The ‘Lion’ class was to have comprised six battleships, and was designed for the Royal Navy in the late 1930s as what was in essence a larger and improved version of the ‘King George V’ class battleship with 16-in (406-mm) guns. The class design changed several times in response to the removal of treaty restrictions on size and in reflection of war experience.
The choice of 14-in (356-mm) guns in a mix of quadruple and twin turrets for the main battery of the ‘King George V’ class had been dictated by the Second London Naval Treaty, which limited battleships to a standard displacement of 35,000 tons and a main calibre of 14 in (356 mm). When Japan refused to agree to the treaty terms, however, the maximum calibre permitted reverted to 16 in (406 mm) in April 1937.
Robert Farley, writing for Nationalinterest.org, states:
“A Second London Naval Treaty, taking force in 1936, essentially gave up on the project of arms limitation because of the defection of Japan. The treaty didn’t prevent World War II, and the decision of the Japanese and Italians to defect in the 1930s certainly gave them a leg up on the next war.”
The Admiralty then began preliminary design work on a 35,000-ton ship armed with 16-in (406-mm) guns, and this was sufficiently promising for the Director of Naval Construction to be instructed to investigate such designs further, and at the same time provide for several aircraft to be carried. To save design time, many ‘King George V’ class features were incorporated, but the limited displacement proved a major design challenge, and the greater weight of the main armament was offset by a slight reduction in the overall weight of armour and the elimination of two twin 5.25-in (133-mm) turrets.
The design task was eased in March 1938, when the treaty signatories invoked its 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 construction. The new displacement limit was 45,000 tons, but the Admiralty opted for 40,000 tons and nine 16-in (406-mm) guns on the grounds of cost and the need for the ships to dock at Rosyth and Portsmouth. A new design included more armour, more powerful propulsion machinery, the restoration of the two twin 5.25-in (133-mm) turrets, and four aircraft added. On 15 December 1938, the Admiralty approved this design, which posited a ship with an overall length of 785 ft (239.3 m), beam of 105 ft (32.0 m) and maximum draught of 33 ft 6 in (10.2 m). The standard displacement was 40,550 tons increasing to 46,400 tons at deep load.
To save time, the four-shaft machinery design of the ‘King George V’ class was duplicated with alternating boiler and engine rooms. The ‘Lion’ class ships had four sets of single-reduction geared Parsons steam turbines housed in separate engine rooms. Each set consisted of one high-pressure and one low-pressure turbine driving one propeller shaft, and the combined total of 130,000 shp (96928 kW) was designed to provide a speed of 30 kt. The turbines were powered by eight Admiralty-type three-drum boilers in four boiler rooms. The turbines and boilers could be cross-connected in an emergency. The ships were designed to carry 3,720 tons of fuel oil for a maximum range of 14,000 nm (26000 km) at 10 kt.
The main armament was to comprise nine 16-in (406-mm) L/45 guns of a new Mk II design in the hydraulically powered A, B and Y centreline turrets. The maximum gun elevation was increased to +40°, though the guns were loaded at +5°, and the guns fired a 2,375-lb (1077-kg) shell at a muzzle velocity of 2,483 ft (757 m) per second to a maximum range of 40,560 yards (37090 m). Each gun’s rate of fire was two rounds per minute, and each gun was provided with 100 shells per gun. The secondary armament comprised 16 5.25-in (133-mm) L/45 Mk I dual purpose guns in eight twin mounts: these guns had a maximum depression of −5° and a maximum elevation of +70°, and fired an 80-lb (36.3-kg) HE shell at a muzzle velocity of 2,672 ft (814 m) per second. The normal rate of fire was some seven to eight rounds per minute. The guns had a maximum range of 24,070 yards (22010 m), and 400 rounds were provided for each gun. Short-range air defence was provided by 48 2-pdr guns in six octuple mountings: this weapon fired a 40-mm shell weighting 1.684 lb (0.764 kg) at a muzzle velocity of 2,400 ft (730 m) per second to a range of 6,800 yards (6220 m) at a rate of 96 to 98 rounds per minute. Some 1,800 rounds were provided for each gun.
The armour scheme was virtually identical to that of the ‘King George V’ class ships, and based on a 433-ft (132-m) waterline belt of Krupp cemented armour 15 in (381 mm) thick: the belt’s main portion was 15 ft (4.6 m) high, but a lower strake, 8 ft 3 in (2.5 m) high, extended an additional 40 ft (12.2 m) past the ends of the armoured citadel. It tapered vertically from 15 in (381 mm) in thickness to 5.5 in (140 mm) at the bottom edge of the belt, while the plates at the end of the belt were only 11 in (279 mm) thick at the top. Transverse bulkheads 10/12 in (254/305 mm) thick closed off each end of the central citadel. The KCA face-plates of the main gun turrets were 15 in (381 mm) thick and their roofs were 6-in (152-mm) non-cemented armour plates, and their sides remained 7 to 10 in (180 to 250 mm) thick. The main armament barbettes were 15 in (381 mm) thick on the sides, but tapered to 12–13.5 in (305/343 mm) closer to the ship’s centreline.
Intended to resist the impact of a 1,000-lb (454-kg) armour-piercing bomb dropped from 14,000 ft (4265 m), the deck protection was identical to that of the ‘King George V’ class and comprised 6-in (152-mm) non-cemented armour over the magazines, a thickness reduced to 5 in (127 mm) over the machinery spaces. The armour continued forward and aft of the citadel at the lower-deck level. Forward, it tapered in steps from 5 in (127 mm) to 2.5 in (64 mm) near the bow. Aft, it protected the steering gear and propeller shafts with 4.5 to 5 in (114 to 127 mm) 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 the conning tower being hit was very small, so the forward conning tower had only 3 to 4.5 in (76 to 114 mm) of armour.
The underwater protection, also virtually identical to that of the ‘King George V’ class, comprised of a three-layer system of voids and liquid-filled compartments designed to absorb the energy of an underwater explosion. It was bounded on the inside by the 1.75-in (44-mm) 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. The ‘Lion’ class design had a double bottom with a depth of 4 ft (1.2 m).
Construction of the two ships which had been laid down was suspended shortly after the World War II began in September 1939, 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 of the locks of the Panama Canal to increase the depth and effectiveness of torpedo protection system, and bunkers for almost 1,100 more tons of fuel oil were added to increase endurance. In partial compensation for the additional weight, the thickness of the belt armour was reduced by 1 in (25 mm) 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-pdr mounts.
The overall length increased to 793 ft (241.7 m) and beam to 108 ft (32.9 m). The displacement grew to 42,550 tons standard and 47,650 tons deep load. No changes were made to the propulsion machinery, but the speed decreased to 28.25 kt because of the greater displacement. The 4,800 tons of fuel increased endurance to 16,500 nm (30560 km) at 10 kt. The freeboard forward was increased by almost 9 ft (2.7 m), and the radar suite was increased to match that of the battleship Vanguard, then under construction. The additional beam was used to increase the depth of the torpedo protection system amidships from 13.25 ft (4.0 m) to 15 ft (4.6 m). The ship’s crew was estimated at 1,750 officers and men.
Another attempt was started in February 1944 by the DNC to incorporate wartime lessons. Among the proposed changes was the use of an improved 16-in (406-mm) Mk IV gun in a new Mk III turret to fire a heavier shell at a slightly lower velocity, and 12 4.5-in (114-mm) dual-purpose guns in twin mounts as well as nine sextuple Bofors 40-mm guns plus an undetermined number of 20-mm Oerlikon cannon for anti-aircraft protection.
With this ‘Design A’ of 1944 pushing to if not past the edge of what was technically feasible for the time, it was largely abandoned in favour of a simpler ‘Design B’ modification of the 1942 scheme with reduced underwater protection, speed and citadel size in concert with greatly increased freeboard and much of the armour and firepower of ‘Design A’. Two further iterations (‘Design C’ and ‘Design D’) considered alternative ways of saving weight via a reduction of armament or belt thickness, but these were quickly deemed unsatisfactory. ‘Design B’ became the primary focus and seven proposed versions were produced between March 1944 and February 1945, and though design work continued on a spasmodic basis, the British economic situation after World War II meant that work was called to a halt in 1949, so bringing to an end all British battleship design and construction.
On 8 January 1941, Rear Admiral Bruce Fraser, Third Sea Lord and Controller of the Navy, asked the DNC to work up a hybrid aircraft carrier based on the ‘Lion’ class hull. Two months later, a sketch design was presented for consideration, but was not approved as while it retained all three main gun turrets, the flight deck was deemed too short to be useful. A revised version with only the two forward turrets was requested, and this was ready by July. At a displacement ranging from 44,750 tons standard to 51,000 tons deep load, the design’s dimensions included a waterline length of 800 ft (243.8 m), beam of 115 ft (35.1 m) and a draught of 29 ft 6 in (9.0 m). The flight deck was 500 ft (152.4 m) long and had a width of 73 ft (22.3 m). The machinery was unchanged, but enlarged bunkerage increased endurance. The armament comprised six 16-in (406-mm) guns in two triple turrets, 16 5.25-in (1330mm) guns and eight octuple 2-pdr mounts. Twelve fighters and two torpedo bombers could be carried. The design was rejected.
Pairs of ‘Lion’ class ships had been planned to be ordered in the 1938, 1939 and 1940 naval programmes. The first pair, Lion and Temeraire, were ordered on 28 February 1939 from Vickers Armstrongs and Cammell Laird respectively. Lion was laid down at Vickers’ Walker, Newcastle upon Tyne shipyard on 4 July while Temeraire preceded her at Birkenhead on 1 June. Contracts for Conqueror and Thunderer were awarded on 15 August to John Brown and Fairfield, but neither were laid down.
After the start of World War II in September 1939, construction continued desultorily until October when it was suspended by the Admiralty for one year to release labour and material for escorts needed to protect merchant convoys. Construction of the 16-in (406-mm) guns and their turrets was continued. The question of construction was raised again on 12 November 1940 and the decision to suspend construction was reaffirmed, and all three ships which had been ordered were cancelled in 1942, though Lion’s keel was not scrapped until after the war. Only four 16-in (406-mm) guns were completed, and no turrets were completed.