During this period many modifications were made to the bridge to incorporate new equipment and protections. From 1943 they were equipped with better electronics. In the course of the war the corvettes were equipped, among other things, with radar, more and more powerful anti-aircraft weapons (AA MG or 20mm Oerlikon guns), More depth charges and at the end of 1941 with the “Hedgehog” anti submarine weapon. Later the vessels were given a different hull with extended forecastle that improved their thrust and overhang to protect them against the Atlantic seas.
Once it had been decided that corvettes were no longer to be used as coastal escort ship, but on the high seas, some modifications had to be made. The first vessel (launched on ) was completed in 5 months, the subsequent ones at a rate of one every twenty three days. Sixty Flower Class corvettes had been ordered before war broke out and by the end of 1940 at total of 141 of the original design had been ordered.
The main feature of this original design was that in accordance with merchant shipping practice it could easily be built in many small British dockyards and its basic engines could be handled by civilian dockyards. The escort ships of this class were divided from the collaboration between the British Admiralty and the Smiths Dock Company, which in 1938 had a successful design for a commercial whaler called the Southern Pride. Alongside other escort ships she bore the main burden of the battle against the German submarines. The Flower Class corvettes will always be associated with the Battle of the North Atlantic, even though they were also used in all theatres of World War II.