Captain Ken-ichi Horie, aboard the Suntory Mermaid II, prepares to travel solo 4,350 miles from Hawaii to Japan on wave power alone. S. Yamada

It was all smooth sailing for seafaring extremist Ken-ichi Horie. That wasn’t exactly what he was hoping for when he set sail for Japan from Hawaii in the world’s most sophisticated wave-powered boat, named the _Suntory Mermaid II.

As we reported earlier, Horie aimed to make the 4,350-mile cross-Pacific trip in 60 days, about 50 days longer than it would take him in a diesel-powered craft—but infinitely more eco friendly. Instead, the [ 111 days, owing to an unusually long stretch of good weather and flat seas.

Traveling an average of 1.5 knots, 69-year-old Horie certainly didn’t set any speed records but he did set one for the longest ocean voyage made in a wave-powered craft, proving along the way that a fossil-fuel-free propulsion system can work, albeit leisurely, under real-world maritime conditions. Congrats to Mr. Horie and team.