HMS Hever Castle (K521) depth on the fuses of the projectiles until the moment of firing. A single Squid-launched attack had a success rate of 25%. The class was also provided with HF/DF and Type 277 radar. "Hever Castle" was ordered on 23 January 1943. The ship, named for Hever Castle in Hever, Kent, was laid down on 29 June 1943 and launched on 24 February 1944. At some point in 1943, the ship was transferred to the Royal Canadian Navy. The corvette, renamed "Copper Cliff" after a suburb of Sudbury, Ontario, was commissioned into the Royal Canadian Navy on 25 February 1944 with
HMS Hever Castle (K521) (ASW) vessel. However, the design did have criticisms, mainly in the way it handled at low speeds and that the class's maximum speed was already slower than the speeds of the new U-boats they would be facing. A Castle-class corvette was long with a beam of and a draught of at deep load. The ships displaced standard and deep load. The ships had a complement of 120. The ships were powered by two Admiralty three-drum boilers which created . This powered one vertical triple expansion engine that drove one shaft, giving the ships a maximum speed of . The ships