The Lion class was a class of six fast battleships designed for the Royal Navy (RN) in the late 1930s. They were a larger, improved version of the preceding , with guns. Only two ships were laid down before the Second World War began in September 1939 and a third was ordered during the war, but their construction was suspended shortly afterwards. The design was modified in light of war experience in 1942, but the two ships already begun were scrapped later in the year.
None of the other ships planned were laid down, although there was a proposal in 1941 to modify one of the suspended ships into a hybrid battleship-aircraft carrier with two 16-inch gun turrets and a flight deck. Preliminary work for a new design began in 1944 and continued for the next year or so until the RN realised that they were unaffordable in the post-war financial environment.
Design and description
The design of the Lion-class battleships was influenced by the terms of several arms control treaties of the 1920s and 1930s. The Washington Naval Treaty of 1922 had banned new battleship construction, with certain specified exceptions, for a decade. The London Naval Treaty of 1930 extended the ban for five more years, which meant that almost all the First World War-era ships would be eligible for replacement by the Washington Treaty's rules when the London Treaty expired. The British government intended for the 1935 Second London Naval Disarmament Conference to prevent a naval arms race that Britain could ill afford, but the Japanese refusal to sign the resulting Second London Naval Treaty of 1936 thwarted that hope. The three signatories, Britain, France and the United States had agreed to limit the size and gun calibre for the battleships that would be built by the signatories. They were restricted to standard displacement and a main armament calibre of . This dictated the choice of the 14-inch gun for the main battery of the King George Vs (KGV). The treaty contained an "Escalator Clause" that would increase the maximum allowable calibre to 16 inches if the Japanese government failed to sign; this was triggered in April 1937.Raven and Roberts, pp. 108, 158, 280, 315
As it was too late to modify the KGVs to avoid delays in construction, the Board of Admiralty then began preliminary design work on a 35,000-long-ton ship armed with 16-inch guns and it was promising enough that the Director of Naval Construction (DNC) was ordered to further investigate such designs. To save design time, many of the features of the KGVs were incorporated in the new design, but the limited size of the ship was a real challenge for the designers. Maintaining the same speed, protection, and secondary armament as the older ships while using 16-inch guns proved impossible while remaining within the treaty limits. In an effort to remain within treaty limits, the overall weight of armour was slightly reduced and two twin gun turrets as well as aircraft and their facilities were eliminated.Raven and Roberts, p. 315
The treaty-imposed design problems became irrelevant on 31 March 1938, when the signatories of the Treaty invoked the tonnage escalation clause because the Japanese refused to provide any information about their battleship construction programme and the signatories feared that their new ships could be outclassed by the new Japanese battleships. Due to limitations of docking facilities particularly at Rosyth and Portsmouth as well as costs, the Admiralty hoped to have the new limit at ; the limit was eventually settled at because the Americans would accept only that figure or none at all.Friedman, pp. 329–330 The Admiralty in any case decided to limit itself to 40,000 long tons and nine 16-inch guns on the grounds that larger vessels would be unable to dock at the major Royal Navy dockyards at Rosyth or Portsmouth.Brown, p. 37 A new design was prepared with more armour, more powerful machinery, the two twin 5.25-inch gun turrets restored, and four aircraft added. The Admiralty approved this design on 15 December and bids were solicited very shortly afterwards.Raven and Roberts, pp. 316–317
1938 design The 1938 version of the Lion class had a waterline length of , an overall length of , a beam of ,Garzke and Dulin, p. 263 and a maximum draught of .Raven and Roberts, p. 318 They would have displaced at standard load and at deep load. The appearance of the Lions closely resembled that of the KGVs, but included a transom stern to improve steaming efficiency at high speed. The crew complement was estimated to be about 1,680 officers and ratings.Garzke and Dulin, p. 274
In the interests of saving time, the four-shaft unit machinery design from the KGVs was duplicated with alternating boiler and engine rooms. The Lion-class ships would have had four sets of geared Parsons steam turbine sets housed in separate engine rooms, each driving one propeller shaft. They were designed to produce a total of at overload condition and a speed of . The turbines were intended to be powered by eight Admiralty three-drum boilers in four boiler rooms at a working pressure of and temperature of . The turbines and boilers could be cross-connected in an emergency.Garzke and Dulin, pp. 263, 273 The ships were designed to carry of fuel oil. Their maximum estimated range was at a speed of . They would have been equipped with six turbogenerators and two 330-kW diesel generators that supplied the common ring main at 220 volts.Garzke and Dulin, pp. 278–279
The Lion-class ships' main armament consisted of nine newly designed 45-calibre BL 16-inch Mark II guns in three hydraulically powered triple-gun turrets. The maximum elevation of the turrets was increased to +40° although the guns were loaded at +5°. They fired projectiles at a muzzle velocity of ; this provided a maximum range of . Their rate of fire was two rounds per minuteCampbell, p. 24 and the ships carried 100 shells per gun. The secondary armament consisted of sixteen 50-calibre QF 5.25-inch Mk I dual-purpose guns in eight twin-gun mounts. They had a maximum depression of −5° and a maximum elevation of +70°. They fired an high-explosive shell at a muzzle velocity of . At maximum elevation, the guns had a maximum range of . Their normal rate of fire was about 7–8 rounds per minuteCampbell, pp. 44, 46 and 400 rounds were provided for each gun. Short-range air defence was provided by 48 QF 2-pounder "pom-pom" guns in six octuple mountings. The 2-pounder gun fired a , shell at a muzzle velocity of to a distance of . The gun's rate of fire was approximately 96–98 rounds per minuteCampbell, pp. 71–72, 74 and 1,800 rounds per gun were carried by the ships.
Their armour scheme was virtually identical to that of the KGVs. The waterline belt was intended to be made from Krupp cemented armour (KCA) thick and was long. The main portion of the belt would have been high, but a lower strake, high, extended an additional past the ends of the armoured citadel. It was intended to be tapered vertically from 14.7 inches in thickness to at the bottom edge of the belt, while the plates at the end of the belt would have been only thick at the top. Transverse bulkheads thick would have closed off each end of the armoured citadel. At the aft end of the steering gear compartment would have been a transverse bulkhead. The KCA face-plates of the main gun turrets were intended to be 15 inches thick and their roofs would have used non-cemented armour plates. Their sides remained in thickness. The barbettes for the 16-inch guns were intended to be 15 inches thick on the sides, tapering to closer to the centreline of the ship.
Intended to resist the impact of a armour-piercing bomb dropped from a height of , the Lions deck protection was identical to that of the KGV class. It consisted of non-cemented armour over the magazines that reduced to over the machinery spaces. The armour continued forward and aft of the citadel at the lower-deck level. Forward it tapered in steps from five inches down to near the bow. Aft, it protected the steering gear and propeller shafts with of armour. Unlike the Germans, French and Americans, the British no longer believed that heavy armour for the conning tower served any real purpose, given that the chance of hitting the conning tower was very small, and protected the forward conning tower with only of armour.
The underwater protection, also virtually identical to that of the KGVs, would have consisted of a wide three-layer system of voids and liquid-filled compartments meant to absorb the energy of an underwater explosion. It was bounded on the inside by the torpedo bulkhead. Both of the inner and outer voids were fitted with pumps to flood them with water to level the ship (counter-flood) in case she began to list. Over the length of the citadel, this system was found to be proof against of TNT during full-scale trials.Raven and Roberts, pp. 294, 297 The Lion-class ships would have had a double bottom with a depth of .Garzke and Dulin, p. 278
Naval historians William Garzke and Robert Dulin believe that the design of the Lion class would have corrected some of the deficiencies of the KGVs with the notable exceptions of the too-shallow torpedo protection system, caused by limits of the existing infrastructure, and the limited endurance, both of which were addressed in the revised 1942 design. Their 16-inch main battery, although not the most powerful in the world, were superior to the earlier guns used in the s, and they "would have been the most powerful and fastest battleships to have served in the Royal Navy."Garzke and Dulin, pp. 274–275
1942 design Construction was suspended shortly after the war began and the Admiralty took advantage of the time to refine the design in light of war experience in late 1941. The beam was increased to , the maximum width allowed by the locks of the Panama Canal, to increase the depth and effectiveness of the ships' torpedo protection system, and almost of fuel oil were added to increase the ship's endurance. The beam increase meant that many of the Royal Navy home docking facilities, including Rosyth and Portsmouth, could no longer accommodate these ships. The requirement that 'A' turret had to be able to fire directly ahead at 0° elevation was rescinded as it radically reduced freeboard forward and caused the KGVs to take a lot of water over the bow in head seas. To partially compensate for the additional weight, the belt armour was reduced in thickness by to except over the magazines, and the aircraft and their facilities were removed. The space in the superstructure freed up by these changes was used to increase the light anti-aircraft armament to nine octuple and one quadruple 2-pounder mounts.Garzke and Dulin, pp. 264–265
The overall length of the Lion class increased to and the displacement grew to at standard load and at deep load. No changes were made to the propulsion machinery, so the speed decreased to because of the greater displacement. The of fuel increased their endurance to an estimated maximum of at a speed of 10 knots. The freeboard forward was increased by nearly ,Garzke and Dulin, p. 276 and the radar suite was increased to match that of the battleship , then under construction. Because the light cruiser lost all steam power when she struck a mine early in the war, two diesel generators were substituted for two turbo-generators. The extra beam was used to increase the depth of the torpedo protection system amidships from 13.25 ft to . The ships' crew was estimated at 1,750 officers and ratings.Garzke and Dulin, pp. 272–273, 278–279
1944 design