Wind power has had the monopoly on sustainably powering boats for too long, according to one innovative Japanese sailor and designer. Fins that raise and lower with the surrounding waves generate the power to propel the boat while solar power is used for on-board energy needs. Together these alternative energy sources. It took him 108 days – far longer than it would a diesel-powered boat – but Ken’ichi Horie successfully crossed from Hawaii to Japan earlier this year in his wave-powered boat.