| Captain | |
|---|---|
 A Royal Navy captain's rank insignia | |
 A Royal Navy captain's rank insignia (left, with alieutenant at right) during divisions conducted atHMNB Clyde in January 2013 | |
| Country | United Kingdom |
| Service branch |  Royal Navy |
| Abbreviation | Capt |
| NATOrank code | OF-5 |
| Next higher rank | Commodore |
| Next lower rank | Commander |
| Equivalent ranks | |
Captain (Capt.) is a senior officer rank of theRoyal Navy. It ranks abovecommander and belowcommodore and has aNATO ranking code of OF-5. The rank is equivalent to acolonel in theBritish Army andRoyal Marines, and to agroup captain in theRoyal Air Force. There are similarly namedequivalent ranks in the navies of many other countries.
In the Royal Navy, the officer in command of any warship of the rank ofcommander and below is informally referred to as "the captain" on board, even though holding a junior rank, but formally is titled "the commanding officer" (or CO). Until the nineteenth century Royal Navy officers who were captains by rank and in command of a naval vessel were referred to aspost-captains.
Captain (D) or Captain Destroyers, afloat, was an operational appointment commanding adestroyerflotilla orsquadron, and there was a corresponding administrative appointment ashore,[1] until at least a decade after theSecond World War. The title was probably used informally until the abolition offrigate and destroyer squadrons with the Fleet FIRST reorganisation circa 2001.
Ashore, the rank of captain is often verbally described as "captain RN" to distinguish it from the morejunior Army and Royal Marines rank, and in naval contexts, as a "four-ring captain" (referring to the uniform lace) to avoid confusion with the title of a seagoing commanding officer. In theMinistry of Defence, and in joint service establishments, a captain may be referred to as a "DACOS" (standing for deputy assistant chief of staff) or an "AH" (assistant head), from the usual job title of OF5-ranked individuals who work with civil servants.
The rank insignia features four rings of gold braid with anexecutive curl in the upper ring.[2]
When inmess dress or mess undress, officers of the rank of captain and above wear gold-laced trousers (the trousers are known as "tin trousers", and the gold lace stripes thereon are nicknamed "lightning conductors"), and may wear the undresstailcoat (without epaulettes).[3]
