SEATTLE (AP) - A boat caught fire during today's Seafair hydroplane race on Lake Washington, forcing the driver to climb out and jump into the water. It happened during a preliminary heat, when the Plumbing Joint driven by Kevin Aylesworth blew its turbine engine in the last turn. Aylesworth clambered out of the cockpit and jumped into the water as the fire burned. He was taken by boat to an aid station in the pit area, where medical personnel examined him. The U-S Coast Guard and Seattle fire and police departments responded to the fire, which was extinguished with fire-retardant foam.