IN THE AGE OF $3-A-GALLON gasoline, why would anyone want to convert a nine-ton truck into a support vehicle for a round-the-world kayak trip? Precisely because this is the age of $3-a-gallon gasoline. Montana kayakers Tyler Bradt, 20, and Seth Warren, 29, turned their 1987 Toyota—once part of a firehouse fleet near Mount Fuji, Japan—into a biodiesel RV, complete with an onboard press that can squeeze fuel directly from grains like corn and soy. Starting July 1, the pair, usually seen in kayak films plummeting off 70-foot waterfalls, will chase summer south from Prudhoe Bay, Alaska, to Cape Horn, Chile, paddling and preaching the gospel of straight vegetable oil at schools and outdoor shops for nine months. "I'll be calling the ol' Japanese fire truck home for the foreseeable future," says Bradt.

Kavu, Keen, MSR, and Clif Bar have donated $15,000 apiece to the $85,000 project, with Warren and Bradt covering the rest. "It's not just two guys going out to have a fun trip," says Keen marketing manager Erika Bruhn. "The real draw for us was that they're going cross-country educating kids." The two, who hope to extend the trip to Europe, Africa, and Asia, have been test-driving the truck across the U.S. since March, using grain and discarded restaurant grease to fill the gas tanks to their 180-gallon capacity. "Kayakers need alternative fuels," says Warren, "because we're the ones who need SUVs."