Castle Class Corvette (Frigate) Association

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Technical Information
Castle Class Corvette - Technical Specification

This design was prepared at the same time as the "Loch" class frigates for builders who could not accomodate the longer frigate hull, and also to utilise any spare, short slip that was available. Although pre-fabricated construction was considered, it better suited the builders to stick with traditional building methods, to bring the class "on stream" as quickly as possible, without setting up an infrastructure for pre-fabricating.

The design was basically a larger "Flower " class, and although only 35' longer, this was enough to greatly improve sea-keeping and accomodation levels. Armament was along "improved Flower " lines except that a 12" "Squid" mortar replaced the "Hedgehog" launcher, and there was provision for four extra 20mm AA - although these were rarely fitted. The armament was arranged as that of the "Loch" class was, with the "Squid" replacing the 4" gun on the shelter deck, the 4" being moved ahead of this, emphasising the move from gun to "squid" as the main armament. A lattice mast abaft the bridge carried surface warning radar ( SW.RDF ) and HF/DF gear.

Although the same machinery as the "Flower " class was installed, there was no loss in speed due to longer keel and weight reduction measures.

Despite being a great improvement over the "Flower ", they couldn't match the new Frigates that were becoming available in large numbers, and in 1943, production was cut back to place all emphasis on Frigates.

Engines 2 x Admirality 3-drum boilers,1 x triple-expansion reciprocating engine driving 1 shaft @ 2750 ihp
Speed in Knots 16.5
Fuel   /   Range 480 tons Oil   /   9500 miles @ 10 knots
Length (ft/inches) 252 overall
Beam (ft/inches) 36/8
Draught (ft/inches) 13/6-13/9 mean deep load
Displacements (tons) 1060 tons standard; 1590-1630 tons deep load
  • Gun
    • 1 x 1 x 4" LA
    • 2 x 2 x 20mm Oerlikon AA
    • up to 6 x 1 x 20mm Oerlikon AA ( normally 2 )
  • ASW
    • 1 x 3 x 12" Squid A/S mortar
    • Depth-Charge lobbers and rails
Crew Complement 120 (officers & ratings)
Notes on Ship Type This class was a considerable improvement on the Flowers, with more effective ASW armaments with Light AA varying between 4-10 20mm. All ships disposed of 1955-1961, three sunk during the war.