The Wave Runner  

Popular Science has an article on an interesting idea - a wave powered boat. It also has some solar panels for powering onboard devices and a backup outboard engine for emergencies.

This month, 69-year-old Japanese sailor Ken-ichi Horie will attempt to captain the world’s most advanced wave-powered boat 4,350 miles from Hawaii to Japan. If all goes as planned, he’ll set the first Guinness world record for the longest distance traveled by a wave-powered boat and, along the way, show off the greenest nautical propulsion system since the sail.

At the heart of the record-setting bid is the Suntory Mermaid II, a three-ton catamaran made of recycled aluminum alloy that turns wave energy into thrust. Two fins mounted side by side beneath the bow move up and down with the incoming waves and generate dolphin-like kicks that propel the boat forward. “Waves are a negative factor for a ship—they slow it down,” says Yutaka Terao, an engineering professor at Tokai University in Japan who designed the boat’s propulsion system. “But the Suntory can transform wave energy into propulsive power regardless of where the wave comes from.” ...

With a maximum speed of five knots, the Suntory will take two to three months to complete a voyage that diesel-powered craft accomplish in just one. But speed is not the point. The voyage aims to prove that wave propulsion can work under real-world conditions, opening up the technology for commercial applications such as cargo shipping. “Oil is a limited power source,” Horie says, “but there is no limit to waves.”