In the U.S. Navy and Coast Guard, first lieutenant is a position title, instead of a rank. It is held by the officer in command of the deck department. On smaller ships, the first lieutenant holds the rank of lieutenant, junior grade or ensign. On larger vessels, the position is held by a lieutenant or, in the case of extremely large warships such as aircraft carriers, a lieutenant commander or even commander. However, on submarines, where the deck department may only have a few junior sailors, the first lieutenant may be a senior enlisted member, such as a first-class petty officer or chief petty officer.