Astute Buy? Britain Spends Big on its Next Fast Submarines


Building the SSNs
click for video

May 15/18: UK orders more Subs The British government is awarding a contract to BAE Systems in relation to two submarine programs. The company will receive $3.26 billion to continue to the next phase of the Dreadnought program and will deliver the seventh Astute class submarine to the Royal Navy. The SSN Astute Class submarines are the successors to the Navy’s Swiftsure and Trafalger Class submarines. The Astute Class is the only platform used to launch long-range UGM-109 Tomahawk cruise missiles, in order to deliver conventional strikes against land targets. The Dreadnought program comes with a price tag of $41 billion. It is the British replacement project to its fleet of Vanguard class submarines. They will provide the UK’s ‘Continuous at sea deterrence’ capability by carrying the existing Trident missiles, which will not be replaced until the 2040s.


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Astute, pre-launch (click to view full) Britain retired its nuclear-powered 4,900t SSN Swiftsure Class fast attack boats in 2010, and has begun phasing out its follow-on 5,300t SSN Trafalgar Class, before the effects of the ocean’s constant squeezing and release start making them dangerous to use. The last Trafalgar Class boat is expected to retire […]

Astute Pre-Launch

Astute, pre-launch
(click to view full)

Britain retired its nuclear-powered 4,900t SSN Swiftsure Class fast attack boats in 2010, and has begun phasing out its follow-on 5,300t SSN Trafalgar Class, before the effects of the ocean’s constant squeezing and release start making them dangerous to use. The last Trafalgar Class boat is expected to retire by 2022, and replacements were required. Submarines are considered to be a strategic industry in Britain, which remains committed to nuclear-powered submarines for their entire fleet. As such, there was never any question of whether they’d design their own. The new SSN Astute Class were designed to be stealthier than the Trafalgars, despite having 39% more displacement at 7,400t submerged.

Britain’s 6 Swiftsure and 7 Trafalgar Class boats will eventually find themselves replaced by 7 of the new Astute Class. The new submarine class has had its share of delays and difficulties, but the program continues to move forward with GBP 2.75 billion in contracts over the past week.

The New Astute Class SSNs

Astute Class concept

Astute Class concept
(click to view full)

Nuclear weapons are reserved for Britain’s 4 SSBN Vanguard Class boats, but the Royal Navy’s SSNs have a unique role of their own in their fleet. They’re the only platforms used to launch long-range UGM-109 Tomahawk cruise missiles, in order to deliver conventional strikes against land targets. Other navies also use surface ships for this role, but Britain chose not to.

The Astute Class will offer the novel feature of a bunk for each submariner, at the cost of more cramped layouts, and is the 1st British submarine to use an optronic day/night periscope that doesn’t pierce the hull. That periscope may allow the British to move the attack center control room in later boats of class from the top level Deck 1, to a roomier section in Deck 2 and a bit aft. In either case, they’ll be using a common base computing environment for critical systems. The attack center will have more to control, too. Torpedo tubes go from 5 to 6, and a larger weapons room roughly doubles capacity to 36-38 UGM-109 Tomahawk Block IV cruise missiles and Spearfish heavyweight torpedoes. Another weapon will be launched from the large lockout chamber aft of the fin, which allows SBS commandos to exit the sub underwater into a dry deck shelter. A mini-submarine can be mated to the DDS for added mobility.

Astute Class boats have worked to add stealth enhancements via rafted sections throughout, plus new coatings, exterior tiles, and paints. On the listening end, a new 2076 Stage 5 sonar system combines arrays all over the submarine, and it reportedly surprised the US Navy during qualification exercises against a Viginia Class boat. As usual for modern submarines, the Astute Class will also carry advanced electronic eavesdropping gear for quiet above-water snooping. High-bandwidth communications round out key electronics improvements, and allow fast transmission of intercepted signals to Royal Navy vessels or agencies like GCHQ.

A new reactor design won’t require refueling during the submarine’s operating life, which saves hundreds of millions of pounds. It’s mated to a new control system that includes independent diving plane controls handled by a new, complex autopilot system. The control system has been praised by its commanders, but the submarine won’t be able to reach its advertised top speed.


Building the SSNs
click for video

The first 3 Astute Class boats cost about GBP 1.22 billion each (about $2.4 billion in 2008), a price tag that’s very similar to the USA’s new 7,300t Virginia Class.

After HMS Astute has come S120 Ambush, with S121 Artful, S122 Audacious, S123 Anson, S124 Agamemnon, and S125 Ajax in various stages of planning, construction, and testing. All Astute Class submarines will be based at HM Naval Base Clyde, where a GBP 150 million state-of-the-art jetty was built for them.

Contracts & Key Events, 2007 – Present


May 15/18: UK orders more Subs The British government is awarding a contract to BAE Systems in relation to two submarine programs. The company will receive $3.26 billion to continue to the next phase of the Dreadnought program and will deliver the seventh Astute class submarine to the Royal Navy. The SSN Astute Class submarines are the successors to the Navy’s Swiftsure and Trafalger Class submarines. The Astute Class is the only platform used to launch long-range UGM-109 Tomahawk cruise missiles, in order to deliver conventional strikes against land targets. The Dreadnought program comes with a price tag of $41 billion. It is the British replacement project to its fleet of Vanguard class submarines. They will provide the UK’s ‘Continuous at sea deterrence’ capability by carrying the existing Trident missiles, which will not be replaced until the 2040s.

January 19/18: Milestone—4th Sub’s 1st Dunk BAE Systems announced Monday, that the British Royal Navy’s latest nuclear-powered submarine, HMS Audacious, has completed its first dive. Fourth in the Navy’s line of Astute-class attack submarines, the vessel was submerged at BAE’s Barrow, England, facility, and many of the 318-feet long sub’s onboard systems were successfully tested during the submersion. Sea trials will commence later this year before joining the HMS Astute, HMS Artful and HMS Ambush, which are already in service. BAE have three more subs in the Astute-class—Anson, Agamemnon, and a yet-to-be-named seventh vessel—at various stages of construction at the Barrow site.

August 2/17: HMS Astute, a British Royal Navy hunter-killer submarine, has returned to active service after a period receiving a capability upgrade and sea training. Commissioned in 2010, HMS Astute is the first of seven new Astute class hunter-killer submarines being constructed for the Royal Navy. The training period included fire-fighting and damage control exercises and completion of weapon certification of its anti-surface and anti-submarine weapon system. The training also included a simulated war environment and training alongside Canadian Maritime Patrol Aircraft.

April 20/17: BAE Systems will build a sixth Astute-class nuclear-powered submarine for the British Royal Navy following the award of a $1.77 billion MoD contract. Dubbed the Agamemnon, the sub will be about 318 feet long, have a submerged speed of 30 knots and an endurance of 90 days. It can carry Tomahawk missiles as well as torpedoes. The first three Astute class submarines HMS Astute, HMS Ambush and HMS Artful are currently in service with the Royal Navy with a further four in various stages of construction at the company’s site in Barrow, Cumbria.



August 14/15: The Royal Navy’s third Astute-class submarine has begun sea trials. HMS Artful is the third of seven Astute-class boats, with HMS Astute and HMS Ambush, the first two subs in class already in service with the Royal Navy. Artful is slated to join the fleet toward the end of this year.



Astute control room

Control room
(click to view full)

Nov 24/14: Basing. Britain moves a step closer to making HMNB Clyde home to all of its submarines. The Trafalgar Class fast attack boats HMS Torbay and HMS Trenchant will be decommissioned at their current base in Devonport in 2017 and 2019, respectively, since it makes no financial sense to move them now. By 2020, HMS Talent and HMS Triumph will have moved from HMNB Devonport to Scotland, and that will be the end of HMNB Devonport as a submarine base.

This single-base approach offers financial efficiencies, but there’s a real price in terms of strategic vulnerability. Sources: UK MoD, “Ministry of Defence confirms future submarine basing plan”.

Nov 18/14: Sub-contractors. Cohort plc subsidiary SEA Communications receives a GBP 23 million (about $37.5 million) contract from BAE Systems to deliver their “Project Aurora” external communications systems (ECS) for integration into the UK Royal Navy’s submarine fleet, including the Astute Class. It builds on their Coherency for Submarines (CCSM) system, which already serves on upgraded Trafalgar Class SSNs.

ECS’ biggest selling feature is that it works to make the hardware an independent consideration, allowing a simpler and cheaper approach to upgrades. This is Phase 1 of a 2-phase program, and SEA expects another significant order in 2015. Sources: SEA, “Case Study: Submarine External Communication System (ECS) ‘Project Aurora'” [PDF] | SEA, “SEA secures £23m deal to enhance submarine communications”.

Oct 10/14: #2. HMS Ambush returns to HMNB Clyde after a successful maiden mission that lasted about 4 months. The boat left Falsane on July 4/14 to visit Rio de Janeiro in Brazil, before heading for the North Atlantic and the United States. Sources: Royal Navy, “HMS Ambush returns to Clyde after international deployment”.

Oct 7/14: #1: HMS Astute returns to HMNB Clyde after an 8-month deployment. The submarine’s Lady Sponsor, Her Royal Highness The Duchess of Rothesay (The Duchess of Cornwall), joins senior naval officers and over 150 friends and family to welcome her return at a special ceremony at Faslane.

That’s the kind of sponsor you want for your vessel! Sources: Royal Navy, “Happy Homecoming for HMS Astute”.

May 19/14: #3. The 97m long Artful is launched into the water at Barrow-in-Furness. She is scheduled to begin sea trials in 2015. Sources: Royal Navy, “Artful enters the water as latest hunter killer submarine is launched”.

March 26/14: Recognition. Northrop Grumman announces that they’ve received the Customer Focus Award from BAE Systems Maritime-Submarines, in recognition of the role Sperry Marine has played in supplying the Astute Class platform management system (PMS) for the U.K. Ministry of Defence’s (MOD) Astute nuclear-powered submarine program. Sources: NGC, “Northrop Grumman Wins Supplier Award for Role in Royal Navy’s Astute Submarine Programme”.

March 23/14: Mini-sub. British media spot HMS Astute moored off of Gibraltar with a new mini-sub attached to the dry-deck shelter (q.v. Dec 3/12). The mini-sub can reportedly carry 8 Special Boat Service Commandos in full assault gear:

“Before it was mounted to the top of the HMS Astute, the miniature submarine had to be airlifted by helicopter to seas near its destination…. The miniature submarine, codenamed ‘Project Chalfont’, has been tested since it was installed in 2012, but this is the first time it will reach active service…. The miniature submarine’s main duties are for counter intelligence, as it allows for incredibly covert ops from discreet locations, and will now be able to deploy while hidden underwater, rather than having to travel by helicopter, which runs the risk of revealing its position.”

The dry-deck shelter can also be used in simple swim-out mode, without a mini-submarine. Sources: Daily Mail, “Britain’s super-sub: Navy unveils James Bond-style mini submarine carried on board HMS Astute which can launch from under water”.


NAO Report; Failure at Devonport dockyard raises concern over nuclear responsibility; Radiation leak highlights aging submarines issue; Sub-contracts for boats #6-7.

HMS Astute & Type 45

HMS Astute &
HMS Dauntless
(click to view full)

Oct 6/13: Not good. The Independent newspaper reports that a 90-minute breakdown of all reactor coolant supply at Devonport dockyard’s Tidal X-Berths in Plymouth, UK nearly led to a major nuclear incident. Based on a heavily redacted report from the Ministry of Defence’s Site Event Report Committee (SERC), both the electrical power for coolant supply to docked nuclear submarines, and the diesel back-up generators, failed at the dockyard on July 29/12. That failure followed a similar failure involving HMS Talent in 2009, and a partial failure involving HMS Trafalgar in 2011.

The newspaper adds that an internal Babcock investigation blamed the incident on the central nuclear switchboard, but added a note of concern about “inability to learn from previous incidents and to implement the recommendations from previous event reports.” This will not help existing uneasiness over the next generation of nuclear submarines, and “Nuclear scare at Navy submarine base after ‘unbelievable’ failures” adds that:

“Its own “stress test” on Devonport safety, launched after the Fukushima disaster, said that in the event of the failure of both power supplies, heat levels in reactors could be controlled by emergency portable water pumps, and added that such a failure had occurred a “number of times” previously.”

Dockyard failure

Sept 20/13: #3 named. The 3rd Astute Class submarine is formally named “Artful” in a ceremony. The ship’s crew also picks a mascot, in keeping with the ship crest chosen in 1945 by the Admiralty Advisor on Heraldry. “Artful” is a ten-month-old baby ring-tailed lemur at South Lakes Wild Animal Park. While it isn’t a monkey, it is a prosimian primate, and lemurs are generally threatened or endangered throughout their homes in Madagascar. No word on whether the ship’s motto will change to the Latin translation of “We like to move it!” Sources: UK MoD release, Sept 20/13 | Royal Navy release, Sept 20/13.

Sept 10/13: Sub-contractors. DCNS signs their latest contract with BAE Systems for high-efficiency heat exchangers. This one covers 4 sets, for Astute Class boats 6 and 7. The last one will be delivered in mid-2016. Sources: DCNS, Sept 10/13 release.

Sept 10/13: Sub-contractors. Northrop Grumman’s Sperry subsidiary has supplied the final batch of Platform Management System hardware for the S123 Anson (#5), and remains under contract for submarines 4, 6, and 7. The systems do pretty much what you’d expect: control and monitor most of the submarine’s machinery and onboard systems. Sources: NGC, Sept 10/13 release.

July 18/13: #6. Keel laid for Agamemnon at BAE’s Barrow-in-Furness facility. Sources: Royal Navy, July 18/13 release.

May 28/13: SSOP. Thales UK signs a 10-year, GBP 600 million Sensor Support Optimisation Project (SSOP) with the Ministry of Defence. It extends the 2003 Contractor Logistics Support deal that covered electronic warfare/ ESM and sonar system support on an array of submarines and surface ships. Coverage on the Astute Class includes all electronic warfare and ESM sensors, the sonar, and the optronic mast. Read “SSOP: Britain Extends Contracting Innovations into Naval Sensors” for full coverage.

May 25/13: Sub-contractors. Applied Integration in Stokesley, North Yorkshire wins a “multi-million pound” deal to design “visual mechanisms allowing Royal Navy operators and sailors to manage conditions” on S124 Agamemnon and S125 Ajax. Sounds like they’re building touch displays that integrate with platform management and other systems.

This is the firm’s 3rd nuclear submarine contract, and the small firm has consistently delivered beyond its contracts while winning business against larger firms. Co-founder Lee Raywood says something we don’t see often enough in releases and reports: “Our senior engineers are truly exceptional and our staff deserve great credit for our success.” That attitude might have something to do with the fact that their teams win. Sources: The Northern Echo, “Applied Integration, in Stokesley, North Yorkshire, wins contract to supply control systems for HMS Agamemnon and HMS Ajax”.

May 20/13: Bernard Gray, the UK MoD’s Chief of Defence Materiel, talks about the Astute program experience during a Public Accounts Committee hearing concerning carrier strike. Excerpts:

“While I appreciate that the defence industry will quite often say that it wishes to be left alone, thank you very much, my experience is that that is not on the whole a good idea. It is fair to say that on most occasions when I have pushed on specific issues, they are not as well covered off as they should be. If I just let a contract and walked away and invited defence contractor A to get on with it and “Do just please drop by and deliver the equipment at the end of it and I’ll write you a cheque”, I am unlikely to get that equipment.

….If I can take you back to the most salient example of this, in the Astute programme we did what you suggested. It was a disaster. From 1996 to 2003 we let them get on with it. We had a contract and that is what we cared about. In 2003, it almost broke BAE Systems. It cost them hundreds of millions of pounds. We then had to step back in, reformulate the programme and effectively recuperate the whole of our submarine-building activity, which is something that is only beginning to come right some 10 years after that disaster…. My point is that the happy-go-lucky world of us writing out a contract and then allowing industry to get on with it is not one that I live in.”

Sources: HC 113 Public Accounts Committee Session 2013-14, “Public Accounts Committee – Minutes of Evidence.”

May 8/13: HMS Ambush. Without mentioning its April breakdown, the Royal Navy describes its “raft up” exercise to moor alongside RFA Diligence at sea, “assisted by a cluster of tugs”. RFA Diligence is the Royal Navy’s sole vessel for submarine support. They’re still talking about “early 2014” as the submarine’s operational date. Sources: Royal Navy, May 8/13 release.


HMS Ambush sea trials

April 11/13: Schedule. Without ever mentioning HMS Ambush’s breakdown the previous day, the Royal Navy puts out a press release that says HMS Astute will be operational in 2013, after hot weather trials and operational sea training. S119 Astute was commissioned on Aug 27/10.

HMS Ambush [S120] will go through the same trials and training and “be ready to deploy in early 2014.” It remains to be seen what effect yesterday’s breakdown will have on that schedule. Royal Navy.

April 10/13: HMS Ambush. HMS Ambush is towed back to the Faslane naval base after coming to an unexpected halt in the middle of Gare Loch. Crew members are seen by local anti-nuclear protesters standing on top of the vessel, which was venting steam and surrounded by 3 tugs. The exact problem still isn’t clear, as the MoD would say only that:

“Following HMS Ambush’s maintenance period, undertaken at HM’s Naval Base Clyde, an issue with a non-nuclear system was identified. A decision was taken to return it to the base to allow remedial action to take place.”

See: Herald Scotland | The Scotsman.

HMS Ambush breaks down

March 10/13: Aging fleet. Britain’s Daily Express says that Britain’s submarine fleet is now finding it difficult to maintain patrols around the Falkland Islands, even as Argentina becomes more aggressive:

“THE Navy is finding it “increasingly difficult” to deploy a nuclear hunter-killer submarine to patrol British waters around the Falkland Islands. Senior sources made the warning last night, three weeks after the Sunday Express reported exclusively that the forced return of HMS Tireless [due to a reactor leak] means that just one of Britain’s five Trafalgar-class submarines is fully operational and even that is about to undergo a brief period of maintenance after duties in the Middle East…. HMS Torbay is undergoing maintenance, HMS Trenchant will need servicing after its deployment in the Middle East, HMS Talent is awaiting decommissioning and HMS Triumph, which should have been decommissioned last year, is being used for training.

HMS Astute, the first of our new £1.2billion Astute class submarines, is still not fully operational.”

Aging fleet

March 1/13: S120. A formal commissioning ceremony takes place at Naval Base Clyde for the 2nd boat in the class, though its sea trials aren’t finished yet. There ceremony comes fully 2 1/2 years after the commissioning of HMS Astute.

In January 2013, BAE Systems was granted a Certificate of Acceptance for Ambush, formalizing the transfer from the builder to the Ministry. UK MoD

HMS Ambush commissioned

Feb 25/13: Sub-contractors. Thales announces a contract from BAE for the last 2 Sonar 2076 systems in the Astute program, to equip Agammemnon and Ajax as long-lead buys. Those are the last submarines in the program.

A complete sonar system includes both inboard and outboard of the bow, fin, intercept and flank arrays, and the associated inboard processing. The cost of this contract isn’t announced, but based on past contracts, it’s more than GBP 60 million.

Feb 22/13: BAE’s overall results were down in 2012, but the submarine yard in Barrow is one of the bright spots, thanks to work on the Astute SSN program and the Successor Class next-generation SSBN. North-West Evening Mail.

Feb 17/13: Radiation Leak. The Trafalgar Class fast attack boat HMS Tireless experiences a small reactor coolant leak. It’s contained within the sealed reactor compartment, but the submarine will be out of action for 10 months in drydock. The boat was launched in 1984, had experienced a previous radiation leak off of Gibraltar in 2000, and was due for decommissioning in 2013. The only reason this wasn’t the end of her career is the Astute program’s delays, which led to Navy to extend her planned service to 2017.

The incident underscores the issues involved in operating submarines beyond their expected lifetimes. It also underscores issues with British force structure. Right now, the Royal Navy has 7 SSNs, but HMS Tireless is out of action, HMS Astute still isn’t fully operational after running aground in 2010, and a 3rd boat is in maintenance. That leaves just 4 operational submarines, instead of the recommended 7 + 1 spare. Scottish Express.

Feb 13/13: Reactors. The UK MoD signs a 10-year, GBP 800 million (then about $1.2 billion) contract with Rolls Royce, financing the Submarines Enterprise Performance Programme (SEPP) envisioned in the 2010 SDSR. The goal is to consolidate costs under one contract with consistent incentives, and improve operational efficiency in the infrastructure that delivers and supports the UK’s naval nuclear propulsion systems. They’re hoping for a GBP 200 million saving over this 10 years. Time will tell.

SEPP isn’t technically part of any one program. Contracts for products and services to deliver and support the submarine programs themselves will continue in parallel. Royal Navy | Rolls Royce.

Feb 1/13: Sub-contractors. Babcock announces a contract to supply its weapon handling and launch system (WHLS) for the 6th and 7th Astute class submarines, with a total value around GBP 55 million.

The WHLS and its combat system interfaces were developed to handle the complicated task of loading, moving, and readying large weapons like heavy torpedoes, missiles, mines, etc. within the confined space of a submarine. Babcock’s Weapons Handling Equipment (WHE) sub-system uses a semi-automated and modular approach to maximize storage, and a “unique” method of shock mounting that offers adaptable protection according to the number of weapons stored on each stowage tier. Babcock’s programmable firing valve (PFV) technology allows the system to match the launch requirements precisely to a range of variables including weapon type, boat speed and depth, using less air and making less noise.

Babcock WHLS systems are used in Britain’s Astute Class, and a variant will also be featured in Spain’s diesel-electric S-80 boats.

Jan 13/13: NAO Report. Britain’s National Audit Office releases their 2012 Major Projects Report [PDF]. The Astute Class is featured, and the table of planned vs. actual cost, time, and performance for various milestones on pg. 39 is interesting, but most of the program’s major dislocations lie in the past. They do offer a quick update regarding the fleet’s progress.

The Astute Class Training Service (ACTS) has provided training for the ships companies of both HMS Astute and Ambush, and delivered its 1st Submariner Qualification course for the Royal Navy.

S120 Ambush, launched in January 2011, has finished fitting out and is in trials and testing, following her first test dive in the shipyard’s basin in early October 2011.

S121 Arful continues construction in the Devonshire Dock Hall at Barrow, and “is making good progress”. Diesel Generator Trials successfully completed in August 2011.

S122 Audacious has had all hull and casing units moved to the Devonshire Dock Hall.

S123 Anson recently got underway with manufacturing, following her October 2011 keel-laying.

2011 – 2012

Main contract for boat #4 Audacious; Grouped long-lead work for boats #5-7; Common Combat System coming for boats #3-7; Various sub-contracts; #2 Ambush goes to trials; #5 Ansom keel-laying.

S120 Ambush

Ambush, pre-trials
(click to view full)

Dec 10/12: #5-7 lead ins. The UK Ministry of Defence awards BAE a GBP 1.5 billion contract to begin early build work on S123 Anson, and begin long-lead time buys of supplies like nuclear reactors for boats #6 Agamemnon & #7 Ajax. The Ministry of Defence touts these contracts as safeguarding 3,000 skilled jobs at Barrow-in-Furness in Cumbria.

Anson is named after after Admiral of the Fleet George Anson, who died in 1762 at the age of 65. Agamemnon & Ajax are 2 famous Greek heroes of the Trojan War. UK MoD.

Long-lead items and work on S123 – S125

Dec 10/12: #4. The UK Ministry of Defence awards BAE a GBP 1.2 billion contract to finish building S122 Audacious, the 4th of 7 planned Astute Class attack submarines. This brings total announced contracts to GBP 1.4 billion (q.v. May 21/07 entry), which is around $2.25 billion at current conversions. The boat is about half way through its build process, and subsequent NAO reports estimate her commissioning in January 2018. The Guardian is less than impressed, pointing out that:

“HMS Astute cannot reach the top speed the MoD boasted it could, sprang a leak that required it to perform an emergency surfacing, and was fitted with electrical circuit boards that failed the navy’s safety standards. A lead-lined water jacket, which surrounds the submarine’s nuclear reactor, was also constructed with metal of the wrong quality. And the living quarters for the 98-strong crew are also more cramped than those on submarines made more than 50 years ago… However, the navy is adamant the vessel can overcome the difficulties.”

Despite its launch in 2007 and commissioning in 2010, HMS Astute is still undergoing sea trials. These have included deep dive trials, and the successful firing of Tomahawk land attack missiles and Spearfish torpedoes. The 2nd submarine, Ambush, is also in sea trials that have tested diving, propulsion, and torpedoes. The 3rd boat, Artful, is reaching the final stages of her construction at Barrow shipyard. UK MoD | BAE Systems | The Guardian.

S122 Audacious main contract

Dec 6/12: Common Combat System. Britain’s Ministry of Defence issues BAE Systems Maritime – Submarines a GBP 46 million contract to create a common combat & navigation system baseline for use in all of the Royal Navy’s nuclear submarines.

“The Royal Navy operates three classes of submarine, totalling 10 vessels, which are used to safeguard the UK’s interests around the world. Currently, different combat systems are used across the fleet. This new contract will help drive adoption of a common combat system across all current and future Royal Navy submarines, with considerable benefits to training, maintenance and updating costs.”

S122 Audacious will introduce a shared computing environment for the combat, navigation, and sonar systems, mounted in common consoles and cabinets, and using “commercial off the shelf” computing electronics. These changes are due to be implemented on the remaining submarines in the class, and have been back-fitted to S121 Artful. The eventual aim is to back-fit the “Common Combat System” to HMS Astute and Ambush, and progressively to the remaining SSN Trafalgar Class and SSBN Vanguard Class boats. The CCS would also implicitly cover Britain’s SSBN Successor submarines, currently in the initial design stages at BAE. UK MoD | BAE.

Dec 3/12: Mini-Sub. HMS Astute has been fitted with an underwater dry-deck shelter (q.v. Dec 5/11) from which Special Boat Service (SBS) commandos could launch a midget submarine designed and built under Project Chalfont. From Strategic Defence Intelligence, “INSIGHT – Astute submarines fitted with Special Forces mini-sub dock”:

“According to a report in The Sunday Times, HMS Astute has sailed from Faslane naval base on the River Clyde with the dock, known as a Special Forces payload bay, fitted behind the conning tower to carry out trials…. the dock is a portable fixture that can be fitted to whichever of the Astute fleet is heading towards a crisis zone…. The SBS currently launch their midget submarines from surface warships or helicopters, risking discovery.”

Nov 15/12: Submarine problems. The Guardian publishes a report concerning issues with the Astute Class. A number can be described as teething problems, but a couple are potentially serious. The “teething problems” category includes a recent episode of leakage during a dive, computer circuit boards that didn’t meet safety standards, questions about the quality of installation of some equipment, and lack of trust in the boat’s new optronic periscope.

More serious problems include corrosion in a new boat, “…the instruments monitoring the nuclear reactor because the wrong type of lead was used [in the shielding]”, and an apparent mismatch between the nuclear reactor and the steam turbine sets:

“At the moment, the boat, heralded as the most sophisticated submarine ever built for the navy, cannot sprint to emergencies or away from an attack – an essential requirement for a hunter-killer boat. It would also be incapable of keeping pace with the Royal Navy’s new aircraft carriers, which will be able to travel at more than 30 knots and need the submarines to protect them.”

Sources: The Guardian, “Slow, leaky, rusty: Britain’s £10bn submarine beset by design flaws”.

Sept 14/12: #2 trials. The Royal Navy announces that S120 Ambush is ready to depart the shipyard and begin sea trials, 9 years after she was laid down and 18 months since she was launched.

June 18/12: Reactors. Britain’s Ministry of Defense signs a GBP 1.1 billion contract with Rolls Royce for submarine nuclear reactor cores, (GBP 600 million) and industrial investment in the Raynesway plant that manufactures them (GBP 500 million). The contracts will secure 300 jobs at Rolls-Royce.

The nuclear reactor cores will be used to power the 7th and final SSN Astute Class fast attack submarine, and the 1st of the Royal Navy’s next generation of SSBN nuclear deterrent submarines, currently known as the Successor Class.

Rolls Royce is the sole Technical Authority for the UK Nuclear Steam Raising Plant, whose reactors have powered British nuclear-powered submarines for the past 50 years. The GBP 500 million infrastructure contract aims extend the operating life of the Rayneway plant in Derby, UK, by more than 40 years. Rolls-Royce will continue to maintain and operate its existing reactor core manufacturing facility, while undertaking a parallel phased rebuild and modernization of buildings on site. UK MoD | Rolls Royce | The Telegraph.

Feb 6/12: Sub-contractors. Thales UK announces a GBP 30+ million sub-contract from BAE Systems Submarine Solutions, to supply S123 Anson’s full Sonar 2076 Phase 5 system. Deliverables will include arrays both inboard and outboard of the bow, plus fin, intercept and flank arrays, and the associated inboard processing.

Thales UK is a major sub-contractor for the program as a whole. Beyond the sonar system, they also supply each Astute Class submarine with its 2 non-hull penetrating CM010 optronic masts, the mast’s UAP4 electronic support measures (ESM) system for gathering, classifying, and locating communications and radar emissions, the ECB680 communications and SEEPIRB emergency beacon buoys, and the UHF satellite communications antenna. Thales.

Dec 5/11: An interview with HMS Astute’s commander highlights some of its features. Among other things:

[HMS Astute commanding officer Cmdr. Iain] Breckenridge ticked off a list of new features aboard the sub…. features a large lockout chamber aft of the fin, or sail, and can carry a drydeck shelter…. “That was a real design driver for the boat, and that’s why we’ve got a big sail,” he explained. “The shapes and curves [of the hull] help the dry deck shelter sit in the right place”…. The captain was especially proud of the sub’s maneuvering and hovering capabilities…. In my situation, I’ve got a much wider operating envelope because, if the stern plane does fail to dive, it’s probably only going to be one of them, and I can immediately correct it by slowing down and putting the noncasualty plane to rise. It gives us a much broader operating envelope.”

Sources: Defense News, “‘Trail-blazing’ U.K. Attack Sub Proves Itself in U.S.”

Oct 13/11: #5. S123 Anson’s keel is formally laid – vertically. The submarine’s “keel” is actually an 11m long x 7m diameter, 190t hull ring that will house the control center for Anson’s propulsion plants, and the diesel generator module. It’s also one of the most sophisticated and technically-challenging parts of the boat, and it’s laid vertically because that position makes the work easier. Royal Navy.

S123 Anson keel laying

Sept 15/11: #5. Astute submarine #5 will take the name HMS Anson when she is commissioned. The 2012 NAO report suggests that this will be in August 2020. BFBS.

Feb 16/11: #4. BAE Systems delivers S122 Audacious’ final hull segment by public road through the town of Barrow-in-Furness, to the huge the Devonshire Dock Hall (DDH). It’s the 270 tonne forward dome.

The boat is still a long way from done. The process of installing all of the machinery in these framework units, and then beginning to join hull pieces, is quite long and exacting. BAE Systems.

Jan 6/11: #2 launched. S120 Ambush is launched. The submarine will still have a fitting-out period before it can even start contractor trials. Royal Navy.

2007 – 2010

1st of class HMS Astute commissioned; Sonar upgrades for S119 – S121.

HMS Ambush control room

S119 control room
(click to view full)

Aug 27/10: HMS Astute. The 1st-of-class submarine S119 Astute is commissioned into the Royal Navy, and becomes “Her Majesty’s Ship Astute.” UK MoD.

HMS Astute

Feb 12/10: Sonar 2076 upgrade. Thales UK announces the ‘Stage 5 Inboard Replacement’ (Stage 5 IR) contract from BAE Systems. They’ll upgrade 3 Trafalgar Class boats, and the first 3 Astute Class submarines, to Sonar 2076 Stage 5 system. Once all of the work is completed, 2076 Stage 5 will be fully deployed across the Royal Navy’s (RN’s) nuclear-powered attack (SSN) submarine fleet.

Thales’ Sonar 2076 is said to have 13,000 hydrophones spread between its inboard and outboard bow, flank, fin, and towed arrays. Stage 5 IR adds new hardware, new software functionality and new algorithms, while moving the sonar system to open architecture electronics. The UK MoD’s long term vision involves the evolution of a common sonar and combat system across their entire submarine flotilla, and an open architecture sonar system is an important milestone along that path. Thales | Aviation Week.

May 21/07: #4 lead-in. The UK MoD has announces a GBP 200 million contract (about $395 million) to begin preparing for construction of the 4th boat at the BAE Systems shipyard at Barrow-in-Furness in Cumbria.

This initial contract for S122 runs to March 2008, and covers initial build work only. The MoD aims to contract for the whole boat by late 2008, and detailed terms and conditions will be agreed over the intervening period.

Additional Readings

The Astute Class

* Royal Navy – Astute Class

* BAE Systems – Astute Class

* BAE Systems, via WayBack – The Astute Launch

* Naval Technology – SSN Astute Class Nuclear Submarine, United Kingdom

* Royal Navy Info – Astute-class Submarine. Unofficial site.


* RUSI (October 2008) – Evolutionary Trends In UK Sonar [PDF]

* Royal Navy – Spearfish Torpedo. Range is just 14-30 miles, significantly below peers like Atlas Elektronik’s new Seahakes. British SSNs are a bit unusual in the modern era, in that they don’t carry anti-ship missiles as an option to accompany their torpedoes.

* DID – Tomahawk’s Chops: xGM-109 Block IV Cruise Missiles

* DID – New Nukes: Britain’s Next-Gen Missile Submarines. The SSBN Successor project, which would carry Britain’s future nuclear deterrent.

News & Views

* The Guardian (Nov 15/12) – Slow, leaky, rusty: Britain’s £10bn submarine beset by design flaws.

* Dougie Coull Photography (Sept 29/12) – HMS Astute – Departing Faslane Naval Base. Note the mounted Dry Deck Shelter.

* Defence Management (March 6/12) – US ‘taken aback’ by HMS Astute. At least the Virginia Class boat USS New Mexico [SSN 779] was.

* Defense News (Dec 5/11) – ‘Trail-blazing’ U.K. Attack Sub Proves Itself in U.S. The captain discusses several features of the boat, while pointing out its first-of-class status.

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