RedactedNarrative: VESSEL ONE WAS TRAVELING, ON PLANE, WEST ON THE ARKANSAS RIVER WHEN THE OPERATOR FELT THE LOWER UNIT IMPACT A SUBMERGED LOG.  THE OPERATOR IMMEDIDATELY NOTICED AN EXTREME VIBRATION IN THE STEERING.  HE STOPPED AND INSPECTED THE PROP AND LOWER UNIT AND NOTICED A PROP WAS BROKEN OFF AND THE SHAFT WAS BENT.