The Lion class battleships were a class

Ship class

A ship class is a group of ships of a similar design. This is distinct from a ship-type, which might reflect a similarity of tonnage or intended use. For example, the is a nuclear aircraft carrier of the Nimitz class....

 of six fast battleships designed for the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 in the late 1930s. They were a larger, improved version of the King George V class

King George V class battleship (1939)

The King George V-class battleships were the most modern British battleships used during World War II. Five ships of this class were built and commissioned: King George V , Prince of Wales , Duke of York , Howe , and Anson .The Washington Naval Treaty of 1922 limiting all of the number,...

 with 16 inches (41 cm) guns. Only two ships were laid down

Keel

In boats and ships, keel can refer to either of two parts: a structural element, or a hydrodynamic element. These parts overlap. As the laying down of the keel is the initial step in construction of a ship, in British and American shipbuilding traditions the construction is dated from this event...

 before World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

 began in September 1939 and a third was ordered during the war, but their construction was suspended shortly afterwards. Their design changed several times in response to the removal of treaty restrictions on size and in light of war experience. None of the other ships planned were laid down, although there was a proposal to modify one of the suspended ships into a hybrid battleship/aircraft carrier with two 16-inch gun turret

Gun turret

A gun turret is a weapon mount that protects the crew or mechanism of a projectile-firing weapon and at the same time lets the weapon be aimed and fired in many directions.The turret is also a rotating weapon platform...

s and a flight deck

Flight deck

The flight deck of an aircraft carrier is the surface from which its aircraft take off and land, essentially a miniature airfield at sea. On smaller naval ships which do not have aviation as a primary mission, the landing area for helicopters and other VTOL aircraft is also referred to as the...

. The two ships already begun were scrapped

Ship breaking

Ship breaking or ship demolition is a type of ship disposal involving the breaking up of ships for scrap recycling. Most ships have a lifespan of a few decades before there is so much wear that refitting and repair becomes uneconomical. Ship breaking allows materials from the ship, especially...

 after the end of the war.

Design and description

The choice of 14 inches (36 cm) gun and the mix of quadruple and twin turret

Turret

In architecture, a turret is a small tower that projects vertically from the wall of a building such as a medieval castle. Turrets were used to provide a projecting defensive position allowing covering fire to the adjacent wall in the days of military fortification...

s for the main battery of the King George Vs had been dictated by the Second London Naval Treaty

Second London Naval Treaty

The Second London Naval Disarmament Conference opened in London, the United Kingdom, on 9 December 1935. It resulted in the Second London Naval Treaty which was signed on 25 March 1936.- Description :...

, which limited battleships to 35000 long tons (35,561.8 t) standard displacement and a main calibre of 14 inches. However, when the Japanese Government refused to agree to its terms, the maximum calibre allowed reverted to 16 inches in April 1937. The Board of Admiralty then began preliminary design work on a 35,000-ton ship armed with 16-inch guns and they were promising enough that the Director of Naval Construction

Director of Naval Construction

The Director of Naval Construction was a senior British civil servant post in the Admiralty, that part of the British Civil Service that oversaw the Royal Navy. The post existed from 1860 to 1966....

 (DNC) was ordered to further investigate such designs, providing for several aircraft as well. To save design time, many of the features of the King George Vs were incorporated in the new design, but the limited size of the ship was a real challenge for the designers. The increased weight of the main armament was compensated for by a slight reduction in the overall weight of armour and the elimination of two twin 5.25 inches (13 cm) gun turrets.

The designer's issues were made much easier on 31 March 1938 when the signatories of the Treaty 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 battleships. The new limit was 45000 long tons (45,722.3 t), but the Admiralty decided to limit themselves to 40000 long tons (40,642 t) and nine 16-inch guns on cost grounds. 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.

1938 design

The 1938 version of the Lion class had an overall length of 785 feet (239.3 m), a beam

Beam (nautical)

The beam of a ship is its width at the widest point. Generally speaking, the wider the beam of a ship , the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position...

 of 105 feet (32 m), and a maximum draught

Draft (hull)

The draft of a ship's hull is the vertical distance between the waterline and the bottom of the hull , with the thickness of the hull included; in the case of not being included the draft outline would be obtained...

 of 33 in 6 in (10.21 m). They displaced 40550 long tons (41,200.8 t) at standard load and 46400 long tons (47,144.7 t) at deep load. The appearance of the Lions closely resembled that of the KGVs, but with a transom stern

Transom (nautical)

In naval architecture, a transom is the surface that forms the stern of a vessel. Transoms may be flat or curved and they may be vertical, raked forward, also known as a retroussé or reverse transom, angling forward from the waterline to the deck, or raked aft, often simply called "raked", angling...

 to improve steaming efficiency at high speed.

In the interests of saving time, the four-shaft unit machinery design from the King George Vs was duplicated with alternating boiler and engine rooms. The Lion-class ships had four sets of single-reduction geared Parsons steam turbine

Steam turbine

A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Sir Charles Parsons in 1884....

s housed in separate engine rooms. Each set consisted of one high-pressure and one low-pressure turbine driving one propeller shaft. They were designed to produce a total of 130000 shp at overload condition and a speed of 30 knots (16.3 m/s). The turbines were powered by eight Admiralty-type three-drum water-tube boiler

Water-tube boiler

A water tube boiler is a type of boiler in which water circulates in tubes heated externally by the fire. Fuel is burned inside the furnace, creating hot gas which heats water in the steam-generating tubes...

s in four boiler rooms at a working pressure of 400 pound per square inch and temperature of 700 °F (371.1 °C). The turbines and boilers could be cross-connected in an emergency. The ships were designed to carry 3720 long tons (3,780 t) of fuel oil

Fuel oil

Fuel oil is a fraction obtained from petroleum distillation, either as a distillate or a residue. Broadly speaking, fuel oil is any liquid petroleum product that is burned in a furnace or boiler for the generation of heat or used in an engine for the generation of power, except oils having a flash...

. Their maximum estimated range was 14000 nautical miles (25,928 km) at a speed of 10 knots (5.4 m/s). They were equipped with six 330 kW turbogenerators and two 330-kW diesel generator

Diesel generator

A diesel generator is the combination of a diesel engine with an electrical generator to generate electrical energy....

s that supplied the common ring main at 220 volt

Volt

The volt is the SI derived unit for electric potential, electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery.- Definition :A single volt is defined as the...

s.

The Lion-class ships' main armament consisted of nine 45-calibre

Caliber (artillery)

In artillery, caliber or calibredifference in British English and American English spelling is the internal diameter of a gun barrel, or by extension a relative measure of the length....

 BL 16-inch Mk II

BL 16 inch /45 naval gun

The BL 16 inch Mark I was a British naval gun introduced in the 1920s and used on the Nelson class battleships. The barrel was 45 calibres long, /45 in shorthand, meaning it was 45 x 16 inches = 720 inches long....

 in three triple, hydraulically powered gun turrets designated 'A', 'B', and 'Y' from bow to stern. The maximum elevation of the turrets was increased to +40° although the guns were loaded at +5°. They fired 2375 pounds (1,077 kg) projectiles at a muzzle velocity

Muzzle velocity

Muzzle velocity is the speed a projectile has at the moment it leaves the muzzle of the gun. Muzzle velocities range from approximately to in black powder muskets , to more than in modern rifles with high-performance cartridges such as the .220 Swift and .204 Ruger, all the way to for tank guns...

 of 2483 ft/s (756.8 m/s); this provided a maximum range of 40560 yards (37,088 m). Their rate of fire was two rounds per minute. The ships carried 100 shells per gun. The secondary armament consisted of sixteen 45-calibre QF 5.25-inch Mk I dual purpose gun

Dual purpose gun

A dual purpose gun is a naval artillery mounting designed to engage both surface and air targets.-Description:Second World War-era capital ships had four classes of artillery: the heavy main battery, intended to engage opposing battleships and cruisers ; a secondary battery for use against enemy...

s in eight twin gun mounts. They had a maximum depression of −5° and a maximum elevation of +70°. They fired a 80 pounds (36.3 kg) high-explosive shell at a muzzle velocity of 2672 ft/s (814.4 m/s). Their normal rate of fire was about 7–8 rounds per minute. At maximum elevation, the guns had a maximum range of 24070 yards (22,010 m). 400 rounds were provided for each gun.
Short-range air defence was provided by 48 QF 2-pounder guns

QF 2 pounder naval gun

The 2-pounder gun, officially designated the QF 2-pounder and universally known as the pom-pom, was a 1.575 inch British autocannon, used famously as an anti-aircraft gun by the Royal Navy. The name came from the sound that the original models make when firing...

 in six octuple mountings. The 2-pounder gun fired a 40 millimetres (1.6 in) 1.684 pound (0.76384955108 kg) shell at a muzzle velocity of 2400 ft/s (731.5 m/s) to a distance of 6800 yards (6,217.9 m). The gun's rate of fire was approximately 96–98 rounds per minute. 1800 rounds per gun were carried by the ships.

Their armour scheme was virtually identical to that of the King George V class. The waterline

Waterline

The term "waterline" generally refers to the line where the hull of a ship meets the water surface. It is also the name of a special marking, also known as the national Load Line or Plimsoll Line, to be positioned amidships, that indicates the draft of the ship and the legal limit to which a ship...

 belt was composed of Krupp cemented armour

Krupp armour

Krupp armour was a type of steel armour used in the construction of capital ships starting shortly before the end of the 19th century. It was developed by Germany's Krupp Arms Works in 1893 and quickly replaced Harvey armour as the primary method of protecting naval ships.The initial manufacturing...

 (KCA) 15 inches (381 mm) thick and was 433 feet (132 m) long. The main portion of the belt was 15 feet (4.6 m) high, but a lower strake

Strake

A strake is part of the shell of the hull of a boat or ship which, in conjunction with the other strakes, keeps the sea out and the vessel afloat...

, 8 inch high, extended an additional 40 feet (12.2 m) past the ends of the armoured citadel. It tapered vertically from 15 inches in thickness to 5.5 inches (140 mm) at the bottom edge of the belt, while the plates at the end of the belt were only 11 inches (28 cm) thick at the top. Transverse bulkheads

Bulkhead (partition)

A bulkhead is an upright wall within the hull of a ship or within the fuselage of an airplane. Other kinds of partition elements within a ship are decks and deckheads.-Etymology:...

 10–12 in (254–304.8 mm) thick closed off each end of the central citadel. At the aft end of the steering gear compartment was a 4 inches (10.2 cm) transverse bulkhead. The KCA face-plates of the main gun turrets were 15 inches thick and their roofs 6 inches (15 cm) non-cemented armour plates. Their sides remained 7–10 in (17.8–25.4 ) in thickness. The barbette

Barbette

A barbette is a protective circular armour feature around a cannon or heavy artillery gun. The name comes from the French phrase en barbette referring to the practice of firing a field gun over a parapet rather than through an opening . The former gives better angles of fire but less protection...

s for the 16-inch guns were 15 inches thick on the sides, but tapered to 12–13.5 in (30.5–34.3 ) closer to the centreline of the ship.

Intended to resist the impact of a 1000 pounds (453.6 kg) armour-piercing bomb dropped from a height of 14000 feet (4,267.2 m), the Lions deck protection was identical to that of the King George V class. It consisted of 6 inches (15 cm) non-cemented armour over the magazines that reduced to 5 inches (13 cm) 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 2.5 inches (6 cm) near the bow. Aft, it protected the steering gear and propeller shafts with 4.5–5 in (11.4–12.7 ) 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 3–4.5 in (7.6–11.4 ) of armour.

The underwater protection, also virtually identical to that of the King George Vs, consisted of a 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 1.75 inches (4.4 cm) torpedo bulkhead

Torpedo bulkhead

A torpedo bulkhead is a type of armor common on the more heavily armored warships, especially battleships and battlecruisers of the early 20th century. It is designed to keep the ship afloat even if the hull was struck underneath the belt armor by a shell or by a torpedo...

. 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 1000 pounds (453.6 kg) of TNT during full-scale trials. The Lion-class ships had a double bottom

Double bottom

A double bottom is a ship hull design and construction method where the bottom of the ship has two complete layers of watertight hull surface: one outer layer forming the normal hull of the ship, and a second inner hull which is somewhat higher in the ship, perhaps a few feet, which forms a...

 with a depth of 4 feet (1.2 m).

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 of the locks

Lock (water transport)

A lock is a device for raising and lowering boats between stretches of water of different levels on river and canal waterways. The distinguishing feature of a lock is a fixed chamber in which the water level can be varied; whereas in a caisson lock, a boat lift, or on a canal inclined plane, it is...

 of the Panama Canal

Panama Canal

The Panama Canal is a ship canal in Panama that joins the Atlantic Ocean and the Pacific Ocean and is a key conduit for international maritime trade. Built from 1904 to 1914, the canal has seen annual traffic rise from about 1,000 ships early on to 14,702 vessels measuring a total of 309.6...

 to increase the depth and effectiveness of ship's torpedo protection system, and almost 1100 long tons (1,117.7 t) of fuel oil were added to increase the ship's endurance. The requirement that 'A' turret had to be able to fire directly ahead at 0° elevation was rescinded as it radically reduced freeboard

Freeboard (nautical)

In sailing and boating, freeboardmeans the distance from the waterline to the upper deck level, measured at the lowest point of sheer where water can enter the boat or ship...

 forward and caused the King George Vs 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 1 inches (2.5 cm) except over the magazines

Magazine (artillery)

Magazine is the name for an item or place within which ammunition is stored. It is taken from the Arabic word "makahazin" meaning "warehouse".-Ammunition storage areas:...

, 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.

The overall length of the Lion class increased to 793 feet (241.7 m) and the beam to 105 feet (32 m). The displacement grew to 42550 long tons (43,232.9 t) at standard load and 47650 long tons (48,414.8 t) at deep load. No changes were made to the propulsion machinery, but the speed decreased to 28.25 knots (15.4 m/s) because of the greater displacement. The 4800 long tons (4,877 t) of fuel increased their endurance to an estimated maximum of 16500 nautical miles (30,558 km) at a speed of 10 knots. The freeboard forward was increased by nearly 9 feet (2.7 m), and the radar suite was increased to match that of the battleship , then under construction. Because the cruiser lost all steam power when she struck a mine

Naval mine

A naval mine is a self-contained explosive device placed in water to destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, an enemy vessel...

 early in the war, two diesel generators were substituted for two turbo-generators. The additional beam was used to increase the depth of the torpedo protection system amidships from 13.25 feet (4 m) to 15 feet (4.6 m). The ships' crew was estimated at 1750 officers and men.

1944 design

Another attempt was made in 1944 by the DNC to incorporate wartime lessons and improve the ships' design, but he concluded that "the power of modern weapons had increased so much that ever-increasing armour and torpedo protection was required until it became incompatible with the limited offensive power of the ship." No effort was made to investigate the torpedo protection system, nor were their characteristics finalized. Naval historians William Garzke and Robert Dulin speculate that the ships might have been 830 feet (253 m) long, with a beam of 115 feet (35.1 m), and a draught of 35 feet (10.7 m). They might have displaced about 56500 long tons (57,406.8 t). They would have used an improved Mk IV version of the 16-inch gun that fired a heavier shell at a marginally lower velocity.

Hybrid aircraft carrier

On 8 January 1941, Rear Admiral Bruce Fraser

Bruce Fraser, 1st Baron Fraser of North Cape

Admiral of the Fleet Bruce Austin Fraser, 1st Baron Fraser of North Cape GCB, KBE was a senior British admiral during World War II.-Early naval career:Fraser joined the Royal Navy as a Cadet on 15 January 1904...

, Third Sea Lord and Controller of the Navy

Third Sea Lord

The Third Sea Lord and Controller of the Navy was formerly the Naval Lord and member of the Board of Admiralty responsible for procurement and matériel in the British Royal 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 it was not well liked by the participants. This design retained all three main gun turrets and the flight deck was deemed too short to be useful. A revised version with only the two forward turrets retained was requested and was ready in July. In this design, the displacement ranged from 44750 long tons (45,468.2 t) at standard load and 51000 long tons (51,818.6 t) at deep load. The design's dimensions included a waterline length of 800 feet (243.8 m), a beam of 115 feet (35.1 m) and a draught of 29 in 6 in (8.99 m). The flight deck was 500 feet (152.4 m) long and had a width of 73 feet (22.3 m). The machinery was unchanged, but 600 LT of additional oil increased her endurance to 14750 nautical miles (27,317 km) at 10 knots. The hybrid's armament consisted of six 16-inch guns in two triple turrets, sixteen 5.25-inch guns and eight octuple 2-pounder mounts. Twelve fighters and two torpedo bombers could be carried. The Director of Naval Gunnery was particularly pungent in his assessment of the design, "The functions and requirements of carriers and of surface gun platforms are entirely incompatible ...the conceptions of these designs ...is evidently the result of an unresolved contest between a conscious acceptance of aircraft and a subconscious desire for a 1914 Fleet ...these abortions are the results of a psychological maladjustment. The necessary readjustments should result from a proper re-analysis of the whole question, what would be a balanced fleet in 1945, 1950 or 1955?" Not surprisingly, the design was rejected.

Construction

Six Lion-class ships were planned, two each 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

Keel

In boats and ships, keel can refer to either of two parts: a structural element, or a hydrodynamic element. These parts overlap. As the laying down of the keel is the initial step in construction of a ship, in British and American shipbuilding traditions the construction is dated from this event...

 at Vickers' Walker, Newcastle upon Tyne

Walker, Newcastle upon Tyne

Walker is a residential suburb and electoral ward just east of the centre of Newcastle upon Tyne, England. Walker's name is a hybrid of Old English and Viking Norse, "Wall-kjerr", where "kjerr" is Norse for "marshy woodland"...

 shipyard on 4 July while Temeraire preceded her at Birkenhead

Birkenhead

Birkenhead is a town within the Metropolitan Borough of Wirral in Merseyside, England. It is on the Wirral Peninsula, along the west bank of the River Mersey, opposite the city of Liverpool...

 on 1 June. Contracts for Conqueror and Thunderer were awarded on 15 August to John Brown

John Brown & Company

John Brown and Company of Clydebank was a pre-eminent Scottish marine engineering and shipbuilding firm, responsible for building many notable and world-famous ships, such as the , the , the , the , the , and the...

 and Fairfield. It is uncertain if Conqueror was actually ordered, but Thunderer was not. Neither ship was ever laid down.

After the start of World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

in September, 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-inch guns and their turrets was to continue, however. The question was raised again on 12 November 1940 and the decision to suspend construction was reaffirmed. All three ships ordered were cancelled in 1942, but Lions keel was not scrapped until after the end of the war. Only four 16-inch guns, and no turrets, were ever completed.