Operator was discovered face down in the water floating. Operator was found by a fishing partner in another boat who discovered victim after he was late to meet at the Riverside Public Boat Ramp at 1600 hrs. boat was recovered 4 days later from the bottom of the river by SCDNR dive team.  THe boat was overloaded. It is assumed the boat took on water and sank.  THe operator subsequently drowned.