Class overview
Name	Cyrus class
Operators	Royal Navy
Completed	16
General characteristics
Type	Sixth rate (later rated as ship sloops)
Tons burthen	454 80⁄94 (as designed)
Length	115 ft 6 in (35.20 m) (gundeck) 97 ft 2 in (29.62 m) (keel)
Beam	29 ft 8 in (9.04 m)
Depth of hold	8 ft 6 in (2.59 m)
Propulsion	Sail
Sail plan	Full-rigged ship
Complement	135
Armament	UD: 20 × 32-pounder carronades and 2 × 6-pounder chase guns

The Cyrus-class sixth rates of the Royal Navy were a series of sixteen-flush decked sloops of war built to an 1812 design by Sir William Rule, the Surveyor of the Navy. The first nine ships of the class were launched in 1813 and the remaining seven in 1814. The vessels of the class served at the end of the Napoleonic War. They were built on the lines of HMS Hermes, which was based in turn on the French ship Bonne Citoyenne.

The Cyrus class was intended to be the counter to the new Frolic-class ship-rigged sloops that were under construction for the United States Navy. No encounter took place between any vessel of the Frolic class and one of the Cyrus class, but HMS Levant was captured by the American frigate USS Constitution.^[1]

With the re-organisation of the rating system which took place in the Royal Navy effective from 1 January 1817, the Cyrus-class flush-decked ships were re-classified as 20-gun sloops.

• Gardiner, Robert (1996). The Naval War of 1812. Caxton pictorial history. ISBN 1-84067-360-5.
• Rif Winfield, British Warships in the Age of Sail, 1793-1817, Chatham Publishing, London 2005.