RedactedNarrative: Investigator narrative for Desert Sun houseboat fire at Lake Powell, Glen Canyon National Recreation Area (GLCA).  Date of the fire was September 13, 2023.  At about 12:10pm while underway on both engines, the Desert Sun houseboat experienced an explosion and fire in or around the engine compartment that resulted in a total loss of the vessel.  There were 29 people aboard the vessel at the time of the fire.  All were able to escape into the water and passing vessels without injuries.  The vessel burned completely and sank to the bottom of Lake Powell.
  
  The Desert Sun was a 2002 model Stardust houseboat, 75 feet long with a beam of 16ft.  The hull, as well as the on-board fuel tanks were constructed of welded aluminum.  The vessel was powered by two MerCruiser 383 stroker engines. Both engines were contained in a shared, closed compartment with separate access hatches.  In between the two engines was the on-board 24 horsepower Westerbeke generator.  Desert Sun was operated out of the Antelope Point Marina and had an active mooring and maintenance contract with the marina. The vessel was owned by Arizona Desert LLC and operated as a time-share amongst the multiple owners. Desert Sun was insured by Markel American Insurance Company, the policy was in effect and in good standing with no recent changes.
  
  The fire resulted in the complete sinking of the remaining aluminum hull therefore, no in-person scene investigation took place.  The responding Law Enforcement Rangers from GLCA gathered written witness statements from the adults on board the vessel at the time of the fire.  The team followed up with interviews of the vessel’s partial owners.  Through witness statements and interviews it was clear that there had been on-going mechanical issues with the starboard engine.  It had intermittent times that the engine would not start.  Owners took the boat out for their week of use in June and had no issues with the starboard engine.  However, subsequent users would use it for a time and then be unable to start it.  This led to the starboard engine not being used for the month leading up to the day of the fire. 
  
  Subject1 was the owner using the vessel on the day of the fire.  He stated that no less than 5 different mechanics from Antelope Point Marina had attempted to fix the starboard engine.  His week of use was coming up and he needed to use both engines because of the amount of weight he would have on the boat and the distance he planned to travel.  He reached out to another maintenance company, Unlimited Houseboat Services (UHS) in order to try a last attempt at fixing the troublesome engine.  That morning, a mechanic from UHS identified that the timing was off.  He replaced the spark plugs and adjusted the timing.  The starboard engine started and was run for approximately 30 minutes prior to departure to ensure it was operating properly.  The owner and mechanic were satisfied that the engine was running properly and the vessel left the dock.  The team made numerous attempts to contact and interview the mechanic that worked on the boat the morning of the incident but were unable to make contact.  Boat owners were able to provide some, not all, of the repair invoices from the last year but none from the month previous to the incident.
  
  The vessel was underway on both engines, with the bilge pump running and the generator secured. Approximately 45 minutes after leaving the dock, Operator noticed the starboard engine RPMs began to drop despite the throttle placement.  As he began to investigate if there was an issue, he decided to shut down the engine but before he could, a very loud explosion occurred at the rear of the boat.  Instantly several passengers recognized 5-foot flames at the rear of the boat, yelling “fire!”  The boat’s occupants began to evacuate and all made it into the water or good Samaritan boats without injury.
  
  The vessel’s fuel tank was full of 200 gallons of fuel when it left the dock.  There was also an auxiliary tank on the rear deck with approximately 150 gallons of fuel. Based upon the information provided and gathered, it is consistent with a fire where there was a buildup of flammable fluids and/or gases in the engine compartment.  This buildup was able to overcome the natural ventilation provided and got the explosive range and was possibly ignited by either one of the running engines or the running bilge pump.  There’s no way to survey the hull to be certain.  This ignition likely spread to the auxiliary tank and free burning gasoline spread the fire quickly throughout the vessel.  Based on a reasonable degree of investigative certainty, the fire is ruled as accidental pending any additional information that may determine otherwise.
  
NameOfBodyOfWater: LAKE POWELL
NearestCityTown: PAGE                          