Just a pair of floral boardies and a surfboard - for 50nm.

Skeleton Bay - eat your heart out. This guy just surfed for 50nm in the Alenuih?h? Channel, between the Hawaiian islands of Maui and Hawai'i.

Using nothing but a shortboard and a hydrofoil, Kai Lenny made the crossing earlier this week as part of his 'Downwind Challenge'. He's on a mission along with Sustainable Coastlines Hawaii to clean up the beaches in Hawaii, so each time he stops he's getting together with the locals and stripping the beach of plastic waste.

Not only in Hawaii, Lenny has been cleaning up the beach all over the world; "The beautiful beach in front of our house in Tahiti was littered with trash." He comments online "With our combined speed, Doug and I cleaned up most of the beach at Papara in about 10 minutes. It was honestly way to easy to do, and so much better to enjoy later."

But lets get back to the surfboard he used, It's a little yellow shortboard, around 6'0" and shaped by Naish. Not that it matters, because it spends most of its time out of the water thanks to a hydrofoil below the surface. This is how Lenny manages to surf for such long distances on unbroken waves. If he falls off (which is rare), he's such a quick paddler, and the foil generates so much lift, he can simply paddle back into the ocean swell, pop up and then pump the foil up to speed.

Red Bull are making a short film about the project, due out on the 18th April; and Lenny has crossings planned for the rest of the Hawaiian Islands by kite, sailboard and SUP in the coming weeks.