Lieutenant (navy)
"First lieutenant" in naval usage
In the U.S. Navy or U.S. Coast Guard, the billet of first lieutenant describes the officer in charge of the deck department or division, depending on the size of the ship. In smaller ships that have only a single deck division, the billet is typically filled by an ensign; while in larger ships, with a deck department consisting of multiple subordinate divisions, the billet may be filled by a lieutenant commander. On submarines and smaller Coast Guard cutters, the billet of first lieutenant may be filled by a petty officer.
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