Nimitz Class Nuclear Powered Aircraft Carriers, USA
The Nimitz Class aircraft carriers are the largest warships ever built. With over 6,000 personnel (crew and aircrew), the carrier has a displacement of 102,000t, and a flight deck length of 332.9m. All nine nuclear-powered Nimitz class carriers have been built by Newport News Shipbuilding (now Northrop Grumman Ship Systems), based in Virginia.
Tasked with a multi-mission attack/ASW role, the first of class, USS Nimitz, was commissioned in 1975. The latest, USS Ronald Reagan (CVN 76), was commissioned in July 2003. Other hulls are: USS Dwight D Eisenhower (CVN 69), Oct 1977; USS Carl Vinson (CVN 70), Mar 1982; USS Theodore Roosevelt (CVN 71), Oct 1986; USS Abraham Lincoln (CVN 72), Nov 1989; USS George Washington (CVN 73), Jul 1992; USS John C Stennis (CVN 74), Dec 1995; USS Harry S. Truman (CVN 75) July 1998.
The keel for the tenth and last Nimitz Class, USS George H.W. Bush (CVN 77), was laid in September 2003 and the carrier will enter service in 2009. The vessel will have a modernised island house with new radar tower and transparent armour windows as well as upgraded navigation and communications systems. It will also have a new aircraft launch and recovery system and JP-5 fuel system for improved storage and handling of aircraft fuel. This will be the first transition ship to a new class of carriers, CVN 78 (formerly known as CVN 21 and CVNX), planned for construction start in 2007 and delivery in 2014. Northrop Grumman Newport News will be the prime contractor for the program and Raytheon will be responsible for weapons system integration. CVN 78 will incorporate new technologies including a new multi-function radar system, volume search radar and open architecture information network, providing a significantly reduced crew requirement, and a new nuclear power plant.
DESIGN
The more recent Nimitz Class carriers (CVN72-CVN76) have a displacement of 102,000t fully loaded. They have a length of 317m and beam of 40.8m. The carrier reaches a maximum speed of over 30 knots, and accommodates a complement of 3,184 personnel (with 203 officers); 2,800 aircrew (with 366 officers); and 70 flag (with 25 officers).
AIRCRAFT
The 50 TACAIR air wing includes up to 82 aircraft. Typically this would be: 12 F/A-18E/F Hornets, 36 F/A-18 Hornets, 4 E-2C Hawkeyes, and 4 EA-6B Prowlers fixed-wing; and the following helicopters: 4 SH-60F and 2 HH-60H Seahawks. The carrier can also deploy S-3B Viking aircraft, but these are being phased out and replaced with the F/A-18E/F Super Hornet. The S-3B Viking is to be finally decommissioned in 2009. The last operational deployment of the F-14, deployed on US carriers since 1972, was in March 2006 and the final aircraft is scheduled to decommission in September 2006.
Air wings can be varied according to the nature of the operation: for example, in 1994, 50 army helicopters replaced the usual air wing on the USS Dwight D Eisenhower during operations off Haiti.
The flight deck measures 333 x 77m and is equipped with four lifts, four steam-driven catapults and four arrester wires. The carrier is capable of launching one aircraft every 20 seconds.
In April 2005, the US Naval Air Systems Command (NAVAIR) selected General Atomics Electromagnetic Systems for the System Development and Demonstration (SDD) phase of the Advanced Arresting Gear (AAG) program, to provide a new arrestor system for USN carriers.
MISSILES
The more recently built carriers are armed with three Raytheon GMLS Mk 29 eight-cell launchers for Nato Seasparrow surface-to-air missiles. Seasparrow has a range of 14.5km and semi-active radar terminal guidance. The carriers are also being fitted with the Raytheon RAM (Rolling Airframe) missile system, which provides short-range defence against incoming anti-ship missiles, including sea-skimming missiles.
GUNS
There are four Raytheon/General Dynamics 20mm Phalanx 6-barrelled Mk 15 close-in weapon systems which have a firing rate of 3,000 rounds/min and a range of 1.5km.
COUNTERMEASURES
Decoys include four Sippican SRBOC (Super Rapid Bloom Off-Board Chaff) 6-barrelled Mk 36 decoy launchers, which deploy infrared flares and chaff, SSTDS torpedo defence system and AN/SLQ-25 Nixie torpedo countermeasures system, from Sensytech Inc of Newington, Virginia.
The Raytheon AN/SLQ-32(V) electronic warfare system detects hostile radar emissions by two sets of antennae and the system analyses the pulse repetition rate, the scan mode, the scan period, and the frequency. The system identifies the threat and direction, provides a warning signal and interfaces to the ship's countermeasures systems.
COMBAT SYSTEMS
The carriers’ combat data systems are based around the Block 0 or 1 naval tactical and advanced combat direction system (ACDS) with communications Links 4A, 11, 14, and 16. Weapons control is managed by three Mk 91 Mod 1 MFCS directors for the Seasparrow missile. USS Nimitz and USS Ronald Reagan have been fitted with the SSDS Mk2 Mod 0 ship self defense system, developed by Raytheon. The SSDS will provide automated self-defence against anti-ship cruise missiles (ASCMs) by integrating and co-ordinating the ship’s weapon and electronic warfare systems.
USS Nimitz has also been fitted with the Lockheed Martin TIS (Tactical Input Segment) digital reconnaissance processing system, which can receive real-time imagery from airborne sensors.
SENSORS
Air search radars include the ITT SPS-48E 3-D, operating at E/F-band; Raytheon SPS49(V)5, C/D-band; and Raytheon Mk 23 TAS, D-band. Surface search radar is the Northrop Grumman Norden Systems SPS-67V, operating at G-band.
PROPULSION
The nuclear-powered carrier has two General Electric pressurised water reactors driving four turbines of 260,000hp (194MW) and four shafts. There are four emergency diesels of 10,720hp (8MW).
Falta el Enterprise, pero no pertenece a la clase Nimitz
