Royal Navy Astute class submarines

Astute class submarines of the Royal Navy
Chrono date: 
2010 Aug 27

The Astute-class submarines are the next-generation nuclear fleet submarines of the UK Royal Navy. The class sets a new standard for the Royal Navy in terms of weapons load, communication facilities, stealth and crew comfort. The boats are being constructed by BAE Systems Submarine Solutions at Barrow-in-Furness. Seven boats will be constructed. The first of class, Astute, was launched in 2007 and commissioned in 2010, and the second, Ambush, was launched on 6 January 2011.[2]

Class overview
Builders: BAE Systems Submarine Solutions
Operators: Royal Navy
Preceded by: Trafalgar class
In commission: 27 August 2010 —
Building: 5: Ambush, Artful, Audacious, Agamemnon, Anson
Planned: 1: Ajax
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 (56+ km/h) submerged
Range: Only limited by food and maintenance requirements.
Test depth: Over 300 m
Complement: 98 officers and men (capacity of 109)
Sensors and processing systems:
  • Thales Sonar 2076
  • Atlas DESO 25 echosounder
  • 2 x Thales CM010 optronic masts
  • Raytheon Successor IFF
Armament: 6 x 21-inch (533 mm) torpedo tubes
  • A combination of up to 38:[1]
    • Spearfish torpedoes
    • Tomahawk Block IV cruise missiles



  • 1 Background
  • 2 Design
  • 3 Construction and delays
  • 4 Submarines of the class
  • 5 General characteristics
  • 6 See also
  • 7 References
  • 8 External links


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." 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 17 March 1997, the Ministry of Defence announced that it would place a £2 billion order for three submarines and that they would be called the Astute class. On 26 March 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). 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 were entirely decommissioned by 2010, when only the first of the Astute class was coming into service. Trafalgar was decommissioned in December 2009, to be followed by Turbulent in 2011.[4] 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.[5]


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 the 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 diameter 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.[6] 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.[7] The vessel is equipped with the advanced Sonar 2076, which is an integrated passive/active search and attack sonar suite with bow, intercept, flank and towed arrays. 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 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.[8] The Astute-class submarines can be fitted with a dry deck shelter which allows special forces (e.g. SBS and SAS) soldiers to deploy whilst the submarine is submerged.[9]

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.[10] 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."[11] Other issues were the insufficient capabilities within GEC-Marconi which became evident after contract-award and poor programme management.[5][12][13] 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.[14] The MoD also signed a design and production drawing work contract through the U.S. Navy which ran from 2004 to 2007.[15] 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.[16] 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.[17] As of March 2008 the programme was 48% (or £1.2 billion) over-budget and 47 months late.[3] Further delays due to a range of technical and programme issues brought the programme to a position of 57 months late and 53% (or £1.35 billion) over-budget by November 2009, with a forecast cost of £3.9 billion for the first three Astute boats.[18]

Submarines of the class

Name Boat Pennant number Status Laid down Launched Date of commission
Astute 1 S119 On sea trials 31 January 2001 8 June 2007[19] 27 August 2010
Ambush 2 S120 Fitting out 22 October 2003 6 January 2011[2] Expected 2012
Artful 3 S121 Under construction 11 March 2005    
Audacious 4 S122 Under construction[20] 24 March 2009    
Agamemnon 5 S123 Initial build phase underway[21]      
Anson 6 S124 On order; long-lead items ordered      
Ajax 7 S125 Planned (confirmed Oct 2010)      

As of August 2006 BAE Systems was negotiating for a contract to build another four Astute-class submarines (boats 4 to 7).[22] The fourth boat was ordered on 21 May 2007, to be called Audacious, and the names of boats 5, 6, and 7 have been agreed as Agamemnon, Anson, and Ajax.[23] Upon the beginning of sea trials of 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.[24] On 25 March 2010, BAE Systems were given the go-ahead by the government to begin construction on boats 5 and 6, being given a £300 million contract for the "initial build" of boat 5 and "long lead procurement activities" for boat 6.[25] In the same week the government re-affirmed their commitment to the construction of seven Astute-class submarines. The order of 7 Astute-class boats was confirmed in the Strategic Defence and Security Review of October 2010. In December that year it was confirmed by the MoD that "early work" was under way on boats 5 and 6.[26]

General characteristics


  • Thales Underwater Systems Sonar 2076
  • Atlas Hydrographic DESO 25 depth-finding echosounder
  • Two Thales Optronics CM010 optronic masts in place of conventional periscopes.
  • Raytheon Systems Ltd Successor IFF system


  1. ^ "Astute Class Fact File". Royal Navy website.
  2. ^ ab "BAE Systems Barrow submarine Ambush’s maiden voyage". NW Evening Mail. 7 January 2011. Retrieved 26 January 2011.
  3. ^ abcd National Audit Office Ministry of Defence Major Projects Report 2008: Project Summary Sheets p.24
  4. ^ House of Commons Hansard Written Answers for 3 September 2007
  5. ^ ab "Mr Astute". Naval 31 August 2007. Retrieved 2010-11-04.
  6. ^ Astute Fascinating Facts
  7. ^ Countdown to launch of first Astute submarine at Barrow shipyard
  8. ^ BBC News Scotland, A vision of evolving technologies 30 August 2007, 13:06 GMT
  9. ^ Dr Lee Willett, The Astute-Class Submarine, Capabilities and Challenges, RUSI (2004)
  10. ^ Odell, Mark (12 December 2002). "BAE warning sends share price to 7-year low: News of 'additional issues' on two big defence contracts takes market by surprise". Financial Times.
  11. ^ House of Commons Hansard Written Answers for 9 Mar 2006
  12. ^ MPs probe £900m overspend on late submarines
  13. ^ National Audit Office Ministry of Defence Major Projects Report 2008: Project Summary Sheets "Exceptional difficulties arose with the introduction of a computer aided design system, the availability of trained staff and project management"
  14. ^ "US team to work on submarine order". (BBC News). 8 April 2003. Retrieved 3 January 2007.
  15. ^ U.S. Navy contracts. U.S. Department of Defense. September 3, 2004. Retrieved 13 February 2008
  16. ^ Boxell, James (24 November 2006). "Royal Navy's weapons projects affected by delays and cost troubles". Financial Times (The Financial Times Limited): p. 2.
  17. ^ "New UK nuclear submarine launched". BBC News. June 8, 2007. Retrieved 15 June 2007.
  18. ^ Defence Select Committee (23 February 2010). Defence Equipment 2010. House of Commons. p. Ev 97. HC 99. Retrieved 2010-03-09
  19. ^ "New UK nuclear submarine launched". BBC. 8 June 2007. Retrieved 8 June 2007.
  20. ^ Naval Ship Building Boat 4 news
  21. ^ Naval Ship Building Boat 5 news
  22. ^ "New nuclear sub is lifeline for Barrow". BBC News Online. 28 August 2006. Retrieved 9 March 2007.
  23. ^ "Royal Navy - Careers - Live Chat". Royal Navy. Retrieved 9 March 2010.
  24. ^ Independent Britain's £1.3bn new sub Astute sets sail (17 November 2009)
  25. ^ North West Evening Mail £300 million order to boost shipyard
  26. ^ MoD Second Astute Class submarine officially named

External links

  • BAE Systems Astute Microsite
  • 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
  • How to Build a Nuclear Submarine. BBC Television documentary, first broadcast 27 Jun 2010.
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