Dido-class cruiser

The Dido class was a class of sixteen light cruisers built for the British Royal Navy. The design was influenced by the inter-war Arethusa-class light cruisers. The first group of three ships were commissioned in 1940, the second group (six ships) and third group (two ships) were commissioned between 1941–1942. 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, and were designed with five turrets, each with twin 5.25 guns in high angle mountings, far more modern in design than previous light cruiser turrets, and offering efficient loading up to 90 degrees [1] to give some DP capability. 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 Q position depended on some use of aluminium in structure and the non availability of aluminium [2] 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. The Bellona's were designed from the outset with four turrets, but with radar-guided guns, and carried an increased light anti-aircraft armament.

HMS Argonaut in wartime camouflage, November 1943 just after repairs at Philadelphia Navy yard
Class overview
Name: Dido class
Preceded by: Arethusa class/Town class
Succeeded by: Crown Colony class
  • Dido
  • Bellona
Built: 1937–1943
In commission: 1940-1966
Completed: 16
Lost: 5
Scrapped: 11
General characteristics
Type: Light cruiser
  • Standard: 5,700 to 5,900 tons
  • Full load: 6,900 to 7,600 tons
Length: 512 ft (156 m) overall
Beam: 50 ft 6 in (15.39 m)
  • Dido class: 14 ft (4.3 m)
  • Bellona class: 15 ft (4.6 m)
  • Four Admiralty 3-drum boilers
  • Four Parsons steam turbines
  • Four shafts
  • 62,000 shp (46 MW)
Speed: 32.25 knots (59.73 km/h; 37.11 mph)
  • 1,100 tons fuel oil
  • 2,414 km (1,500 mi) at 30 kn (56 km/h; 35 mph)
  • 6,824 (4,240 miles) at 16 knots
  • Dido class: 480
  • Bellona class: 530

From the initial trials of the lead ship of the class, Bonaventure, the new light cruisers were considered a significant advance, [3] and later, in action in the Mediterranean Sea, they were surprisingly effective in protecting crucial convoys to Malta and managed to see off far larger ships of the Italian Royal Navy. The 5.25-inch (133 mm) 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 saw off far more. Four original Dido-class ships were lost during the war: HMS Bonaventure, HMS Charybdis, HMS Hermione, and HMS Naiad. The original ship of the class, HMS Dido, was mothballed in 1947 and decommissioned ten years later. HMS Euryalus 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. HMS Spartan was the only ship of the sub-class to be sunk, struck by a German Fritz X while supporting the Anzio landings.

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 two 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-to-handle 5.25-inch shells[4] 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.

HMS Royalist was ordered to be rebuilt, by Winston Churchill, for potential action alongside HMS Vanguard against the post-war Soviet Sverdlov-class cruisers and Stalingrad-class battlecruisers. In 1956, Royalist was loaned to the Royal New Zealand Navy (RNZN), with whom it served until 1966. Despite being part of the RNZN, Royal Navy officers made up the majority of the senior command. During the Indonesia–Malaysia confrontation, it was regarded not only as the last Dido-class ship but also the last cruiser of the Royal Navy. The ship was decommissioned in 1967.


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 King George V-class battleships. A shortage of the guns, due to difficulties in manufacturing them, led to the first group being armed with only eight 5.25-inch guns in four twin turrets. The fifth twin turret was added later to Dido only. The first group was also armed with a 4-inch (102 mm) gun for firing star shell and two quadruple QF 2-pounder (40 mm) "pom-poms".

The second group had the five twin 5.25-inch guns but did not have the 4 in (102 mm) gun. The third group's armament was changed due to the shortage of 5.25 in guns, being armed with eight 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 & B 4.5 turrets were mounted on the top of conjoint deckhouses, extending the superstructure to allow the 2 cruisers to play a flagship role with more accommodation and radar rooms. The high mounting of the 4.5 turrets foreshadows the high freeboard and superstructure of the twin 4.5 A & B mounting on the County GMDs, 20 years later. The high rate of fire of the 4.5 turrets and the unique arrangement for a British cruiser of the shell and charge being loaded in a combined case, together with simpler DP twin DCT (Red DCT for A & B and Blue for X & Y), meant that Scylla and Charybdis were arguably the only members of the Dido class that were true AA cruisers.[5] The 4-inch (102 mm) 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 (133 mm) RP10MkII guns in four twin turrets and had greatly improved anti-aircraft armament, with twelve 2-pounder guns and twelve Oerlikon 20 mm cannons. The bridge of the Bellona class was lowered by one deck compared to the previous three groups, which allowed full radar control to be fitted to the 5.25-inch turrets and 2-pounder guns, due to the decreased topweight. 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.


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. The class lost five ships during the war (Bonaventure, Charybdis, Hermione, Naiad, and Spartan); in addition Scylla 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. Bellona, Black Prince and Royalist were lent to the Royal New Zealand Navy post-World War II. In 1956, Diadem was sold to Pakistan and renamed Babur.

Ship modifications


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

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

Phoebe completed with four turrets and was fitted with a 4-inch gun in "Q" position forward of the bridge. The latter was landed during her refit between November 1941 and April 1942 at New York City, along with the .5-inch machine guns and Type 279 radar, while a quadruple 2 pdr supplanted 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 damage. During repairs in the first six months of 1943, all three quadruple 2 pdr mounts were landed, as were seven single 20 mm, to be replaced by three quadruple 40 mm Bofors guns and six twin 20 mm. Radar Type 272 was also fitted. A turret was replaced in July 1943. Her light anti-aircraft weaponry in April 1944 was twelve 40 mm (3 × 4) and sixteen 20 mm (6 × 2, 4 × l).

Dido had four turrets and a 4-inch gun similar to Phoebe. The 4 in and the machine guns were removed in the latter half of 1941 at Brooklyn Navy Yard, when Q 5.25 in turret was shipped and five single 20 mm were fitted. In the early summer of 1943 three single 20 mm were exchanged for four twin 20 mm and the radar outfit was altered by the addition of Types 272, 282, 284 and 285. April 1944 lists show only eight 20 mm.

Euryalus completed with her designed armament. In September 1941 the .5 in MGs were landed and five single 20 mm fitted. Two more were added by September 1942. By mid-1943 two single 20mm had been removed and four twin 20 mm shipped. The type 279 radar was replaced by types 272, 281, 282 and 285. In a long refit from October 1943 to July 1944, Q turret was replaced by a quadruple 2 pdr and two twin 20 mm were fitted. Radar 271 and 272 were removed and types 279b, 277 and 293 fitted.

Hermione was also completed as a five-turret ship. She had the .5 in MGs removed in October/November 1941 and received five single 20 mm.

Sirius was completed with five turrets and five 20 mm. She had received two more 20 mm by mid-1943. One of these was landed at Massawa at the end of 1943 and two 40 mm Bofors Mk III were fitted. She is listed as having only seven 20 mm as light AA in April 1944. By April 1945 she had two Mk III 40 mm fitted and had landed two single 20 mm.

Cleopatra was completed with two 2-pounders in 1942 in lieu of the .5 in MGs but these were removed in the middle of the year and replaced by five 20 mm. A sixth 20 mm was added in mid-1943. During repairs between November 1943 and November 1944, Q turret was removed, as were two quadruple 2 pdr and five 20 mm. Three quadruple 40 mm Bofors and six twin 20 mm were fitted and the singles numbered four. In 1951 the US sourced quad bofors and Oerilikon's were replaced by 3 twin MK 5 Bofors and 8 single Mk 7.

Argonaut was completed with four single 20 mm in lieu of the .5 in MGs. She had Q turret removed during repairs in 1943/44, and lost the four single 20 mm. She received a quadruple 2 pdr in lieu of the 5.25 in, and had five twin 20 mm fitted. By April 1944 her light AA comprised three quadruple 2 pdr, six twin power-operated 20 mm and five single. By the end of the war with Japan she had received five 40 mm Bofors and three single 40 mm Bofors Mk III.

Scylla was completed with four twin 4.5 in Mk III in UD MK III mountings because of a shortage of 5.25 in mountings. The forward superstructure was considerably modified to accommodate these and also to increase crew spaces. Her light AA on completion was eight single 20 mm. Six twin power-operated 20 mm were added at the end of 1943.

Charybdis was also completed with four twin 4.5 inch, and had in addition a single 4 in Mk V forward of X mounting. Her light AA at completion was four single 20 mm and two single 2 pdr. The 4 inch starshell gun and two single 2 pdr were removed and replaced by two twin and two single 20 mm, probably in 1943.


Spartan received no alterations as far as is known.

Royalist was converted to an escort carrier squadron flagship immediately on completion, when an extra two twin 20 mm were fitted as well as four single 20 mm. She was the only ship to receive an extensive postwar modernisation ordered for the RN but was later sold to New Zealand. Plans were drawn up to fully modernise the four improved Didos with either four twin 3 inch L70 guns or Mk 6 4.5 inch guns. However, that would have required building new broad beamed Didos (as was seriously considered in 1950–54). This was because the magazines of the Royalist type could hold only enough 3 inch ammunition for 3 minutes and 20 seconds of continuous firing.[6] The refit of Royalist was shortened and that of Diadem abandoned because new steam turbines were regarded as both necessary and unaffordable. Royalist′s reconstruction, like that of Newfoundland, incorporated much of the RN's late 1940s and early 1950s view of a desirable cruiser. Royalist′s 5.25 inch armament was given some of the improvements of the final 5.25 inch mounts built for Vanguard, but not the extra space or power ramming. Also added was a secondary armament of 3 STAAG auto twin 40mm, new 293, 960M radar and Type 275(2 sets) DP fire control for the 5.25 guns, and a lattice mast. (Royalist was loaned to the RNZN in 1956, in exchange for Bellona).

Bellona had four single 20 mm added by April 1944, and received an extra eight single 20 mm by April 1945. (She was loaned to the RNZN after the war and operational 1946–52, the twin Oerlikons had been replaced by 6 single MK3P 40mm in the RNZN unique kiwi electric powered mount, but Bellona was never actually fitted with 6 standard tacymetric directors, requested by the RNZN for controlling the Bofors. The RNZN mothballed the quad pom pom mounts for manning reasons, but maintained the single oerlikons on HMNZS Bellona.).

Black Prince and Diadem also received eight single 20 mm, and had a further two twin 20 mm by early 1945. (Black Prince was loaned to the RNZN after the war and was operational briefly in 1947 before part of her crew mutinied and were discharged, and after a 1952 refit with 8 single Mk3P 40mm which were electric powered, like the RN Mk 9 and 6 single Oerlikon and operated till 1955, which included a visit to the 1953 Fleet Review at Spithead. Diadem was sold to Pakistan in 1956, after a modest refit with 293 and 281 radar and standardised 40mm twin and single light AA guns. Her 5.25" guns were fired in Pakistan's brief war with India in 1961. Diadem became a cadet training ship in 1962 and was renamed Babur).

Post-war development

Post war in the expanded 1951 programme of the Korean War Emergency a broad beam Bellona class armed with four twin Mk 6 4.5 guns [7] was considered as a cruiser option along with the 1951 Minotaur class [8] and the Tiger class completed with two Mk 24 6 inch turrets and four twin Mk 6 4.5.

Ships in class

Name Pennant Builder Laid down Launched Commissioned Fate
Dido group
Dido 37 Cammell Laird, Birkenhead 26 October 1937 18 July 1939 30 September 1940 Broken up at Barrow-in-Furness, 1957
Argonaut 61 21 November 1939 6 September 1941 8 August 1942 Broken up at Newport, 1955
Charybdis 88 9 November 1939 17 September 1940 3 December 1941 Sunk at Battle of Sept-Îles, 23 October 1943
Phoebe 43 Fairfield, Govan 2 September 1937 25 March 1939 27 September 1940 Broken up at Blyth, 1956
Hermione 74 Alexander Stephen and Sons, Glasgow 6 October 1937 18 May 1939 25 March 1941 Torpedoed by the German submarine U-205, 16 June 1942
Bonaventure 31 Scotts, Greenock 30 August 1937 19 April 1939 24 May 1940 Torpedoed by the Italian submarine Ambra, 31 March 1941
Scylla 98 19 April 1939 24 July 1940 12 June 1942 Broken up at Barrow-in-Furness, 1950
Naiad 93 Hawthorn Leslie, Hebburn 26 August 1937 3 February 1939 24 July 1940 Torpedoed by the German submarine U-565, 11 March 1942
Cleopatra 33 5 January 1939 27 March 1940 5 December 1941 Broken up at Newport, 1958
Sirius 82 Portsmouth Dockyard, Portsmouth 6 April 1938 18 September 1940 6 May 1942 Broken up at Blyth, 1956
Euryalus 42 Chatham Dockyard 21 October 1937 6 June 1939 30 June 1941 Broken up at Blyth, 1959
Bellona group
Bellona 63 Fairfield, Govan 30 November 1939 29 September 1942 29 October 1943 Broken up at Barrow-in-Furness, 1959
Royalist 89 Scotts, Greenock 21 March 1940 30 May 1942 10 September 1943 Broken up at Osaka, 1968
Diadem 84 Hawthorn Leslie, Hebburn 15 December 1939 26 August 1942 6 January 1944 Transferred to Pakistan, 1956. Renamed Babur. Deleted 1985.
Black Prince 81 Harland and Wolff, Belfast 2 November 1939 27 August 1942 20 November 1943 Broken up at Osaka, 1962
Spartan 95 Vickers-Armstrongs, Barrow-in-Furness 21 December 1939 27 August 1942 10 August 1943 Sunk by aircraft, 29 January 1944
  • HMS Ulysses, a 1955 novel by Alistair Maclean, is based on Royalist's late war cruises on Arctic convoys to Murmansk. MacLean puts emphasis on the high quality radar fit and the ship's primary air defense role from the start. Also noted is the ship's high trial speed of supposedly near 39 knots; the exceptional difficulty of the crew sleeping in these small cruisers, a problem for every Royalist crew from 1943 to 1965; and its supplementary anti-submarine capability.
  • Sailor of the King (called Single-handed in the United States), the 1953 film adaptation of C.S. Forester's novel Brown on Resolution, used the Dido-class cruiser HMS Cleopatra to represent two fictional Royal Navy ships. The first ship, "HMS Amesbury", is sunk in a heroic battle with the more powerful German raider "Essen". ("Essen" was represented by HMS Manxman with large mock-up gun turrets.) Cleopatra reappears as "HMS Stratford", and triumphs at the end of the film. The two battle sequences depict the ship firing her guns and torpedoes in some detail. In the original novel, Brown's ship was an HMS Charybdis.

See also


  1. Roberts. J and Raven.A. British cruisers of WW2. Arms and Armour, p 275
  2. Roberts and Raven, p 275, col 3, lines 11-14
  3. Roberts and Raven, p275
  4. D. Murfin. Damnable Folly? Small Cruiser Designs for the Royal Navy Between the Wars in Warship 2011. Conway (2011) p139
  5. R. Hughes. Through the Waters. A gunnery officer on HMS Scylla 1942-3. W . Kimber. London (1956) p 25-29
  6. D. Murfin. "Damnable Folly? Small Cruiser Designs for the Royal Navy Between the Wars" in Warships 2011. Conway. London, p139.
  7. D. Murfin. Damnable Folly? Small Cruiser Designs for the Royal Navy Between the Wars in ,'Warship 2011'. Conway Maritime. London (2011)p 139
  8. B.Watson. The changing face of the world's Navies 1945 to present. Arms & armour. London (1991) p79


  • Colledge, J. J.; Warlow, Ben (2006) [1969]. Ships of the Royal Navy: The Complete Record of all Fighting Ships of the Royal Navy (Rev. ed.). London: Chatham Publishing. ISBN 978-1-86176-281-8.
  • R Gardiner, R Gray : Conway's All the World's Fighting Ships: 1906–1921 (1985) ISBN 0-85177-245-5
  • Dido class at Uboat.net
  • Bellona class at Uboat.net
  • WWII cruisers
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