Dido-class cruiser

The ''Dido'' class consisted of sixteen light cruisers built for the Royal Navy during World War II. The first group of three ships were commissioned in 1940, the second group (six ships) and third group (two ships) were commissioned between 1941 and 1942. A fourth group, also described as the Improved Dido, or the ''Bellona'' class (five ships), were commissioned between 1943 and 1944. Most members of the class were given names drawn from classical history and legend. The groups differed in armament and for the ''Bellona''s, in function. The ''Dido'' class were designed as small trade protection cruisers with five turrets, each with twin 5.25" guns in high angle mountings, far more modern in design than previous light cruiser turrets, offering efficient loading up to 90 degrees elevation to give some dual-purpose capacity. While some damage was experienced initially in extreme North Atlantic conditions, modified handling avoided the problem. The fitting of the three turrets forward in A, B and C positions depended on some use of aluminium in the structure and the lack of aluminium after Dunkirk was one of the reasons for only four turrets being fitted to the first group of three, while the third group had four turrets with twin 4.5" guns.Raven & Roberts, p. 275 The ''Bellona''s were designed from the start with four turrets with radar-aimed guns and greater light anti-aircraft armament.

From the initial trials of the lead ship of the class, ''Bonaventure'', the new light cruisers were considered a significant advance and later, in action in the Mediterranean Sea, they were surprisingly effective in protecting convoys to Malta and saw off far larger ships of the Italian Royal Navy. The gun was primarily a surface weapon but it was intended to fire the heaviest shell suitable for anti-aircraft defence and accounted for around 23 aircraft and deterred far more. The original ''Dido''-class ships , , and were lost in the war. The original ship of the class, , was put into reserve in 1947 and decommissioned ten years later. was the last remaining in-service ship of the original class, being decommissioned in 1954 and scrapped in 1959.

The ''Bellona'' class (as well as four rebuilt ''Dido'' ships) were mainly intended as picket ships for amphibious warfare operations, in support of aircraft carriers of the Royal Navy and United States Navy in the Pacific. was the only ship of the sub-class to be sunk, struck by a German Fritz X glide bomb while supporting the landings at Anzio. Two ships were to be modified to be command ships of aircraft carrier and cruiser groups intended for action against German battlecruisers. Originally these were ''Scylla'' and ''Charybdis'' of the third group but after the loss of ''Charybdis'' in 1943, ''Royalist'' of the fourth (''Bellona'') group was selected; these were also known as the Modified Dido.

Post-war modernisation proposals were limited by the tight war emergency design which offered inadequate space and weight for the fire control and magazines for four or five 3-inch twin 70 turrets combined with the fact the heavy 5.25-inch shells fitted when the cruisers were built had a large burst shock which made them a more effective high level AA weapon than post war RN 4.5-inch guns.Murfin, p. 139 was rebuilt for potential action alongside the battleship against the post-war Soviet s and s. ''Royalist'' was loaned to the Royal New Zealand Navy (RNZN) from 1956 to 1966.

Armament

The class were intended to be armed with ten 5.25-inch (133 mm) guns in five twin turrets, which were of the same circular design as the secondary armament in the s. Due to a shortage of the guns, caused by difficulties in manufacturing them, the first group were built with only four 5.25-inch gun turrets. Only HMS ''Dido'' had the fifth turret added later. The first group was also armed with a gun for firing star shells and two quadruple QF 2-pounder (40 mm) "pom-poms" for anti-aircraft defence.

The second group had all five twin 5.25-inch turrets and did not require the 4-inch gun. The third group's armament was changed due to the shortage of 5.25-inch guns and had eight QF 4.5-inch (113 mm) guns in four twin turrets instead. The 4.5-inch gun was better suited to the primary anti-aircraft role of the ''Dido'' class. The forward (A and B) 4.5-inch turrets were mounted on the top of conjoint deckhouses, extending the superstructure with more accommodation and radar rooms to allow the two cruisers to operate as flagships. The high rate of fire of the 4.5-inch turrets, together with simpler dual-purpose twin Director Control Tower (DCT), meant that ''Scylla'' and ''Charybdis'' were arguably the only members of the ''Dido'' class that were true AA cruisers. The 4-inch gun was also fitted and the 2-pounder armament was increased from eight to ten.

The ''Bellona'' subclass differed in appearance somewhat from their predecessors. They had eight 5.25-inch RP10 Mk II guns in four twin turrets and had greatly improved anti-aircraft armament, with twelve 2-pounder guns and twelve Oerlikon 20 mm cannon. The bridge of the ''Bellona'' class was lowered by one deck compared to the previous three groups. This reduced topweight and so full radar control could be fitted to the 5.25-inch turrets and 2-pounder guns. These ships used the HACS high angle fire control system. The two funnels were more upright than the raked ones of the original ''Dido'' class.

Service

In World War II, the ''Dido'' class saw much action, including the Battle of Cape Matapan, the Second Battle of Sirte, Operation Torch, Operation Overlord and the Battle of Okinawa, as well as many other duties in the Mediterranean and Pacific. Five ships were lost during the war: , , , , and . was badly damaged by a naval mine and declared a constructive total loss. The post-war survivors continued in service; all were decommissioned by the 1960s. , and were lent to the Royal New Zealand Navy post-World War II. In 1956, was sold to Pakistan and renamed ''Babur''.

Ship modifications

''Dido''s

''Bonaventure'' completed with only four twin 5.25 in turrets because of shortages and received a 4-inch starshell gun in "X" position. She received a radar set before October 1940 but was otherwise unaltered.

''Naiad'' was completed with five turrets. She received five single 20 mm in September 1941 and had Type 279 radar by this time.

completed with four turrets and was fitted with a 4-inch gun in "C" position forward of the bridge. The latter was 'landed' (removed) during her refit between November 1941 and April 1942 at New York City, along with the 0.5-inch machine guns and Type 279 radar, while a quadruple 2 pdr replaced the 4-inch gun and eleven single 20 mm guns were fitted. Radars were now Type 281, 284 and 285. The "A" turret was temporarily removed at the end of 1942 after torpedo