UNIT 1 WAS LOADING HIS VESSEL ONTO HIS TRAILER, WHILE OPERATOR OF UNIT 2 WAS DROPPING OFF THE OWNER OF UNIT 2 ONTO THE DOCK AND HAD THE BOAT POSITIONED BEHIND UNIT 1. THE OPERATOR OF UNIT 2 THEN PULLED AWAY FROM THE DOCK AND CUT UNIT 2 TO THE LEFT TO DO APPROXIMATELY AN 180 DEGREE TURN, AND IN DOING SO, THE REAR LEFT SIDE OF UNIT 2 HIT THE MOTOR OF UNIT 1 BREAKING OFF A SECTION OF THE SKEG AND BENDING ONE OF THE FINS OF THE PROPELLER. THE OWNER/ OPERATOR OF UNIT 1 WAS KNOCKED DOWN DUE TO THE IMPACT. CONCLUDING THE INVESTIGATION THE OPERATOR OF UNIT 2 WAS ISSUED A CITATION FOR NEGLIGENT BOAT OPERATION.