RedactedNarrative: OPERATOR OF VESSEL ONE LEFT "KAHUNA MART" AFTER FUELING THE VESSEL.  AFTER IDLING APPROXIMATELY 25-50 YARDS, FROM "KAHUNA MART", THERE WAS A LOUD BOOM.  THE OPERATOR AND OCCUPANT LOOKED BACK TO SEE THE MOTOR BOX BLOWN OFF AND ON FIRE.  THE OPERATOR ATTEMPTED TO GET THE FIRE EXTINGUISHER BUT DECIDED TO GRAB PFDS INSTEAD AND SWIM BACK TO "KAHUNA MART".