RedactedNarrative: On the afternoon 5-30-16  while working boating enforcement on Cherokee Lake,  I observed a white 21 foot Baja Islander 208 boat being towed towards Kidwells Ridge Access Area.  At this time, I was flagged down by the operators wife. The operator stated that they had struck a submerged rock. Operator stated they had been on the water since about 12:00 hours. They had been cruising upstream from the Dam and headed towards Kidwells Ridge Access Area.  Operator advised the boat was on plane and traveling approximately 20mph.  The outdrive struck the submerged rock between PT  9 and Pt 10.The collision occurred at approximately 13:40 hours. A man who was camping on a nearby island gave the operator a tow back to Kidwells Ridge Access Area where the operator had launched his boat. The entire outdrive of the motor was broken loose and the prop was bent in several places. The skeg was also sheared off.  No hull damage was present.