2010 - Present: Astute Class
The Royal Navy's Astute class submarine is a nuclear powered attack submarine to replace the five Swiftsure Class submarines launched between 1973 and 1977. The Astute ships are to be named Astute, Ambush, Artful, Audacious, Agamemnon, Anson & Achilles. Astute began construction in 2000. The first of class was rolled out on July 8th, 2007 and completed in 2009.
Astute is designed to fulfil a range of key strategic and tactical roles including anti-ship and anti-submarine operations, surveillance and intelligence gathering and support for land forces. Displacing 7,400 tonnes and measuring 97 metres from bow to propulsor, Astute is significantly larger than the Swiftsure Class and Trafalgar Class submarines that she will replace but requires fewer crew to operate her due to the advanced technology and automated systems on board.

HMS Astute coming into Gibraltar with a dry deck shelter attached. The DDS is used to house and launch a SEAL Delivery Vehicle operated by the Special Boat Service for their insertion and extraction.
That technology encompasses many innovations designed to improve operational effectiveness while also reducing costs to help achieve the affordability challenges facing the Ministry of Defence.
The 2076 Sonar system is the most effective in the world, giving Astute a key tactical advantage in locating and identifying other vessels, while the stealth characteristics of the submarine design make it the quietest the Navy has ever operated, enabling it to avoid detection and fulfil its role within the "Silent Service".
Unlimited power is provided by the pressurised water nuclear reactor that is capable of powering a city the size of Southampton. It is expected that the reactor cores will last the full 25-30 years of the Astute boats' life. In 1997 it was said that the new cores would allow the reactors to achieve a 10 per cent reduction in running costs compared to previous British SSNs.
A guide to the Royal Navy's Astute class nuclear-powered attack submarines.
The Astute is capable of remaining submerged and circumnavigating the globe during a 90-day patrol, creating her own air and fresh water from the ocean. Astute is equipped with a digital optical mast system to replace the traditional periscope and this offers low light and infra-red capabilities to enable her to rapidly capture and analyse visual data, and share it with the rest of the fleet.
Luxury is not a word that appears in the submarine vocabulary, Astute is all about operational capability, but her crew will be the first to each have their own bunk, removing the need for "hot bunking" when during shifts one crewman would occupy a bunk vacated by another. Astute also has a comparatively large and extremely well-equipped galley to ensure the meals that punctuate the round the clock watch system are of the highest standard.
COMBAT SYSTEM
The combat data system is the SMCS tactical data handling system from BAeSEMA. Strachan and Henshaw which provide the weapon handling and launch system (WHLS).

The submarine launched Harpoon UGM-84 is a sea-skimming anti-ship missile with maximum velocity in excess of 0.8 Mach and range in excess of 70 miles.
MISSILES
The Astute is equipped with the Tomahawk Block III cruise missile from Raytheon and Submarine Harpoon produced by Boeing, both fired from the 533 mm torpedo tubes. Tomahawk is equipped with the TERCOM Terrain Contour Mapping Assisted Inertial Navigation System. The Terrain Contour Mapping for use over land combines onboard radar altimeter measurements with terrain mapping data installed in the missile. The Block III improvement package provided an improved propulsion system and terminal guidance and also covered the installation of the Navstar Global Positioning System receiver in the missile. The GPS provides location and velocity data of the missile.
TORPEDOES
Astute has six 533 mm torpedo tubes, and is equipped with Spearfish torpedoes and mines. There is capacity for a total of 36 torpedoes and missiles. The Spearfish torpedo from BAE Systems is wire-guided with an active/passive homing head. The range is 65km at 60 knots. Spearfish is fitted with a directed energy warhead.
COUNTERMEASURES
The countermeasures suite includes decoys and Electronic Support Measures (ESM). The UK Royal Navy issued a requirement for a new communications band electronic support measures (CESM) to be fitted to the Astute Class (and also the Trafalgar and Swiftsure Class submarines). The system provides advanced communications, signal intercept, recognition, direction finding and monitoring capability. The submarines are fitted with non-hull penetrating ESM masts.
SENSORS
Astute is fitted with I-band navigation radars. The sonar is the Thomson Marconi Sonar 2076 integrated suite with bow, intercept, flank and towed arrays. Astute -class submarines dispense with conventional periscopes in favour of two non-hull penetrating CM010 optronic masts developed by Pilkington Optronics. McTaggart Scott supply the masts. The CM010 mast includes thermal imaging, low light TV and colour CCD TV sensors.
PROPULSION
The nuclear power is provided by the Rolls-Royce PWR 2. The other main items of machinery are two GEC turbines, and a single shaft with a pump jet propulsor. There are two diesel alternators, one emergency drive motor and one auxiliary retractable propeller. CAE Electronics provide the digital, integrated controls and instrumentation system for steering, diving, depth control and platform management.
The PWR 2 second-generation nuclear reactor was developed for the Vanguard Class Trident submarines. Current generations of PWR would allow submarines to circumnavigate the world about 20 times, whereas the latest development of PWR allow circumnavigation 40 times without refuelling. The major equipment components in the development of PWR 2 are the reactor pressure vessels from Babcock Energy, main coolant pumps from GEC and from Weir, and protection and control instrumentation from Siemens Plessey and Thorn Automation.
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