RedactedNarrative: VESSEL 1 WAS UNLOADING AT THE CHICKEN CREEK CAMPGROUND BOAT RAMP.  THE OPERATOR ATTEMPTED TO START THE ENGINE AND THE ENGINE COMPARTMENT EXPLODED.  THE OPERATOR AND JUVENILE PASSENGER JUMPED OVERBOARD AND WENT TO SHORE.  THE OPERATOR STATED HE TRIED TO START THE ENGINE AND IT WOULD NOT START. AFTER THE FIRST ATTEMPT, HE TURNED ON THE VENTILATION FOR APPROX. 20-30 SECONDS AND THEN ATTEMPTED TO START THE ENGINE AGAIN AND THAT'S WHEN THE EXPLOSION OCCURRED.