County - class cruiser The County - class was a class of heavy cruiser s built for the 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 Treaty 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 ) . The thirteen 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 . 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 . Design & development . The 10 , 000 ton treaty cruisers were the first type of warships built to internationally - agreed restrictions . These restrictions posed new engineering challenges and forced compromises upon designers 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 and independent fighting power . This determined the need for a long hull and the use of four 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 deck ed and with a high freeboard , and was strongly built . This afforded high initial stability , 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 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 . 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 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 were later 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 " . 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 was sufficient to only give protection against shell splinters . A 1 . 25 inch ( 32 mm ) protective deck covered the machinery spaces , 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 the citadel amidships had thinner armour 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 - thick 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 and modifications . " Kent " - class . 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 weight for the designers to work with while remaining within the Treaty requirements ; they were between 150 and 250 tons under the treaty limits and it was estimated that a further 200 - odd tons could be gained through various savings . A armoured belt , 4 . 5 inches thick , was added amidships , extending down 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 mountings , Mark VII , were added on either side of the bridge . The 4 - inch guns 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 and therefore was not given such an extensive modernisation . While she received the 4 - inch armour belt and the double 4 - inch gun mounts like her sisters , 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 for her sisters , but the multiple 2 pounders and their directors were carried aft , by the lattice structure . Naval historian H . Trevor Lenton estimates that despite the best attempts , none of these ships stayed within the treaty limits ; " Kent " s 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 . 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 not present , reducing the beam by 2 feet , and the hull was lengthened by ; these changes translated into a ¾ knot increase in speed . To remedy the loss of the bulge protection , there was a second skin of inner plating to provide the same effect . The bridge was moved aft to lessen the effects of muzzle blast from B turret when the guns were trained 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 removed and replaced by new fore and aft superstructures and two upright funnels modelled on the contemporary Crown Colony - class cruisers . 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 , 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 . The modifications to " London " added heavy weights fore and aft and severely overstressed the hull . As a result 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 instead and cracks began to appear under the waterline . It took underwater reinforcements and refits extending into 1943 to remedy the situation . 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 " London " s underwent similar alterations as the " Kent " s 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 torpedo armament and was transferred to the Royal Australian Navy in early 1943 to replace " Canberra " . " Norfolk " - class . 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 – to have been named " Northumberland " and " Surrey " – were never placed . This was due to the change in administration in 1929 that ushered in a minority Labour government under Ramsay Macdonald . The new government cancelled the ships as an economy measure and as a gesture to the forthcoming London Naval Conference . 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 . 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 . During the war , UP rocket launchers were initially added , but they 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 . " Dorsetshire " was sunk in 1942 and so it was only " Norfolk " that underwent a refit in 1944 during which her aircraft , catapult and X turret were removed . 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 . 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 . The class saw service in nearly every theatre of the war . " Norfolk " , " Suffolk " , and " Dorsetshire " were involved in the pursuit of " Bismarck " and " Prinz Eugen " . " Berwick " fought a gunnery action with " Hipper " , and " Norfolk " again fought German Navy surface units during Battle of the North Cape . " Suffolk " , and " Sussex " suffered bomb damage from Luftwaffe aircraft , and both required substantial repairs . Three of the class were lost ; with " Canberra " being hit by naval gunfire at the Battle of Savo Island then scuttled by an American destroyer , and " Cornwall " and " Dorsetshire " both bombed and sunk by Japanese carrier borne aircraft during the Indian Ocean raid . The survivors began decommissioning in 1948 , and were all decommissioned by the mid - 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 , with an enormous single funnel – though " Canarias " received two funnels in a later refit – and an equally tall forward superstructure .