RedactedNarrative: UNIT 1 WAS UNDERWAY AT FULL POWER CRUISING WHEN THE VESSEL BEGAN TO SMOKE. THE OPERATOR NOTICED IT WAS AN ELECTRICAL FIRE SMELL SO HE OPENED THE HATCH AND EVERYTHING UNDER THE HATCH WAS ON FIRE. THE OPERATOR IMMEDIATELY STOPPED THE VESSEL ANCHORED AND USED THE FIRE EXTINGUISHER TO PUT OUT THE FIRE. THE OPERATOR CLAIMED THE FIRE CAME FROM A BATTERY ISOLATOR