C-class cruiser

The C class was a group of twenty-eight light cruisers of the Royal Navy, and were built in seven groups known as the Caroline class (six ships), the Calliope class (two ships), the Cambrian class (four ships), the Centaur class (two ships), the Caledon class (four ships), the Ceres class (five ships) and the Carlisle class (five ships). They were built for the rough conditions of the North Sea, and proved to be rugged and capable vessels, despite being somewhat small and cramped.

The Caroline class were all ordered in July and August 1913, as the first six of eight "light armoured cruisers" under the 1913 programme. The ships were launched in 1914 or 1915 and commissioned in 1915. They had an armament of two single 6 in aft, eight 4 in and two 6-pounder guns. Their anti-aircraft (A/A) weaponry consisted of four 3-pounder. Their aft 6 in guns were superfiring; the class had three funnels. During the First World War, the ships of the class underwent a variety of alterations, including the removal of the 4-inch (102 mm) guns in Caroline, Carysfort and Comus, being replaced by two extra 6-inch (152 mm) guns, while Cleopatra, Conquest and Cordelia retained one or two of the 4-inch (102 mm) guns, with two 2-pounder guns being added to some of the ships.

The two ships of the Calliope sub-class – HMS Calliope and Champion – were the last pair of the eight "light armoured cruisers" to be ordered in July and August 1914 under the 1913 Programme. They both had geared steam turbines, the first Royal Navy cruisers to be so fitted. They also had increased belt armour; Champion had just two screws. They were commissioned in mid to late 1915, as modifications to the Caroline subclass with higher speeds, a more efficient boiler layout and a reduction in the number of funnels to two. The two ships had different machinery types for comparative purposes. Calliope and Champion underwent similar gun armament modifications to the Caroline subclass. They also had underwater tubes rather than the deck mounted weapons of the Caroline subclass and were given two twin deck mounted torpedo tubes during the war but these were later removed to reduce top weight.

The Cambrian class were ordered in September 1914 under the 1914–15 Programme, and commissioned between 1915 and 1916. The ships had two funnels rather than the three of the Caroline subclass, following on from the developments in the Calliope subclass. The Cambrian subclass had similar armament to the previous sub-class, with their main armament being four 6-inch (152 mm) guns in single mounts. Their secondary armament consisted of eight 4-inch (102 mm) guns. They were later removed, with Canterbury and Champion retaining one single 4-inch (102 mm) gun. The rest of the ships used either two or three 3-inch (76 mm) guns.

The Centaur subclass were ordered in December 1914, and built using materials originally intended for two scout cruisers to be built for Turkey. These vessels were launched and commissioned in 1916. The class also had geared turbines as well as four screws. They retained the two funnels introduced to the C class by the Cambrians. Their main armament was five 6 in guns in single mounts. Their 4-inch (102 mm) guns were mostly replaced in a similar fashion to the previous sub-classes, with smaller calibre weapons.

The Caledon class were all ordered in December 1915 and commissioned in 1917. The ships retained the two funnels of the previous two sub-classes. Their propulsion was slightly different from the previous sub-classes. Their superstructure was also slightly altered. They had a main armament of five 6-inch (152 mm) guns and a secondary armament of two 3 in guns, as well as an AA armament of four 3 pounder guns. The surviving ships of the class saw World War II, undergoing a number of modifications along the way. Five Oerlikon 20 mm cannons were added to all ships. Caledon herself had a different armament, as she underwent an extensive rebuild to become an AA cruiser. She was armed with the effective 4-inch (102 mm) gun, of which she had twelve, two 40 mm Bofors and eight 20 mm Oerlikons.

The Ceres class were ordered in March and April 1916 and commissioned in 1917 and 1918. These ships were very "wet" forward, which was remedied in the subsequent Carlisle sub-class with the addition of a "trawler bow". Their main armament consisted of five 6-inch (152 mm) guns, while their secondary armament consisted of two 3-inch (76 mm) weapons, of which a further one was later added to Ceres herself. Four 3-pounder guns were also fitted.

Three ships underwent extensive rebuilds during the 1930s, becoming anti-aircraft (AA) cruisers, resulting in all previous armament being removed. The ships were Coventry, Curacoa and Curlew, with Curacoa being the last of the three to be rebuilt in 1939; the other two ships having been converted in 1935. Coventry and Curlew were given ten QF 4 inch Mk V naval gun for their AA role, disposed in single mounts one forward, three on each beam and three aft. Sixteen QF 2-pounder naval gun Mark VIII as two 8-barelled Mark VI mountings ("multiple pom-poms") were fitted aft (one removed by 1939). Torpedo tubes were removed, and two High-Angle HACS gun directors and a Pom-Pom director added. Curacoa received similar gun directors but a slightly different armament, being equipped with eight QF 4 inch Mk XVI naval gun in twin mountings replacing 6 inch guns number 1,3,4 and 5; and four QF 2-pounder naval gun Mark VIII as a 4-barelled Mark VII mounting ("multiple pom-pom") replacing 6 inch gun number 2 forward of the bridge. Later on in the Second World War, four 20 mm Oerlikons were added. Cardiff and Ceres were to have undergone the same conversion, but this was prevented by the outbreak of war.