Please select your home edition
Edition
Maritimo 2023 S600 LEADERBOARD

Introducing the most efficient boat motor ever - the all-electric Candela C-Pod

by Candela 20 Aug 2021 03:06 PDT

It will last a lifetime without maintenance, is four times more efficient than the best electric outboards and makes for a totally silent boat ride. With the launch of the Candela C-Pod boat motor, the Swedish marine tech company Candela is aiming to disrupt boating as we know it.

Combustion engine outboards are noisy, require expensive maintenance, cost a small fortune to run and emit more CO2 per kilometer than most road vehicles.

All this is set to change with the revolutionary Candela C-Pod, an electric pod drive developed by Europe's leading electric boat manufacturer, the Stockholm-based tech firm Candela.

What would be the best boat propulsion one could imagine? Here are some ideas: electric, completely silent, without oil changes and with an almost unlimited lifetime. Add to that almost no losses - converting most of the energy to thrust, says Gustav Hasselskog, Candela's Founder and CEO

In other boat motors, be it electric or fossil fuel, the motor is typically situated in a box above the waterline, transferring thrust to the propeller through a complicated set of shafts, bearings and gears. The Candela C-Pod gets rid of the gears altogether. Two ultra-compact yet very powerful electric motors are mounted under the water in a torpedo-like socket, directly driving the propellers. Each motor is coupled directly to a propeller, which minimizes friction losses. Contra rotating propellers add the benefit of very high propeller efficiency.

The engineering challenge was to make the electric motors compact enough. Being submerged, they have to have a very small diameter in order to cause minimal drag, explains Hasselskog.

To accomplish this, Candela's engineers had to rethink electric motor design bottom-up. Electric motor volume is not driven by power. Instead, it is largely proportional to torque. And power is torque times rpm. For the Candela C-Pod motors, Candela opted to increase the rpm and lower the torque to boost the Candela C-Pod's power density. The best way was to split the thrust needed on two propellers. The reason is that the maximum rpm is limited by the speed of the propeller tip moving through water. At around 45 m/s propeller speed, the pressure in the flow around the propeller reaches vacuum and starts to boil. That creates noise, damage and inefficiencies. The speed of the tip of the propeller is a product of rpm and propeller diameter. So splitting load on two propellers allows for propellers with smaller diameter and thereby higher rpm - and in turn smaller motors.

By placing the motors under the water, Candela also elegantly solved the problem all electric motors face: heat. The Candela C-Pod engineers designed the slim pod drive to be directly and efficiently cooled by the flow of seawater, thereby enabling higher operating temperatures and extracting more power from the motors.

The first obstacle towards a very small high-power motor is heat. You can take any motor and give it three times more electricity than it is rated for. It will work. But only for a few seconds. Then it melts. With Candela C-Pod, we have almost unlimited cooling power - we just need to get heat from the coils to the surrounding water flow, says Hasselskog.

Ultimate silence

An added benefit is silence. Gasoline outboards are some of the noisiest machines out there. Decibel levels climb into the 90s as they near wide-open throttle; some noisy boats hit 100 decibels - loud enough to damage the human ear. Even conventional electric outboards are not as quiet as they could be, since the gears emit a whining sound at high speeds.

Candela C-Pod has no gears and is therefore totally quiet. No rattling, no squeaking, absolutely no noise, even at 30 knots, says Hasselskog.

Boat owners are used to paying big bucks for maintenance. Diesel and gasoline engines require annual oil and filter changes, as well as winterization. And commercial boat operators typically have to swap their outboards every two years since gear houses are not designed for more than thousand hours.

Freed from gears and with very few moving parts, the Candela C-Pod will last several thousand hours - without any maintenance whatsoever.

For the average leisure boat user, this means you can just use the motor and forget about the usual hassle with service and winterization. The Candela C-Pod will outlast you and probably your kids as well, says Hasselskog.

The Candela C-Pod was born from the unique requirements Candela place on electric drive trains. The company's electric hydrofoil craft fly above the water on foils and consume 80% less power than traditional powerboats. Making a more efficient motor directly translates to huge gains in range.

The Candela C-Pod will be fitted to the Candela P-30 electric shuttle ferry, the Candela P-12 water taxi as well as future leisure boats.

Developing 50 kW for take-off, a single Candela C-Pod has enough thrust to propel Candela's 28 foot, 12-person water taxi, the Candela P-12, at a speed of 30 knots. For the company's bigger 30-person shuttle ferry, the Candela P-30, two Candela C-Pod's will provide the same speed.

Candela C-Pod facts

  • Power: 50 kW
  • Weight: 26 kg
  • Propellers: Contra rotating propellers
  • Propeller efficiency: 80%
  • Maintenance-free operating period 3000+ hours

Candela C-Pod benefits

  • Most efficient boat motor - longer range on battery power than other electric motors
  • Totally silent - no gears
  • No maintenance
  • Very long service life
  • Zero emissions, oil spills or pollution

Related Articles

First Candela C-8 Polestar Edition delivered
A luxury edition of Candela C-8 with bespoke interior designed by Polestar's design team Electric hydrofoil boat maker Candela has delivered the first produced Candela C-8 Polestar edition - a limited design edition of Candela's C-8 in collaboration with electric performance car brand Polestar. Posted on 4 Jul
Production of C-8 'powered by Polestar' starts
Candela announces production of the first units has started Production has begun of Candela's revolutionary C-8 'powered by Polestar' electric daycruiser, ushering in a new era where electric boats can cover hundreds of miles in a day, with DC charging. Posted on 18 Oct 2023
Electric boat shatters world record
Candela's latest version of its C-8 foiling craft covers 483 miles in a day Imagine traveling by electric boat from London to Amsterdam and back within 24 hours? During a recent endurance challenge, the electric, hydrofoiling Candela C-8 covered a distance equivalent to that journey, setting a new world record. Posted on 21 Sep 2023
Candela C-8 Polestar Edition
Iconic design meets electric performance at sea Premium electric car maker Polestar (Nasdaq: PSNY) and electric hydrofoil boat maker Candela reveal the next phase of their partnership - the Candela C-8 Polestar edition. Posted on 24 May 2023
World's most popular boat type goes electric
Center console boats are the most popular recreational vessels on the water Center console craft for fishing, families, and watersports are the most popular type of boats in the world - and also some of the most power-consuming vessels on water. Posted on 5 Apr 2023
Candela reveals longest-range electric boat
A significant breakthrough for electrification at sea with Polestar batteries and DC charging With up to 57 nm (65 US miles) of expected range and DC charging, the foiling Candela C-8 'powered by Polestar' is designed to upend the hegemony of fossil fuel boats. Posted on 18 Jan 2023
Polestar and Candela join forces
Polestar will provide battery and charging systems for Candela's highly efficient flying boats The Swedish electric car maker Polestar will provide battery and charging systems for Candela's highly efficient flying boats. The battery deal will enable Candela to scale up production swiftly, bringing mass-market electric boats one step closer to real Posted on 23 Aug 2022
Candela P-8 Voyager debuts in Venice
The next generation of electric passenger boats flies above the water at high speeds Unveiled today in Venice, the new foiling Candela P-8 Voyager lets its passengers travel silently and comfortably through wake-sensitive areas or over delicate coral reefs, without leaving a trace. Posted on 31 May 2022
France SailGP Team introduces Candela C-7
The world's first electric hydrofoil chase boat As the Formula 1 of sailing returns for the Mubadala United States Sail Grand Prix, the French team has an ace up its sleeve: Candela C-7, the world's first electric hydrofoil chase boat, which might help them score in the new Impact league. Posted on 26 Mar 2022
Candela C-8 outsells combustion engine boats
The first flying electric daycruiser The Swedish tech company Candela has racked up more than 60 orders for its revolutionary, 290 000-euro electric boat, the Candela C-8. That makes the flying C-8 one of the fastest-selling 28-foot boats on the market. Posted on 26 Mar 2022
Maritimo 2023 M600 FOOTERTrinidad and Tobago - Sail Service Stay