Zf174. A closer look at the USNS Pecos T-AO 197 moored to the Alava Extension Wharf on the 10th of June 2021. It is a United States Naval Ship of the Military Sealift Command (MSC). Military Sealift Command (MSC), division within the U.S. Navy charged with delivering supplies to bases and ships worldwide through the operation of a wide variety of resupply, transport, and auxiliary ships.