New Supra electric towboat powered by 320kW EVOA E1 drivetrain
The new EV 550 Supra electric towboat brings another electric entry to the world of high power, high speed water sports boats with a 440 hp motor and E1 drive train from EVOA.
Supra is a division of the Skier’s Choice corporation and the one of the world’s premier wakeboarding / wakesurfing / watersport towboat manufacturers.
EVOA is an electric propulsion specialist with a background in the E1 electric race car circuit. They first came to boating attention last year by providing the drive drain and battery technology for the Launch 25 GTE from legendary boat maker Chris-Craft. That was introduced at the Miami International Boat Show, as was the EV 550 this year.
The system designed for the 24 foot (8 metre) Supra is EVOA’s E1 electrified performance package, which is based on an 800 Volt architecture that delivers 550 lb-ft of torque (745 n-m) with a battery storing 155 kiloWatt hours of energy. That architecture also enables Level 2 charging.
Supra electric boat ‘creates a new paradigm’
Electrification Project Manager Rob Loucks and his son Hunter worked with the EVOA Team doing the on-water watersports testing of the EV550. Rob said “This is a game-changer for the industry and for families like ours who cherish these moments on the water. The sensation of power and silence as we glided over the water was unique and awe-inspiring, unlike anything we’ve experienced before and unmatched in the world of ICE powered boats. It creates a new paradigm for how we enjoy watersports.”
The key to all of this is EVOA’s axial flux motor technology. Flux is the term for the strength of a magnetic force. In most electric motors the magnets and the flux run along the length of the motor’s cylinder. That is called a radial flux configuration.
An axial flux motor has the magnets in ‘pucks’ at the ends of the cylinder. It is called axial flux because the flux runs along the axis (not the radius), and is also referred to as a ‘pancake motor’ because of the end pieces.
EVOA’s Managing Partner Mike Anderson says what that means in practical terms is that their axial flux motors have four times the torque density (torque per weight of the motor) of radial flux motors.
When a lighter motor can deliver the same power as a heavier one, that is going to reduce the energy required to move the boat through the water and improve range, much like the benefits of a lighter battery.
In the case of batteries the density is energy density – how much electricity can be stored per battery weight – measured in kiloWatt hours per kilogram (kWh/kg). On that front, EVOA is also at the leading edge with batteries that can hold 210 kWh/kg.
Electric boat batteries from Formula E racing
Mike grew up in Michigan as a competitive water skier, studied engineering at college and naturally gravitated to the boating industry working with watersport boat manufacturers.
When electric vehicles began to appear on the scene, he became intrigued with the idea of electric motors for boats as he considered all the noise and fumes and spillages he’d seen over the years.
The kicker for him was when he was in a meeting with people from a performance boat manufacturer (not Supra) who were almost bragging that it would burn 25 US gallons (95 litres) of fuel per hour.
So he started up EVOA with the goal of building high powered electric propulsion systems for those kinds of boats and took a page out of the auto racing world where the big manufacturers use the competition as testing grounds for new technology.
He and his partners reached out to the recently launched Formula E international electric car racing championships and started a relationship with the Williams team, who later joined up with Jaguar. Willams/Jaguar developed the standardized batteries for the auto racing circuit and in 2019 EVOA brought that 800 volt architecture to the US and started talking to boat manufacturers.
“That’s where the pedigree for our battery came from,” Mike told me at the Miami show. “They’re the same cells that are being used in the races, and we’re bringing them to the marine market. They are very robust and have been tested to the extreme. That’s one under the TV there, (on the left in the photo above) it’s actually one out of a Formula E car.”
The combination of the radial flux motor and battery efficiencies adds up to a pretty incredible package. You can see from the photo below with the EVOA electric motor hooked up to prop drive how small it is compared to the space a 440 ICE motor would take up. Four battery modules are distributed throughout the boat to provide the 115 kiloWatt hours of electricity.
During the testing of the EV 550 all of the on-water usage was timed and EVOA advisor Jeff Shupe says “People overestimate how long they are actually going fast in a boat. When you look at the clock, you board or ski for a few minutes, then the rider falls, the boat slows down, circles back, you make sure everything is alright, then go again for a few minutes. Then it’s someone else’s turn, so you switch the lifejackets, that takes more time. For average use the Supra EV 550 can give you about 3 hours of watersports on one charge.”
This is similar to the two other electric wakeboard / towing boats on the market – the Arc Sport and the Super Air Nautique GS22E.
The EV 500 is not yet included on the Supra website and the Chris-Craft Launch 25 GTE was always meant to be a concept boat. It toured a number of midwest lakes and marinas in the summer of 2023 and has stirred up a lot of interest in a production model. (You can sign up for news and updates using the ‘Chris-Craft’ link below.
EVOA is also working with other boat manufacturers to bring electric propulsion to different kinds of boating. On their website there is a short video clip of a Barletta pontoon (Barletta, like Chris-Craft, is a division of Winnebago) and in Miami there was mention of a top secret project they are hoping to be able to announce soon.
They also showed a high power electric outboard at Miami that will soon be on the market. All things considered, their axial flux motor and Formula E proven battery system provide any boat builder or owner with a high performance electric option. Lots more to come!
