RedactedNarrative: At approximately 19:30 on 11/22/22 I received a call from TWRA dispatch that Claiborne county dispatch had gotten a 911 call from someone at Cedar Grove Marina stating that a houseboat was on fire in the harbor at the marina, nearest the shoreline of the Cape Norris Community.  We responded to the scene.  Upon arriving on scene we found a houseboat,, fully engulfed in flames, along with floating cottage (4B boat) FC-2481, a small fish and ski type boat also fully engulfed, and the dock to which they were moored fully engulfed in flames, with the dock roofing partially collapsed.  Fire apparatus on scene were having difficulty reaching the fire from the shoreline. Fire hoses were loaded onto the two patrol boats and dragged nearer to the engulfed boats where water could be more effectively applied to the fire until the fire was extinguished.  Eventually the fires were able to be extinguished but not before the floating cottage, the houseboat and the fishing boat were totally destroyed.  Also damaged in the fire was the floating cottage, which was moored nearest the fire suffering damage in the form of melted siding and other heat related damage to the dock and roof.  While speaking with Owner on scene it was determined that noone was onboard the houseboat and noone was occupying the 4B boat at the time of the fire.  Owner did state that one individual had been onboard the houseboat earlier that evening and had left to go fishing prior to the fire beginning. Owner also stated that when he first saw the fire that boat boats were on fire therefore he had no way of knowing which structure began the fire.  The individual who had been on board the houseboat prior to the fire was identified.  Upon interviewing he stated that he had been on board the houseboat earlier in the day cleaning up an had left somewhere around 18:30 to go fishing.  Owner stated that there were two space heaters plugged in and operating on the houseboat when he left to go fishing.  He further stated that while fishing, he received a call from  the owner of the adjacent 4B boat, informing him that the houseboat was on fire.  He stated that he had no knowledge as to how or where the fire began.  Upon speaking with the owner of the houseboat, he advised that he had recently had an individual come and do an inspection on the houseboat. He advised that he had only recently purchased the boat and had attempted to get the boat insured.  He stated that his insurance company requested the inspection prior to issuing a policy on the vessel.  I requested that he provide me a copy of the inspection report which he said he would.  Once received a copy of that report will be included with this report.  Upon speaking with the owner of the 4B boat, which was also completely destroyed stated that his boat was closed up for the season and no devices, heaters, chargers etc. were being used on his floating cottage at the time of the fire.  The owners of the fish and ski boat have yet to be located, therefore no vessel information is available for that vessel as it was completely destroyed. The investigation into this incident is ongoing and information will be added to this report as it is gathered.  These events occurred on Norris Lake in Claiborne County TN.