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Essex class aircraft carrier
From Wikipedia, the free encyclopedia
| Essex class Aircraft carrier | |
|---|---|
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| Class overview | |
| Type: | Aircraft carrier |
| Name: | Essex class |
| Preceded by: | Yorktown-class aircraft carrier |
| Succeeded by: | Midway-class aircraft carrier |
| Ships in class: | 32 ordered, 26 laid down, 24 commissioned |
| General characteristics | |
| Displacement: | 27,200 tons 36,380 tons full load |
| Length: | 872 ft (266 m) |
| Beam: | 93 ft (28 m) |
| Draught: | 23 ft (7.0 m) |
| Propulsion and power: |
Westinghouse geared turbines; 8 - Babcock & Wilcox boilers connected to four shafts |
| Speed: | 33 knots (61 km/h) |
| Range: | 15,000 nmi. at 15 knots (28,000 km at 28 km/h) |
| Protection: | 1.5 in (38 mm) hangar deck, 2.5 to 4 in (64 to 102 mm) belt |
| Armament: | 12 × 5-inch (127 mm) guns |
| Aircraft: | 80–100 |
Essex was a class of aircraft carriers of the United States Navy, which constituted the 20th century's most numerous class of heavy warships, with 24 ships built. These included members of the "long-hull" Ticonderoga variant/subclass, which some consider a separate class in their own right. Thirty-two were originally ordered, however six were cancelled before construction, and two were cancelled after construction had begun. The Essex-class, along with the three Midway-class carriers, were the backbone of the Navy's combat strength in the years after World War II, until the supercarriers began to come into the fleet in numbers during the 1960s and 1970s.
Contents |
The preceding Yorktown-class carriers formed the basis from which the Essex class was developed. Designed to carry a larger air group, and unencumbered by pre-war naval treaty limits, the USS Essex (CV-9) was over sixty feet longer, nearly ten feet wider in beam and more than a third heavier. A longer, wider flight deck and a deck-edge elevator facilitated more efficient aviation operations, enhancing the ship's offensive and defensive air power. Machinery arrangement and armor protection was greatly improved from previous designs. These features, plus the provision of more anti-aircraft guns, gave the ships much enhanced survivability. In fact, none of the Essex-class carriers were lost and two of them, Franklin (CV-13) and Bunker Hill (CV-17), came home under their own power even after receiving heavy damage.
US carriers had the same amount of deck armor as that carried by their British counterparts. While debates raged, and continue to this day, regarding the effect of placement (flight deck level on British ships vs. hangar deck level on American ships), British designers' comments tended to disparage the use of deck armor, and serious historians, such as D.K. Brown in Vanguard to Trident, generally see the American arrangement to have been superior, until the larger size of the first supercarriers necessitated a deeper hull, and thus moving the strength deck to the flight deck.
After the abrogation by Japan from disarmament treaties, the U.S. took a realistic look at its naval strength. With the Naval Expansion Act of Congress passed on May 17, 1938, an increase of 40,000 tons in aircraft carriers was authorized. This permitted the building of USS Hornet (CV-8) and USS Essex (CV-9) which was to become the lead ship of its class.
CV-9 was to be the prototype of the 27,000-ton (standard displacement) aircraft carrier, considerably larger than the Enterprise (CV-6) yet smaller than the Saratoga (CV-3) (a battlecruiser converted to a carrier). These were to become known as the Essex-class carriers, although this classification was latter dropped in the 1950s. On September 9, 1940, eight more of these carriers were ordered and were to become the Hornet (CV-12), Franklin (CV-13), Ticonderoga (CV -14), Randolph (CV-15), Lexington (CV-16), Bunker Hill (CV-17), Wasp (CV-18) and Hancock (CV-19). The last two of the 13 originally programmed CV-9 class aircraft carriers, Bennington (CV-20) and Boxer (CV-21), were ordered on December 15, 1941.
It should be noted that the Lexington, Wasp, Hornet and the Yorktown names were not their originally intended ones, but were used in line with the Navy’s intent to carry on the traditions of their fighting predecessors who were lost during combat in 1942. It should also be noted that of the original 13 ordered Essex-class ships, several of them, the Ticonderoga (CV-14), Randolph (CV-15), Hancock (CV-19), and Boxer (CV-21) were modified during construction as part of the "long hull" group, with the bow extended into a "clipper" shape to provide room for additional anti-aircraft armament.
Nineteen more Essex-class ships were ordered or scheduled, starting with ten of them on August 7, 1942. Only two of the ships, the Bon Homme Richard (CV-31) and the Oriskany (CV-34) were laid down as Essex "short hull" keels. The remainder became the Ticonderoga or "long hull" class ships. CV-16 was originally laid down as the Cabot, but was renamed Lexington during construction after the Lexington (CV-2) was lost in the Battle of the Coral Sea in May 1942; she was commissioned on February 17, 1943. CV-10, originally to be named the Bon Homme Richard, was renamed after the Yorktown (CV-5) was lost at the Battle of Midway on June 7, 1942. CV-18's name was changed from Oriskany after the Wasp (CV-7) was sunk in September 1942 in the South Pacific while escorting a troop convoy to Guadalcanal, and the CV-12's name was changed from Kearsarge after the Hornet (CV-8) was lost in October 1942 in the Battle of Santa Cruz Islands.
In summary, during WWII and until its conclusion by Allied forces, the US Navy ordered 32 aircraft carriers of the Essex- and the related Ticonderoga-class, of which the keels of 26 were laid down, 24 actually being commissioned.
In drawing up the preliminary design for USS Essex (CV-9), particular attention was directed at the size of both her flight and hangar decks. Aircraft design had come a long way from the comparatively light planes used in carriers during the 1930s. Flight decks now required more takeoff space for the heavier fighters and bombers being developed. Most of the first-line carriers of the pre-war years were equipped with flush deck catapults, but owing to the speed and size of these ships very little catapulting was done — except for experimental purposes.
With the advent of war, airplane weights began to go up as armor and armament got heavier; crew size aboard the planes also increased. By the war’s end in 1945, catapult launchings would become more common under these circumstances with some carrier commanding officers reporting that as much as 40% of launchings were effected by the ships’ catapults.
The hangar area design came in for many design conferences between the naval bureaus. Not only were the supporting structures to the flight deck to carry the increased weight of the landing and parked aircraft, but they were to have sufficient strength to support the storing of spare fuselages and parts (50% of each plane type aboard) under the flight deck and still provide adequate working space for the men using the area below.
A startling innovation in the Essex was a port-side deck-edge elevator in addition to two inboard elevators. Earlier, experiments with a ramp arrangement between the hangar and flight decks, up which aircraft were hauled by crane proved too slow. The Navy's Bureau of Ships and the Chief Engineer of A.B.C. Elevator Co., designed the engine for the side elevator. Essentially, it was a standard elevator, 60 by 34 ft (18 by 10 m) in platform surface, which traveled vertically on the port side of the ship. The design was a huge success which greatly improved flight deck operations over carriers prior to the Essex.
Since there was no large hole in the flight deck when the elevator is in the ‘down’ position, a critical factor if the elevator were to ever become inoperable during combat operations, the development of the side elevator was a significant improvement in flight operations. Its new position made it easier to continue normal operations on deck, irrespective of the position of the elevator. The elevator also increased the effective deck space when it was in the ‘up’ position by providing additional parking room outside the normal contours of the flight deck, and increased the effective area on the hangar deck by the absence of elevator pits. In addition its machinery was less complex than the two inboard elevators, requiring about 20% fewer man-hours of maintenance.
Ongoing improvements to the class were made, particularly with regards to the ventilation system, lighting systems and the trash burner design and implementation.
These carriers had better protecting armor than their predecessors, better facilities for handling ammunition, safer and greater fueling capacity, and more effective damage control equipment.
The tactical employment of U.S. carriers changed as the war progressed. In early operations, through 1942, the doctrine was to operate singly or in pairs, joining together for the offense and separating when on the defense—the theory being that a separation of carriers under attack not only provided a protective screen for each, but also dispersed the targets and divided the enemy’s attack. Combat experience in those early operations did not bear out the theory and new proposals for tactical deployment were the subject of much discussion.
As the new Essex- and Independence-class carriers became available, tactics changed. Experience taught the wisdom of combined strength. Under attack, the combined anti-aircraft fire of a task group's carriers and their screen provided a more effective umbrella of protection against marauding enemy aircraft than was possible when the carriers separated.
When two or more of these task groups supported each other, they constituted a fast carrier task force. Lessons learned from operating the carriers as a single group of six, as two groups of three, and three groups of two, provided the basis for many tactics which later characterized carrier task force operations. With the evolution of the fast carrier task force and its successful employment in future operations.
The pride of the carrier, known as the "Sunday Punch", was the offensive power of 36 fighters, 36 dive bombers and 18 torpedo planes. The F6F Hellcat would prove to be superior to the Japanese Zero. It was twice as powerful as the Zero and could therefore climb higher and fly faster. Due to the increase in power, the Hellcat could carry an enormous amount of firepower, boasting six .50 caliber (12.7 mm) machine guns with a rate of fire of over 1,000 rounds per minute. The SB2C-1 Helldiver, was a dive-bomber with a capacity of 2,650 pounds (1,200 kg) of ordnance or one torpedo. The Grumman TBF/TBM Avenger was designed as a torpedo plane, but often used in other attack roles. Some Essex-class carriers, such as the Bunker Hill (CV-17), also included squadrons of F4U Corsairs in Fighter-Bomber squadrons (VBFs), the precursor to modern Fighter-Attack (VFA) squadrons.
The defensive plan for the carriers was to use radio and radar in a combined effort to concentrate anti-aircraft fire.
The ship boasted four twin 5 in (127 mm) gun turrets, seventeen quad-barrel, 40 mm, anti-aircraft guns and 65 single, 20 mm, close-in defense guns. With a range of ten miles and a rate of fire of fifteen rounds per minute, the 5-inch guns fired the deadly VT shells. The VT shells, known as proximity fuzed-shells, would detonate when they came within 70 feet (21 m) of an enemy aircraft. The 5-inch guns could also aim into the water, creating waterspouts which could bring down low flying aircraft such as torpedo planes. The Bofors 40 mm guns were a significant improvement over the 1.1"/75 (28 mm) guns mounted on the earlier Lexington- and Yorktown-classes.
The Essex class also made use of advanced technological and communications equipment. The Mark 4 sweeping radar was installed but could not track incoming low-level intruders and was quickly replaced with the improved Mark 12 radar. The Plan Position Indicator (PPI) radar was used to keep track of ships and enabled a multi-carrier force to maintain a high-speed formation at night or in foul weather. The new navigational tool known as the Dead Reckoning Tracer was also implemented for navigation and tracking of surface ships. The Identification Friend or Foe (IFF) was used to identify hostile ships and aircraft, especially at night or in adverse weather. The four-channel very high frequency (VHF) radio permitted channel variation in an effort to prevent enemy interception of transmissions. A four-channel radio also allowed for simultaneous radio contact with other ships and planes in the taskforce.
Throughout the very large program to build Essex-class aircraft carriers, modifications were constantly made. The number of 40 mm and 20 mm anti-aircraft cannons was greatly increased, new and improved radars were added, the original hangar deck catapult installation was taken out completely, the ventilation system was massively revised, details of protection were altered and hundreds of other large and small changes were executed. In fact, to the skilled observer, no two ships of the class looked exactly the same.
Beginning in March 1943, one visually very significant change was authorized for ships then in the early stages of construction. This involved reshaping the bow into a rather elegant "clipper" form to provide deck space for two 40 mm quadruple gun mountings, thus greatly improving forward air defenses. Thirteen ships were completed to this "long-hull"-, or Ticonderoga-, class. Four of these were finished in 1944, in time to join their short-hull Essex-class sisters in Pacific combat operations. The rest went into commission between early 1945 and late 1946.
Their construction greatly accelerated, the Essex-class formed the backbone of the Navy's mobile air striking power during the climactic years of the Pacific War. Due to their large and spacious hangars, and the innovation of the angled flight deck, they could easily accommodate jet aircraft. With their larger contemporaries of the Midway-class, these carriers sustained the Navy's air power through the rest of the 1940s, during the Korean War era and beyond.
Five of the long-hulls were laid up in 1946–47, along with all of the short-hulls. Eight stayed on active duty to form, with the three much larger Midways, the backbone of the post-war Navy's combat strength. Though the Truman administration's defense economies sent three of the active Essexes into "mothballs" in 1949, these soon came back into commission after the Korean War began. Ultimately, all thirteen had active Cold War service.
Five of them were thoroughly rebuilt in the early 1950s under the SCB-27 program, and four of these were further modernized a few years later to the SCB-125 design. Another got a combined SCB-27 and SCB-125 redo, while yet another was given a modest reworking to test the revolutionary "angled deck" landing area.
Even after the arrival of the Forrestal-type "super carriers", the Essex-class remained vital elements of naval strength. By the mid-1950s, fourteen of them had been modernized along the lines of Oriskany (CV-34), with all but one of those being further updated under the SCB-125 program to facilitate operation of high-performance fighters and heavy attack aircraft.
Korean War and subsequent Cold War needs ensured that twenty-two of the twenty-four ships had extensive post-World War II service, all initially with attack air groups. As bigger carriers entered the fleet, 18 of the Essex-class were reassigned to the anti-submarine warfare (ASW) mission. Unmodernized ships began to leave active service in the late 1950s, but three had about a decade of additional duty as helicopter assault transports for the Marine Corps. The updated units remained active until age and the increasing fleet of supercarriers drove them from the high seas from the late 1960s into the middle 1970s. However, one of the very first of the type, Lexington (CV-16), ran on until 1991 as the Navy's training carrier.
Of the six unmodernized long-hull Essexes, three decommissioned in the late 1950s and early 1960s and were promptly reclassified as aircraft transports (AVT), reflecting their very limited ability to safely operate modern aircraft. The other three, converted to Landing Platform Helicopter (LPH) amphibious assault ships, were active until about 1970. The two least modernized units went into reserve in the mid-1960s, and the rest passed out of the active fleet between 1969 and 1976. All were scrapped, most in the 1970s, although Shangri-La survived until the late 1980s.
Several of the Essex-class ships played a part in the Apollo program, as recovery ships for unmanned and manned spaceflights, from 1966 to 1973.
On February 26, 1966, USS Boxer (CV-21) recovered the command module from AS-201, the first unmanned flight of a production Apollo Command and Service Module.[1] AS-202, another sub-orbital test flight of the command module, was recovered in August by USS Hornet (CV-12).[2] (The capsule is currently on display on Hornet.) USS Bennington (CV-20) recovered the command module of Apollo 4, the first unmanned flight of the Saturn V launch vehicle, on November 9, 1967.
Eleven months later, USS Essex (CV-9) recovered the astronauts of Apollo 7, the first manned mission in the Apollo program, after eleven days in orbit.[3] USS Yorktown (CV-10) recovered the astronauts of Apollo 8, after their historic first manned flight around the Moon;[4] and USS Princeton (CV-37) recovered Apollo 10.[5]
USS Hornet (CV-12) played a significant part in history when she recovered the astronauts from the first two moon landing missions, Apollo 11[6] and Apollo 12.[7] The first steps on earth of returning moonwalkers Neil Armstrong and Buzz Aldrin, with Command Module Pilot Michael Collins, are marked on her hangar deck, as part of her Apollo program exhibit. Some of the subsequent missions utilized amphibious assault ships as support vessels; however, USS Ticonderoga (CV-14) recovered the astronauts of the last two moon missions, Apollo 16[8] and Apollo 17.[9]
In the post-Apollo era, USS Ticonderoga (CV-14) again acted as a recovery ship for the astronauts of the Skylab 2 mission, the first manned mission to Skylab, the first U.S. orbital space station.[10]
Four of the Essex-class ships have been preserved, and opened to the public as museums:
- Yorktown (CV-10), at Patriot's Point, Mount Pleasant, South Carolina
- Intrepid (CV-11), in New York City
- Hornet (CV-12), in Alameda, California
- Lexington (CV-16), at Corpus Christi, Texas.
Oriskany was sunk in 2006 to form an artificial reef off the coast of Pensacola, Florida.
| Ship | Keel laid | Launched | Commissioned | Decommissioned |
|---|---|---|---|---|
| USS Essex (CV-9) | April 1941 | July 1942 | December 1942 | June 1969 |
| USS Yorktown (CV-10) | December 1941 | January 1943 | April 1943 | June 1970 |
| USS Intrepid (CV-11) | December 1941 | April 1943 | August 1943 | March 1974 |
| USS Hornet (CV-12) | August 1942 | August 1943 | November 1943 | June 1970 |
| USS Franklin (CV-13) | December 1942 | October 1943 | January 1944 | February 1947 |
| USS Ticonderoga (CV-14) | February 1943 | February 1944 | May 1944 | September 1973 |
| USS Randolph (CV-15) | May 1943 | June 1944 | October 1944 | February 1969 |
| USS Lexington (CV-16) | July 1941 | September 1942 | February 1943 | November 1991 |
| USS Bunker Hill (CV-17) | September 1941 | December 1942 | May 1943 | January 1947 |
| USS Wasp (CV-18) | March 1942 | August 1943 | November 1943 | July 1972 |
| USS Hancock (CV-19) | January 1943 | October 1944 | April 1944 | January 1976 |
| USS Bennington (CV-20) | December 1942 | February 1944 | August 1944 | January 1970 |
| USS Boxer (CV-21) | September 1943 | December 1944 | April 1945 | December 1969 |
| USS Bon Homme Richard (CVA-31) | February 1943 | April 1944 | November 1944 | July 1971 |
| USS Leyte (CV-32) | February 1944 | August 1945 | April 1946 | May 1959 |
| USS Kearsarge (CV-33) | March 1944 | May 1945 | March 1946 | February 1970 |
| USS Oriskany (CV-34) | May 1944 | October 1945 | September 1950 | September 1976 |
| USS Antietam (CV-36) | March 1943 | August 1944 | January 1945 | May 1963 |
| USS Princeton (CV-37) | September 1943 | July 1945 | November 1945 | January 1970 |
| USS Shangri-La (CV-38) | January 1943 | February 1944 | September 1944 | July 1971 |
| USS Lake Champlain (CV-39) | March 1943 | November 1945 | June 1945 | May 1966 |
| USS Tarawa (CV-40) | March 1943 | May 1945 | November 1945 | June 1967 |
| USS Valley Forge (CV-45) | September 1944 | November 1945 | November 1946 | January 1970 |
| USS Philippine Sea (CV-47) | August 1944 | September 1945 | May 1946 | December 1958 |
The Oriskany (CV-34) was ordered and laid down as an Essex-class vessel, was completed in 1950 to the much modified SCB-27A design.
Reprisal (CV-35), laid down in July 1944 at the New York Navy Yard and launched in 1945, was scrapped incomplete after tests; and Iwo Jima (CV-46) was laid down at Newport News Shipbuilding yards in January 1945 but cancelled in August 1945 and broken up on the shipways.
Six fiscal-year 1945 ships, none of which received names, were assigned to Bethlehem Steel Company (CV-50), New York Navy Yard (CVs 51 & 52), Philadelphia Navy Yard (CV-53) and Norfolk Navy Yard (CVs 54 and 55). Their construction was cancelled in March 1945.
- Faltum, Andrew (1996), The Essex Aircraft Carriers. The Nautical and Aviation Publishing Company of America ISBN 1-877853-26-7
- Donald, David, and Daniel J. March (2001), Carrier Aviation Air Power Directory. AIRtime Publishing ISBN 1-880588-43-9
- This article includes text from the public domain Dictionary of American Naval Fighting Ships.
- ^ AS-201, NASA (NSSDC ID: APST201)
- ^ AS-202, NASA (NSSDC ID: APST202)
- ^ Apollo 7, NASA (NSSDC ID: 1968-089A)
- ^ Apollo 8, NASA (NSSDC ID: 1968-118A)
- ^ Apollo 10, NASA (NSSDC ID: 1969-043A)
- ^ Apollo 11, NASA (NSSDC ID: 1969-059A)
- ^ Apollo 12, NASA (NSSDC ID: 1969-099A)
- ^ Apollo 16, NASA (NSSDC ID: 1972-031A)
- ^ Apollo 17, NASA (NSSDC ID: 1972-096A)
- ^ SP-4012 NASA HISTORICAL DATA BOOK: VOLUME III PROGRAMS AND PROJECTS 1969-1978, Table 2-49, Skylab 2 Characteristics
- Aircraft carrier classes:
- Ticonderoga-class cruiser
- List of aircraft carriers of the United States Navy
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| Short-hull carriers | Essex · Yorktown · Intrepid · Hornet · Franklin · Lexington · Bunker Hill · Wasp · Bennington · Bonhomme Richard · Kearsarge · Oriskany |
| Long-hull carriers (Ticonderoga-class) |
Ticonderoga · Randolph · Hancock · Boxer · Leyte · Kearsarge · Reprisal · Antietam · Princeton · Shangri-La · Lake Champlain · Tarawa · Valley Forge · Iwo Jima · Philippine Sea |
| List of aircraft carriers of the United States Navy | |