The teen taking an electric boat round Britain

Harry Besley departed on his journey in mid-July in a rigid inflatable boat (RIB) powered solely by electricity

Electric cars, buses and bikes are all now commonplace. But as we seek to decarbonise transport, electric boats and ships are still very unusual. Even more unusual is the challenge undertaken by 18-year-old Harry Besley. He is trying to be the first person to go round the UK in an electric power boat. The BBC caught up with him as he reached the Isle of Wight.

Harry is nearly there. After a month on the water, the Taunton teenager aims to return to his starting point at Lyme Regis in Dorset on Thursday.

Pausing to charge his rigid inflatable boat (RIB) at Cowes on the Isle of Wight, he said: "It's been a long way. It's been quite tiring. We haven't got much sleep. We have to leave based on the tide, and the tide does not play to our schedule."

He had left Shoreham before dawn, taking advantage of tides and cool early morning weather.

At a very slow five knots, the battery will last for 55 miles. At 20 knots, that drops to just 25 miles.

Crossing the Irish Sea and navigating the Scottish Islands was challenging. Without many places to plug in. Sometimes they have used a portable charger.

Jaqui Besley told the BBC about the challenges her son has faced charging the boat

His support crew is led by mum Jaqui.

"At some stops we've been pulling the boat out of the water to put it on a trailer and take it to a car charger," she said.

"In supermarket car parks, a fast charger is ideal. We've been doing that in the middle of the night to meet the next tide."

Harry avoided the worst of the worst part of the journey round the tip of Scotland by passing through the Caledonian Canal and Loch Ness.

After charging stops in Shoreham, Cowes, Poole and Portland, Harry will nearly be at the start and finish line in Lyme Regis.

He says he will become the youngest person to circumnavigate the UK in a powerboat, and the first person to achieve it in an electric boat.

What next? "Sleep!" he says. "Then A-level results in a few days. After that, who knows?"

The point? Proving what is possible.

And, just like plugging in an electric car, charging an electric boat should get easier in the years ahead.