RedactedNarrative: V1 HAD JUST FUELED UP AT ADVENTURE MARINA IN FORT WALTON BEACH.  THE OPERATOR TURNED THE KEY TO THE STARBOARD ENGINE, AND AN EXPLOSION OCCURRED.  SEVERAL OCCUPANTS WERE EJECTED AND THE REMAINING VOLUNTARILY ENTERED THE WATER.  THE VESSEL BURNED FOR SEVERAL HOURS CAUSING CATASTROPHIC DAMAGE TO THE VESSEL.
  
  On 05/28/16, just before noon, V1 (Alabama Vessel AL-1531-RB) pulled up to the fuel dock at Adventure Marina in Fort Walton Beach for fuel.  V1 was facing east.  After fueling V1, the operator attempted to start the starboard engine.  Within seconds, an explosion occurred, causing multiple occupants to be ejected and others to abandon V1 and swim to shore.  The explosion caused minor damage and minor injuries to a nearby vessel and occupants (FL-5530-RB). 
  
  Shortly after the explosion, a local boat captain partially untied V1 and pushed it away from the fuel dock.  V1 ultimately rotated 180 degrees and was re-secured to the dock.  V1 was now facing west.  Fire Rescue attempted to put the fire out.  Eventually, V1 was moved away from the fuel dock and beached on the shoreline to the west of the dock where Fire Rescue continued to fight the fire.  
  
  The operator stated multiple times that he always kept the exhaust blowers on while he is on the boat.  After speaking to the State Fire Marshall Detective, it appears there is no immediately apparent reason for the explosion.  One possibility is that the exhaust blowers were not turned on, or that the switches or wiring was faulty leading the operator to believe they were on when in fact they were not.  
  
  The scene around V1's explosion revealed scattered glass on the dock as well as on the nearby shoreline extending approximately 55' from V1.  Also a window latch was located on the south side of the Adventure Marina building approximately 63' from V1.  After reviewing statements from the operator, occupants, witnesses, and physical evidence, I conclude that there are no violations and the cause of the accident is unknown.
  
   Occupant1: Head and neck trauma, began hurting after the accident.; Occupant3:2 cm laceration on right leg, 5" below the knee; Occupant2:1st degree burns on right leg (9%) and hematoma on head; Occupant4:Abrasion to left shin and burns on both thighs
  