RedactedNarrative: Preliminary information is that deceased initially was operating the vessel but because of the cold air temperature decided to go into the cabin and lay down on the couch.  
  
  When they arrived to their destination his father who took over operation of the vessel docked the vessel and went to check on his son who he thought was sleeping.  He was unresponsive.  MA CPAC detective went to the vessel and there was a heavy odor of exhaust fumes inside the cabin. 
  
   ER DR advised that deceased carbon monoxide levels were greater than 50 and a normal read is 0-5.  Cause of accident engine exhaust leak.