RedactedNarrative: On September 21, 2019 Operator was operating his vessel on Nickajack Lake in Marion County Tennessee.  He had been out most of the day and after sunset he was heading upriver. Operator at some point noticed something in the water, at the last second he swerved to his right and struck what he later realized was a large rockpile located in the water marking the old railroad bed.   Operator indicated he was traveling approximately 55 mph at the time of the impact. He was able to get the vessel to TVA Shellmound Recreation Area and get it loaded on the trailer.