Passengers on board were taking turns jumping off a rope swing into the water and then swimming back to the boat.  The injured who had been drinking during the day, swam back to the boat and the same time the operator put the boat in reverse and struck the swimmer.  The operator took the proper precautions to comply with the improper lookout law by looking into his rear view mirror and having a passenger as a lookout according to the witness statements and investigator and no one saw the swimmer behind the boat.  The injured was either underwater or too close to the swim platform to be seen and also did not indicate verbally he was behind the vessel.  The investigator concluded that it was the actions of the swimmer that caused this accident not the operator. 
Groton