RedactedNarrative: Saturday night, October 10th, 2015, operator was operating his vessel on Center Hill Lake in DeKalb County, TN.  They were driving to Cove Hollow Marina after attending the fall cruise on the lake.  While operating his vessel downstream around the peninsula that extends from the mouth of Holmes Creek the fog became extremely heavy.  Operator said the visibility was extremely low and he was having to rely on his cell phone''s GPS.  He said that the GPS was showing them to be in the channel when he saw the rocky shoreline appear directly in front of them.  He made an abrupt port turn to avoid a head on collision with the rocky shoreline.  The boat hit the boulders with the bow angling to the left.  The keel toward the bow struck from the boulders and knocked a hole in the fiberglass.  The boat traveled on the rocky shoreline for approximately 30 feet before it came to a stop.  The boat has substantial damage to the hull and the lower units of the I/O engines.