RedactedNarrative: At approximately 1317 hours a 40ft formula completed fueling with 129 gallons of gasoline at tarpon point marina, in cape coral, florida. the operator of v1 attempted to start one of the engines, the engine failed to start. the operator then attempted to start the other engine, several clicking sounds were heard and a large explosion occurred below deck. the explosion shattered the windshield sending broken glass and other debris flying. the engine cover was blown off and landed on v2 which was docked behind v1. several people helped the occupants off the vessel before the vessel was engulfed in flames. the harbor master pushed the burning vessel away from the dock to create distance from the fuel pumps. a good samaritain vessel towed the v1 away from the docks, cape coral f.d. arrived and attemtped to extinguish the fire, vessel eventually sank.