Principal naval transport officer (Royal Navy)

In the Royal Navy, a principal naval transport officer (P.N.T.O.) later known as principal sea transport officer (P.S.T.O.) is a shore-based flag officer or captain responsible for sea transport duties, and to assist the senior naval officer in the preparation of naval orders and conduct disembarkations.

History
The Naval Transports Service was created by the Royal Navy on 22 December 1916. From 1915 to 1916 the Eastern Mediterranean Squadron had a principal naval transport officer based at Mudros who held a commodore rank. The officers were employed as part of the Naval Transport Service. In 1921 the Naval Transport Service was restyled as the Sea Transport Service.