Lexington class aircraft carrier
Encyclopedia
The Lexington class aircraft carrier
s were the first operational aircraft carriers in the United States Navy
. ( was a strictly developmental ship.) There were two ships in the class: and .
The Lexington-class carriers were constructed on hulls originally laid down as battlecruiser
s after World War I
. But under the Washington Naval Treaty
of 1922, all U.S. battleship and battlecruiser construction was cancelled. However, the Treaty allowed two of the unfinished ships to be converted to carriers.
They proved extremely successful as carriers, supporting wide-scale operations. Experience with the
Lexington class convinced the Navy of the value of large carriers. The Lexington class carriers were the largest aircraft carriers in the fleet until the Midway-class carriers
were completed. The class served in World War II
, seeing action in many battles. Though Lexington was lost in the first carrier battle (Coral Sea
), Saratoga served to the end of the war.
as battlecruisers, with heavy guns, high speed, and moderate armor protection. The Navy laid down six ships of the class from 1916 to 1919. When the battlecruisers were cancelled under the Washington Naval Treaty, two of the unfinished ships were designated for completion as carriers.
Aside from their great size, their most innovative feature was the "hurricane bow," a configuration of carriers where the bow
was sealed up to the flight deck
; this turned out to be the most useful of the three possible configurations for a carrier's bow (the other two being an additional flying-off deck and an antiaircraft battery).
These ships were given a 866.17 by teak
flight deck. Their hangar had a clear height of 20 feet (6.1 m) and encompassed 33528 square feet (3,114.9 m²). It was the largest enclosed space afloat, civilian or military, when built. The hangar was 424 feet (129.2 m) long and its width varied from 68 to 74 ft (20.7 to 22.6 ), constrained by the bulky funnel uptakes and boat compartments. The height of the hangar was not exceeded on an American aircraft carrier until the ships appeared in the mid-1950s. Aircraft repair shops, 108 feet (32.9 m) long, were aft of the hangar and below them was a storage space for disassembled aircraft, 128 feet (39 m) long. The hangar was divided by a single fire curtain just forward of the aft elevator
.
The forward elevator was 30 by 60 ft (9.1 by 18.3 m) and had a capacity of 16000 pounds (7,257.5 kg). A 20 by section of the flight deck adjoining the rear edge of the elevator could split down the centerline to lift aircraft otherwise too long. The aft elevator measured 30 by and could only lift 6000 pounds (2,721.6 kg). Munitions were delivered from the magazine
s by two bomb lifts and one torpedo lift. All elevators were hydraulically powered. Aviation gasoline
was stored in eight compartments of the torpedo protection system and their capacity has been quoted as either 132264 gallons (500,673.7 l) or 163000 gallons (617,022.2 l). A flywheel
-powered aircraft catapult
, 155 feet (47.2 m) long, was fitted at the bow; it could launch a 10000 pounds (4,536 kg) aircraft at a speed of 48 knots (26.1 m/s). It was removed in 1934 as unnecessary.
propulsion had been selected for the battlecruisers and was retained when they were converted into aircraft carriers because American companies struggled to produce the very large geared turbines necessary for such big ships. "It was efficient, rugged and always reliable. But it was also heavy, intricate, and not easy to maintain and keep tuned up." The machinery also required special ventilation measures to dissipate heat and to keep out any salt air.
Each propeller was 14 in 9 in (4.5 m) in diameter and each of the four propeller shafts was powered by two 22500 shp electric motor
s acting in tandem. These motors were about five times the size of any earlier electric motor. Four General Electric
turbo generator
s powered each propeller shaft and each was rated at 35200 kW, 5000 volt
s and 4620 amp
s of direct current
(DC). Each of the four AC
alternator
s produced 40,000 KVA
. Sixteen water-tube boiler
s, each in their own individual compartment, provided steam for the generators at a working pressure of 295 pound per square inch and a temperature of 460 °F (237.8 °C). Two other advantages of the turbo-electric drive were that the substitution of flexible electric cables for bulky steam-lines meant that the motors could be mounted further to the rear of the ship, which reduced both vibration and weight by shortening the propeller shafts and that the ship could go astern at full power simply by reversing the electrical polarity
of the motors. The turbo-electric machinery of the Lexington-class ships was designed to produce a total of 180000 shp and propel the ships at 33.25 knots (18.1 m/s), but each ship reached over 202000 shp and 34.5 knots during sea trial
s in 1928. Six 750 kW DC turbo generators were installed in the upper levels of the two main turbine compartments.
The ships carried a maximum of 6688 long tons (6,795.3 t) of fuel oil
, but only 5400 long tons (5,486.7 t) of that was usable as the rest had to be retained as ballast
in the port fuel tanks to offset the weight of the island and main guns. They demonstrated a range of 9910 nautical miles (18,353.3 km) at a speed of 10.7 knots (5.8 m/s) with 4540 long tons (4,612.9 t) of oil.
was not then convinced that aircraft could be an effective and sufficient armament for a warship. Thus the design as carriers included a substantial gun battery of eight 8-inch 55 caliber guns
in four twin gun turret
s. These turrets were mounted above the flight deck
on the starboard side, two before the bridge, and two behind the funnel. The guns in theory could fire to both sides, but it is probable that if they were fired to port (across the deck) the blast would have damaged the flight deck. The guns could be depressed to –5° and elevated to +41°; they were loaded at an angle of +9°. They fired 260 pounds (118 kg) projectiles at a muzzle velocity
of 2800 ft/s (853.4 m/s); this provided a maximum range of 31860 yd (29,133 m) at maximum elevation. A 20 feet (6.1 m) rangefinder
was fitted on top of the pilothouse to provide fire control for these guns.
Their anti-aircraft
armament consisted of twelve 25-caliber 5-inch guns which were mounted on single mounts, six on each side of the ship. They had a maximum elevation of 85°. They fired 53.85 pounds (24.4 kg) projectiles at a muzzle velocity of 2110 ft/s (643.1 m/s). Their maximum range against surface targets was 17700 yd (16,184.9 m) at 30° elevation and they had an anti-aircraft ceiling
of 27400 yd (25,054.6 m) at 85° elevation.
The experience of the "Fleet Problem" exercises of the 1930s showed that planes were sufficient and the guns were unnecessary. The guns were removed from both ships just after Pearl Harbor
. (The removed guns were used as shore-defense guns in Hawaii.) The 8-inch gun turrets were to be replaced with dual 5" DP gun turrets (the standard mounting on U.S. battleships and cruisers). On Saratoga, which had been damaged and was under repair for several months, this was done, but Lexington was rushed back into action with quad 1.1" mounts. Lexington was sunk before receiving her intended 5" guns.
of the Lexington-class ships tapered 7–5 in (17.8–12.7 ) in thickness from top to bottom and angled 11° outwards at the top. This angle increased the armor's relative thickness to horizontal, close-range fire, albeit at the cost of reducing its relative height which increased the chance of plunging shellfire going over or under it. It covered the middle 530 feet (161.5 m) of the ships. Forward, the belt ended in a bulkhead
that also tapered from seven to five inches in thickness. Aft, it terminated at a seven-inch bulkhead. This belt had a height of 9 in 4 in (2.84 m). The third deck over the ships' machinery and magazine
was armored with two layers of Special treatment steel
(STS) totaling 2 inches (5.1 cm) in thickness. The steering gear, however, was protected by two layers of STS that totaled 3 inches (8 cm) on the slope and 4.5 inches (11 cm) on the slope.
The gun turrets were protected only against splinters with 0.75 inches (1.9 cm) of armor. The conning tower was 2–2.25 in (5.1–5.7 ) of STS, and it had a communications tube with two-inch sides ran from the conning tower down to the lower conning position on the third deck. The torpedo
defense system of the Lexington-class ships consisted of three to six medium steel protective bulkheads
that ranged from 0.375 to 0.75 in (0.9525 to 1.9 ) in thickness. The spaces between them could be left empty or used as fuel tanks to absorb the detonation of a torpedo's warhead
.
Lexington participated in several raids on Japan
ese bases, but was sunk in May 1942 at the Battle of Coral Sea.
Saratoga served in several battles in 1942 through 1944, and was twice torpedoed by Japanese submarines, but on each occasion reached port under her own power. In September 1944, she was relegated to training duties, but she returned to combat duty in 1945. She was disabled by Japanese bombers in February 1945, and in June returned to training duties and to transporting returning troops to the U.S.
With the development of jet aircraft after the war, Saratoga became obsolete. Her hangar was large enough for jets, but her elevators were too small. In July 1946, she was used as a target for atomic bomb tests in Operation Crossroads
, and sank at Bikini Atoll
.
Aircraft carrier
An aircraft carrier is a warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Aircraft carriers thus allow a naval force to project air power worldwide without having to depend on local bases for staging aircraft operations...
s were the first operational aircraft carriers in the United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
. ( was a strictly developmental ship.) There were two ships in the class: and .
The Lexington-class carriers were constructed on hulls originally laid down as battlecruiser
Battlecruiser
Battlecruisers were large capital ships built in the first half of the 20th century. They were developed in the first decade of the century as the successor to the armoured cruiser, but their evolution was more closely linked to that of the dreadnought battleship...
s after World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
. But under the Washington Naval Treaty
Washington Naval Treaty
The Washington Naval Treaty, also known as the Five-Power Treaty, was an attempt to cap and limit, and "prevent 'further' costly escalation" of the naval arms race that had begun after World War I between various International powers, each of which had significant naval fleets. The treaty was...
of 1922, all U.S. battleship and battlecruiser construction was cancelled. However, the Treaty allowed two of the unfinished ships to be converted to carriers.
They proved extremely successful as carriers, supporting wide-scale operations. Experience with the
Lexington class convinced the Navy of the value of large carriers. The Lexington class carriers were the largest aircraft carriers in the fleet until the Midway-class carriers
Midway class aircraft carrier
The Midway class aircraft carrier was one of the longest lived carrier designs in history. First commissioned in late 1945, the lead ship of the class, was not decommissioned until 1992, shortly after service in Operation Desert Storm in 1991.-History:...
were completed. The class served in 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...
, seeing action in many battles. Though Lexington was lost in the first carrier battle (Coral Sea
Battle of the Coral Sea
The Battle of the Coral Sea, fought from 4–8 May 1942, was a major naval battle in the Pacific Theater of World War II between the Imperial Japanese Navy and Allied naval and air forces from the United States and Australia. The battle was the first fleet action in which aircraft carriers engaged...
), Saratoga served to the end of the war.
Development
The Lexington-class were originally designedLexington class battlecruiser
The Lexington-class battlecruisers were the only class of battlecruiser to ever be ordered by the United States Navy.The Lexington class were the only class of U.S. Navy ships to be officially referred to as battlecruisers. The World War II-era , officially classified as "large cruisers", but some...
as battlecruisers, with heavy guns, high speed, and moderate armor protection. The Navy laid down six ships of the class from 1916 to 1919. When the battlecruisers were cancelled under the Washington Naval Treaty, two of the unfinished ships were designated for completion as carriers.
General description
Their official displacement on commissioning was 33000 LT (33,529.7 t) (in accordance with the Washington Treaty). In reality both ships were well in excess of that and displaced 36000 LT (36,577.8 t) at standard load. At full load (with fuel, ammunition, aircraft, gasoline, and stores) they displaced 47700 LT (48,465.6 t).Aside from their great size, their most innovative feature was the "hurricane bow," a configuration of carriers where the bow
Bow (ship)
The bow is a nautical term that refers to the forward part of the hull of a ship or boat, the point that is most forward when the vessel is underway. Both of the adjectives fore and forward mean towards the bow...
was sealed up to the 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...
; this turned out to be the most useful of the three possible configurations for a carrier's bow (the other two being an additional flying-off deck and an antiaircraft battery).
Design
The Lexington-class aircraft carriers set the pattern for future American carrier designs of very large and long ships with topside flight decks, starboard-side islands, and a high-volume hangar decks. The tall funnel directed smoke well away from the flight deck and avoided smoke-fouling problems common with other early carriers.These ships were given a 866.17 by teak
Teak
Teak is the common name for the tropical hardwood tree species Tectona grandis and its wood products. Tectona grandis is native to south and southeast Asia, mainly India, Indonesia, Malaysia, and Burma, but is naturalized and cultivated in many countries, including those in Africa and the...
flight deck. Their hangar had a clear height of 20 feet (6.1 m) and encompassed 33528 square feet (3,114.9 m²). It was the largest enclosed space afloat, civilian or military, when built. The hangar was 424 feet (129.2 m) long and its width varied from 68 to 74 ft (20.7 to 22.6 ), constrained by the bulky funnel uptakes and boat compartments. The height of the hangar was not exceeded on an American aircraft carrier until the ships appeared in the mid-1950s. Aircraft repair shops, 108 feet (32.9 m) long, were aft of the hangar and below them was a storage space for disassembled aircraft, 128 feet (39 m) long. The hangar was divided by a single fire curtain just forward of the aft elevator
Elevator (aircraft)
Elevators are flight control surfaces, usually at the rear of an aircraft, which control the aircraft's orientation by changing the pitch of the aircraft, and so also the angle of attack of the wing. In simplified terms, they make the aircraft nose-up or nose-down...
.
The forward elevator was 30 by 60 ft (9.1 by 18.3 m) and had a capacity of 16000 pounds (7,257.5 kg). A 20 by section of the flight deck adjoining the rear edge of the elevator could split down the centerline to lift aircraft otherwise too long. The aft elevator measured 30 by and could only lift 6000 pounds (2,721.6 kg). Munitions were delivered from the magazine
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:...
s by two bomb lifts and one torpedo lift. All elevators were hydraulically powered. Aviation gasoline
Avgas
Avgas is an aviation fuel used to power piston-engine aircraft. Avgas is distinguished from mogas , which is the everyday gasoline used in cars and some non-commercial light aircraft...
was stored in eight compartments of the torpedo protection system and their capacity has been quoted as either 132264 gallons (500,673.7 l) or 163000 gallons (617,022.2 l). A flywheel
Flywheel
A flywheel is a rotating mechanical device that is used to store rotational energy. Flywheels have a significant moment of inertia, and thus resist changes in rotational speed. The amount of energy stored in a flywheel is proportional to the square of its rotational speed...
-powered aircraft catapult
Aircraft catapult
An aircraft catapult is a device used to launch aircraft from ships—in particular aircraft carriers—as a form of assisted take off. It consists of a track built into the flight deck, below which is a large piston or shuttle that is attached through the track to the nose gear of the aircraft, or in...
, 155 feet (47.2 m) long, was fitted at the bow; it could launch a 10000 pounds (4,536 kg) aircraft at a speed of 48 knots (26.1 m/s). It was removed in 1934 as unnecessary.
Propulsion
Turbo-electricTurbo-electric
A turbo-electric transmission uses electric generators to convert the mechanical energy of a turbine into electric energy and electric motors to convert it back into mechanical energy to power the driveshafts....
propulsion had been selected for the battlecruisers and was retained when they were converted into aircraft carriers because American companies struggled to produce the very large geared turbines necessary for such big ships. "It was efficient, rugged and always reliable. But it was also heavy, intricate, and not easy to maintain and keep tuned up." The machinery also required special ventilation measures to dissipate heat and to keep out any salt air.
Each propeller was 14 in 9 in (4.5 m) in diameter and each of the four propeller shafts was powered by two 22500 shp electric motor
Electric motor
An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...
s acting in tandem. These motors were about five times the size of any earlier electric motor. Four General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...
turbo generator
Turbo generator
A turbo generator is a turbine directly connected to an electric generator for the generation of electric power. Large steam powered turbo generators provide the majority of the world's electricity and are also used by steam powered turbo-electric ships.Smaller turbo-generators with gas turbines...
s powered each propeller shaft and each was rated at 35200 kW, 5000 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 and 4620 amp
Ampere
The ampere , often shortened to amp, is the SI unit of electric current and is one of the seven SI base units. It is named after André-Marie Ampère , French mathematician and physicist, considered the father of electrodynamics...
s of direct current
Direct current
Direct current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...
(DC). Each of the four AC
Alternating current
In alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....
alternator
Alternator
An alternator is an electromechanical device that converts mechanical energy to electrical energy in the form of alternating current.Most alternators use a rotating magnetic field but linear alternators are occasionally used...
s produced 40,000 KVA
Volt-ampere
A volt-ampere is the unit used for the apparent power in an electrical circuit, equal to the product of root-mean-square voltage and RMS current. In direct current circuits, this product is equal to the real power in watts...
. Sixteen 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, each in their own individual compartment, provided steam for the generators at a working pressure of 295 pound per square inch and a temperature of 460 °F (237.8 °C). Two other advantages of the turbo-electric drive were that the substitution of flexible electric cables for bulky steam-lines meant that the motors could be mounted further to the rear of the ship, which reduced both vibration and weight by shortening the propeller shafts and that the ship could go astern at full power simply by reversing the electrical polarity
Electrical polarity
Electrical polarity is present in every electrical circuit. Electrons flow from the negative pole to the positive pole. In a direct current circuit, one pole is always negative, the other pole is always positive and the electrons flow in one direction only...
of the motors. The turbo-electric machinery of the Lexington-class ships was designed to produce a total of 180000 shp and propel the ships at 33.25 knots (18.1 m/s), but each ship reached over 202000 shp and 34.5 knots during sea trial
Sea trial
A sea trial is the testing phase of a watercraft . It is also referred to as a "shakedown cruise" by many naval personnel. It is usually the last phase of construction and takes place on open water, and can last from a few hours to many days.Sea trials are conducted to measure a vessel’s...
s in 1928. Six 750 kW DC turbo generators were installed in the upper levels of the two main turbine compartments.
The ships carried a maximum of 6688 long tons (6,795.3 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...
, but only 5400 long tons (5,486.7 t) of that was usable as the rest had to be retained as ballast
Sailing ballast
Ballast is used in sailboats to provide moment to resist the lateral forces on the sail. Insufficiently ballasted boats will tend to tip, or heel, excessively in high winds. Too much heel may result in the boat capsizing. If a sailing vessel should need to voyage without cargo then ballast of...
in the port fuel tanks to offset the weight of the island and main guns. They demonstrated a range of 9910 nautical miles (18,353.3 km) at a speed of 10.7 knots (5.8 m/s) with 4540 long tons (4,612.9 t) of oil.
Armament
The Navy's Bureau of Construction and RepairBureau of Construction and Repair
The Bureau of Construction and Repair was the part of the United States Navy which from 1862 to 1940 was responsible for supervising the design, construction, conversion, procurement, maintenance, and repair of ships and other craft for the Navy...
was not then convinced that aircraft could be an effective and sufficient armament for a warship. Thus the design as carriers included a substantial gun battery of eight 8-inch 55 caliber guns
8"/55 caliber gun
The 8"/55 caliber gun formed the main battery of United States Navy heavy cruisers and two early aircraft carriers...
in four twin 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. These turrets were mounted above the 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...
on the starboard side, two before the bridge, and two behind the funnel. The guns in theory could fire to both sides, but it is probable that if they were fired to port (across the deck) the blast would have damaged the flight deck. The guns could be depressed to –5° and elevated to +41°; they were loaded at an angle of +9°. They fired 260 pounds (118 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 2800 ft/s (853.4 m/s); this provided a maximum range of 31860 yd (29,133 m) at maximum elevation. A 20 feet (6.1 m) rangefinder
Rangefinder
A rangefinder is a device that measures distance from the observer to a target, for the purposes of surveying, determining focus in photography, or accurately aiming a weapon. Some devices use active methods to measure ; others measure distance using trigonometry...
was fitted on top of the pilothouse to provide fire control for these guns.
Their anti-aircraft
Anti-aircraft warfare
NATO defines air defence as "all measures designed to nullify or reduce the effectiveness of hostile air action." They include ground and air based weapon systems, associated sensor systems, command and control arrangements and passive measures. It may be to protect naval, ground and air forces...
armament consisted of twelve 25-caliber 5-inch guns which were mounted on single mounts, six on each side of the ship. They had a maximum elevation of 85°. They fired 53.85 pounds (24.4 kg) projectiles at a muzzle velocity of 2110 ft/s (643.1 m/s). Their maximum range against surface targets was 17700 yd (16,184.9 m) at 30° elevation and they had an anti-aircraft ceiling
Ceiling (aeronautics)
With respect to aircraft, a ceiling is the maximum density altitude an aircraft can reach under a set of conditions.The word ceiling can also refer to the height of the lowest obscuring cloud layer above the ground.-Service ceiling:...
of 27400 yd (25,054.6 m) at 85° elevation.
The experience of the "Fleet Problem" exercises of the 1930s showed that planes were sufficient and the guns were unnecessary. The guns were removed from both ships just after Pearl Harbor
Attack on Pearl Harbor
The attack on Pearl Harbor was a surprise military strike conducted by the Imperial Japanese Navy against the United States naval base at Pearl Harbor, Hawaii, on the morning of December 7, 1941...
. (The removed guns were used as shore-defense guns in Hawaii.) The 8-inch gun turrets were to be replaced with dual 5" DP gun turrets (the standard mounting on U.S. battleships and cruisers). On Saratoga, which had been damaged and was under repair for several months, this was done, but Lexington was rushed back into action with quad 1.1" mounts. Lexington was sunk before receiving her intended 5" guns.
Armor
The waterline beltBelt armor
Belt armor is a layer of heavy metal armor plated on to or within outer hulls of warships, typically on battleships, battlecruisers and cruisers, and on aircraft carriers converted from those types of ships....
of the Lexington-class ships tapered 7–5 in (17.8–12.7 ) in thickness from top to bottom and angled 11° outwards at the top. This angle increased the armor's relative thickness to horizontal, close-range fire, albeit at the cost of reducing its relative height which increased the chance of plunging shellfire going over or under it. It covered the middle 530 feet (161.5 m) of the ships. Forward, the belt ended in a bulkhead
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:...
that also tapered from seven to five inches in thickness. Aft, it terminated at a seven-inch bulkhead. This belt had a height of 9 in 4 in (2.84 m). The third deck over the ships' machinery and magazine
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:...
was armored with two layers of Special treatment steel
Special treatment steel
Special Treatment Steel , also known as Protective Deck Plate. Originally developed by Carnegie Steel around 1910, it became the U.S. Navy Bureau of Construction and Repair standard form of high-percentage nickel steel used on all portions of a warship needing homogeneous direct impact protection...
(STS) totaling 2 inches (5.1 cm) in thickness. The steering gear, however, was protected by two layers of STS that totaled 3 inches (8 cm) on the slope and 4.5 inches (11 cm) on the slope.
The gun turrets were protected only against splinters with 0.75 inches (1.9 cm) of armor. The conning tower was 2–2.25 in (5.1–5.7 ) of STS, and it had a communications tube with two-inch sides ran from the conning tower down to the lower conning position on the third deck. The torpedo
Torpedo
The modern torpedo is a self-propelled missile weapon with an explosive warhead, launched above or below the water surface, propelled underwater towards a target, and designed to detonate either on contact with it or in proximity to it.The term torpedo was originally employed for...
defense system of the Lexington-class ships consisted of three to six medium steel protective bulkheads
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...
that ranged from 0.375 to 0.75 in (0.9525 to 1.9 ) in thickness. The spaces between them could be left empty or used as fuel tanks to absorb the detonation of a torpedo's warhead
Warhead
The term warhead refers to the explosive material and detonator that is delivered by a missile, rocket, or torpedo.- Etymology :During the early development of naval torpedoes, they could be equipped with an inert payload that was intended for use during training, test firing and exercises. This...
.
World War II service
Lexington and Saratoga were both attached to the Pacific Fleet when the war broke out.Lexington participated in several raids on Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
ese bases, but was sunk in May 1942 at the Battle of Coral Sea.
Saratoga served in several battles in 1942 through 1944, and was twice torpedoed by Japanese submarines, but on each occasion reached port under her own power. In September 1944, she was relegated to training duties, but she returned to combat duty in 1945. She was disabled by Japanese bombers in February 1945, and in June returned to training duties and to transporting returning troops to the U.S.
With the development of jet aircraft after the war, Saratoga became obsolete. Her hangar was large enough for jets, but her elevators were too small. In July 1946, she was used as a target for atomic bomb tests in Operation Crossroads
Operation Crossroads
Operation Crossroads was a series of nuclear weapon tests conducted by the United States at Bikini Atoll in mid-1946. It was the first test of a nuclear weapon after the Trinity nuclear test in July 1945...
, and sank at Bikini Atoll
Bikini Atoll
Bikini Atoll is an atoll, listed as a World Heritage Site, in the Micronesian Islands of the Pacific Ocean, part of Republic of the Marshall Islands....
.