sublieutenant

Sub-lieutenant is a naval rank used by several Commonwealth and other navies to denote a junior commissioned officer. The term is derived from lieutenant with the prefix sub-, indicating a lower grade within the lieutenant line. In most navies that use it, sub-lieutenant sits above the entry-level ranks for new officers (such as midshipman or acting sub-lieutenant) and below the rank of lieutenant. The exact path and terminology vary by country; in many services, officers begin as midshipmen or cadets, graduate to acting sub-lieutenant, and are promoted to sub-lieutenant after an initial period of training and probation, then to lieutenant after meeting service time requirements or professional qualifications.

Responsibilities for sub-lieutenants typically include duties associated with general naval leadership and practical skills at the junior officer level. They may serve as watch officers, navigation officers, or department officers on ships, submarines, or shore establishments, and may be responsible for small teams or divisions, as well as assisting senior officers in planning and administration. The role often combines hands-on operational duties with ongoing professional development and mentorship of more junior personnel.

Insignia and title conventions differ by country and era. Many navies use a simple set of rank stripes or other insignia on the shoulder or sleeve to identify a sub-lieutenant, with the exact design varying by service. The rank remains in use in several navies today, though some forces have restructured or renamed their officer ladders over time.