RedactedNarrative: On may 24, 2015 at approximately 1145 hours operator informed me that he was operating his vessel near the mouth of big creek just north of russell bridge on lake sidney lanier.  Operator observed another vessel in front of him.  He shifted his vessel into reverse in order to try and avoid the other vessel.  Operator advised me that he did not hit the other vessel or any fixed object.  Operator vessel began to fill up with water and eventually sank.  Operator advised me that he thinks there may have been a breach in the hull or the bilge pump may have malfunctioned.  The vessel remains on the bottom of the lake at the moment.