United States Ship (abbreviated as USS or U.S.S.) is a ship prefix used to identify a commissioned ship of the United States Navy and only applies to a ship while she is in commission. Before commissioning, she is referred to as "Pre Commissioning Unit" (PCU).[1] After decommissioning, she is referred to by name, with no prefix.[2]
From the early beginnings of the U.S. Navy there had been no standard method of referring to U.S. Navy ships until 1907 when President Theodore Roosevelt issued Executive Order 549 on 8 January stating that all US Navy ships were to be referred to as "The name of such vessel, preceded by the words, United States Ship, or the letters U.S.S., and by no other words or letters".[2]
Today's Navy Regulations define the classification and status of naval ships and craft: