RedactedNarrative: Vessel 1 was pulling two people on a tube.  One of the subjects fell off the tube.  Vessel 1 turned around and pulled alongside the subject who had fallen off the tube.  The operator believed he had put the vessel into neutral when he pulled alongside the displaced tuber.  The person who was still on the tube  had made it to the rear of the vessel and was attempting to board the vessel when he was caught it the prop of vessel 1.  The operator had failed to put the vessel into neutral and put the vessel into reverse.  victim was transported by ambulance to the hospital for treatment.  Investigation is pending.