RedactedNarrative: While on patrol on lake norman in the area of slanting bridge, myself and officer had been working the wake zone under slanting bridge.  Several minutes later, i heard a noise to my right and turned to see.  At that point i observed a vessel on fire and several individuals in the water.  Officer maneuvered our patrol boat to assist the individuals in the water.  I proceeded to throw pfds to those in the water and help them onboard our patrol vessel.  I assisted a male and a female passenger onboard our vessel.  At that point, proceeded to the nearby marina where fire and ems was located.  
  
  The operator of the vessel stated he had issues with the boat the entire time he owned it.   He said he had worked on the vessel periodically.  He stated they had been on the water for about 4 hours prior to stopping at the landing marina, and had had no issues that day.  After stopping at the marina and proceeding back on to the water, operator stated the backfire flame arrestor was working properly.  
  
  At about 200-300 yards from the dock, the operator stated he smelled gas and proceeded to cut the motor off.   At that point, the vessel caught on fire.  Operator stated that he had filled the vessel with fuel that morning at a nearby gas station.  he did not fill the tanks entirely and put around $35.00 in fuel, about 15 gallons.  I asked the operator if he had conducted any mechanical upgrades recently in regards to fuel system, battery, etc.  He stated he had not, and any general maintenance was completed several months prior.
  
  Exact cause of fire is unknown.  The vessel is burned to a point where it is difficult to determine the ignition point.
  
  Two people suffered burns.