Oberleutnant zur See

Oberleutnant zur See (OLt zS or OLZS in the German Navy, Oblt.z.S. in the Kriegsmarine) is traditionally the first and highest Lieutenant grade in the German Navy. It is grouped as OF-1a in NATO, equivalent to a Lieutenant Junior Grade in the United States Navy, and a Sub-Lieutenant in the British Royal Navy

The rank was introduced in the Imperial German Navy by renaming the former rank of Premier Lieutenant in 1890. In navy context officers of this rank were simply addressed as Herr Oberleutnant. To distinguish naval officers from officers of the army, the suffix zur See (at sea) was added in official communication, sometimes shortened to z.S. or Oblt.z.S. The rank has since been used by the Reichsmarine, the Kriegsmarine, and the German Navy. In the Volksmarine the rank was originally used in the same way until the suffix zur See was dropped. In the Kriegsmarine engineers (Ingenieur - Ing.) of the same rank would be Oberleutnant (Ing.).