RedactedNarrative: UNIT 1 AND UNIT 2 WERE TRAVELING SOUTHEAST ON LAKE GREENWOOD AT APPROXIMATELY 20-30 MPH.  UNIT 2 WAS BEHIND UNIT 1 ON THE PORT SIDE.  UNIT 1 TURNED TO PORT RESULTING IN A COLLISION BETWEEN UNITS 1 AND 2.  UNIT 1 STRUCK UNIT 2 IN THE STARBOARD REAR.