Petty Officer 3rd Class Geoffrey Martin, gunner’s mate, assigned to Riverine Squadron 1, fires a GAU-17A gun from the bow of a riverine assault boat during live fire battle drills at Fort Knox, Ky. RIVRON-1 participated in a three-day field exercise to prepare for an upcoming deployment. (U.S. Navy photo by Petty Officer 3rd Class Bryan Weyers, mass communication specialist)