Photos: One-of-a-kind powerboat

The four Earthrace crew members, who are from New Zealand, are docking in 30 cities. They've already been to New Zealand, Samoa, Vancouver, Hawaii, Seattle and San Francisco and they're headed through the Panama Canal, up the East Coast, then through the St. Lawrence Seaway into the Great Lakes, and down the Mississippi into New Orleans.

In March 2007, the crew will race the Earthrace powerboat in an international competition to circumnavigate the globe at about 24,000 nautical miles, starting in Barbados. Earthrace, which will be the first official boat in the competition to be powered by biodiesel, aims to break the world record of 75 days.

Extremely high-tech, the boat is a so-called trimaran at about 78 feet in length with a hull design that can slice through waves. It's constructed largely of a lightweight carbon composite, which is typically used in military aircraft, and Kevlar. It's equipped with two low-emissions diesel engines called Cummins Mercruiser Diesel engines, which can hold as much as 3,000 gallons of biodiesel. The weight of the craft doubles when the boat is refueled.

Inside the Earthrace boat, there are two seats for navigating the wave-piercing trimaran. So far, Earthrace has barreled through and survived waves as high as 40 feet in seas off New Zealand. The powerboat can travel a maximum speed of 45 knots, or 55 mph.

The Earthrace Project has so far raised about $3 million in cash and sponsorships, including a $750,000 second mortgage on Bethune's home in New Zealand, to build the powerboat and fund the trip to 30 cities in six months. Sponsors include Panasonic, Cummins Mercruiser, BioDiesel Oils NZ, Reef Bulk Fuels and Hiway Stabilizers Environmental.

Earthrace's unique design allows the boat to travel through the middle of a massive wave to come out the other side. The hull, which is curved and designed to stay above water while the boat pierces waves at about 24 feet tall, ventilates the cabin in stormy seas.

Bethune holds court in the powerboat he commissioned from navel architect Craig Loomis Design Group. The boat was built by Calibre Boats, a purveyor of high-tech custom yachts. Bethune has been living on the boat for the last couple of months with three other crew members in tight quarters. The boat technically sleeps eight, but there are only six bunk beds that line the inside of the front of the boat.

Two bunk beds are laid out under a skylight at the nose of the vessel. Among the four crew members of Earthrace, it's first-come first-served to the beds.

Bethune on the deck of the Earthrace powerboat in a San Francisco port. The boat looks like a giant winged Batmobile on the ocean, with tribal drawings etched into the vessel.