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HMAS Canberra sailing into Sydney Harbour in 1930.jpg
Canberra passing under the Sydney Harbour Bridge in 1930
Class overview
Operators:  Royal Navy
 Royal Australian Navy
Succeeded by: York class
Subclasses: Kent, London, Norfolk
In commission: 1928 - 1959
Planned: 2
Completed: 13
Lost: 3
Retired: 10
General characteristics Kent class[1]
Displacement: 10,400 tons average standard / 14,150 tons average full load
Length: 590 ft (180 m) p/p / 630 ft (190 m) (o/a)
Beam: 68 ft (21 m) across bulges
Draught: 17.25 ft (5.26 m) standard / 21.5 ft (6.6 m) full load
Propulsion: 8 x Admiralty 3-drum boilers, Parsons (Brown-Curtis in Berwick) geared steam turbines on 4 shafts, 80,000 shp
Speed: 31.5 kts (30 kts full load)
Range: 8,000 nm at 10 kts
2,300 nm at 30 kts
Complement: 685 private ship, 710 flag, 784 war
Armament:
Armour: Main belt:
  • 4.5 in (110 mm) with 1 in closing bulkheads (Berwick, Cumberland, Suffolk, Kent & Cornwall only, from 1935-)
Lower deck:
  • 1.25 in over machinery
  • 1.5 in over steering gear
Main box citadels:
  • 1-4 in sides
  • 1 to 2.5 in (25 to 63 mm) crowns
Turrets:
  • 1 in faces, sides, rears, crowns & barbettes
General characteristics London class
Displacement: 9,840 tons standard average / 13,315 tons full load
Length: 595 ft (181 m) p/p (181 m) / 632 ft 9 in (192.9 m) (o/a)
Beam: 66 ft (20 m)
Draught: 17 ft (5.2 m) standard (5.2 m) / 21 ft 6 in full load (6.6 m)
Speed: 32.25 kts (31 kts full load)
Complement: 700 private ship, 852 war
Armament:
Armour: Main belt:
  • 3.5 in with 1 in closing bulkheads (London only, from 1938-)
Notes: Other characteristics as per Kent
General characteristics Norfolk class
Displacement: 10,300 tons standard / 13,775 tons full load
Complement: 710 private ship, 819 war
Armament:
Notes: Other characteristics as per London
For the pre-World War I armoured cruisers, see Monmouth class[2]

The County class was a class of heavy cruisers built for the British Royal Navy in the years between the First and Second World Wars. They were the first post-war cruiser construction for the Royal Navy and were designed within the limits of the Washington Naval Conference of 1922. Such ships, with a limit of 10,000 tons standard displacement and 8-inch calibre main guns may be referred to as "treaty cruisers" (the term "heavy cruiser" was not defined until the London Naval Treaty of 1930[1]).

The fifteen Counties were built in three distinct sub-classes : the Kent, London and Norfolk classes. They were the only 10,000-ton 8-inch gun, or "A", cruisers that the Royal Navy built. The Counties are remembered for their distinctive three-funnel layout and service in all the major naval theatres of World War II.

In an attempt to extract more ships from the treaty limits, the navy planned to construct 8,250-ton "B" ships; six of which could be built in place of five Counties. The extra ship that this afforded was an attractive proposition for a navy that had the immense peacetime commitments of empire[3] [1]. In the event, peacetime economies and politics intervened and only two B-type cruisers were built, a 6-gun modified County design; the York class.

Contents

Design & development

The 10,000 ton treaty cruisers were the first type of warships built to internationally-agreed restrictions[3]. These restrictions posed new engineering challenges and forced compromises upon designers[1] in how to extract the best balance of speed, armament and protection. The United States Navy adopted a design with triple-gun turrets, allowing the hull to be shortened thus saving weight that could be put into protection. This approach however was at the expense of requiring increased installed power, as the speed of a ship is a function of the ratio of length to beam. The Royal Navy had a requirement for a vessel for colonial trade route defence, which required a good cruising range and speed. This determined the need for a long hull and the use of twin-gun turrets, with any remaining displacement invested in protection.

The design was conservative in nature, especially when compared to the contemporary Nelson-class battleships built to satisfy the same treaty. The long (630 feet overall) hull was flush decked and with a high freeboard, and was strongly built. This afforded high initial stability[1][3], which contributed to the protection scheme. The machinery spaces followed the traditional layout of boiler rooms ahead of engine rooms, separated by an amidships magazine. The two boiler rooms exhausted into four uptakes, the central pair being combined to form a thickened central funnel. The three-funnel design was handsome, but somewhat impractical in terms of utilisation of internal space[1]

As had been trialled in the wartime cruiser HMS Emerald whose completion had been delayed post-war, the Counties featured a new design of forward superstructure incorporating the navigating bridge, wheelhouse, signalling and compass platforms and gunnery director in a single block. This advance considerably rationalised the separate armoured conning tower and myriad of decks and platforms of older designs. Moving the fire-control equipment from the mast negated the need for a heavy tripod, and light pole masts sufficed for signalling yards and the spread of wireless antennae.

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Armament

The guns, BL 8 inch Mark VIII (203 mm, L/50), were equally disposed in superfiring twin-turrets fore and aft. The turret design was needlessly complicated[1] [4] by the original requirement that they should be capable of anti-aircraft fire and were thus provided with a maximum elevation of 70°, despite the inability to train and elevate sufficiently quickly to track aerial targets and the complete lack of a suitable fire control system.

Secondary armament consisted of four QF 4 inch Mark V (102 mm, L/45) guns in single mounts HA Mk.III fed from the amidships magazine. There were quadruple-tube torpedo launchers, one each side, amidships. The single 4-inch Mk V guns would later be replaced by Mk XVI guns in paired mountings. In a fruitless attempt to keep within treaty limits, the Mark XVI mounting was stripped down to reduce the weight, the result being the Mark XVII, an exercise described as "ridiculous punctiliousness"[5]. They were later converted back to standard Mark XVI mounts.

The initial design called for two octuple mountings for the QF 2 pounder Mk.VIII anti-aircraft autocannon, but as a weight saving exercise these were not initially shipped, and the existing QF 2 pounder Mark II was carried in lieu on four single mounts. Space was provided for a rotating catapult and a crane for operating aircraft, although again these were initially not provided.

Protection

The initial design left little weight to distribute amongst protection, particularly in light of the fastidiousness of the designers to stick to the letter of the treaty. Thus, the traditional side-belt of armour was dispensed with, and the 1 inch (25 mm) side plating afforded only splinter protection. A 1.25 inch (32 mm) protective deck covered the machinery spaced, and there were "box citadels" protecting the magazines and shell rooms; 2.5 inch (64 mm) crowns and 4 inch (102 mm) sides, closed by 2.5 inch bulkheads. The aft box citadel had slightly reduced thicknesses at the ends, and that amidships was thinned as it lay within the confines of the armoured deck and side plating. There was a 1.5 inch (38 mm) arch over the steering gear closed by a 1 inch forward bulkhead. The turrets and barbettes received only thin splinter plating, as did the compass platform. There were external bulges to provide torpedo protection.

Differences & modifications

Kent class

Profile and plan of HMS Cumberland. This shows her post 1943, with the large hangar removed and a lattice superstructure added in its place to carry radar sets and gunnery directors. Like Suffolk, she was cut down aft when originally rebuilt to reduce displacement.

The initial seven ships – HM Ships Berwick, Cornwall, Cumberland, Kent, and Suffolk and HMAS Australia and Canberra for the Royal Australian Navy – formed the Kent class. All were ordered in 1924 and commissioned in 1928. It was quickly found necessary to heighten the funnels by some 15 feet (4.5 m) to clear the flue gasses from the aft superstructure. The Australian ships, Australia and Canberra had them raised a further 3 feet (0.9 m). Between 1930 and 1933 the aircraft and catapult were added, as was a high-angle HACS director for the 4-inch guns. Kent received an additional pair of 4-inch guns in 1934, and she, Berwick and Cornwall each received a pair of QF 0.5 inch Vickers machine guns added abreast the fore funnel.

By the mid-1930s, the British Kents were due for modernisation. However, there was little surplus of weights for the designers to work with; they were between 150—250 tons under the treaty limits and it was estimated that a further 200-odd tons could be gained through various savings[1]. A 6-foot deep armoured belt, 4.5 inches thick, was added amidships, extending from the armoured deck to 1 foot below the waterline. Cumberland and Suffolk had the aft superstructure razed and replaced by a large hangar for two aircraft and a fixed athwartships catapult. A crane was fitted on either side of the after funnel and the rear gunnery, navigation and control positions were relocated to the hangar roof. The single 2 pdr guns were removed and quadruple moutings, Mark VII, were added on either side of the bridge. The 4-inch were relocated, and the rearmost pair were replaced by twin mountings Mark XIX for the QF 4 inch Mark XVI. To keep weight within acceptable margins, the hull was cut down by one deck aft of Y turret. Berwick and Cornwall were similarly converted but with more weight in hand the hull was not cut down, all four 4-inch mounts were twins and the 2 pounder guns were octuple mounts. By 1939, the torpedo tubes had been removed in all four ships.

Kent had less weight available for improvements, therefore was not given such an extensive modernisation. She retained the rotating catapult and after superstructure, with an additional fire-control position mounted on a distinctive lattice structure aft. Her anti-aircraft armaments were improved as per her sisters, but the multiple 2 pounders and their directors were carried aft, by the lattice structure.

Naval historian H. Trevor Lenton[1] estimates that despite the best attempts, none of these ships stayed truly within the treaty limits; Kents full load displacement was 14,197 tons, indicating a standard displacement of around 10,600 tons. Lenton expresses doubts whether the Admiralty ever informed the Government of these excesses, as with war imminent, "there were more pressing demands on their time".

London class

Profile and plan of HMS London. This shows her post-1943, with her aircraft facilities removed and light anti-aircraft weaponry and electronics fit considerably increased. London's profile is far removed from the original stately appearance of the County class.

The second group, the four ships of the London class (HMS Devonshire, London, Shropshire and Sussex), closely followed the design of the Kents. The external bulges were lost, reducing the beam by 2 feet, and the hull was lengthened by 2.75 feet, which translated into a ¾ knot increase in speed. To remedy the loss of bulge protection, instead there was a second skin of inner plating to provide the same effect. The bridge was moved aft to lessen the effects of blast from B turret when training abaft the beam. They had heightened funnels as-built. The aircraft and catapult had been fitted by 1932.

In all ships bar Sussex, four 4-inch guns were added in single mountings abreast the funnels. The single 2 pounder guns were removed, and two quadruple mounts for 0.5 inch Vickers machine guns were added. Shropshire acquired an additional anti-aircraft fire control director. Early in the war, the additional 4-inch guns were removed, and the original 4 guns altered to the Mark XVI twin mounts. The octuple 2 pounder guns that had originally been designed in were also finally added.

From 1938 to 1941, London received an altogether more comprehensive modernisation. Her upperworks were razed, and replaced by new fore and aft superstructures and two upright funnels modelled on the contemporary Crown Colony class. The forward superstructure block incorporated a large hangar opening onto an athwartships catapult between the superstructure blocks. There was a catapult on either side of the after funnel. The 4-inch anti aircraft guns were replaced by twin mountings and relocated to the after superstructure, with the torpedoes a deck below. The 2 pounder guns were carried on the hangar roof and the multiple Vickers guns mounted, one each, on the roofs of B and X turrets. A 3.5 inch (89 mm) belt, 8 feet deep, was added abreast the machinery spaces, extending up to the armoured deck. However, the hull had originally been carefully designed to reduce weight based on the initial arrangements. London's modifications, with heavy weights added fore and aft, resulted in a severely overstressed hull, and cracks and loose rivets began to appear on the upper deck. The upper deck was reinforced, which caused the stress to be transmitted through the lower hull, and cracks began to appear under the waterline. It took underwater reinforcements and refits extending into 1943 to remedy the situation[1][3].

The outbreak of war prevented what had ended up being a rather fruitless cosmetic rebuild being extended to the rest of her sisters, as had originally been intended. The remaining Londons thus never received side armouring or the improved aircraft complement.

In the 1930s, the last three Londons underwent similar alterations as the Kents did, having their eight 21 inch (533 mm) torpedo tubes removed, and one twin 8 inch (203 mm) turret removed, although London retained it. One ship, Shropshire, retained her "X" Turret as well as her Torpedoes and was transferred to the Royal Australian Navy in early 1943 to replace Canberra.

Norfolk class

Profile and plan of HMS Norfolk. This is post-1944, with X turret landed to allow for heavy increases in anti-aircraft and electronics fit. She carries a total of six multiple 2 pounder mountings, each with an associated radar-equipped director unit.

The final pair of Counties – Norfolk and Dorsetshire – formed the Norfolk class. Orders for another two ships that had been deferred from the 1927-8 and 1928-9 programmes – Northumberland and Surrey – were never placed. This was due to a change in administration in 1929 that ushered in a minority Labour government under Ramsay Macdonald, which cancelled the ships as an economy measure and a gesture to the forthcoming London Naval Conference[3]. They were repeats of the Londons with minor alterations.

The bridge and after superstructure were lowered. The 8-inch gun turrets were Mark II variants that were intended to offer weight savings, but ended up being heavier than the Mark I variant![3]. The 4-inch guns were relocated forwards, in order that they did not obstruct the catapult and aircraft which had been mounted lower down than in their predecessors. During 1937, the 4-inch guns were replaced by twins, octuple 2 pounders were added around the after superstructure and the single guns forward were removed. These improvements pushed the standard displacement over 10,400 tons[1].

During the war, UP launchers were initially added, but were later removed along with the Vickers guns. These were replaced by the altogether more useful 20 mm Oerlikon gun. An additional director for the 4-inch guns was added, and the pole masts were replaced by tripods to support the additional weight of masthead electronics. A refit in 1944 saw the Norfolk, by now a singleton in the class, lose her aircraft, catapult and X turret. This allowed four quadruple 2 pounder mounts and their directors and four single 40 mm Bofors guns to be added. An extra superstructure was added aft to carry barrage directors, fitted with radar Type 283, which finally allowed the main armament to serve in its intended anti-aircraft role.

Comparison of classes

*: Post 1935 refit, not in Australia or Canberra
**: Post 1938 rebuild, London only

Ships

Service

The County class saw much service during the Second World War. HMS Norfolk and Suffolk were equipped with radar which was used to good advantage when they shadowed the Bismarck during the RN's attempts to hunt her down after the sinking of HMS Hood.

The class saw service in nearly every theatre of the war. A number of losses were suffered by the class, with Canberra, Cornwall and Dorsetshire all being destroyed.

The survivors were all decommissioned by the 1950s, except Cumberland which was an armaments trials ship testing the automatic 6 inch and 3 inch guns that would be fitted to the Tiger class. She was scrapped in 1959.

Canarias class

Two ships based on the County class, Canarias and Baleares of the Canarias-class, were designed in the UK and constructed in Spain by the Vickers-Armstrongs subsidiary Sociedad Española de Construcción Naval. Completed in the late 1930s for the Spanish Navy, they saw service during the Spanish Civil War. Although they shared a common hull, machinery and main armament the Spanish ships had a notably different appearance, sporting an enormous single funnel and an equally tall forward superstructure.

References

  1. ^ a b c d e f g h i j k British and Empire Warships of the Second World War, H. T. Lenton, Greenhill Books, ISBN 1-85367-277-7
  2. ^ 'Castles of Steel, Robert K. Massie, 2004, Balantine Books, ISBN 0345408780
  3. ^ a b c d e f Treaty Cruisers: The First International Warship Building Competition, Leo Marriot, 2005, Leo Cooper Ltd., ISBN 1-8441-5188-3
  4. ^ NavWeaps.com, British 8"/50 (20.3 cm) Mark VIII
  5. ^ Naval Weapons of World War Two, John Campbell, Conway Maritime, 2002, ISBN 0-8517-7924-7

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