RedactedNarrative: Received a 911 call from a bank fisherman advising of a vessel sinking below the Ozark Lock and Dam.  Upon arrival at the scene, both occupants of V1 were located safe after they swam to the bank.  They advised that they tried to anchor in front of the generators but realized the generators were running so they moved over in front of the flood gates.  The operator stated he anchored V1 from the stern and then dropped an anchor from the bow.  The stern anchor got caught and V1 began taking on water.  Both occupants were able to put on PFD's and swim to the bank.  The lock master advised that every gate was open slightly with a flow of 58,200 CFS.  V1 was not located until the following day.  It was upside down with the bow anchor hung in a rock jetty; so Ken's Towing company was contacted to remove the vessel.