The vessel was traveling upstream just passed the first interstate bridge 1/2 mile above Bettys Island ramp on the Caney Fork river.  The motor on the vessel quit running and the vessel started drifting back downstream.  The driver jumped up and went to the front of the boat to use the trolling motor. The trolling motor only worked for a few minutes and quit working. The boat began to drift back downstream and struck a bridge pilon and capsized. The occupants grabbed PFDS and swam to shore. They were picked up by other fishermen and taken back to the ramp. Upon arrival i did not find the boat at the accident site.  We shortly foun d the boat adrift just above Bettys Island and pulled it to the ramp.
CLIFTON                       