Atlantic Exercise The littoral combat ship USS Sioux City conducts live-fire exercises with a 57mm gun during operations in the Atlantic Ocean, April 2, 2021. Sioux City is supporting naval operations to maintain stability and security in the Atlantic and Arctic Ocean. SHARE: Download: Full Size (0.48 MB) Tags: Navy Credit: Navy Petty Officer 2nd Class Marianne Guemo VIRIN: 210402-N-RL695-2003A.JPG Photo Gallery