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.
The five "Empire" class rescue escorts were provided to quickly rescue the crews of sinking ships, and as such they were re-armed for AA defence only, and had extra lifeboats aft. The crew normally associated with the weapons were replaced by lifeboat crews, and more accomodation was provided. A larger and better staffed sick-bay was also incorporated into the design. They were manned by the Merchant Navy.