RedactedNarrative: UNIT1 LAUNCHED FROM HWY 34 LANDING ON LAKE GREENWOOD.  AFTER TURNING ON BLOWERS, OPERATOR IDLED AWAY FROM DOCK AND PLACED TWO PASSENGERS INTO A TOWABLE AND BEGAN TO BRING THE VESSEL UP TO SPEED.  AT THIS POINT AN EXPLOSION OCCURRED  CAUSING A FIRE.  THE OPERATOR THREW THE REMAINING PASSENGERS INTO THE WATER TO PREVENT THEM FROM GETTING BURNS.  OPERATOR ATTEMPTED TO EXTINGUISH FIRE WITH MULTIPLE FIRE EXTINGUISHERS WITH NO SUCCESS.  ONE PASSENGER WAS TAKEN TO HOSPITAL FOR TREATMENT OF BURNS.  The operator also suffered burns. FUEL/VAPOR IGNITED DUE TO BLOWER FAILURE OR FAILURE TO PROPERLY VENT.