The Collaborative International Dictionary
Post-captain \Post"-cap`tain\, n. A captain of a war vessel whose name appeared, or was ``posted,'' in the seniority list of the British navy, as distinguished from a commander whose name was not so posted. The term was also used in the United States navy; but no such commission as post-captain was ever recognized in either service, and the term has fallen into disuse.
Wiktionary
n. (context obsolete UK US English) A captain of a war vessel whose name appeared, or was "posted", in the seniority list of the navy.
Wikipedia
Post-captain is an obsolete alternative form of the rank of captain in the Royal Navy.
The term served to distinguish those who were captains by rank from:
- Officers in command of a naval vessel, who were (and still are) addressed as captain regardless of rank;
- Commanders, who received the title of captain as a courtesy, whether they currently had a command or not (e.g. the fictional Captain Jack Aubrey in Master and Commander or the fictional Captain Horatio Hornblower in Hornblower and the Hotspur); this custom is now defunct.
Once an officer had been promoted to post-captain, his further promotion was strictly by seniority; if he could avoid death or disgrace, he would eventually become an admiral (even if only a yellow admiral).
In the Royal Navy of the time, an officer might have a rank, but not a command. Until the officer had a command, he was "on the beach" and on half-pay. An officer who was promoted from commander was a captain, but until he was given a command, he was on half-pay. Once the captain was given a command, his name was "posted" in the London Gazette.
An officer "took post" or was "made post" when he was first commissioned to command a rated vessel — that is, a ship too important to be commanded by a mere commander. Unrated vessels could also in some cases be commanded by post-captains. Being "made post" is portrayed as the most crucial event in an officer's career in both Forester's Horatio Hornblower series and O'Brian's Aubrey-Maturin series.
A junior post-captain would usually command a frigate or a comparable ship, while more senior post-captains would command larger ships. An exception to this rule was that a very junior post-captain could be posted to command an admiral's flagship, which was almost always a large ship of the line. The admiral would usually do this to keep his most junior captain under close observation, and subject to his direct supervision. Captains commanding an admiral's flagship were called " flag captains". One example of an admiral appointing a junior post-captain to command his flagship in this way is the appointment of Alexander Hood to the command of HMS Barfleur, flagship of his brother, Admiral Sir Samuel Hood.
Sometimes, a high-ranking admiral would have two post-captains on his flagship. The junior of the two would serve as the flag captain and retain responsibility for the day-to-day operation of the vessel. The senior of the two would be the fleet captain, or " captain of the fleet", and would serve as the admiral's chief-of-staff. These two captains would be listed in the ship's roll as the "second captain" and "first captain", respectively.
After 1795, when they were first introduced on Royal Navy uniforms, the number and position of epaulettes distinguished between commanders and post-captains of various seniorities. A commander wore a single epaulette on the left shoulder. A post-captain with less than three years seniority wore a single epaulette on the right shoulder, and a post-captain with three or more years seniority wore an epaulette on each shoulder. (National Maritime Museum Uniform Collection, see below.) In the O'Brian series, Aubrey "wets the swab" -- that is, he celebrates his promotion to commander and the acquisition of his "swab" or epaulette with the consumption of copious amounts of alcohol.
Note that the term was descriptive only: no-one was ever styled "Post-Captain John Smith".
Usage examples of "post-captain".
As a post-captain on the active list, on detached service, I am under the orders of the Admiralty and of nobody else on earth.
Real captains, full captains, we call post-captains - we say a man is made post when he is appointed to a sixth-rate or better, an eight-and-twenty, say, or a thirty-two-gun frigate.
I have seen so many squadrons formed, delayed in port, delayed still longer, the date put off, put off again, and then, when their officers had all their stores aboard for say a six months' voyage, dispersed, the whole scheme given up, the commodore sent back among the mere post-captains and reduced to begging in the Street, having spent his last guineas on a rear-admiral's gold lace.
He had scarcely relied upon it: on the remoter stations there were few post-captains to spare.
So there I was, hauled up in front of half a dozen post-captains and two admirals: Lord Keith was one of the admirals.
After a longish pause Jack said, 'You do not rate post-captains and admirals very high among intelligent beings, I believe?