Operator of vessel 1 moved approx 200 ft south of shoreline so that the operator and passenger could swim.  Operator failed to set an anchor prior to entering the water.  While swimming, the operator noticed the vessel drifting away and tried to swim to the boat.  Passenger 1 was able to swim back to the boat and tried to retrieve a life jacket for the operator.  When the passenger attempted to throw the life jacket, she noticed that the operator had submerged.  Passenger 1 stated the operator never resurfaced.  Passenger 1 remained on vessel 1 and the vessel drifted to the shoreline.  Area of the accident was approx 1602 ft ne of kiowa i boat ramp and approx 150 feet s of kiowa i camp site 150.  Operators body was recovered at approx 1945 hours the same day.
WAURIKA