RedactedNarrative: SYNOPSIS
  I responded to reports of a vessel on fire in Face Canyon. I arrived on scene to find an Antelope Point Marina houseboat that had it's starboard side generator start on fire.  The fire was extinguished with fire extinguishers by the vessel renters/occupants prior to our arrival.  NPS fire personnel responded. Fire was deemed to be electrical in nature.
  
  INITIAL CALL
  At approximately 1655 hours on 7/21/19, I overheard NPS dispatch sending Dangling Rope area Ranger to a call for a houseboat fire in Face Canyon. I was just clearing a contact and informed NPS dispatch I would respond as well from my location near Lone Rock.  While in route NPS Ranger requested a response from the Wahweap NPS fire vessel.  NPS fire personnel responded they would also be in route with the fire vessel. I arrived on scene at approximately 1720 hours.
  
  INVESTIGATION
  NPS Ranger was already on scene and informed me the fire had already been extinguished by the vessel occupants.  I observed the starboard side engine/generator compartment door was open.  Inside I could see some smoldering still occurring from the starboard side generator, specifically from electrical components on the generator. I also observed two empty fire extinguishers nearby and a lot of extinguisher powder on the generator.  
  
  The houseboat renter informed me they had noticed smoke coming out of the compartment housing the generator and had everyone who was on the vessel exit the vessel to shore and removed their personal ski type vessel from the stern area of the houseboat.  He stated he had turned off the breakers for the generator and then when the smoke had gotten even worse they had used 2 fire extinguishers on the generator and extinguished the fire.  
  
  Subject stated he thought the smell of the fire indicated it was primarily an electrical fire.  It did not appear the fire had accessed any type of fuel source (gasoline for generators or engines).  I noted that there was still some smoke/smoldering coming from some electrical components on the far starboard side of the generator where the most amount of extinguisher dust appeared to be (likely source of fire/primary target for the extinguishers to be aimed at). Subject stated that area seemed to be where the fire had originated from.
  
  Subject informed me they had stayed on this same vessel the previous night at the docks at Antelope Marina and had issues with this generator that night.  He stated the issue was brought the attention of the rental company staff and someone had come and taken a look at it.  Subject stated the Antelope Point Marina personnel had told him it was fine and wouldn't be a problem.
  
  I also spoke with subject2, who had been on board the vessel at the time of the fire.  He explained that he had originally noticed the smoke coming from that compartment and notified Subject of the issue.  He informed me that when the smoke had become heavier they had used the fire extinguishers to contain the fire. 
  
  I then awaited the arrival of NPS fire personnel to make sure the fire was completely extinguished and to get their opinion on what type of fire it may have been.  The NPS fire vessel arrived at approximately 1740 hours.  NPS Rangers/Fire Fighters surveyed the fire and checked for heat levels in the generator compartment.  I asked the NPS fire personnel if they also believed the fire had been primarily electrical in nature and they stated that was their opinion.  NPS Ranger/Fire Fighter pointed out there was a fire suppression system inside the generator compartment that had not functioned.  He pointed out the gauge on the extinguisher cylinder for the suppression system was in the red on the overcharged side.
  
  Antelope Point Marina personnel also arrived on scene to survey the damage and assist their customers.  I spoke with a male who identified himself as the manager of the boats.  I asked him if he thought the generator was a total loss and he stated it was.  I asked him approximately how much a new generator would cost to replace it, and he stated about $25,000. He had his co-workers start making calls to get a replacement houseboat on its way up to replace this one.
  
  CONCLUSION
  The following conclusions are based on witness accounts, my experience in vessel accident investigations and the opinions of NPS fire personnel who were on scene.
  
  It would appear that there was some type of mechanical and/or electrical issue with the electrical components on the starboard side generator which caused the electrical components to catch on fire.  Fortunately, someone observed smoke coming from the exhaust vent from the generator comparment and alerted others to the possible fire.  Although power was quickly turned off to the generator, it still caught fire and the vessel occupants then took appropriate action and extinguished the fire using portable fire extinguishers on the vessel before the fire could ignite any of the fuel sources (gasoline) in close proximity and within the generator.  This fire should have been extinguished by the onboard fire suppression system present in the generator/engine compartment.  There was a failure in the suppression system on the vessel.  Had the occupants/renters not extinguished the fire themselves the fire would have likely continued and ignited the existing fuel sources in close proximity which would have led to the entire vessel becoming engulfed in flame.
  
  Photos of the generator and the fire suppression system bottle are attached.  It is hard to tell from the angle of the photo, but the gauge on the bottle had the needle in the red area indicated as "oversharged".
  