RedactedNarrative: Previous to this fire the operator of vessel #1 fueled up at a gas station and states prior to launching make a point to leave the engine compartment open for a few minutes to release any built up vapors. He detached his vessel from his trailer, engaged the throttle in reverse, placed it in neutral and upon clutching ahead he heard a "pop" in the area of the engine compartment and observed smoke weeping from the seals of the cover. He lifted the cover to the engine compartment and immediately saw exposed flames originating from the base of the engine. He discharged the vessels type B-II fire extinguisher but was unsuccessful at distinguishing the flames. As the flames grew large and hotter and the smoke became more and more dense he abandoned the vessel and swam to shore. As this point his vessel drifted into vessel #2 which was moored and both vessels became fully engulfed in flames. No injuries but both vessels a total loss. Cause of accident is built up gasoline vapors within the engine compartment and/or fuel leakage within the bilge area.