At 11.7 meters long and 5.7 meters wide, the catamaran can handle up to 30 divers for recreational diving or conducting research.

From its first sea trials, the Heliodive has cruised at 20 knots and proved itself ready for scuba diving. What's different, though, is that the catamaran – born of a dream that industrial designer Alexis Synodinos made a reality – relies entirely on solar panels and plugs into recharge when back in port.

The all-aluminium boat, built in Vendée, delivers a completely clean adventure for divers who want to protect the ecosystem they love to explore. "This boat is truly a friend of divers because it works without fuel, noise, biocide, smoke or smell," said Synodinos in a recent interview at Saint-Mandrier.

First, there was the choice of aluminium to build the Heliodive. The builders explain that it's the best material for the project, because of the exceptional durability, the easy repairs and the relatively maintenance-free simplicity. It's also lightweight, leaving the entire boat weighing in at just seven tons without the people. At full passenger and crew capacity, the Heliodive maxes out at 10 tons.

The Heliodive was built to be thin, and that makes for easier navigation and penetration in the water. It's also modular, making it easier to move around or build and ship to customers. The sections can be hauled on standard freight trailers, and fit inside 40-foot "high cube" rail or sea shipping containers.

Assembly is designed to be safe and easy, including the deck and power systems. Atop the aluminium frame is a plastic-filled fiberglass floor, which also works to reduce the weight and the costs. Above the catamaran deck is a roof that houses 56 solar panels delivering a total of 5,600 watts. The Heliodive design also includes either four lithium batteries at 50 kWh, or eight lithium batteries at 100 kWh.

They're fully recharged in 3 to 6 hours, depending on which battery configuration is used, simply by plugging in when back at dock. That means that without relying on the solar panels, the Heliodive can manage a 14-hour run at a low 5-knot speed, or 2 hours at 14 knots. The solar power extends the continuous supply of clean-energy electricity.

All of that power runs two Torqeedo Deep Blue 80cv (65 kw) engines, online at 345 volts. The engines have their own sustainability story, since Torqeedo was launched on the shores of Lake Starnberg in Germany by Christoph Ballin and Friedrich Böbel. The two envisioned a future for electric boat motors, much the way Elon Musk and others have for cars, and now have a Torqeedo presence in 50 countries.

"What Tesla has done for cars in making electric accessible and acceptable, we believe Torqeedo will create similar waves on the water," says Jason Hodder, a product manager working in Australia.

Seasoned boaters take a little time to adjust to the quiet of fossil-free boat engines, but most divers in search of a pristine environment for their professional or personal experiences welcome the change immediately. Heliodive uses the most powerful Torqeedo engines, and when paired with the light aluminium construction and the battery systems, Synodinos says Heliodive can sail all day and night.

"It would be difficult to make it more economical and more eco-friendly," he says.