the petrol outboard motors which are among the noisiest machines in circulation, some reach 100 decibels, a volume loud enough to damage the human ear“.
“Even conventional electric outboards aren’t as quiet as they could be, as the gears make a whining sound at high speeds.” Candela C-POD “has no gears and is therefore totally silent. No rattling, no creaking, absolutely no noise, even at 30 knots “. Word of Hasselskog.
Even on maintenance, a comparison is made with other products. “Boat owners are used to paying big bucks for maintenance. Diesel and gasoline engines require annual oil and filter changes. And commercial boat operators typically have to change their outboards every two years as the gearboxes aren’t designed for more than a thousand hours. “
“Free of gears and with very few moving parts, the C-POD Spark Plug will last several thousand hours, without any maintenance. For the average recreational boat user, this means you can just use the engine and forget the usual hassle and it will outlive you and probably your kids as well. Always says Hasselskog
With the C-8 the technology based on foils has been improved, “it reduces energy consumption by 80% compared to conventional boats”, and a longer range is announced: “C-8 can sail longer distances than any other electric speedboat before it: over 50 nautical miles on battery power at a speed of 22 knots (25.31 mph). At a speed of 22 knots, it draws only 16 kW / 21 hp from the battery. For comparison, a normal 28-foot planing cruiser is typically equipped with a 300 horsepower gasoline outboard motor.
“On the technological front, the flight controller has also been improved, which automatically and instantly adjusts the blades to keep the boat level and stable, even in adverse weather conditions”. “It features true fly-by-wire steering with autopilot functions.” The focus is on more relaxed driving over long distances. “When the driver releases the rudder, the boat will automatically follow the set course”. Comment Hasselskog
All settings, from turning on the cooler to navigating, are controlled by the 15.4-inch screen running the user interface. Then there is the Candela App to control the boat’s systems from land. For the future, new functions are planned that can be updated directly through the App. The C-8’s rudder position is simple and clean, the C-FOIL retractable system makes the C-8 a true electric boat without compromise. In surface mode, the foils and the Candela C-POD are protected by the hull. In extreme weather conditions that prevent foiling, the C-8 can be driven like a conventional boat, albeit with a reduced range.
The C-8 made of carbon fiber is 8.5 meters long and 2.5 meters wide; cruising speed 20/22 knots, 30 the maximum; 44 kWh of lithium-ion battery capacity; autonomy from 50 nautical miles to 20/22 knots; Candela C-POD engine, 55 kW; charging time 2 hours with three-phase; accommodation sleeping places: 2 adults, 2 children, places for 6 + 2 people.
C-8 comes as an open day cruiser or hardtop with a retractable sunroof and can be customized to suit your needs and preferences through a list of additional amenities such as a beverage cooler, freshwater shower, projectors, radar and more still. The layout of the exterior of the boat includes a cockpit with 8 seats with the first three seats for the pilot and his co-pilots. At the rear, a large sunbathing area and a platform for accessing the sea.
Below deck there is a comfortable forward cabin complete with bathroom that can accommodate two adults and two children. The optional premium sound system with subwoofer and six speakers allows for a unique concert experience aboard the quietest electric boat ever .
Indeed, a boat has been designed that is a candidate to be one of the most efficient ever built capable of delivering so much power despite the small size of the engine designed to have little friction and a virtually infinite life, as well as minimal maintenance.
All features that attracted attention and the owners immediately rushed to book this boat for which the shipyard has already received more than 100 orders and is already the best-selling electric boat model in Europe today. Candela Boats’ goal is to produce 400 boats for a substantial series production by 2024 already.