Innovation economy

They want to power your boat with a battery

Flux Marine, a startup with new backing from the Winklevoss twins, says it has a better kind of motor.

Jonathan Lord, one of the three cofounders of Flux Marine, an East Greenwich, R.I., startup that's bringing battery power to boat motors. Matthew J Lee/Globe staff

EAST GREENWICH, R.I. ― It’s a chilly late March day at the marina in East Greenwich, with most of the big boats still wrapped in their white winter plastic. But Ben Sorkin is striding toward a slip to show off a small Zodiac inflatable boat that his company, Flux Marine, has been working on.

What’s unique about this boat is that rather than a fuel tank, it carries a lithium-ion battery. And mounted on the transom is an electric outboard motor that Flux plans to start selling this summer.

Sorkin’s company will announce Wednesday that it has raised $15 million to provide boat owners with an alternative to the noisy and pollution-spewing outboard. The investors include Ocean Zero and Winklevoss Capital, founded by Harvard alums Tyler and Cameron Winklevoss. Featured in the movie “The Social Network,” the twin brothers have since amassed a fortune in cryptocurrency. Flux also landed nearly $2 million in tax incentives from the state of Rhode Island on Monday for promising to add 80 new jobs by the end of 2024; it currently employs 12 people.

Flux, founded in 2017 by Sorkin and two classmates at Princeton, is part of a small flotilla of companies that say it’s time for recreational boating to go electric. Most marinas like the one in East Greenwich already have more power outlets on the docks than they do gas pumps. Sorkin says boaters who love having access to pristine lakes and rivers sometimes accidentally leak oil and gas into those same crystal-clear waterways. Outboard motors lack catalytic converters, too, so they emit hundreds of times more particulate pollution per gallon of gas than car engines.

But as is the case with electric cars, boaters will have to pay a premium to go electric. In the long run, savings will come from lower fuel and ― possibly ― maintenance expenses. Flux’s 40 horsepower outboard will sell for $18,500 with a battery pack, compared with $4,000 for a comparable gasoline motor. But the cost of actually running it, Sorkin estimates, will be about five to 10 times less expensive per mile than a gas motor.

Sorkin grew up in a boating family, spending summers fixing and restoring boats on the shores of Lake George in New York. He also volunteered at an environmental education center, Up Yonda Farm. In college, where he studied mechanical engineering, those two interests began to converge. One summer, with a little bit of grant funding from Princeton, Sorkin took an old gas outboard, removed the innards, and installed an electric motor. “We had a 10 horsepower electric outboard, which was larger than anything available at the time,” he says. When he demonstrated it on lakes in New Jersey and New York, he says, people wanted to know when they could buy one.

The following summer, Sorkin landed an internship at Tesla Motors, where he focused on battery systems. “It was a fantastic way to dive into understanding the trends and technology behind electrification,” he says — including the fact that boat motors have to output more continuous power because water creates far more drag on the vehicle’s hull than air does against a car cruising down the highway.

Flux began life as a nights-and-weekends project in 2017 and was accepted into the MassChallenge startup program in 2018. Sorkin left his full-time job in 2020 to focus on Flux.

The company has taken “a blank slate approach” to designing the outboard, he says. It uses a belt drive, rather than a shaft, to transmit power from the motor at the top to the propeller in the lower unit. There’s a closed-loop cooling system, rather than pulling in seawater to cool the engine. Both those design features, Sorkin says, cut down on the costs and time of maintenance and winterization. A battery sits inside the boat, where a fuel tank normally would. It can be charged by any sort of outlet — even a standard 110-volt household one. Standing on the inflatable tender in East Greenwich, Sorkin says this size boat would take about seven hours to completely charge from the 125-volt outlet that is already installed nearby on the dock.

As for the range of electric boats, “it’s very dependent on how you use it,” he says. “If you’re running with a wide-open throttle, you’d get about 25 miles, and if you’re just trolling around, it’d be upwards of 200 miles.”

An initial focus for Flux is selling outboards ranging from 15 to 70 horsepower and installing them on existing boats at its facility in East Greenwich. “We will have customer boats in the water this summer,” Sorkin says. The company is also marketing a $100,000 powerboat that would come equipped with the 70 horsepower electric motor and battery.

Flux may be an early entrant, but it won’t have the water to itself for very long. Big motor and boat manufacturers that include Mercury, Yamaha, and Bombardier have announced plans for electric outboards and boats. And a Swedish company, Candela, is planning to start deliveries this year of the $330,000 C-8, a 28-foot powerboat with a hydrofoiling system that lifts it up out of the water to reduce drag and give it a longer range. (The company says it can travel more than 50 miles at a zippy speed — for a boat — of 27 miles per hour.)

One of Candela’s first customers is Will Graylin, a tech entrepreneur who lives in Winchester and owns a summer house on Lake Winnipesaukee in New Hampshire. Graylin already has electricity running to his dock, used for bubblers that keep ice from forming in the winter. And with the lake’s surface frequently roiled by boat wakes, “we think it’s the perfect type of boat for that type of lake travel,” since being elevated on foils will help it cut through the chop. But “if you’re going to go deep-sea fishing to the outer banks,” he says, “you probably wouldn’t choose this particular vehicle.”

Graylin remembers being one of the first people in the Boston area to take delivery of Tesla’s Model S sedan about a decade ago. “It was me and Danny Ainge standing there in Watertown waiting for the truck to show up,” he says. “This was before they had a dealership.”

As with the Tesla, he purchased the Candela on faith, without having a test drive. “I’m just kind of a geek,” he says, when it comes to electric-powered vehicles.

But Candela, Flux, and other producers of electric boats and outboards will likely need to do a lot of educating and marketing to mainstream boaters, at least according to Dave McShane, owner of McShane Yacht Sales in Marshfield. McShane notes that many boaters have “got the need for speed,” and like to show off how much power their boat has. As for electric propulsion, he says that over the past year, none of his customers have asked him about it.

“It’s not a mainstream conversation,” he says.

Correction: An earlier version of this article misstated the price of the company’s electric motor with a battery pack. The Globe regrets the error.

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