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I can’t help but feel the word ‘completed’ is being stretched to its limit there.

If by ‘completed’ the MoD mean Anson, Agamemnon, and Agincourt might all be in one physical piece then it’s just about conceivable.

Anything else seems, especially given my experience in Barrow over the last three years, wildly optimistic. On the upside, however, it might mean Faslane is actually ready to accommodate the crews.

Barry Larking

‘The nuclear deterrent and undersea warfare is obviously one of the most sensitive and secretive aspects of UK defence and publicity must be carefully controlled and censored.’

The first rule of security must be why take the risk? The potential for even inadvertent disclosures (or an accumulation of traceable facts over time) must be obvious. Just concentrate on getting the bl**dy things in the water.


This isnt Area 51 where only vetted people are even allowed, the Barrow base is in the middle of a small town, a submarine launch from the building hall and later even leaving the dock and heading out to sea will be common knowledge. The secrecy should only begin to cover operations once they in in service not before, like it did previously.

Gavin Gordon

By the halfway point, the Astute project itself should be being described as painless. For the MOD to co-opt the cloak of secrecy as a plainly visible attempt to cover its and BAES blushes is contemptably derisory.


So the Americans are at the early stages of developing the new W93 warhead to replace W76 & W88 on Trident, in 15-20 years time. Britain is likely to build its own version of W93.


Possibly its time to start thinking about joint projects, possible the new SSNs could be designed and built with the USN or the French Navy’s. The complete development and infrastruture costs for nations such as the UK and France for a run program of 6 or 7 boats might be just a touch to much. Also with limited build numbers if something goes wrong then there is a complete mess in the construction phase meaning old boats have to carry on costing more in repairs, refits upgrades etc or we loose capability as there is no replacement boats in the fleet to pick up the slack.


The USA would want control and the French would want control and When the French didn’t get it they would withdraw and go it alone and so should we. Honest.

Gavin Gordon

We may have to think about the US, you know. We ‘ve had a good technology ‘co-operative engagement’ with them in certain areas for well over half a century, and that is continuing to date. Also note that our future designs are looking closer to theirs, at least outwardly (link to the discussion on hull shapes below if you wish).
However, the US themselves could be sensible and still take a look at the Type 26 design as a basis for their frigate, since there is probably no better and it’s scheduled for North America already. As argued elsewhere, the US Navy is approaching its own crisis with future programmes, albeit maybe not quite so self inflicted as we seem currently to enjoy. Be interesting to get an American viewpoint on this subject if there’s one out there, I think.

Tim Wilson

What about rumours of more Astutes and Cummings pushing for this?

Steve Taylor

Where would they built? That’s the problem. Barrow is finishing of the A-boats and has started on the D-boats.


Portsmouth or Plymouth, so the Navy can keep an eye on things.


Could you elaborate on the rumours please?

Lee H

Hi Tim
What Cummings is looking for is outcomes, what you can do with capabilities and how much you can get out of them. You can do a lot with an SSN, the mere rumour of their presence makes adversaries change their operating procedures – something that can be done with a surface vessel….but you cannot see a submarine so you have the added value of stealth. The SSN also has a variety of sensor and weapon fits, it is a force multiplier – this is why the Russians for example continue, against budgetary constraints, to deliver top class submarines to the their fleet.
The review that is now ongoing will look at what platform satisfies what role best against each defence mission – its time to think outside of the box, having a submarine east of Suez for example is a lot more of a deterrent than a Type 23 frigate for example. To fulfil the missions required of the current submarine fleet probably require more submarines than we have available so to quote the Defence Secretary “we have to cut our cloth accordingly” – however if the government aspire to do more then you need the correct number of assets to complete the tasks asked. Steve TAYLOR below notes that submarines are best used in a 4 boats to 1 operational ratio, we are at least therefore a submarine short – simple math tells us that. Fleet planners are therefore doing the best they can with the assets they have, is that good enough – in someone likes CUMMINGS mind probably not – you either do something properly or not at all. Gone are the days were we just scrape by, doing too much with too little – stretching our forces to breaking point and then asking them to do more.
However, before we chase boat 8 we also have to recognise that it will not have gone past CUMMINGS eyes, more importantly the new Minister of Defence Procurements eyes (now the defacto No2 in the MoD, a Boris loyalist and a financier by profession) that the MoD’s track record on submarine sustainment and procurement is poor at best, criminal at worst – you only have to read NAO reports (£1.3Bn wasted on poorly executed, poorly managed projects (no one held to account either)), it will not have been missed. You also have, as stated above, boat 5 which is 17 months late and has been 96% complete for a bit “too long”.
Is boat 8 fantasy, maybe – is it required, probably.
Can the SDA deliver it – I leave that to the readers, reminding them that the Chief Exec got a £185k bonus last year…..

In my humble opinion however I believe we do need it, we just have to match ambition with reality. Barrow can build it, not today but if they knew boat 8 was coming it gives them the 5-7 years to employ and train the right people and gets the orders for long lead items (gear boxes, reactors etc) in the order book now – Global Britain and all that……


Not entirely sure how a submarine deters the IRG in the way a T23 can. Unless you’re suggesting that we lob a couple of TLAM Tehran-wards every time the IRG harass commercial shipping. Fair to say that the Persian Gulf ain’t exactly an easy operating environment for a large SSN either.

Lee H

Hi N-a-B
I take you are specifically talking about the GD T23 currently in the Persian Gulf, I was talking in the wider context of what you can do with single platforms.
I accept that within the Persian Gulf region an SSN would be somewhat boxed in and that a GD surface vessel (T23 or T31) is ideally suited to the environment.
An SSN however, with TLAM for example, has the ability to be used as a strategic asset in a way that the GD surface platform couldn’t. Having one routinely deployed East Of Suez shows our global intent and gives our potential adversaries something to think about – we indirectly shape their thinking (they change their posture to meet the threat, change their production lines to produce more ASW platforms instead of AAW or ASurW for example).
We need to look at what we can do with the platforms – use them in the correct context and match them to the defence missions. It is one of the reasons people like CUMMINGS are interested in the submarine, the community and what it can achieve.


All nice in theory. Trouble is that theoreticians tend to be untroubled by inconvenient facts – such as equations not being either / or solutions – and make (or direct) decisions accordingly.

I can’t actually think of one “potential adversary” EoS that would be particularly concerned about an RN SSN, let alone change their strategic behaviours. Our potential adversaries in most areas tend to be worried about our large, vociferous friend which drives their behaviour. Where we do add value is allowing our friend to be somewhat less diluted around the globe by taking responsibility nearer to home. This is a large part of what QEC will bring to the party, provided that our egg-headed friend isn’t obsessing over clouds of DF21 or cyber.

SSN are highly valuable assets. But far from all-powerful. Worth noting that once T26 is in service we should have a surface launched TLAM (or equivalent) capability as well.

Lee H

Whilst the friend has always found us a willing and able “gap filler” closer to home, allowing it to deploy elsewhere we now have to look to a future where we start to do things ourselves – as an independent forward looking nation….yes I know, great soundbite but little substance.
Working with our friend we should be seen as fulfilling our own requirements not giving the US xx Fleet a back up aircraft carrier so they can operate better with 10 carriers (11 being the requirement).
QEC will add extra dimensions to the UK’s ability to shape events in the world, we just have to have the political will to enact it – no point having an aircraft carrier if you are never going to use it. This, I think, is partly the Bald Eagles point:
The Carriers, a £6.2Bn vanity project conceived in a time when we were working at the worlds policeman, now doesn’t quite fit into a political world where the political classes are afraid to make forthright decisions when it comes to deploying potential kinetic effect to defeat the enemy (think Syria – now look at the place. Think Libya – now look at the place).
It isn’t that I am not a fan of the QEC class, it only works if we can use it properly, independently and with the political will behind it when it comes to the tough times – deploying aircraft to deter and defeat the enemy.
Our egg-headed friend isn’t obsessing about clouds (very yesterday by the way), or cyber – what he is doing is challenging the status quo – we can either react badly to it (and come off second best) or embrace some of the concepts and turn them to our advantage.
He is a person who is outcome based, wants to get stuff done – sounds like the military to me.
Helping shape the argument, bringing people like him along for the journey, can only be a good thing. If he likes submarines and what they can do, lets use that – but remind him and others that submarines only solve part of the problem, you need a fully rounded capability to satisfy the needs of the mission – this feeds the strategy that enables the vision. (Pretty sure I was taught that somewhere)

Steve Taylor

The USN has worked our carriers into their escort’s workload. Despite the disparity in size between the two services the co-operation is genuine not tokenism.

I was excited by the thought of two new large deck carriers back 20 years ago. But as a centre piece to a fleet of 32 escorts, 12 SSN’s, and a clutch of amphibs. Now not so much.

You aren’t getting to get a fair hearing on this site about the carriers. Too many armchair admirals keen to fight WW3 or refight the Falklands.

The fact that Not A Boffin regularly gets downvoted when he is a naval architect specialising in warships tells you all you need to know about the commentators here.


Shocker Steveie weevy crying about being downvoted yet again. BTW, not that NAB needs you to be his hero, but pretty sure he regularly gets upvoted and downvotes are the exception rather than the rule for him. (case in point on this article he has 5 comments, 4 of which [at time of me posting] have upvotes and one is zero… oh dear, then again I know facts don’t really sit that well with you Stevie boy)

But yes, we’re all fanboys and you are a the kremlin appointed god and if we don’t agree with what you say it’s clearing becuase we don’t give “fair hearings.”

Gavin Gordon

Forgive me Lee H, but you really have sold into the Cummings view of defence. Of course submarines, but there is no more powerful surface unit than a Carrier since it acts as a hub for the most powerful weapon systems and counter systems – alongside associated range.
A current aircraft, fixed wing or rotory, starts off very intelligent due to the crew but, either way, the carrier will still be able to host numerous unmanned systems over its extended lifespan. ASW was the rational behind the Invincibles during the Cold War, after all; though the QEs hold all the more potential. If you argue for smaller surface combatants, you risk the above advantage since modern fixed & rotary assets are each similar in their own right to many surface units.
It has yet to be demonstrated that the nation that defaults to the submarine answer more or less alone, as in the past, will ultimately win a conflict. They are a huge threat, and one must include them to be credible, but they are also somewhat one-trick-ponies lacking overall flexiblity.

Gavin Gordon

I may have a previous post in the system somewhere, Lee. If it appears, please leave out the first statement.


If you take the QNLZ through the Beagle channel we only have to do it once every 10 years to make our point.


Syria and Libya were two places where outside intervention ( yes the CIA and Gulf states channelled heavier weapons to the rebels in Syria ) made the fairly stable situation under existing dictators worse.
And bombing campaigns did happen , indeed the QE used its F-35Bs operationally over Syria – but UN resolution only allows ISIS targets .

You wouldnt want UK to be involved in aggression on a whim /national interests would you … well not since Blair went with Bush on a full invasion ( which they didnt call it that either)

James Fennell

I haven’t heard the rumours – but we surely need more. Most effective thing we have, and we’ve sorely run down a most brilliant capability. Can build more at Barrow no problem, and elsewhere if needed (sections are built elsewhere anyway). In 1980s we were building the last T-boats, Vanguards and Upholders simultaneously,


I’ve also heard rumours of a push for a small fleet (6 or so) of conventional AIP submarines along the lines of the German 212, Chinese 039A Yuan or Japanese Soryu class. They would operate in coastal waters or be used for sneaky beaky ops freeing up SSN’s for ops of a longer duration. Cheap to build and run, lower personnel and extremely quiet, they could play a big role in future maritime ops.

Steve Taylor

I think when Agincourt is commissioned we will lose Astute. The question will be whether the RN can have two SSN’s available with only 6 hulls. Submarines are best operated on 4 for 1 basis. They have always been complex. It seems new technology is only adding to complexity not reducing it. We only have SSN’s because we have CASD. Our priority should be the (North) Atlantic and not patrolling the Indian Ocean giving token support to the USN (and RAN).

One wonders if our boats were built on the Clyde not in Barrow whether Brown would have interfered with the production drumbeat?

Submarines are a tool of realpolitik, where as our carrier programme was born out of elective interventionism of Blair’s program to promote himself on the world stage. Blair has gone. We live in a multipolar world. CASD and Russia are still with us.


On what basis do you think we’ll lose Astute when Agincourt enters service?

The rule of 3 works fine for normal deployments, 4 are used for CASD to add redundancy.

“We only have SSNs because we have CASD” this simply isn’t true. The decision was taken in the 90s to ditch conventional boats (which would’ve been well suited to local defence) and focus on nuclear boats because they offered more global expeditionary capability. They’ve also provided our only naval cruise missile platform for the past decade.


One possible reason could be that by 2026 the RN will have been operating no more than 6 SSN’s for over 10 years. Finding the crew for a 7th could be a challenge and as with most capabilities the penny pinchers will no doubt question why a fleet of 7 Astute’s is required going forwards when they’ve made do with less for a number of years.

The commitment was to build 7, not necessarily operate that many, plus it’s clear Agincourt only survived the 2010 SDSR due to long-lead items like the reactor already being ordered and the need to sustain work/skills at Barrow until Dreadnought ramped up.


Scrapping a modern submarine halfway through its service life wouldn’t make sense even as a cost cutting exercise. All of the investment has already been made, hence why the usual pattern we’ve seen for the past few decades has been old platforms scrapped with no or fewer replacements.

Fortunately however, recent reports seem to indicate the penny pinchers are outnumbered by increasing numbers of MPs calling for higher defence spending, with the PM among them. As the article points out, there’s no practical way of increasing our SSN fleet beyond what’s planned until after the Dreadnought build, but an increase in the assets that support them or do the same role (e.g. MPAs and frigates with cruise missiles) would alleviate the strain on the fleet and allow them to be deployed only where they’re really needed.


They’ve six years to rise to that challenge.

By the end of 2016, the submarine service employed 560 warfare ratings, down from 890 in 2010, following Dave’s decimations. So submariner warfare rating numbers took a far harder hit proportionally from the 2010 SDSR than the Navy in general (37% vs 15%). Nevertheless, if it can’t find/train a crew or two of 100 in six years, something is even more wrong with the Navy’s ability to recruit/retain and plan than appears on the surface.


The sonar branch of the submarine service is falling to pieces. They’re desperately short, cannot recruit enough to fill the gaps and struggle to retain who they do have. It’s been that way for the last few years but the submarine warfare branch’s issues seems a real blindspot for the RN.

Steve Taylor

3 works for surface ships, but 4 is a better figure for submarines.

Operating CASD with 4 just about works. When the R-boats were put into service the RN wanted 5 hulls. As I said above submarines aren’t getting less complex because of technology but more so. If 3 works for CASD you should perhaps telephone them to say not to worry about Vanguard’s refit.

Astute is different to the rest of the class. She will require more upkeep because of that. Given current trends I doubt there will be enough crew to keep 7 at sea.


4 is better in all cases, fleet submarines aren’t special in that regard. The rule of 3 still works for peacetime/limited war operations.

As I said, the 4th boat for CASD is for redundancy. In the event of an accident or unforeseen issue with one boat, CASD can still be maintained with 3 boats in the short to mid term. The issue with that when you’re down to just 3, you have no redundancy; any significant issue whatsoever means you lose CASD capability. That’s why 5 R-Class boats were initially wanted, because it’s double redundant, and it’s why the Liberal Democrat proposal to operate just 3 bombers for CASD as a “minimum deterrent” was torn apart as being impractical.

Astute isn’t different to the rest of the class. She was constructed less efficiently, but she’s the same design as Ambush and Artful. Audacious is the first of the “Batch 2” subs that have design improvements over the first 3 boats.

Steve Taylor

Primary sources on the R-boat procurement suggests to me that why 4 works and did work 5 was the preferable number for guaranteed deterrent. It was nothing to do with double redundancy, it was about ensuring redundancy. The only way you could double redundancy was by having 8 hulls. You should consider that CASD is always at war as it were.

Of course more of anything is better. Submarines are a factor more complicated than surface ships at least. One in long term refit, one working up, one deployed, and one alongside in maintenance that takes a lot than escort’s maintenance period.

Well we will have to agree to disagree about Astute.


Double redundancy may have been a poor choice of words on my part. By double redundant I meant that you still have a redundancy if one boat is unavailable. Apologies for poor phrasing


It’s not completely unthinkable. A few years back when both Trenchant and Talent were undergoing maintenance periods that were proving to be quite troublesome the idea was actually broached of paying-off one or the other off early to free up manpower and save some money. The answer was a resounding no, as the powers that be wanted as many hulls as possible.


Was this when the cracked reactor casings were discovered on the T and remaining S class boats? If so, that’s a slightly different situation than what is being suggested with Astute above, significant investment being needed to keep the boat in service would definitely count as a economic reason to scrap it. Astute fortunately doesn’t (and hopefully never will) need major reactor repairs


Because he workd for the Kremlin and therefore needs to spread miasma 😉


Why would we lose Astute? Please clarify.


Steve, the issue from next year is going to get much more difficult. We will need three SSNs at sea, one operating with an SSBN, one with the CSG and one on independent command (roaming/hunting). It brings the RN needs for SSNs back to the original 12 that we used to have. Its why I keep wondering if due to budget difficulties the RN should have 6 SSNS for CASD and the CSG plus one SSN in reserve in case of a major problem and 8 SSKs for the Atlantic and the GIUK Gap. I’m not sure but I think the cost ratio is three SSKs for one SSN.

Steve Taylor

You have to factor USN SSN’s into that too. But they are running out of submarines too.

The main focus for RN SSN operations in the Indian Ocean at the moment. How often one goes to the north to monitor the Russians is only know to the MoD(N). The SSBN main defence is it stealthiness.


Is operating a SSN with the active SSBN always been the case?


If the original PWR2 reactors were not designed with the intention of being refuelled (as shown by HMS Vanguard problems), have the versions fitted to Astute had any changes to make it easier? If not, is the diagram showing potential refuelling somewhat questionable?

If the replacement boomers are expected to last 45 years – are their reactors designed to be refuelled?


The original PWR2 reactor core as used in the Vanguards was designed to be replaced. Core H, as used in the Astutes since build and the Vanguards since refueling, has a design life of 25 years but isn’t meant to be replaced.

HMS Vanguard herself is getting a second refueling because she’s expected to soldier on beyond the life remaining in her core. The Astutes haven’t had any modifications because Vanguard should be the only boat that needs Core H replacing, the plan being that continuous production from Dreadnought to SSNR produces a replacement for HMS Astute on time.

Based on the fact that Vanguard is getting that refueling though, it is theoretically an option to extend the life of the Astutes. Personally, I think it’s highly unlikely, but predicting the MoD thought process a decade from now is basically impossible.


The Astute saga indicates that the UK government either needs to accept that a continuous build program and 12 or SSN/SSBN’s in service at any one time needs to be properly funded, or we otherwise need to partner with The Americans (forget the French!) on designs to keep the costs down and the construction re-risked.

At this stage with Barrow having to play catch up on the last 4 boats and then dive straight into building Dreadnought & co the only way to increase numbers before the 2030’s would be to buy some SSK’s. A controversial move – but not unthinkable.


An alternative is to build the SSKs and buy some Yankee boomers. The outrageous unit cost of the Dreadnoughts is more than twice that of the Columbia class (and three times that of the Triomphants). Paying $20bn to the US would need some kind of reciprocal spend, but I imagine something could be arranged.

Matt Wright

You are applying common sense to a political industrial situation. Tactically and strategically we would still need fully independent control and operations.


I’m talking about buying some subs from General Dynamics rather than BAES. Assuming the US grants an export licence, what would “fully independent control” have to do with it?


Where on Earth are you getting those costs from? From what I can find, the cost for the 4 Dreadnoughts themselves is £12.7bn in today’s money (although this is from 2013), versus $115bn for 12 Columbias (from 2019, but this is being criticised as a low estimate). Comparing unit costs, that’s £3.2bn for a Dreadnought, vs £7.4bn for a Columbia. For further reference, the last Triomphant class boat cost 3.1bn Euros in 2009 money (about £3.5bn today). That rubbishes your claims of “twice that of the Columbia class (and three times that of the Triomphants)”.

Lets assume a worst case scenario. Lets double the price of the Dreadnoughts (which may have already happened since the figure I provided above), so £6.4bn. That’s STILL cheaper than the already low estimate for Columbia, before we consider that there would definitely be an FMS export tax. On top of that, the Columbias are all being built at a single yard for delivery in the same time scale as Dreadnought. So it’s quite simply impossible: it would require the USN to agree to give up submarines that it needs to maintain it’s own forces.


What ever happened to Ajax as a name of one of the class ?


Seems it was never actually confirmed as the name for Astute number seven, just widely expected to be so.

I’ve seen a number of posters etc., that were produced years ago when the Astute-programme started dotted around Barrow and elsewhere that had the names and associated crests on them. Some had Ajax on there, some didn’t. I also saw documentation produced for the last four of class on them that named the boats as Audacious, Anson, Agamemnon, and Ariadne. I was half expecting that name to be announced. Agincourt surprised everyone.

Personally, I’d have opted for ‘Adder’.


Changed it and Ajax was my favourite name of them all….

Bloke down the pub

Many of the issues with the submarine fleet would appear to be linked to the type of nuclear reactor used. There are designs in existence, developed for the small modular reactor electricity generation market, that seem to be a better option. Molten salt reactors for example can be re-fuelled with much less disruption to operation. As Rolls-Royce does not produce them, the UK will, no doubt, ignore them.


Yes, but RR is part of a consortium developing civil SMR, so there might be a spinoff from that.


No SSN-operating nation is considering them either, so nowt to do with RR. More to do with them being a paper design with – as yet – no provenance.

As a rough estimate, the western powers have operated something like 200+ PWR over a period of nigh-on seventy years, plus a couple of metal-cooled experimental variants. That ignores the hundred-odd reactors Ivan took to sea and the handful of Chinese ones. That’s provenance, particularly considering the lack of incidents with the western ones.

But doing that takes a great deal of technical and procedural care and includes dealing with ever more onerous risk-mitigations required by ever more onerous regulation. There’s also the small matter of accessing a highly shielded compartment within a very demanding (in terms of shape, material, space etc) pressure hull. That’s why it costs.

Supportive Bloke

And also we have a design that is shock proof and well tested.

For the tiny numbers of nuclear subs we build we cannot start totally new blank paper reactor designs. What we have works reliably and is very safe.

It is really hard fitting something like this into a pressure hull anyone as others have pointed out.


Probably heresy to ask this but given the advances made in technology, the cheaper costs and performance of modern diesel electric submarines, should the U.K. not consider a conventionally powered class of submarines to bolster the fleet?

Gavin Gordon

It’s not total heresy, Alex, and will likely come about if risk escalates. Smaller subs have their own pros.


Likely that autonomous fuel cell/battery only submarines will fill that gap


Not heresy at all. Nuclear power is largely a scam. It’s no coincidence that no sane private sector investor will touch a nuclear power plant without massive government subsidies/guarantees. Not only would the up front cost of diesel-electric submarines be lower but the decommissioning cost would be exponentially lower. The Navy has been kicking the can down the road for some time by not decommissioning it’s nuclear submarines. At some point it is going to have to bite the bullet and the cost is likely to lead to further cuts in the fleet and/or personnel.


I wondered what. One Astute seems to cost as much as 3 modern conventional subs. Wouldn’t we be better off with a force of 7 SSN’ s and 3 SS’s?

James Fennell

Not really, the 12 new Australian subs went that way and are costing just as much to build as Astute, If you want a big blue water sub it’s going to cost a packet, SSK or SSN. Nuclear does have greater operating costs, due to mid life refuelling and all of the safety considerations, infrastructure and disposal costs, but for a submarine the advantages of nuclear are manifold.


Probably not. NATO has rather a lot of ssks. Enough to hold much of the the much reduced Russian navy near home in the closed seas ,and sink much of whats out. You need SSNs to do the offensive and defensive strategic roles though -dealing with opposing SSN/GN or posing a counterforce capability where and if needed .You may also want to use an SSN to repeat the Falkands experience and keep hostile navies in port a very long way away and need endurance and transit speed to get there fast. And size gives you stowage space for more than a handful of SLCM. Upholder was designed to be built in numbers and to provide a barrier against a much more numerous threat. 3 would be a short barrier.

The basic problem is the failure to build the RN SSN fleet deemed needed in 98. 12, was cut to 10 and 8 and 7 with zero justification. Tasks,, remained essentially the same and some new ones emerged after 98. Oceans didnt shrink in size. Thats removed any incentive to retain or build more production capacity , production gaps meant relearning skills and produced lengthening production times, and increased costs. Its not an unique problem – the US used to be able to produce 6 ssn a year but is now having problems getting to 3 a year when facing problems sustaining required force levels


Out of interest, does anyone know why the Astutes are shaped somewhat differently in their front section than most other western submarines? It’s quite noticeable, but have no idea why, and why it isn’t being transferred on to the SSNR…

Gavin Gordon

Front -no. Back due to the PWR2 again – designed for the larger bomber class. But you probably know this already!


I didn’t, no, so thank you! The front remains a mystery then…

Gavin Gordon

I was not personally aware but you’ve prompted a check. Try the Secret Projects Forum for same question and an interesting input by ‘Moose’. Good a reason as any. Cheers


Thanks for that, the ongoing discussion through that thread was really interesting!


The UK has mostly used what is technically called a ‘conic -elliptic’ shaped bow, you can see a similar shape in the first Dreadnought when it was launched. The US approach is called hemispherical.
The most hydrodynamic efficient shape , Ogive gives the least volume behind, while hemispherical gives the most volume- which suited USN spherical sonar arrays. As well the USN put its torpedo tubes further back in the hull, angled out.
A research paper conclusions based on CFD computer models said:
In this paper, a study of the equations of bow form of submarines and CFD analysis on them, has been performed. These are the most famous equations in submarine form design. For a well judgment and the best selection of the bow form, the most important factors in bow form design must be counted such as: minimum flow noise specially around sonar and acoustic sensors, minimum submerged resistance and general arrangement and volume demands.
Elliptical type shapes give the best results, while hemispherical is the worst for resistance. As in all engineering the end result is balancing conflicting demands
Journal of Scientific and Engineering Research 2016


Thanks, that seems to bear out other assumptions: the best fit given the RN’s slightly different approach with sonar.

James Fennell

Sonar related. The Trafalgars have a similar bow profile. The 2076, 2008 and 2019 sonars have quite a few different arrays. Passive that listen for vessel acoustics (including towed, flank and bow arrays), passive intercept that listen for and home in on other sonars, and active for both attack and obstacle detection and avoidance. There are also UWT systems (underwater telephone), which use sound waves to communicate long distances underwater (like whales).


Would it not make more sense to build a Dreadnought SSGN than a SSN(R)? Seems like building and operating two different designs at a time could be an avoidable expense.


Because an 18000 te SSBN can’t behave like an 8000te (preferably a bit less) SSN. Or go where they go and do what they do.


That does raise the question of why the SSN( R ) concept, as referenced in the article, was allowed to climb to 9,200 and will it be going on a diet at some point before construction starts?


Does it? 9,000t is still half the weight of a Dreadnought…

Captain Nemo

A little out there, though I’m sure that it’s probably been mooted before, why not a single class of twelve, each with four Common Missile Compartments?
A boat could therefor hold one ballistic missile per CMC in the deterrence role (with a varying number of warheads) or half a dozen FCASW per CMC in the attack role, you then have a scalable number of deterrence or attack subs according to the perceived global threat and a larger pool of usable assets, one of the main criticism’s of CASD being that it’s dead money.

I’m not sure what constitutes the accepted level of deterrence post cold war though I believe that the number of warheads has reduced over time, currently one per trident iirc, so you maybe (or maybe not) lose a little in megatons on the day to day but gain a little by being able to put more bombers to sea in extremis which makes the deterrent more survivable and so more deterring.


Ever wondered what the reaction might be from a potential strategic target if – for example – a cruise missile launch occurs from a submarine known to be carrying ballistic missiles?

The whole point of the deterrent is that it deters in three ways – being guaranteed to be available, being guaranteed to put a warhead on the most important targets and being undetectable. People who criticise CASD as being dead money, don’t understand what it does.

Aside from the issue that you can’t use an 18000te boat like you would an 8000te boat.

Captain Nemo

Mm? Oops sorry, nearly chewed a whole crayon.

That’s not what I said (though suspected I’d be answering this), I said a single class, I was quite specific in the separation of roles and that’s actually the argument against nuclear tomahawks.

Cruise missiles are still going to come out of the sea.

How would they know it was our boat? How do they know where our boat is? Damn, wish we had two out.

I know what a deterrent is, there would still be a guaranteed deterrent, at no point did I say there wouldn’t be, I simply questioned the modern interpretation of an acceptable size for CASD and suggested that the ability to potentially operate multiple boats in that role would itself strengthens the deterrent.
Various parties recently offered various solutions to the deterrent including no deterrent, continuous deterrent and no continuous deterrent (kill you later), so I’d suggest that it’s open to interpretation.

Yet, the criticism of dead money remains, it now also exists within the armed forces who must carry the cost from the core budget.

I didn’t specify an eighteen thousand ton boat (but I knew I’d be answering that too).

What I was actually expecting from you was how it would not be feasible for a submarine to be sized so as to satisfactorily perform both roles, which is of course your area of expertise.

Kind regards,


Well Astute class is 11.3m beam and the existing SSBN Vanguard class is 12.8m beam . So the missile tubes can fit inside a beam of 1.5m more than the new Astutes.
Maybe the Astute 11.3m will work with a hunchback design with the tubes projecting above the usual deck. Another option might be instead of two parallel rows of missile tubes we have a single row. This would reduce the hull diameter a bit. This is complicated by the UK wanting to buy the US hardware – ‘lock ,stock and tube’ to go with the US Trident missiles.
The RN has had a long history of thinking innovatively, and for the future missile boats with a single row of tubes , maybe even down to 10 tubes might be the way to save costs by a continuing build of Astute class hull sections


Russia is barely going to notice 1 Trident each from a small percentage of your force actually on station. And they would have to always be deployed on station, within range, in survivable waters. No country relies on one or two nuclear weapons to deter. They all measure their rquirements in terms of numbers of key targets, or forces required to cause high levels of damage, or high percentages of enemy populations put at risk . Most have requirements ranging into hundreds of warheads, the Russians, Americans and possibly now the Chinese count in thousands.

The deterrent cant be put at risk by being spotted sinking ships or blowing up tactical targets with slcm. Its protecting our and Nato bases , and 30 to 40 % of the population from death by incineration or radiation. We already have the worlds only nuclear force which isnt a triad or diad of sea/air and land systems, and half as many warheads as France in the stockpile. We already have literally a minimum deterrent .

Bloke down the pub

When the replacement for the Vanguard boats was first proposed, my preferred option was for a vessel with just four vertical launch tubes. Apart from launching Trident, they could’ve carried either a significant load of Tomahawks, swimmer vehicles or USVs. Hopefully, the reduced cost would’ve allowed for an extra boat, which would increase flexibility. If this article’s predictions are correct, it looks like we might get somewhere close to this with the Astute replacements, sans Trident obviously. Better late than never.


Trident missile tubes are a hyper expensive way to launch Tomahawks. The USN uses its a different launch tube the 87 in diameter VPM ( As well as the existing TLAM tubes) which can fit in the front of the subs pressure hull for that and similar missiles. They can carry 6 or so Tomahawks per VPM. probably the Astute production is too far advanced to make a change for boats not yet delivered

Steve Taylor

Google Virginia Payload Module.

There is little point in investing so much in a hull for four tubes.


Wasn’t one of the original design goals for the Common Missile Compartment the ability for it to be adaptable to host either Trident or TLAM and maybe other stuff such as USVs? Did that design goal make it through to the final product? Part of Dreadnought funding was a U.K. contribution to the CMC development I believe. Presumably the Virginia Payload Module was a project before CMC was completed. If that multi-role capability did make it into CMC I wonder whether the USA has any plans to exploit that flexibility in the future

I had wondered the same thing as you BlokedtPub. Far too late now, and maybe it wouldn’t have made financial sense anyway, but if multi-role CMC is/was a reality I had wondered what economies could be had from moving to a single class with 4 or 6 CMC tubes with a view to the sum of the SSBN sub budget plus the next-gen SSN sub budget combined being able to fund more than 4 + 7 of a unified class due to savings from only 1 design process and other economies from a bigger build. My thoughts were that no boat would have ever gone out with a mixed load, it would always be on either a CASD or SSN deployment, but with most of the onboard systems common there might have also been some savings in logistics, maintenance, crew training & flexibility, and the SSN-tasked boats would have got a big uplift in capability due to the CMC in TLAM mode.

Bloke down the pub

That’s just about how I saw it. One other advantage would be that any opposition wouldn’t know in advance what the sub was carrying when she went to sea.

Geoffrey Simon Hicking

The larger and more complex the submarine, the less that can be built. So, 3 in total this time? Or 4? One wonders if we will be able to build any the next time after that, but there’s nothing anyone can do about that.

Paul T

Absolutely – the SSN(R) rendering looks huge but it falls into the ever diminishing resources trap – work out your requirement,be it 7,8,10 or even 12 Submarines then design and build your Submarine to fulfil those numbers.Whats the point of having another Gold Plated solution then realising your budget can only stretch to 3.


Size is not directly proportional to cost. Especially for a Nuclear boat, where you are not paying to fill it up with F76.

My understanding is that SSN(R) will have commonality with Dreadnought, for reactor and propulsion plant, saving huge cost on development, in service support, training etc. So bigger is likely cheaper when all this is accounted for.

Also presumably allows more living space, Astute is quite pokey in places by all accounts.

Last edited 2 years ago by Ben Robins
Bloke down the pub

That was my feeling too for those who thought a new diesel electric sub was needed.
AS well could be useful as a close ( 50km) escort for a carrier where it can provide sonar data via a quick transmit from a raised mast without surfacing

Hugh Jarce

Why don’t we start building diesel-electric/AIP subs for home waters defence, especially for the GIUK gap, to escort the Vanguard subs when leaving and returning to Faslane and to escort Russian ships in our waters? One of these diesel-electric/AIP subs could also operate around the Falklands and off Gibraltar. These subs could also complement the Type 31s for home waters defence, plus a Type 31 and one of these subs in the Falklands would be far better than just a River-class OPV. In UK waters, these subs and Type 31s would also be complemented by Poseidons, AEW aircraft and Typhoons. Diesel-electric/AIP subs would be far cheaper to build and operate than nuclear-powered Astutes and they seem like a no-brainer for home waters defence.

I’d like to see the Type 31s fitted with Mk 41 launchers though, which would give them the ability to fire VL-ASROCs, LRASMs and TLAMs (can’t see the need for TLAMs for home waters defence, but the option is there), plus Sea Ceptor CAMM missiles can be quad-packed in the Mk 41 cells. The TEU containers would provide the ability to carry Schiebel Camcopter S-100s, which can carry LMM/Martlet missiles and the boat bay would enable Type 31s to carry Arcim surface drones to detect subs and mines. Also the image at doesn’t show any decoys like SSTD (Surface Ship Torpedo Defence) or SeaGnat. Will the Type 31 be getting any decoys? Also this picture differs to the one at which shows a bow-mounted sonar. Is the Type 31 no longer going to be getting that?


why is our Gov trying to get rid of our armed forces all together its disgusting what they have done to all of them cutting back on funds


The treasury has operated a 10 year rule since the 1920s which assumes no major war in 10 years. Its now crept out to nearly 15 years fot the Army -which made things worse when it fouled up its armour programmes

This was almost disasterous in WW2 as even when rearmament started about 1932 it made defeats almost inevitable up to 1942 when modern kit like decent tanks and bombers arrived.. Luckily radar,air defence command and control, Spitfires and Hurricanes, and limited warship building avoided total defeat.

Its entirely irresponsible now as our recent wars in 1982 and 1990 came with 4 days notiice. We do not control when we will need the capacity – whether its in Kuwait, Kosovo or Estonia.
Russia was recently weeks away from starting a major crisis in Europe by attacking the Ukraine, Iran is 2 years from the bomb which would cause a major war when an attempt was made to stop that. Estimates are that a Chinese invasion of taiwan could be feasible in 6 years. And even if we avoided direct involvement, all these might see a need to replace US forces elsewhere.

The Treasury also has a culture of declaring unmet needs met, and then cutting whats then deemed an acceptable level to an even more inadequate one.

This has two fallout consequences. Production of lower and lower quantities is spun out more to keep producers in business, unit costs rise, deliveries are slow, more refits are needed. And gaps when skills are lost and devlopments in the threats , mean the cost of new technology rises even faster than it would anyway.

So we have an conomy that grows slowly, technology costs rising rapidly.,deliveries are slow and few, and ship numbers are falling. And we face countries that worry less about budgrts, make up financial numbers , build much faster, and are actually preparing to fight- soon.

Last edited 2 years ago by Rnsc8397
Rob V

Why not design the new SNN(R) for a 50 year life and include 4 vertical tubes so they can be multi functional. They would then become a shorten version of Dreadnought.