RedactedNarrative: VESSEL 1 WAS TRAVELING EASTBOUND JUST WEST OF THE SPILLWAY.  VESSEL 2 WAS PERFORMING "DOUGHNUTS" IN A COUNTER-CLOCKWISE DIRECTION JUST WEST OF THE SPILLWAY DAM.  OPERATOR OF VESSEL 2 STATED HE DID NOT SEE VESSEL 1.  OPERATOR OF VESSEL 1 STATED HE WAS GOING TO PASS BY VESSEL 2 ON THE NORTH (STARBOARD) SIDE OF VESSEL 2 WHEN VESSEL 2 TURNED OUT OF HIS "DOUGHNUT" AS VESSEL 1 WAS PASSING.  VESSEL 2 STRUCK VESSEL 1 NEAR THE STERN ON THE STARBOARD SIDE PUNCTURING A HOLE IN THE HULL CAUSING VESSEL 1 TO BEGIN SINKING.  AREA OF IMPACT WAS APPROX 156 FEET WEST OF THE EAST SHORELINE AND APPROX 120 FEET NORTH OF THE SOUTH SHORELINE AND APPROX 2608 FEET EAST OF THE WEST SHORELINE.