Captain-class frigate

HMS Cosby, an example of the Buckley-subclass.
Class overview
Builders:	Boston Navy Yard Mare Island Navy Yard Bethlehem-Hingham
Operators:	Royal Navy
Subclasses:	Buckley class Evarts class
Built:	1941–1943
In service:	1943–1956
Completed:	78
Lost:	7 sunk 8 Constructive Total Loss
General characteristics
Type:	Frigate
Displacement:	1,140 long tons (1,158 t) (Evarts) 1,400 long tons (1,422 t) (Buckley)
Length:	289 ft 6 in (88.24 m) (Evarts) 306 ft (93 m) (Buckley)
Beam:	35 ft (11 m) (Evarts) 36 ft 9 in (11.20 m) (Buckley)
Draft:	9 ft (2.7 m) (Evarts) 11 ft (3.4 m) (Buckley)
Decks:	7
Installed power:	7,040 bhp (5,250 kW) (Evarts) 13,500 shp (10,070 kW) (Buckley)
Propulsion:	See text
Speed:	20 knots (37 km/h; 23 mph) (Evarts) 24 knots (44 km/h; 28 mph) (Buckley)
Range:	5,000 nautical miles (9,300 km; 5,800 mi) at 15 knots (28 km/h; 17 mph) (Evarts) 5,500 nautical miles (10,200 km; 6,300 mi) at 15 knots (28 km/h; 17 mph) (Buckley)
Boats & landing craft carried:	Royal Navy 27-foot (8.2 m) whaler US Navy standard ship's boat
Complement:	156 (Evarts) 186 (Buckley)
Sensors and processing systems:	SA & SL type radars Type 128D or Type 144 series Asdic MF Direction Finding antenna HF Direction Finding Type FH 4 antenna
Armament:	3 × 3 in (76 mm) /50 Mk.22 guns 1 × twin Bofors 40 mm mount Mk.I 7–16 × 20 mm Oerlikon guns Mark 10 Hedgehog A/S projector 2 x rails, 4 x throwers, up to 200 depth charges QF 2-pounder naval gun

The Captain class was the designation given to 78 frigates of the Royal Navy, constructed in the United States of America, launched in 1942–1943 and delivered to the United Kingdom under the provisions of the Lend-Lease agreement (under which the United States of America supplied the United Kingdom and other Allied nations with materiel between 1941 and 1945). They were drawn from two sub-classes of the American destroyer escort (originally British destroyer escort) classification: 32 from the Evarts subclass and 46 from the Buckley subclass. Upon reaching the UK the ships were substantially modified by the Royal Navy, making them distinct from the US Navy destroyer escort ships.

Captain-class frigates acted in the roles of convoy escorts, anti-submarine warfare vessels, coastal forces control frigates and headquarters ships for the Normandy landings. During the course of World War II this class participated in the sinking of at least 34 German submarines and a number of other hostile craft; 15 of the 78 Captain-class frigates were either sunk or written-off as a constructive total loss.

In the post-war period, all of the surviving Captain-class frigates except one (HMS Hotham) were returned to the US Navy before the end of 1947 in order to reduce the amount payable under the provisions of the Lend-Lease agreement; the last Captain-class frigate was returned to United States custody in March 1956.

It was the intention of the Admiralty that these ships would be named after captains who served with Vice-Admiral Horatio Nelson at the Battle of Trafalgar, but as building continued it became necessary to delve back further into history for the names of well-regarded admirals and captains.