Astute class submarine

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HMS Astute on the shiplift after rollout
Class overview
Builders:	BAE Systems Submarine Solutions
Operators:	Royal Navy
Preceded by:	Trafalgar class
Building:	3: Ambush, Artful, Audacious
Planned:	7 (in total)
Completed:	1: Astute
General characteristics
Displacement:	7,400 tonnes submerged
Length:	97 m (323 ft)
Beam:	11.3 m (37 ft)
Draught:	10 m (33 ft)
Propulsion:	Rolls-Royce PWR 2 reactor, MTU 600 kilowatt diesel generators
Speed:	29 knots (54 km/h) submerged
Range:	Only limited by food and maintenance requirements.
Test depth:	300 m
Complement:	98 officers and men(capacity of 109)
Sensors and processing systems:	Thales Underwater Systems Sonar 2076, Atlas Hydrographic DESO 25 depth-finding echosounder, 2 x Thales Optronics CM010 periscopes, Raytheon Systems Ltd Successor IFF system
Armament:	6 × 21 inch (533 mm) torpedo tubes, 38 Tomahawk Block III cruise missiles, Non-Disclosed number of Spearfish torpedoes, UGM-84 Harpoon and naval mines

The Astute-class submarines are the next-generation nuclear fleet submarines of the Royal Navy. When completed, the boats will set a new standard for the Royal Navy in terms of weapons load, improved communications facilities, stealth and comfort for the crew. The boats are being constructed by BAE Systems Submarine Solutions at Barrow-in-Furness.

Contents 1 Background 2 Design 3 Construction and delays 4 Boats 5 General characteristics 6 References 7 External links

[edit] Background

The Royal Navy has changed its submarine-employment strategy from the Cold War emphasis on anti-submarine warfare to the concept of "Maritime Contributions to Joint Operations."

Original plans were for seven boats of the Astute class to replace five Swiftsure-class submarines (Sovereign, Superb, Sceptre, Spartan, and Splendid) and the two oldest Trafalgar-class boats (Trafalgar and Turbulent). The Swiftsure class entered service between 1973 and 1977 and will be entirely decommissioned by 2010, when only the first of the Astute class will be coming into service. HMS Trafalgar was decommissioned in December 2009, to be followed by HMS Turbulent in 2011.^[1]

An estimated 5,900 people are employed directly as a result of the project; 3,500 BAE Systems staff at Barrow and 2,400 other people around the UK.^[2]

Approval for studies to define the "Batch 2 Trafalgar Class" (what would become the Astute class) was given in June 1991. In July 1994 risk reduction studies were authorised in parallel with the formal bid phase of the project.^[3]

On March 17, 1997, The Ministry of Defence announced that it would place a £2 billion order for three submarines and further that they would be called the Astute class. On March 26, 1997, the contract was signed with GEC-Marconi Limited for the first three boats: Astute, Ambush and Artful. These names were last given to Amphion-class submarines that entered service towards the end of World War II. GEC would build the submarines at its VSEL subsidiary (now BAE Systems Submarine Solutions).

[edit] Design

Astute-class boats are powered by a Rolls-Royce PWR2 (Core H) reactor and fitted with a pump-jet propulsor. The PWR2 reactor was developed for Vanguard-class ballistic missile submarines. As a result Astute-class boats are about 30 per cent larger than previous British attack submarines, which were powered by smaller reactors. It is the first Royal Navy submarine class to have a bunk for each member of the ship's company, ending the practice of 'hot bunking', whereby two sailors on opposite watches shared the same bunk.^[4]

Like all Royal Navy submarines, the bridge fin of the Astute-class boats is specially reinforced to allow surfacing through ice caps. They can fire Tomahawk cruise missiles from their launch tubes, including the new "tactical Tomahawk" currently under development. More than 39,000 acoustic tiles mask the vessel's sonar signature, giving the Astute class a better stealth quality than any other submarine previously operated by the Royal Navy.^[5] The vessel is equipped with the advanced 2076 Sonar System, which is capable of identifying and tracking vessels across thousands of square miles of ocean.

The Astute Combat Management System is an evolved version of the Submarine Command System used on other classes of submarine. The system receives data from the boat's sensors and displays real time imagery on all command consoles. The Type 2076 sonar is an integrated passive/active search and attack sonar suite with bow, intercept, flank and towed arrays. The submarines also have DESO 25 high-precision echosounders, two CM010 non-hull-penetrating optronic masts which carry thermal imaging and low light TV and colour CCD TV sensors.^{[citation needed]}

[edit] Construction and delays

BAE Systems issued a profit warning on 11 December 2002 as a result of the cost overruns and delays it was experiencing with the Astute class and also the Nimrod MRA4 maritime reconnaissance/attack aircraft.^[6] The delay was caused primarily by the problems of using 3D CAD; Armed Forces Minister Adam Ingram said in 2006 that "Due to the complexity of the programme, the benefits that CAD was envisaged to provide were more difficult to realise than either MOD or the contractor had assumed."^[7] Other issues were the insufficient capabilities within GEC-Marconi which became evident after contract-award and poor programme management.^[2][8][9] BAE and the Ministry of Defence reached an agreement in February 2003 whereby they would invest £250 million and £430 million respectively to address the programme's difficulties.^[3]

A major element of this was the enlisting of advice and expertise from General Dynamics Electric Boat.^[10] The MOD also signed a design and production drawing work contract through the U.S. Navy which ran from 2004 to 2007.^[11]

Work on the second and third submarines, Ambush and Artful, proceeded well with major milestones such as the closure of Ambush's reactor compartment, demonstrating significant schedule advance compared with Astute. BAE Systems and the MoD have made efforts to reduce costs and achieved significant cost-cutting and productivity gains.^[12] A £580 million cost increase was agreed in 2007 due to maturing of the design requiring more materials, inflationary costs, and "some programme throughput assumptions at the Barrow site not being borne out."^[3]

First-of-class HMS Astute was launched by Camilla, Duchess of Cornwall on 8 June 2007.^[13]

As of December 2008 the programme was 48% (or £1.2 billion) over-budget and 47 months late.^[3]

[edit] Boats

Name	Pennant number	Status	Laid down	Launched	Expected date of commission
Astute	S119	On sea trials	31 January 2001	8 June 2007[14]	2010
Ambush	S120	Under construction	22 October 2003		2011
Artful	S121	Under construction	11 March 2005		2012
Audacious	S122	Under construction	24 March 2009		2013
[A-05]	S123	Planned; long-lead items ordered
[A-06]	S124	Planned; long-lead items ordered
[A-07]	S125	Planned

As of August 2006 BAE Systems was negotiating for a contract to build another four Astute-class submarines (boats 4 to 7).^[15] The fourth boat was ordered on 21 May 2007, to be called Audacious.

The Guardian reported in January 2008 that proposals for budget cuts to the UK armed forces could restrict the Astute class to just the first four boats, with all further orders being cancelled,^[16] though long-lead items have been purchased for further boats. In January 2009, Secretary of State for Defence John Hutton stated in an interview that the government was "absolutely committed to building seven Astute submarines".^[17]

Upon the beginning of sea trials of HMS Astute in November 2009, it was reported that long-lead items for boats 5 and 6 have been ordered, including their nuclear reactor cores, and that the stated intention of the MoD was for a total of seven Astute-class submarines.^[18]

[edit] General characteristics

• Sensors:
  • Thales Underwater Systems Sonar 2076
  • Atlas Hydrographic DESO 25 depth-finding echosounder
  • Two Thales Optronics CM010 periscopes
  • Raytheon Systems Ltd Successor IFF system

[edit] References

[edit] External links

• Royal Navy official site
• Cutaway Diagram(pdf)
• Photos from the roll out / launch (BBC)
• ThisIsLondon article "Britain launches massive submarine that can hear a ship from across the Atlantic" (June 8, 2007)
• Navy Matters - Astute Class
• BAE Systems: Murray Easton Interview

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