TOKYO — Japanese adventurer Kenichi Horie took more than three months to sail from Hawai'i to Japan in a boat powered by the energy of ocean waves, but says he was blessed with good weather and tasty fish.

"The sea was so calm, and the weather was so great throughout my journey. That's why it took me so long," he said yesterday.

Before he left Hawai'i in March, Horie said expected the trip to take 2 1/2 months.

The 4,800-mile voyage, which began in Honolulu, ended Friday when his 3-ton yacht docked in Wakayama in western Japan.

The trip — which Horie claims was the world's longest solo voyage in a wave-powered boat — is just the latest journey using green technology for the 69-year-old sailor.

In 1992, Horie pedaled a boat from Hawai'i to Okinawa in southern Japan.

In 1996, he sailed nearly 10,000 miles from Ecuador to Tokyo aboard a solar-powered boat made from recycled aluminum beer cans.

Horie's most recent trip would have taken just 10 days in a regular diesel-powered boat.

But he said he is raising awareness about ecology, although his endeavors may take a bit longer.

His boat, which relies on wave energy to move two fins at its bow and propel it forward, sailed at an average speed of 1.5 knots — slower than humans walk.

"I've been thinking about riding a wave-powered boat for 30 years, and finally my dream came true. The journey was so fun, and it was easy," he said in a telephone interview from his yacht in Osaka Bay in western Japan.

Horie ate mostly rice and curry that he brought along on the boat, but sometimes ate squid and flying fish that he caught.

The 31-foot boat, the Suntory Mermaid II, was designed to right itself if it capsized and was equipped with an engine and a sail for emergencies. But they were never needed because Horie didn't encounter a single storm.

Equipment on the boat, made of recycled aluminum, was all solar-powered, including navigation radios, a microwave and even Horie's razor.