Two men ride on a white solar-powered powerboat on a lake.
The prototype Solar Sal 24 was launched on Earth Day last week in Lake St. George in Liberty. The solar-powered powerboat was built by Belmont Boatworks in Belmont. Credit: Courtesy of Belmont Boatworks

On a windy day last week, a Maine company made history when it launched a prototype of the first-ever completely solar-powered powerboat on a Waldo County lake.

“I’m pretty blown away by it,” Dan Miller, the owner of Belmont Boatworks, said Wednesday of the launch of Solar Sal 24 on Lake St. George in Liberty. “It was really fantastic. She did everything she was supposed to do, and did it perfectly.”

Solar Sal, which Miller describes as an open day boat, is different from other solar/plug-in hybrids that are currently on the market, including some pontoon boats. The only way to charge its batteries and the electric motor is with the solar panels on the boat’s canopy.

“It doesn’t rely on any backup,” he said. “There’s no plug.”

The 24-foot passenger vessel is the first production boat to be sold by Sustainable Energy Systems, a family company based in both Troy, New York, and Bellingham, Washington, that has done pioneering work in solar-powered boats. Solar Sal 24 was designed by J.F. Bedard, a marine architect based in Florida, and built by Belmont Boatworks. It is the first of at least three that the Maine firm will construct, but Miller hopes that lots of people will be interested in Solar Sal.

“The goal is to set up to build an infinite amount,” he said. “If they sell, then we’ll carry the ball as far as it goes.”

The boat, which is 100 percent powered by solar panels on its canopy, burns no oil or gasoline, causes no water pollution and generates very little noise. It can carry up to 10 passengers, though it comfortably seats six, and has a small galley and a head with a composting toilet.

Four people stand on a white solar-powered boat attached to a dock
Solar Sal 24, the prototype solar-powered boat that was built by Belmont Boatworks, can carry up to 10 passengers. Credit: Courtesy of Belmont Boatworks

“It’s a little, open day boat,” Miller said.

Solar Sal can travel at a steady — though sedate — speed of about seven knots “all day long,” Miller said. When the sun dips below the horizon, the boat’s bank of batteries will take over. There’s enough power stored in those that it could run all night long, just at a slightly slower speed. Seven knots is fast enough to bring a boat from Belfast to Castine in an hour and a half.

That’s slow for a powerboat but fast compared with a sailboat, Miller said.

“One of the things that I think solar technology is going to do is slow us down,” he said. “Our American need for speed is probably going to suffer a little bit. This boat is not going to be for speed boaters.”

It will be priced at $124,500, a figure that is based on what the prototype has cost, he said.

“They’re coming out at a time when I think they’re really, really needed, to counter climate change,” Miller said. “And now, fuel’s really expensive, so it’s a good time to have them around.”

David and Harriet Borton of Sustainable Energy Solutions learned about Belmont Boatworks when they hired John O’Donovan, a carpenter from the Maine company, to help them with a different prototype.

When that project  — a solar-powered  tour boat for the Hudson River Maritime Museum — was completed, the Bortons moved on to a new solar-powered project with O’Donovan and then Belmont Boatworks. The boatbuilding company began to work on the Solar Sal 24 project about two years ago, Miller said. 

Supply chain disruptions slowed down their progress. Although a Florida company was supposed to deliver some parts and pieces in the spring of 2021, that never happened. Ultimately Miller and his daughter drove south at the end of December to pick them up themselves, “just to get the ball rolling,” he said.

It made it extra special for Miller that Solar Sal launched on Earth Day, something he has been celebrating for more than 30 years.

“The Solar Sal is not just for environmentalist weirdos and science geeks like me. She’s not just a way to prove a point,” Miller wrote on his Facebook page after the Friday launch. “She’s really a great, efficient mover. She’s stable, comfortable, well powered and pretty … This technology can help shape the way recreational and commercial boaters interact with our oceans and our planet. ”  

Correction: This story has been clarified to note that there are other solar/plug-in consumer pleasure boats on the market.