Editing Lieutenant (section)

===First lieutenant===
{{Main|First lieutenant}}

===="First lieutenant" in naval use====
The first lieutenant in the [[Royal Navy]] and other Commonwealth navies, is a post or appointment, rather than a rank. Historically the lieutenants in a ship were ranked in accordance with seniority, with the most senior being termed the "first lieutenant" and acting as the [[second-in-command]]. Although lieutenants are no longer numbered by seniority, the post of "first lieutenant" remains. In minor war vessels, [[destroyer]]s and [[frigate]]s the first lieutenant (either a lieutenant or lieutenant-commander) is second in command, [[executive officer]] (XO) and head of the executive branch; in larger ships where a commander of the warfare specialization is appointed as the executive officer, a first lieutenant (normally a lieutenant-commander) is appointed as his deputy. The post of first lieutenant in a [[shore establishment]] carries a similar responsibility to the first lieutenant of a [[capital ship]].

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 upon the size of the ship. In smaller ships with 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]].