RedactedNarrative: Operator WAS TRAVELING WEST ON THE ENO RIVER AT ABOUT 18:00 HRS.  HE STATED HE WAS MOVING LESS THAN 20 MPH AND STRUCK A SUBMERGED LOG.  THE VESSEL CAME TO A COMPLETE STOP.  THE BACK WASH CAME OVER THE TRANSOM.  THE AMOUNT OF WATER CAUSED THE VESSEL TO SWAMP AND IT IMMEDIATELY BEGAN TO SINK.  operator SAFELY SWAM TO SHORE AND CALLED FOR HELP.  Restricted vision was entered because of the poor visibility (rain, dark).