|The oldest class among these cruisers, typed light cruisers after the London Naval Treaty, was the Caledon Class of three ships, Caledon, Calypso and Caradoc. All laid down early in 1916, they were completed in 1917 and
saw duty as scouts with the Grand Fleet. They were the 4th variant of the C Class cruisers and displaced 4,180-tons (standard), 4,950-tons (full load). Armed with five single gun mounts with gun shields on centerline, they
also had two 3-in QF HA guns, two 2pdr and eight 21-inch torpedo tubes. The machinery plant developed 40,000shp driving two shafts for a maximum speed of 29-kts, when in good condition. Armor was a modest 3-inch
belt with a 1-inch armored deck. The following class were ordered as the Caledon Class was laid down. They were to be virtual repeats of the Caledon Class but before they were laid down, their design was modified. Unlike
the Caledon Class, which had no superfiring 6-inch guns, the forward superstructure was enlarged and heightened, allowing B mount to be raised into a superfiring position. Because of the extra top weight and higher center
of gravity, the hull was lengthened from 449-feet, 10-inches (147.5m)(oa) to 451-feet, 6-inches (137.6m)(oa) and the beam from 42-feet 9-inches to 43-feet 6-inches to add stability. Weight increased to 4,290-tons
(standard), 5,276-tons (full load). Because of these changes, they were from a sub-class called the Ceres Class. Five ships were laid down in the summer of 1916 with all launching late spring/early summer 1917. Ceres and
Cardiff completed in June 1917, Curlew in December 1917 and Curacoa and Coventry in February 1918. The machinery remained 40,000shp but probably because of the new lines was half a knot faster at 29.5-knots than
the Caledon Class. The range was the same, 5,900nm at 10-knots but obviously the range would plummet in speeds above a 10-knot crawl.
In 1930 The London Naval Treaty was signed, which placed a ceiling on cruiser tonnage, something lacking in the Washington Treaty. The C Class cruisers were too old and of limited value with their surface action 6-inch
guns to take up part of the cruiser tonnage allocated to the Royal Navy. To get the C Class cruisers of the Caledon and Ceres Classes off of the cruiser list it was decided to convert all of both classes to anti-aircraft cruisers.
The design was started in 1934 and Coventry and Curlew were selected to be the trial ships. Conversion started in 1935 and finished 1936. All of the original armament was removed and the ships were fitted with ten 4-inch
Mk V HA single guns and two eight-barreled (40mm) Mk VI pom-pom mounts. The 4-inch guns were mounted with four on centerline, one forward and three aft and three on each beam amidship. Additionally, two HA
directors were fitted. The 4-inch guns were hand-me downs from other ships in which they had been replaced with twin 4-inch mounts. In 1938 and 1939 the aft pom-pom mount was removed to give to other ships and
were replaced by two worthless quadruple Vickers .50 machine gun mounts. As it turned out the only other ship of the C Class to receive the AA cruiser conversion was Curacoa, which was converted in 1939 but with twin
4-inch Mk XIV in place of the 1,3,4, and 5single gun positions, a quadruple pom-pom in number 2 gun’s position, two quadruple Vickers .50 machine guns, one on each side of the fore funnel and finally two single barrel