Nimitz class

USS Carl Vinson (CVN 70) in the Pacific in 2003
Overview
Type	Aircraft carrier
units	10 built, 10 in service (including 1 in overhaul)
Namesake	Admiral Chester W. Nimitz
period of service	since 1975
Technical specifications
displacement	over 97,000 tons (fully loaded)
length	317 meters (waterline), 332.85 meters (flight deck)
width	40.84 meters (fuselage), 76.80 meters (flight deck)
Draft	12.50 meters
crew	3200 crew + 2480 aircraft personnel
drive	2 nuclear reactors, 4 propellers
speed	30+  knots
Armament	4 Phalanx cannons, 3 Sea Sparrow starters. Will be replaced by 2 Sea Sparrow and 2 Rolling Airframe starters
Aircraft	up to 85

The Nimitz-class is a class of nuclear-powered aircraft carriers in the United States Navy . The lead ship USS Nimitz , the first unit of the class, was put into service in 1975, the tenth and last in early 2009. With a displacement of around 97,000 tons , the carriers were the largest warships until the Gerald R. Ford class was commissioned in 2017 of the world. You can carry up to 85 planes. The carriers can be used almost indefinitely, only kerosene and food supplies have to be replenished regularly. The construction of a Nimitz- class ship last cost over six billion US dollars and takes around five years from keel-laying to commissioning. The ships are designed for a service life of around 50 years.

The ten Nimitz- class ships formed the entire US aircraft carrier fleet from the decommissioning of the USS Enterprise (CVN 65) on December 1, 2012 until the commissioning of the USS Gerald R. Ford on July 22, 2017. They are the backbone of the US armed forces for extensive combat operations such as the 1990 Second Gulf War or the 2003 Iraq War and the subsequent occupation of Iraq until 2011 . In addition to the direct support of military operations, the aircraft carriers are also used to create a threatening backdrop by simply being present off the coast of a state. A humanitarian mission was supported in one case.

history

planning

Outwardly, the John F. Kennedy (front) can hardly be distinguished from the porters of the Nimitz class (behind Theodore Roosevelt )

Abraham Lincoln in dry dock in 1990

The first plans for an aircraft carrier that would far outstrip those of the World War II carriers, a so-called “supercarrier”, were made shortly after the end of the war. After political pressure from the Air Force , among others , the construction of the USS United States (CVA-58) was canceled in 1949 only days after the keel was laid. After the outbreak of the Korean War , the Truman government changed its attitude and laid down the Forrestal class , whose first unit was added to the fleet in 1955. Outwardly, this already resembled the Nimitz class. In 1961, the first Kitty Hawk- class carrier went into service, and that same year the USS Enterprise (CVN-65) , the first nuclear-powered aircraft carrier with eight nuclear reactors in the fuselage.

Defense Secretary Robert McNamara , who had served in the United States Army Air Forces and had little sympathy for the Navy, blocked the construction of further expensive nuclear-powered vehicles for the time being and pushed through two additional oil-fired vehicles. It was not until 1967 that the Navy received approval to use the SCB-102 design, which was already in the drawer , from which the Nimitz class was developed. This was essentially the concept of the immediately preceding USS John F. Kennedy (CV-67) , which was adapted to the installation of only two reactors. The concept benefited from the fact that, on the one hand, the oil bunkers were omitted, and on the other hand, massive space could be saved by reducing the number of reactors in the hull to two.

Since in the late 1960s many of the state-owned naval yards had withdrawn from the construction of new ships and were increasingly devoting themselves to overhauling the fleet, only the private Newport News Shipbuilding (NNS) in Newport News , Virginia was able to deliver the nuclear-powered "supercarriers" manufacture. At the beginning, three units were planned. As a guideline for the construction time, the Navy was aiming for around four years, similar to how NNS had managed the Enterprise . However, the construction was plagued by problems, strikes by the shipyard workers did the rest to delay the completion of the Nimitz by two years. Since the capacities of NNS did not allow the construction of two girders at the same time, the overall program was also delayed. Therefore - and due to the galloping inflation in the early 1970s - the construction time and the costs increased. While in 1973 each of the first two units had been estimated to cost less than $ 700 million, the Navy estimated it to be up to $ 2 billion per carrier by 1977.

This increase in costs caused the Carter administration to refuse the procurement of further carriers of the class and instead to prefer a design just half the size for a conventionally powered carrier under the design name CVV , which was extremely unpopular with the Navy. However, in 1980, against Carter's will, the United States Congress approved a fourth unit of the Nimitz class. The entire Navy and thus also the Nimitz procurement program benefited greatly from the election of Ronald Reagan , whose Navy Minister John F. Lehman launched the “ Navy of 600 Ships ” program. At the end of 1982, the Navy received a Nimitz two-pack from this , and another in 1988, increasing the class to eight units. The last two units in the class were approved in 1994 and 2001, prices now around $ 4.5 billion for the Reagan and $ 6.3 billion for the Bush .

The completion of the Enterprise and the start of construction on the Nimitz startled the Soviet Navy . With the Moskva class, it only had two flight deck cruisers . Defense Minister Andrei Gretschko then started the 1153 Orel project in 1973 , which aimed at a nuclear-powered aircraft carrier that was around 20% smaller and similar to American units. After Grechko's death in 1976, however, his successor Dmitri Ustinov soon ended the project; instead, only the four much smaller Kiev- class carriers were added to the fleet from 1975 onwards . Shortly before the end of the Cold War, the Soviet Union made a second attempt to build nuclear-powered aircraft carriers. In 1988 the Ulyanovsk , which was quite similar to the Orel, was laid down, a second porter was to follow. However, after the fall of the Soviet Union, construction was canceled in 1992. The largest Soviet / Russian carrier since 1991 is the conventionally powered Admiral Kuznetsov .

Ships

Surname	Identifier	order procurement	Keel laying	Launch	Indienst- position	Overhaul ( RCOH)	home port
USS Nimitz	CVN-68	31 Mar 1967	June 22, 1968	May 13, 1972	03rd May 1975	1998-2001	Naval Base Kitsap , Bremerton , WA
USS Dwight D. Eisenhower	CVN-69	June 29, 1970	Aug 15, 1970	Oct 11, 1975	Oct 18, 1977	2001-2005	Naval Station Norfolk , Norfolk , VA
USS Carl Vinson	CVN-70	0Apr 5, 1974	Oct 11, 1975	15th Mar 1980	13 Mar 1982	2005-2009	Naval Air Station North Island , San Diego , CA
USS Theodore Roosevelt	CVN-71	Sep 30 1980	Oct 31, 1981	Oct. 27, 1984	Oct 25, 1986	2009-2013	Naval Air Station North Island, San Diego, CA
USS Abraham Lincoln	CVN-72	Nov. 27, 1982	0Nov 3, 1984	Feb 13, 1988	Nov 11, 1989	2013-2017	Naval Station Norfolk, Norfolk, VA
USS George Washington	CVN 73	Dec. 27, 1982	Aug 25, 1986	July 21, 1990	04th July 1992	2017–	Naval Station Norfolk, Norfolk, VA
USS John C. Stennis	CVN-74	June 30, 1988	13 Mar 1991	Nov 13, 1993	0Dec 9, 1995		Naval Base Kitsap, Bremerton, WA
USS Harry S. Truman	CVN-75	June 30, 1988	Nov 29, 1993	0Sep 7 1996	July 25, 1998		Naval Station Norfolk, Norfolk, VA
USS Ronald Reagan	CVN-76	Aug 12, 1994	Feb 12, 1998	10 Mar 2001	July 12, 2003		Yokosuka Naval Base , Yokosuka , Japan
USS George HW Bush	CVN-77	Feb 26, 2001	May 19, 2003	0Oct 9, 2006	Jan. 10, 2009		Naval Station Norfolk, Norfolk, VA

construction

Carl Vinson during the finishing work on the pier

The island is lifted onto the deck of the George HW Bush

All girders were built in the largest dry dock on the American continent, Newport News Shipbuilding's 670 meter long dry dock 12. The dock can be divided into two parts, so that another ship can be built in the front part. The construction of a girder of the class begins a few months before the keel is laid, with the concrete and wooden blocks on which the keel is placed and the first metal parts are cut. After the keel is laid, the shipyard has around 33 months until the ship is “launched”. However, the porters no longer actually slide over the slipway into the water, as the traditional term of the launch suggests. Instead, the dry dock is flooded, causing the ship to float.

The girders are manufactured in a modular manner. This means that entire sections are welded together along the dry dock and equipped with all piping and the like as far as possible. This process, originally developed by Litton-Ingalls , speeds up a lot of work because it does not have to be carried out in the confines of the already finished hull. The modules, known as “superlifts”, are then lifted into the dry dock by gantry cranes and welded there. These modules, like the bow, weigh over 700 tons. In total, a carrier is made up of around one hundred of these superlifts. The bow area and the deckhouse called the "island" belong to the largest parts.

However, it is not possible to completely manufacture a Nimitz- class carrier in the dry dock. The dry dock can only be flooded to ten meters and the canal to the shipyard also offers limited space. However, the draft of a fully equipped porter is slightly greater. That is why the carrier is launched as early as possible and - taking into account the tide - is towed to a deep water pier by NNS on the James River , where the further equipment of the hull takes place. For this, up to 2,600 shipyard workers are deployed on a carrier per shift. After the equipment, the shipyard conducts its own test drives, after which the Navy takes over the ship and thus takes possession of it. After the Navy test drives, the carrier goes back to the shipyard, where the last problems found are eliminated. Only then does it come into service.

For the construction of about 40 million are for the entire time person-hours expended.

Naming

The first unit and thus traditionally also the class are named after Admiral Chester W. Nimitz , who led the US Navy in the Pacific War . All of the following carriers were named after politicians. In addition to Presidents Eisenhower , Roosevelt , Lincoln , Washington , Truman , Reagan, and Bush Sr. , two congressmen were honored to be the namesake of a bearer of this class. This is Carl Vinson , an MP from Georgia, and John C. Stennis , a Senator from Mississippi. Both had campaigned in a special way for the expansion of the navy.

Four of the units ( Carl Vinson , John C. Stennis , Ronald Reagan and George HW Bush ) broke with the US Navy tradition of naming ships only after deceased people.

Modernizations

View of the flight deck of the Carl Vinson during an overhaul (RCOH)

Due to the time lag between the first and the last unit of the class, technical innovations were integrated into the units under construction. A first major change occurred from the Theodore Roosevelt . These received, for example, reinforced Kevlar armor in the hull. More modern armament was installed on the last two girders from the factory, as were minor changes to the hull and island. In addition to the details mentioned, the George HW Bush , which is to serve as a kind of technology demonstrator for the next class of aircraft carriers, has undergone major changes .

On older vehicles, the smaller modernizations are retrofitted on the regular overhauls. These usually take less than twelve months and can be carried out at several shipyards, some of which are state-owned. Units stationed in the Pacific are regularly modernized in the Puget Sound Naval Shipyard .

RCOH

In addition to these shorter dwell times , each of the porters has to go back to the shipyard in Newport News for a much more extensive overhaul, the so-called Refueling and Complex Overhaul (RCOH). As a mid-term overhaul, it takes place after around 25 years of use and takes around four years. During this overhaul, the nuclear fuel in the reactors will be renewed so that enough fissile material will be available for the reactors to operate in the second half of their life. Many rooms are being modernized, and external work is also taking place on the island. In addition, the entire hull is repainted, and the propellers and rudders are reconditioned. An aircraft carrier is located at Newport News Shipbuilding, where the work is being carried out; That costs around two billion dollars per ship for over 20 million person-hours. Half of the Nimitz carriers have now been overhauled.

business

period of service

Share of classes in the US Navy's active carrier fleet

At the same time as the Nimitz entered the fleet in 1975, the last World War II carriers of the Essex class of active combat units were decommissioned. Thus, at the end of 1976, the aircraft carrier fleet of the US Navy still consisted of the three units of the Midway class , the four Forrestals , the four Kitty Hawks , the Enterprise and the Nimitz . The Dwight D. Eisenhower replaced the Midway- class USS Franklin D. Roosevelt (CV-42) in 1977 , and the Carl Vinson joined the fleet in 1982, increasing the size of the carrier fleet to 14. During the final years of the Cold War, the Navy owned after the arrival of the Theodore Roosevelt in 1986 so 15 carrier combat groups.

Since the two remaining Midways as well as all four Forrestals and one Kitty Hawk were deactivated in the 1990s , but only four Nimitz carriers have been added (since 1989) , the number of active carriers fell to twelve. The USS Constellation (CV-64) was replaced by the Ronald Reagan in 2003 , but the early departure of the John F. Kennedy in 2007 could not be offset; the number of carrier combat groups in service fell to eleven. In 2009 the USS Kitty Hawk (CV-63) was decommissioned and replaced by the George HW Bush . After the early decommissioning of the Enterprise on December 1, 2012, the carrier fleet still includes the ten Nimitz units, of which only nine are ready for use because one unit is always in the shipyard for mid-term overhaul.

The successor to the Nimitz class is the Gerald R. Ford class . Its first unit, the USS Gerald R. Ford (CVN 78) , entered service on July 22, 2017 and replaces the decommissioned Enterprise in order to increase the number of operational carriers back to ten. Two further units are to replace the Nimitz and Dwight D. Eisenhower in 2022 and 2027 respectively . Overall, it is planned to replace the ships of the Nimitz class one-to-one with carriers of the Gerald R. Ford class every five years.

Operational basics

Of the ten carriers in the class, five were stationed in the Pacific and four in the Atlantic in April 2017, one (Abraham Lincoln) is in the shipyard for the mid-term overhaul. While all Atlantic units (Dwight D. Eisenhower , Harry S. Truman , George HW Bush , Theodore Roosevelt) have their home port in Naval Station Norfolk , the Pacific ships are on five bases, Naval Station Everett (Nimitz) , the Naval Base San Diego (George Washington) , Naval Air Station North Island (Carl Vinson) , Naval Base Kitsap (John C. Stennis) , and the US base in Yokosuka , Japan (Ronald Reagan) .

The total cost of operating and supporting a Nimitz- class carrier by dollar value in 1997 is nearly $ 15 billion over its lifetime. With the assumed 50 years of service, the operation of a carrier costs almost 300 million dollars per year. In addition to personnel costs, training, fuel, maintenance and modernization costs are included, but not the costs for the RCOH and the nuclear fuel. Including RCOH, construction and disposal, a carrier costs the American taxpayer a total of around $ 22 billion or $ 444 million per year.

The costs vary greatly between port lay times and missions. While the operation including pay in the port costs around 250,000 dollars per day, the rate per day at sea is around 2.5 million dollars.

Performed missions

In 1980 helicopters were made ready for Operation Eagle Claw in the Nimitz hangar

The first offensive deployment of a Nimitz- class carrier was the failed Operation Eagle Claw , in which helicopters rose from the Nimitz type ship in 1980 to end the hostage-taking of Tehran . The Nimitz was later replaced by her sister ship Dwight D. Eisenhower . The Nimitz carrier aircraft achieved their first aerial victories in 1981 when two F- 14s shot down two Libyan Sukhoi Su-22s over the Great Syrte . These had attacked the F-14.

Since then, carriers of the class have been regularly used offensively in the Persian Gulf , first in Operation Earnest Will in 1988 , then in the Second Gulf War and in the 1990s in Operation Southern Watch , in which the aircraft monitored the no-fly zone over Iraq. The last wars in Afghanistan and Iraq would hardly have been feasible without the support of the floating airports.

Among other things, to protect Taiwan , a porter is repeatedly sent to the region around the island. The fact that the Nimitz crossed the Formosa Strait between the mainland and the island in late 1995 in response to the resurgence of the Taiwan conflict was seen as a serious threat to the People's Republic. Only three months later, the carrier was withdrawn from the Persian Gulf and reached the waters around Taiwan after a two-week voyage after the People's Republic had carried out missile tests in the direction of the island. Chinese politicians then warned the US not to allow the carrier to enter the street again, but the Navy rejected this. The Nimitz was also used in the region for the presidential election in March 2008 .

The carriers can also be used for humanitarian tasks. In 1991, Abraham Lincoln helped evacuate the area around the erupting Pinatubo volcano in the Philippines and brought thousands of American citizens to safety. After the seaquake in the Indian Ocean in 2004 , the Abraham Lincoln was again sent off the coast of Sumatra . Even after Hurricane Katrina , the porter Harry S. Truman was off the Gulf Coast to support the relief efforts for the population by helicopter. The fresh water generator systems on board, which can produce large quantities of fresh water, were particularly valuable .

technology

hull

Dimensions and deck layout

The view from above of the Harry S. Truman shows the dimensions of the carrier

The Ronald Reagan heeled during rudder test to port

The ships of the Nimitz class are 317 meters long at the waterline , the hull is 40.8 meters wide. Since the flight deck extends beyond the fuselage, the girders measure 76.8 meters at their widest point, the length over everything, including the flight deck, is 333 meters. When fully loaded, the draft is around 12.5 meters. With a displacement of more than 97,000 tn.l. are the units of the largest warships in the world. The hull, like the superstructure, is made entirely of steel. All parts of the fuselage that are underwater while driving and are therefore exposed to the risk of torpedo hits consist of a double side wall with free spaces between the steel layers in order to absorb as much as possible of the pressure wave from an exploding warhead. Above that, the hull is made of simple steel armored with Kevlar. Above the flight deck there is only the deckhouse, called the island, which is located in the rear third on the starboard side.

The final unit, George HW Bush , has many edges, including those of the flight deck, rounded to reduce the radar reflective area of the carrier. To reduce the water resistance, the last two girders (besides the Bush also the Ronald Reagan ) also have a bulbous bow .

In addition to the two reactors, the machine systems and numerous ammunition and fuel bunkers are installed right at the bottom of the fuselage. On the one hand, this offers the advantage that the relevant part of the fuselage is always flooded with water and therefore cannot be reached directly by anti-ship missiles . On the other hand, the stability of the ships also increases, since top-heaviness is avoided.

There is a special deck naming scheme on girders. The decks above the engine rooms are counted down to the hangar. The fourth deck, on which the auxiliary machinery is located, follows from below, the third deck which, in addition to other engine rooms, houses the galley and lounges as well as the medical facilities, and the second deck, which houses workshops and offices as well as the trade fairs . In use, the waterline runs between the third and second deck. Above this is the main hangar deck, which takes up the entire middle section of the ship. Only in the overhangs to the flight deck are there other rooms in addition to the hangar. The refueling systems and other workshops are located on the main deck.

Above the hangar, which takes up three decks, the decks are now counted up. This is followed by the 01 deck with additional stores and workshops, the 02 deck with all rooms for the flag officer and his staff, and the gallery deck (03), which again takes up the entire width. This is where, among other things, the relay rooms for the stay and briefings of the flight personnel as well as warehouses and workshops are located. The Combat Information Center , the ship's operations center , and other control stations, for example for reconnaissance data, are also located here .

The crew quarters are spread over the entire ship.

Flight deck and hangar

Animation of take-offs and landings on board the Dwight D. Eisenhower

Control room of the "Air Boss", who is responsible for all aircraft movements on the flight deck and in the vicinity of the carrier

The flight deck is 333 meters long and at its widest point 76 meters wide, the total area is 18,000 m². It is designed as an angled flight deck, which means that it has a runway along the central axis of the ship over the bow and another runway , which is angled 9 ° 3 'to the left to the longitudinal axis. This allows aircraft to take off from the bow and take off and land on the angled deck at the same time. Each carrier has four steam-powered aircraft catapults , two each for the angled runway and the runway over the bow. The catapults are numbered 1 to 4 from starboard. The catapults are controlled from two Integrated Catapult Control Stations . These ICCS are retractable capsules embedded in the flight deck that were used for the first time on the carriers of the class.

Four safety ropes are stretched across the runway, into which the landing pilot has to hook a hook attached to the tail of his aircraft in order to bring the aircraft to a stop at a maximum of 120 meters. So that the carrier can be identified from the air, especially in multi-carrier formations, the identification number is attached in a large format in the bow area on the flight deck. The angled runway is also marked.

The hangar is 208 meters long, 33 meters wide and has three decks, i.e. 7.6 meters high. It is a single room, but can be divided by three sliding doors, which among other things helps to contain possible fires. Aft of the hangar there are workshops and test stands for the engines, in front of the hangar is the forecastle , in which, among other things, the anchor capstans for the two 30-ton anchors and the 140-ton, 330-meter-long anchor chains are located.

A maximum of 50 to 60 aircraft can be accommodated in the hangar, which is why aircraft often have to be parked on deck on an emergency trip. The hangar is connected to the flight deck by four elevators. Their openings let daylight into the hangar when the weather is good, and they are closed when it rains or winds. The elevators - there are two to starboard in front of the island and one behind it and another to port at the height of the aft starboard elevator - are made entirely of aluminum in order to save weight and increase the payload.

island

View of the three bridges of the Abraham Lincoln

The island is the only deckhouse and the only substantial structure that rises above the flight deck. The island also serves as a carrier for the antenna forest: a large part of the electronics is installed on it, as it is not in the way of flight operations and also has the highest possible location. The height of the island can be compared to a 23-story high-rise building.

In the island, the numerical deck designation is continued from the hangar level upwards. The 08 deck is the bridge of the unit leader, i.e. the admiral who is in command of the entire combat group . Above is the nautical bridge on which the aircraft carrier's commander sits and controls the movements of his ship. The chart table for navigation and the helm are also located here. Above it again on the 10th deck, i.e. seven floors above the flight deck, there is the main flight control, where the "Air Boss" is in command. From here, the crew has the best view of the flight deck; take-offs and landings as well as aircraft movements in the airspace around the carrier are coordinated here. The Geierhorst, an open-air terrace with a clear view of the entire flight deck, is also located on this level. As part of the half-time overhaul, the height of the island will be reduced by two floors, which is also done for camouflage reasons, as it offers less reflective surface.

The island is also marked on both sides with the illuminated identification number.

In-flight aircraft

A look at the flight deck of the Harry S. Truman shows the different types used

Each carrier in the class can accommodate around 85 aircraft - rigid and rotary wing aircraft . Often, however, there are only 60 to 72 aircraft on board. These are organized in a Carrier Air Wing and are divided into several squadrons . There is enough kerosene on board to carry out 16 days of uninterrupted flight operations. The porters can take over kerosene from escort ships on the high seas to extend the duration of the mission.

Up to four squadrons, i.e. 48 aircraft or around half of the maximum capacity, consist of different versions of the McDonnell Douglas F / A-18 Hornet . Usually half of these are F / A-18 A / B / C / D Hornet and F / A-18 E / F Super Hornet, which are larger and more powerful. However, the proportion of F / A-18 versions is currently increasing. By 2009 the Lockheed S-3 Viking for submarine hunting and air refueling was completely eliminated; while the tank component was handed over to the F / A-18 E / F Super Hornet , only helicopters and ships are now available for submarine hunts. At the same time, the replacement of the Grumman EA-6 ( electronic warfare ) by the EA-18 Growler , a Super Hornet variant, began. Upon completion, up to 60 F / A-18s can be on board per carrier. However, the F / A-18 A / B / C / D Hornet are expected to be replaced by Lockheed Martin F-35 C Lightning II from 2018 .

Until 2006, in addition to the Hornet, there were also often Grumman F-14 Tomcat fighters on board, around 2000 usually a squadron. During the Cold War, a squadron of Grumman A-6 Intruders and up to two squadrons of Vought A-7 Corsair II were on board for light bombardment.

In addition to the tankers, each Nimitz also carries a squadron of four Grumman E-2 C Hawkeye early warning aircraft and up to ten Sikorsky SH-60F Seahawk or HH-60H Seahawk helicopters . These are used, among other things, for Combat Search and Rescue and anti-submarine hunting, as well as rapid personnel transfers within the combat group. Transport flights to or from land, so-called Carrier Onboard Delivery , are carried out by the Grumman C-2 Greyhound .

drive

George Washington propeller

Each carrier has two pressurized water reactors of the type A4W with a capacity of about 100 megawatts. The A stands for the type on which the reactor is used, here Aircraft Carrier . The 4 means that it is the 4th generation of reactors from the manufacturer named in third place. The W here stands for Westinghouse . The two reactors drive four General Electric steam turbines , each turbine is connected to a shaft. The reactors are set up separately, with tanks and ammunition chambers between them. Each carrier has four five-bladed bronze propellers with a diameter of around 7.6 meters. Each of the propellers weighs around 30 tons. They are staggered, the two waves inboard extending further towards the stern. Behind these are the two oars, which are 8.9 meters high and 6.7 meters long. One weighs 27.5 tons.

The drive section with the reactors is permanently protected internally by a guard team of Marines in order to guarantee the strict access restrictions.

The system's output is around 280,000 shaft horsepower . The achievable speed is kept secret, but is far above the officially stated "30+" knots. Such high speeds help the aircraft to take off and land, as the airflow in combination with the natural wind already creates an air flow around the aircraft that reduces the necessary take-off speed.

Two generators also work per steam turbine to generate the electrical energy required for the ship. Each generates around 8 MW, so that up to 64 MW are available to operate the electrical systems on board. That corresponds to the needs of a city with 100,000 inhabitants. If the reactors fail at sea, four emergency diesel generators can provide 8 MW of power, for example to restart the reactor.

The four fresh water generation systems in each Nimitz can convert up to 1,500 tons of sea water into fresh water per day. This water is used in the propulsion and catapult system as well as to supply the crew.

Armament of the aircraft carrier

A Sea Sparrow was shot down from the starboard platform of the Theodore Roosevelt . In front of it a phalanx cannon with a white dome

The carriers of the Nimitz- class have a purely defensive armament for short-range defense , as they are accompanied by escorts on missions anyway, who carry out possible offensive actions. This saves the space that cruise missiles would take up and can be used to support flight operations.

When commissioned, the first two units had three platforms just below the flight deck on which the weapon systems were set up. Two of them were at the stern, the third at the bow on the starboard side. All newer units were also given a fourth platform ex works on the port bow; the other two were retrofitted. In total, each carrier had three launchers for eight RIM-7 Sea Sparrow rockets and three or (including the port platform) four rapid-fire Phalanx CIWS guns . The forward starboard platform was equipped with a phalanx and a sea sparrow starter. The stern platforms each contained one of the Sea Sparrow starters. At the stern, two more phalanxes were also integrated into the fuselage, but well below the remaining platforms.

The phalanx will be removed as planned for the whole of the fleet as part of the shipyard idle times that are planned anyway. The two systems at the rear are omitted without replacement, as is the gun on the divided platform at the front. A starter with 21 RIM-116 Rolling Airframe Missiles (RAM) is installed on the other bow platform , as well as on one of the two stern platforms, for which the third Sea Sparrow starter is no longer needed. Instead of Sea Sparrows, RIM-162 Evolved Sea Sparrow Missiles (ESSM) will be used in the future , and since 2008 the Stennis has been the first aircraft carrier that can use the new missiles. This means that in future each carrier will have two ESSM starters (bow starboard and stern port) with a total of 16 missiles and two RAM starters (bow port and stern starboard) with a total of 42 missiles. There are also some Browning M2 machine guns to protect against small speed boats .

Sensors and countermeasures

Location electronics

The island and single mast for the Abraham Lincoln SPS-49

Each unit in the class has multiple radars . The 3D radar SPS-48E , which is located on the island, is available as an aerial search radar on every unit from the start . The SPS-48 is manufactured by ITT-Gilfillan and has a range of up to 230 nautical miles. This system also serves, among other things, to supply the missiles with target data. As a 2D aerial search radar, the first two units initially had an SPS-43A from Hughes and Westinghouse with a range of 200 nautical miles. It was soon replaced by the remaining units already installed in the factory SPS-49 (V) 5 of Raytheon , which has improved by 50 miles range. There is also a Mk 23 TAS search radar that detects close range targets for the Sea Sparrow guided missiles. In the course of modernizations, however, it will be gradually replaced by the AN / SPQ-9 B.

In contrast to all other systems, the SPS-49 is installed ex works on its own mast aft of the island. Only in the course of the Refueling and Complex Overhauls will the system be moved to the island in order to create more free deck space. The mast was necessary to avoid interdependencies between the systems. The new structure of the island, which the last two porters have owned from the start, avoids these problems.

For surface target search and navigation, the first three units had a SPS-10F from Raytheon, which was soon replaced by the combination of SPS-64 and SPS-67 (V) , which was later used in series . The range is around 50 nautical miles.

Other electronics

Two Mark 91 fire control radar illuminators SPS-65

Control room for electronic warfare on board the Nimitz

Both the Sea Sparrow and the ESSM are semi-active radar-controlled guided missiles, so they do not have their own active radar, but fly to the target, which is "illuminated" by another radar device. They are therefore dependent on a fire control radar that continuously illuminates the target even after take-off. For this purpose, every carrier in the class has the Mark 91 fire control system . The main components are the three SPS-65 radar illuminators.

Every carrier has the Challenge Athena system for long-distance communication, text and image reception of satellite data as well as reconnaissance or television signals . It was developed after the Navy in the Second Gulf War was not even able to receive the daily issued air tasking orders , but had to have them flown in. From 1992 the system was first tested on the George Washington and later installed on all carriers in the class. The antenna, hidden under a radome , is located on the port deck edge at the stern. In addition, there are antennas for board-to-board radio. On the deck edges there are several short and ultra short wave antennas that can be folded down during flight operations. The CEC system has now been retrofitted on all ships to improve communication with the company's own aircraft and escort ships . Compared to older systems, it is characterized by a significantly higher data rate and interference immunity. It also enables a much better networking of sensors and weapon systems within the combat group.

To relieve the crew during a battle, the first Nimitz aircraft carriers were equipped with the Advanced Combat Direction System . This is a computer-based management system that can autonomously identify, track and, if necessary, attack contacts. Data and commands can also be automatically passed on to escort ships. The Mk-2 version of the more modern and more powerful Ship Self Defense System has been installed since the Ronald Reagan . Since it is planned for the entire fleet, all older porters will also be equipped with the new system when they are modernized with the RCOH.

For electronic warfare , each carrier in the class has version (V) 4 of the SLQ-32 system specially developed for aircraft carriers . This also includes launchers for SRBOC , i.e. for chaff to deflect radar and flare to deceive infrared-guided missiles. Torpedoes can be deflected from the ship by two towed SLQ-25 Nixie baits .

In order to be able to carry out flight operations, every carrier needs short-range radars that monitor air traffic and especially aircraft landing and taking off. For the approach, an SPN-43 is used in combination with the SPN-44 , which are completely redundant. These provide exact azimuth data as well as the absolute and relative speed of approaching aircraft. The final approach including landing can also be carried out completely automatically using the older SPN-42 or the more modern SPN-46. This mode is rarely used, but can be important if the on-board system fails.

crew

Life on board

John C. Stennis sailors in their bunks

Sailors from the Harry S. Truman watch TV material they have produced themselves

The strength of the nautical crew on each carrier is 3,200 men, plus 2,480 men in the air wing. In addition to the pilots, this also includes the maintenance staff. Officers and crew ranks sleep separately, and there are dormitories on several levels below deck. The flight personnel is located directly below the flight deck, as the aircraft on the flight deck and the hydraulically operated catapults and safety ropes cause a lot of noise and the members of the Air Wings are already busy on deck during flight operations.

The nautical crew mostly sleeps and rests under the hangar deck. The teams sleep in three-story bunks, around 60 such bunks per dormitory. Everyone has their own bunk ; the principle of “hot bunking” used on smaller ships, especially submarines , ie dividing a bunk in layers, does not take place. A laundry room and a lounge are attached to each dormitory. Everyone has a locker for personal items . The admiral on board and his staff also sleep and work on the 03 deck directly below the flight deck; these rooms are the most luxurious on board. On the same deck, further towards the bow, the nautical officers also sleep, mostly in two-man cabins. Sailors who work in the carrier's hull often see no sunlight for days: the hull does not have portholes for structural reasons, and access to the flight deck, hangar deck and the island is severely restricted, especially during flight operations.

The fairs are on the second deck and up to 20,000 meals are served every day. To this end, 280 kg of hamburger meat and over 2,000 eggs are fried every day , up to 800 loaves of bread are baked and around 350 kg of vegetables are cooked. In addition, 400 kg of fruit are consumed. Food can be stored on board for up to 90 days.

In a studio, television and radio news are produced on a Nimitz class carrier and fed into the on-board network. Commercial TV channels can also be received on the televisions in the common rooms, which are fed via the Challenge Athena system. This is also used to operate satellite telephones and internet connections, which every crew member can use to contact their home country. Alternatively, the sailors can communicate by post , which is transported ashore and forwarded as soon as the carrier is near the coast. There is also its own hairdresser on board , who does the hair of up to 250 sailors per day, and a laundry that cleans 2.5 tons of laundry. Three services are held daily in an interdenominational chapel on board.

The medical rooms are located on the third deck. The porter serves as a hospital for the entire combat group; Often there are only paramedics on the escort ships. A Nimitz, on the other hand, has a fully equipped dental clinic with five dentists as well as human medical treatment rooms and operating theaters with six doctors. The on-board hospital has 53 beds and there is also an intensive care unit with three beds.

hazards

Firefighters during a simulated fire in the hangar of Harry S. Truman

Not only for the pilots, but also for the flight deck personnel, the service on the porters is the most dangerous in the entire Navy, which is why this group receives a hazard surcharge on their pay . Everyone on the flight deck must be fully concentrated at all times; Inattentiveness between running engines, aircraft taking off and landing and live weapons can cause serious accidents and endanger life. An example of this is the then petty officer John D. Bridges: In 1991 he checked the work of a new recruit while preparing an A-6 Intruder on the flight deck of the Theodore Roosevelt . In a moment of inattention, Bridges approached the plane after the engines were already up. He was sucked in by the running engine, which was blocked by his protective equipment. Only the quick reaction of another crew member, who signaled the pilot to shut down the engine, saved Bridges' life, who was almost unharmed. Also because the accident was recorded by a flight deck surveillance camera, it made headlines around the world.

Much more often, however, jets crash or people go overboard, sometimes due to strong winds. Accidents of this type happen several times a year on the carriers of the class. Aircraft crashes on the flight deck of a carrier or in the stern section due to the following fires, including fire in the hangar deck, can prove to be a threat to the entire ship. The worst accident on board a Nimitz occurred in 1981 on the type ship. An EA-6B Prowler missed the last safety rope and hit aircraft parked next to the runway. A fire broke out and around half an hour after the crash a secondary explosion occurred, presumably from AIM-7 Sparrow missiles from the parked aircraft. In addition to the three pilots, five other men from the air wing and six of the ship's crew were killed and 48 injured. One of the reasons given was drug abuse on board, whereupon the Navy issued a zero tolerance policy for drugs .

Mission profile

George Washington with an escort of cruiser, frigate, destroyer and supply ship

Aircraft carriers are the means of choice for the United States in order to be able to show military presence far away from the home continent. Thus, they are critical to safeguarding American interests abroad. Former Defense Minister William Cohen said of the aircraft carriers: “ If you don't have that forward deployed presence, you have less of a voice, less of an influence ” (German : “ If you don't have this forward presence, you have less Weight, less influence ”). With aircraft carriers, the US Navy can set up a threatening backdrop in front of every coast whose sphere of activity extends far into the target country in order to enforce the interests of the USA without having to rely on other states in the region that make their territory available for troop deployment or stopovers would have to ask. This applies all the more to the nuclear-powered Nimitz carriers, as they are less dependent on a supply of fuel and thus on naval bases. They thus serve as a modern, globally applicable counterpart to the gunboat policy of the 19th century. The threatening backdrop is all the stronger because the combat group is often better equipped than the entire navy of smaller states and the Air Wing is superior to some national air forces. In terms of maritime law, such states cannot do anything against the combat group off their coast, as they are located in international waters .

Aircraft carriers are used exclusively within a combat group called the Carrier Strike Group . In this drive as an escort a mix of two to three destroyers of the Arleigh Burke class , two Kreuzer the Ticonderoga class and two nuclear submarines and a replenishment oiler for supplying the carrier with aviation fuel and the conventionally powered caboose vessels with fuel. The escort ships secure their carrier against attacks from the air or at sea and are also able to fire cruise missiles for preparatory attacks, for example to weaken the enemy air defense before the planes rise to area bombing.

The United States gave up the concept of completely nuclear-powered combat groups early on, which consisted of two to three nuclear cruisers in addition to carriers and submarines . However, the necessary number of cruisers was not available to implement this concept, which was tried and tested in Operation Sea Orbit . Such groups would have been ideal for fast transfers, since they would have the longest stretch at full power can run, without at the destination immediately stash the need. The escorts used today have a range of less than 5000 nautical miles without refueling, which corresponds to a trip from the US east coast to the Mediterranean .

literature

• Tom Clancy : Supercarrier. The world of the American aircraft carrier (= Heyne 19 Heyne-Sachbuch 814). Heyne-Verlag, Munich 2001, ISBN 3-453-21179-0 .
• Stefan Terzibaschitsch : US Navy aircraft carrier. 3rd, expanded edition. Bernard & Graefe Verlag, Bonn 2001, ISBN 3-7637-6200-0 .
• John F. Schank: Planning and Executing the Refueling and Complex Overhaul of the USS Nimitz (CVN 68). Lessons for the Future (= MR / Rand Corporation 1632 Navy ). RAND Corporation, Santa Monica CA 2003, ISBN 0-8330-3288-7 (English)

Web links

Commons : Nimitz class  - collection of images, videos, and audio files

• Official fact file (English)
• Nimitz class on globalsecurity.org (English)
• Nimitz class on naval-technology.com (English)

Individual evidence

1. ↑ United States Navy Fact File , accessed December 9, 2017
2. ↑ Clancy 2001, p. 138
3. ^ Stefan Terzibaschitsch: Sea power USA . Bechtermünz Verlag, Augsburg 1997, ISBN 3-86047-576-2 , p. 284
4. ↑ Chris Miller, David Miller: Modern Warships. Stocker-Schmid Publishing House, Dietikon-Zurich 1990, p. 130
5. ↑ Navy CVN-21 Aircraft Carrier Program: Background and Issues for Congress des Congressional Research Service Report for Congress ( Memento from September 2, 2013 in the Internet Archive ) (English)
6. ^ Robin J. Lee: A Brief Look at Russian Aircraft Carrier Development . Archived from the original on August 6, 2007 ; accessed on March 5, 2013 . 
7. ↑ USS NIMITZ (CVN 68). In: Naval Vessel Register . June 27, 2018, accessed February 13, 2019 . 
8. ↑ USS DWIGHT D EISENHOWER (CVN 69). In: Naval Vessel Register . June 27, 2018, accessed February 13, 2019 . 
9. ↑ USS CARL VINSON (CVN 70). In: Naval Vessel Register . June 27, 2018, accessed February 13, 2019 . 
10. ↑ USS THEODORE ROOSEVELT (CVN 71). In: Naval Vessel Register . June 27, 2018, accessed February 13, 2019 . 
11. ↑ USS ABRAHAM LINCOLN (CVN 72). In: Naval Vessel Register . June 27, 2018, accessed February 13, 2019 . 
12. ↑ USS GEORGE WASHINGTON (CVN 73). In: Naval Vessel Register . June 27, 2018, accessed February 13, 2019 . 
13. ↑ USS JOHN C STENNIS (CVN 74). In: Naval Vessel Register . June 27, 2018, accessed February 13, 2019 . 
14. ↑ USS HARRY S TRUMAN (CVN 75). In: Naval Vessel Register . June 27, 2018, accessed February 13, 2019 . 
15. ↑ USS RONALD REAGAN (CVN 76). In: Naval Vessel Register . June 27, 2018, accessed February 13, 2019 . 
16. ↑ USS GEORGE HW BUSH (CVN 77). In: Naval Vessel Register . June 27, 2018, accessed February 13, 2019 . 
17. ↑ Final keel section of aircraft carrier George HW Bush (CVN-77) on navy.mil ( Memento from May 24, 2006 in the Internet Archive ) (English)
18. ↑ Construction of USS George Washington on the official website of the ship ( memento of October 13, 2014 in the Internet Archive ) (English)
19. ↑ CVN 70 Carl Vinson's Mid-Life RCOH Refueling & Maintenance (English)
20. ↑ Carl Vinson redelivered to Navy ( Memento from January 29, 2013 in the web archive archive.today ) (English)
21. ^ Refueling and Complex Overhaul (RCOH). Retrieved March 10, 2014 . 
22. ↑ US Ship Force Levels, 1886 – present. In: Naval History and Heritage Command . November 17, 2017, accessed February 13, 2019 .  The source contains an error between 1981 and 1991, since the nominal departure of a carrier in 1981 (no commissioning or decommissioning ) and 1990 ( except Coral Sea , but Abraham Lincoln was in service after September 1989) is incomprehensible. The missing units will not be added until 1991. This is also confirmed by Clancy 2001, p. 301 f.
23. ↑ Overview of all carriers of the class in the Naval Vessel Register ( Memento from January 15, 2012 in the Internet Archive ) as well as the respective subpages for the ships
24. ^ Cost-Effectiveness of Conventionally and Nuclear-Powered Carriers . (PDF; 1.9 MB) Study by the Government Accountability Office, p. 74 ff. (English)
25. ↑ Frequently Asked Questions on the official Reagan website . Archived from the original on August 14, 2010 ; accessed on March 5, 2013 . 
26. ↑ China Warns US to Keep Away From Taiwan Strait . In: New York Times , March 18, 1996 (English)
27. ↑ 2 carriers in W. Pacific ahead of Taiwan vote ( Memento from September 5, 2012 in the web archive archive.today ) In: Navy Times (English)
28. ↑ ^{a b c} Ship’s Statistics on the official Abraham Lincoln website . Archived from the original on December 7, 2010 ; accessed on March 5, 2013 . 
29. ↑ navy.mil
30. ↑ Facts and Statistics on the official website of Dwight D. Eisenhower (English)
31. ↑ Clancy 2001, p. 142
32. ↑ SPS-48 from The Warfighter's Encyclopedia of the US Navy. Archived from the original on November 5, 2004 ; accessed on March 5, 2013 . 
33. ↑ SPS-49 from The Warfighter's Encyclopedia of the US Navy. Archived from the original on November 5, 2004 ; accessed on March 5, 2013 . 
34. ↑ CVN-68 Nimitz-class Modernization . GlobalSecurity.org (English)
35. ↑ Clancy 2001, pp. 185 f
36. ↑ Man Sucked Into Jet Engine in FamousPictures Magazine (English)
37. ↑ History of Nimitz ( Memento of 14 December 2014 Internet Archive ) in the official Dictionary of American Naval Fighting Ships (English)
38. ↑ navy.mil: Why the Carriers? (English)
39. ↑ David Miller: The Naval Forces of the World . Bechtermünz Verlag, Augsburg 1998, ISBN 3-8289-5333-6 , p. 14

This article was added to the list of excellent articles on May 5, 2008 in this version .