RedactedNarrative: VESSEL 1 W#AS PARTICIPATING IN A BOAT PARADE THAT HAD APPROX. 2,400 BOATS.  THE WATER WAS EXTREMELY ROUGH DUE TO THE AMOUNT OF BOAT TRAFFIC.  VESSEL 1 TOOK A LARGE WAVE OVER THE BOW AND BECAME SWAMPED. AS MORE WAVES CAME OVER, VESSEL 1 COMPLETELY SANK IN 38 FEET OF WATER.  ALL 8 OCCUPANTS WERE ABLE TO HOLD ON THE OBJECTS FROM VESSEL 1 THAT WERE FLOATING AND WERE PICKED UP BY OTHER BOATERS THAT WERE NEAR.  AREA OF THE ACCIDENT WAS APPROXIMATELY 2.4 MILES WEST OF BELLE STAR MARINA AND APPROXIMATELY 1.7 MILES SOUTH OF INDIAN SPRINGS BOAT RAMP AND APPROXIMATELY .6 MILES EAST OF US HWY 69 NORTH CANADIAN RIVER BRIDGE.