RedactedNarrative: OPERATOR 1 HAD VESSEL ON THE TRAILER, STARTED ONE ENGINE AND WAS ATTEMPTING TO START THE OTHER ENGINE WHEN THE ENGINE COMPARTMENT EXPLODED AND BECAME FULLY ENGULFED.  OPERATOR 1 LEFT VESSEL 1 VOLUNTARILY AND PUSHED VESSEL 1 AWAY FROM THE TRAILER ON THE LAUNCH RAMP.  VESSEL 1 BURNED TO THE WATERLINE.  OPERATOR 1 HAD A MODERATE INJURY BUT REFUSED TREATMENT AT THE SCENE.