I don't usually go to Wiki, but here's what they say. I know nothing about sailboats but I do love he Rev. so I will read just about anything about it.
Historic naval definition:
A three-masted Bermuda sloop of the Royal Navy, ca. 1831. Also called Ballyhou schooners, the RN referred to these as sloops-of-war.
The naval term "sloop" referred to ships with different rigs and sizes varying from navy to navy. "Sloop-of-war" was more of a reference to the purpose of the craft rather than the specific size or sailplan. (Further confusion was caused by the practice of redesignating a vessel simply according to the rank of the commanding officer.) The Royal Navy began buying Bermuda sloops, beginning with an order for three sloops-of-war (HMS Dasher, HMS Driver, and HMS Hunter, were each of 200 tons, armed with twelve 24 pounders) placed with Bermudian builders in 1795. They were intended to counter the menace of French privateers, which the Navy's ships-of-the-line were ill-designed to counter. Eventually, Bermuda sloops became the standard advice vessels of the navy, used for communications, reconnoitering, anti-slaving, anti-smuggling, and other roles to which they were well suited. The most notable examples of these were HMS Pickle, which raced back to England with news of the British victory and the death of Admiral Lord Nelson at the end of the Battle of Trafalgar, and HMS Whiting (79 tons and four guns), which lowered anchor in the harbor of Hampton Roads on 8 July 1812, carrying dispatches. The American privateer Dash, which happened to be leaving port, seized the vessel. The crew of the Whiting had not yet received news of the American declaration of war, and her capture was the first naval action of the American War of 1812. Generally a sloop was smaller than a frigate; however, in the later days of the U.S. Navy's sailing fleet, some of the largest vessels were called sloops because they carried fewer guns than a frigate, as few as 20. The classification of sloop was similar to a corvette
