HMS Agincourt (S125)

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HMS Ambush long.jpg
HMS Ambush (S120), another Astute-class submarine, during sea trials off the coast of Scotland
United Kingdom
NameHMS Agincourt
BuilderBAE Systems Submarine Solutions
Cost£1.640B (budget)[2]
In serviceexpected between 2024 and 2026
IdentificationPennant number: S125
StatusUnder construction[1]
General characteristics
Class and typeAstute-class fleet submarine
  • Surfaced: 7,000 to 7,400 t (6,900 to 7,300 long tons; 7,700 to 8,200 short tons)[3][4]
  • Submerged: 7,400 to 7,800 t (7,300 to 7,700 long tons; 8,200 to 8,600 short tons)[3][4]
Length97 m (318 ft 3 in)[3][4]
Beam11.3 m (37 ft 1 in)[3][4]
Draught10 m (32 ft 10 in)[3][4]
PropulsionRolls-Royce PWR 2 reactor, MTU 600 kilowatt diesel generators
Speed30 kn (56 km/h; 35 mph), submerged[3][4]
Endurance90 days[5]
Test depthOver 300 m (980 ft)
Complement98 (capacity for 109)[3]
Sensors and
processing systems

HMS Agincourt (also known as Astute Boat 7) is an Astute-class nuclear-powered fleet submarine under construction for the Royal Navy and the seventh in her class. The boat's name was confirmed in May 2018, having previously held the in-work name of Ajax.[7]

The confirmation for the seventh and final Astute-class boat was given in the Strategic Defence and Security Review 2010, although the order was not placed until 2018.[8]

On 11 December 2012 the British government announced that long-lead items had been ordered for boats 6 and 7.[9]

On 6 March 2018 the Defence Procurement minister Guto Bebb confirmed that the MoD had gained Treasury approval to sign a contract for Astute Boat 7,[10] after a leaked Navy document had suggested it might not be procured as a cost-saving measure.[11] In May 2018 it was reported that construction of Boat Seven had begun.[12] She has been projected as being ready for service between 2024 and 2026 and will be based at Faslane (HMNB Clyde).[13][14]



In October 2012 it was confirmed that Agincourt would have a PWR2 reactor like the rest of the Astute class.[15] Agincourt's nuclear reactor will not need to be refuelled during the boat's 25-year service. Since the submarine can replenish her air supply and purify water underway and while submerged, she will be able to circumnavigate the planet without resurfacing. The submarine's main limitation will be from the three months supply of food carried for the 98 officers and ratings.


Agincourt will have provision for up-to 38 weapons in six 21-inch (533 mm) torpedo tubes.[16] The submarine will be capable of using Tomahawk Block IV land-attack missiles with a range of 1,000 miles (1,600 kilometres)[17] and Spearfish heavyweight torpedoes.


  1. "£300M facilities investment will transform UK submarine building". BAE Systems, 13 March 2014. Retrieved 26 July 2016.
  2. "Ministry of Defence Major Projects Report 2015 and the Equipment Plan 2015 to 2025" (PDF). National Audit Office. 22 October 2015. p. 43.
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Bush, Steve (2014). British Warships and Auxiliaries. Maritime Books. pp. 10–11. ISBN 1904459552.
  4. 4.0 4.1 4.2 4.3 4.4 4.5 "Astute-class attack submarines". Royal Navy. Retrieved 27 July 2016.
  5. 5.0 5.1 "BAE Systems - Astute class submarines". BAE Systems. Retrieved 25 July 2016.
  6. "UK's most powerful submarine joins the Navy". Ministry of Defence. 27 August 2010. Retrieved 11 April 2011.
  7. "Royal Navy nuclear submarines to get £2.5bn boost". BBC News. 14 May 2018. Retrieved 21 June 2021.
  8. "Second Astute Class submarine officially named". UK Ministry of Defence. 22 December 2010. Retrieved 20 March 2016.
  9. "UK: BAE Systems Secures $1.92 Bln Submarine Deal". 11 December 2012. Retrieved 20 March 2016.
  10. "Contingent Liability: Written statement - HCWS516". House of Commons. 6 March 2018.
  11. Chapples, Natalie (6 March 2018). "MoD announces it will sign a contract for Astute boat seven". The Mail.
  12. Maundrill, Beth (1 May 2018). "Seventh Astute class submarine build underway". Shephard Media. Retrieved 1 May 2018.
  13. "HMS Agincourt". (in English). Retrieved 27 June 2021.
  15. "House of Commons - Written Answers Column 311W". Hansard. UK Parliament. 17 October 2012. Retrieved 20 March 2016.
  16. "Alien submarine breaks technical barriers". BBC News. 7 May 2007. Retrieved 20 March 2016.
  17. "United States Navy Fact File: Tomahawk Land Attack Missile". US Navy. Retrieved 27 July 2016.

External links