Castle-class corvette


The Castle-class corvettes were an updated version of the much more numerous s of the Royal Navy, and started appearing during late 1943. They were equipped with radar as well as asdic.

Design

The Admiralty had decided to cease Flower-class construction in favour of the larger s as the Flower class had originally been intended for coastal escort work and were not entirely satisfactory for Atlantic convoy service. In particular, they were slow, poorly armed and rolled badly in rough seas, which quickly exhausted their crews. However, many shipyards were not large enough to build frigates. The Castle class was designed to be built on small slipways for about half the overall effort of a. The Loch-class frigate was similar to a River but built using the system of prefabrication.
The appearance of Castle-class corvettes was much like the later "long forecastle" variant of the Flowers and they were a little larger.
The most obvious visual difference was the lattice mainmast instead of the pole version fitted to the Flowers. There was also a more square cut look to the stern, although it was still essentially a cruiser spoon type, this difference was only visible from abaft the beam.
The armament differed from the Flower class with the depth charge fitment replaced by one Squid anti-submarine mortar. Hadleigh Castle received the first production Squid mounting; the World War I-era medium-velocity surface-only BL 4-inch Mk IX main gun firing a shell was replaced by the new low-velocity QF 4-inch Mk XIX gun on high-angle/low-angle mounting firing a heavier shell, which added anti-aircraft capability to the existing capability against surface targets such as submarines.
The propulsion machinery was identical to the Flowers and experienced officers felt that they were seriously under powered, having a tendency to turn into the wind despite everything the helmsman could do. The fact that Squid attacks required a fairly low speed only made matters worse.
Most of the Castle-class corvettes had been discarded by the end of the 1950s but a few survived a little longer as weather ships. The last Castle was the Uruguayan training ship Montevideo, originally, which was scrapped in 1975.
Most were operated by the Royal Navy but twelve were transferred to the Royal Canadian Navy before completion and one to the Royal Norwegian Navy. Three Castles were sunk through enemy action and Castles participated in the sinking of seven U-boats.

Ships

Royal Canadian Navy

The following vessels were all originally built for the Royal Navy, but were transferred to the RCN on completion. All their pennant numbers, as well as their names, were changed when transferred.
The initial Castle-class ship was Allington Castle, re-ordered on 9 December 1942 ; another 13 vessels were ordered on 19 December, also under the 1942 War Programme.
PennantName Hull builderOrderedLaid downLaunchedCommissionedPaid offFate
K689Fleming & Ferguson9 December 194222 July 194329 February 194419 June 19441947Scrapped 1958
K412John Lewis & Co. Ltd9 December 19421 July 194311 January 194430 May 19441950Scrapped 22 May 1959
K690John Lewis & Co. Ltd9 December 194226 August 194322 May 194429 September 19441947Scrapped March 1956
K696John Lewis & Co. Ltd9 December 194230 September 19435 August 194430 December 1944Declared Constructive Total Loss, 13 February 1945
K413John Crown & Sons Ltd9 December 194225 June 194325 April 194431 January 19451947Scrapped, 31 October 1960
K529John Crown & Sons Ltd9 December 19422 November 194330 October 194412 May 1945August 1945Scrapped, April 1958
K355Smiths Dock Company9 December 19424 April 194321 June 194318 September 1943August 1946Scrapped, January 1959
K420Smiths Dock Company9 December 19427 May 194317 August 194322 November 19431948Scrapped, 20 June 1959
K691Fleming & Ferguson9 December 194210 September 194314 April 194415 September 19441947Scrapped, 20 June 1959
K443Fleming & Ferguson9 December 194219438 June 1944November 1944Became convoy rescue ship Empire Lifeguard before completion. Scrapped, 22 July 1955
K447 A. & J. Inglis9 December 194230 September 194312 April 19446 September 1944Transferred to Canada as HMCS Humberstone 1944. Sold for mercantile service 1947
K530A. & J. Inglis9 December 194230 September 194320 July 194410 December 19441950Became the weather ship Weather Reporter 1957.
K450Ferguson Shipbuilders9 December 19423 June 194312 February 194429 June 1944Transferred to Canada as HMCS Tillsonburg in 1944. Sold for mercantile service 1947. Sold to Republic of China as Kao An 1952
K695Ferguson Shipbuilders9 December 1942194312 June 1944October 1944Completed as convoy rescue ship Empire Rest.

The remaining eighty-one ships were all ordered for the RN under the 1943 War Programme, of which thirty were completed. Fifty-one of these ships which were cancelled late in 1943 are shown separately below.
Fourteen ordered 19 January 1943, of which 3 were cancelled:
Sixteen ordered 23 January 1943, of which five were cancelled:
Five ordered 2 February 1943:
PennantName Hull builderOrderedLaid downLaunchedCommissionedPaid OffFate
K386S P Austin & Son Ltd2 February 194331 May 194325 November 194324 November 19441947Became the weather ship Weather Adviser in 1960
K387Barclay Curle2 February 194323 April 194319 August 194318 November 19441946Scrapped 24 February 1956
K379Caledon Shipbuilding & Engineering Company2 February 194312 March 194331 July 194317 November 19431947Scrapped 14 June 1958
K388Caledon Shipbuilding & Engineering Company2 February 19436 May 194328 September 194325 February 19441947Scrapped March 1961
K416Caledon Shipbuilding & Engineering Company2 February 19436 August 194323 February 19449 June 1944Sunk by U-482 on 1 September 1944

Three ordered 6 February 1943:
PennantName Hull builderOrderedLaid downLaunchedCommissionedPaid OffFate
K362Swan Hunter6 February 194317 March 194321 June 19438 November 19431947Scrapped 14 May 1958
K372Swan Hunter6 February 19438 April 194316 July 194324 February 19441946Became the weather ship Weather Surveyor in 1960
K374Swan Hunter6 February 19435 May 194316 August 194324 April 1944Transferred to Norway on completion and renamed HNoMS Tunsberg Castle. Sunk by mine 12 December 1944

Two ordered 3 March 1943, three ordered 4 May 1943 and two ordered 10 July 1943 were all cancelled, as were all thirty-six ordered from Canadian shipyards on 15 March 1943.

Royal Norwegian Navy

15 ships ordered for the Royal Navy from UK shipyards as part of the 1943 Programme were all cancelled on 31 October 1943:
The following ships were ordered on 15 March 1943 for the Royal Navy from Canadian shipyards for completion between May 1944 and June 1945, but were all cancelled in December 1943:
The final third of the film The Cruel Sea is set on the Castle-class corvette Saltash Castle.

Post-war conversions

Three were converted to passenger/cargo ships for the Union Steamship Company of British Columbia and were known as the White Boats. They were operated from 1946 to 1958 but were heavy on fuel and had limited cargo capacity, for example they could not carry cars in the hold.