Japanese sailor Kenichi Horie, who has sailed nonstop around the world and crossed the Pacific in a solar-powered boat made of recycled aluminum beer cans, is off on his next solo adventure at sea.

Horie set sail for Japan on March 16 from the Hawaii Yacht Club in what he says will be the world's longest voyage in a wave-powered boat.

The 69-year-old mariner will travel nearly 6,400 km aboard a 3-ton yacht called the Suntory Mermaid II at a speed of up to 5 knots. The journey, which would take a diesel-powered boat about 10 days to complete, is expected to take Horie about 10 weeks.