Astute Class Attack Submarine (SSN) (RN)

[Repulse]

@GibMariner: Stupid questions if you ask me as the government never comments on SSN ops.

A better question would have been "How does the hell the government expect the SSN fleet to cover all the needed and growing commitments given a fleet of 7 SSNs and at times 6?”

Not talking about operations and pretending SSNs are in multiple places only goes so far. Things are hotting up and a return to a 11/12 SSN fleet is going to be needed.

[Engaging Strategy]

A better question would have been "How does the hell the government expect the SSN fleet to cover all the needed and growing commitments given a fleet of 7 SSNs and at times 6?”

Not talking about operations and pretending SSNs are in multiple places only goes so far. Things are hotting up and a return to a 11/12 SSN fleet is going to be needed.

Agreed, but how do we build them? This seems to be the real problem with the UK's substantial attack submarine gap:

sub build.png

If we'd been building SSNs through the 90s to replace the Swiftsures like for like then the problem we've got now wouldn't even have arisen. Instead we're now stuck with a fleet of 7 SSNs because Successor is going to hog all the capacity for the next 16 years. Foreign built SSKs aren't even on the table so what does that leave us with? Expand the construction capacity at Barrow? That's going to be painful and expensive, considering the time it takes to build a skilled workforce. As for facilities, the new Central Yard Complex at Barrow certainly gives BAE more space for fabrication and outfitting (in addition to the existing Devonshire Dock Hall) but do these extra facilities=more build capacity?

[Repulse]

The gap may have gone now, but there was talk in 2010 about the opportunity to build an 8th SSN for sub £1bn before the SSBNs, but it was decided to waste cash slowing down the build cycles for the first 7. Could still be time as I thought a 20 month build cycle was the longest to keep skills?

Whilst I'd like to see a class of very small coastal electric surveillance / attack subs for the RN, SSNs are the only real and cost effective game in town for the RN.

[shark bait]

Things are hotting up and a return to a 11/12 SSN fleet is going to be needed.

That's probably about right, its where Australia has set their requirement, and its where I would like so see our sub fleet. However like ES mentions, there is just no way to fit additional SSN's in. We are going to have make do for the next 23 years with only 7 SSN's.

Looking at the schedule, we will still be building successor by the time HMS Astute reaches the end of her 25 year life, so it seems the only option will be to withdraw her from service for a lengthy overhaul to extend her usable life.

If we want Astute replacements, design studies would have to begin within the next couple of years, which seems impossible, so a life extension looks highly likely.

A life extension could be quite favourable, maintain the Astute class in service longer, and continue building at barrow with a shortened successor, with just two or four tubes, as an SSGN to increase the submarine fleet. That would give us a fleet of;

• 7 x SSN (Astute)
• 4 x SSBN (Successor)
• 4 x SSGN (Short successor)

That the only way the nuke boat fleet can be expanded, and it is a very long time until that can be realised.

In the mean time the only option to increase sub numbers is with an SSK, turning the sub service into a two tier force, with Astute for the long range missions, and SSK for european missions.

[~UNiOnJaCk~]

Great guys, i will just go and fetch those few extra billions we have lying around and you rustle up that spare manpower we have laying idle...

Sorry to be sarcastic, but this is real fantasy fleet territory. We’d all ideally like to have seen more SSNs built, yes. But no-one is even talking about making that a reality so it is pointless to speculate the requirement and it completely ignores the point that, even if it were being talked about in official circles, we have no, realistic, material way of making it happen.

[shark bait]

Great guys, i will just go and fetch those few extra billions we have lying around and you rustle up that spare manpower we have laying idle...

We are going to have make do for the next 23 years with only 7 SSN's.

Do you not read posts before replying? I don't think any was was suggesting going out and buying more subs tomorrow (its a bank holiday after all)

The reality is we have 6 boats, which gives three available. Three boats to cover a massive ocean when subs are proliferating like never before. There is no way only three boats can be justified as enough.

Unfortunately neglecting the fleet in the past has led to this situation, however there is no use crying about that, instead we must learn from than and realise a robust long term plan is needed. Within that long term plan there needs to be a strategy to increase over all nuke boat numbers to counter the growing presence of subs beyond the traditional naval powers.

[~UNiOnJaCk~]

Do you not read posts before replying? I don't think any was was suggesting going out and buying more subs tomorrow (its a bank holiday after all)

The reality is we have 6 boats, which gives three available. Three boats to cover a massive ocean when subs are proliferating like never before. There is no way only three boats can be justified as enough.

Unfortunately neglecting the fleet in the past has led to this situation, however there is no use crying about that, instead we must learn from than and realise a robust long term plan is needed. Within that long term plan there needs to be a strategy to increase over all nuke boat numbers to counter the growing presence of subs beyond the traditional naval powers.

No, i saw that bit as well. Simply put, judging by well-established MoD/Whitehall precedents, 7 is the new benchmark number for the fleet.

When we come to replacing the Astute, short of a war breaking out in the meantime, or Britain becoming an economic superpower within a generation, we will be realistically looking at a one-for-one replacement programme only, in the best case. At worst we will either cut numbers from the outset or, as with so many programmes before now, see numbers cut throughout the development phase of the project.

If you can point out a project in recent years where we replaced a legacy fleet with a successor system and did so in larger numbers than we had before, I’d be happy to retract my statement. I think you'll be hard pressed though because i certainly can't remember one.

You might say, 'but what if our future governments get serious about defence? What then?' Well, i'd say i'd love to believe that will happen - but i seriously can't see it though, not even with our present security situation. It'd take a marked deterioration in global security to see the kind of investment we need now; by which point we might already be screwed to all hell. On this particular point, i'd very dearly like to be proven wrong.

[Repulse]

even if it were being talked about in official circles, we have no, realistic, material way of making it happen.

We do, you just need to cancel the SSBNs or build fewer. No need for a new design just build more of what we have.

[Engaging Strategy]

No, i saw that bit as well. Simply put, judging by well-established MoD/Whitehall precedents, 7 is the new benchmark number for the fleet.

That's not what is being argued here, 7 may be the MoD's planning assumption that makes the figures add up nicely for the Treasury but out in the real world it's very much an inadequate force for what's being asked of it. The Russian Navy currently has 7 SSBNs, 3 SSGNs, 14 SSNs and 7 SSKs assigned to their Northern Fleet while the RN (on a good day) will have 2 SSNs and an SSBN in the Atlantic. Once you factor in a boat to guard the carrier group when it's fully worked up and in service that number sinks to more like 1 on a regular basis. One submarine. For a very long time people cautioned about putting all our warship eggs into a few extremely expensive baskets that we can't, under any circumstances, afford to lose. Well now it's all but happened with the SSN fleet. HMG and the MoD have, for a very long time now, made a series of wholly unrealistic and dangerous assumptions about what is an acceptable and effective level of defence for this country to have. I would rather we face up to the problem and put it right before our chickens come home to roost and a lot of good people probably die.

When we come to replacing the Astute, short of a war breaking out in the meantime, or Britain becoming an economic superpower within a generation, we will be realistically looking at a one-for-one replacement programme only, in the best case. At worst we will either cut numbers from the outset or, as with so many programmes before now, see numbers cut throughout the development phase of the project.

This line of argument completely ignores the simple fact that defence capacity and capability doesn't scale with economic strength in a linear fashion. It's more a matter of national will than anything else. Look at Russia, a country with an economy less than half the size of Britain's but able to build and sustain and use large and relatively modern armed forces because the political will exists to do so. Yes, there is some degree of coasting on old Soviet equipment going on, but in key areas like submarine and warship production and refurbishment they're serious about modernisation and are funding it properly. For another example look to Denmark, a country that spends a tiny proportion of it's budget on defence (~1.3% GDP) yet has a reputation for punching well above it's weight (to coin that awful phrase) because what they bring to the party is good kit, properly resourced, and the determination to use it. We need to stop thinking about defence in terms of inputs and start thinking in terms of what we need our forces to be able to do, then pay the money to get the people and kit to achieve that.

If you can point out a project in recent years where we replaced a legacy fleet with a successor system and did so in larger numbers than we had before, I’d be happy to retract my statement. I think you'll be hard pressed though because i certainly can't remember one.

The key point there is "in recent years". In recent years we've lived through a brief period of near-total US defence hegemony that is increasingly looking like it's ever more speedily coming to an end. In recent years we had a weak and pacific Russia and China. In recent years another conventional war in Europe was unthinkable. See where I'm going with this? The world is changing rapidly and if we don't adapt we run the very real risk of getting caught with our trousers down and something really serious happening, by accident or by design, the likes of which we haven't seen since 1945.

You might say, 'but what if our future governments get serious about defence? What then?' Well, i'd say i'd love to believe that will happen - but i seriously can't see it though, not even with our present security situation. It'd take a marked deterioration in global security to see the kind of investment we need now; by which point we might already be screwed to all hell. On this particular point, i'd very dearly like to be proven wrong.

That's my exact point, we've already seen a marked and very serious deterioration in the global security situation. A United States that if flirting with an isolationist Presidential candidate, a resurgent and revanchist Russia, an increasingly expansionist and assertive China, a crescent of instability in the MENA region. In six years since 2010 all the assumptions made in that defence review have been shredded and thrown to the four winds, we need to be a lot stronger than we currently are; otherwise we run the risk of marching blindly towards a threat that we can't deal with militarily, and after we've passed that point who knows what the world will look like.

[~UNiOnJaCk~]

That's not what is being argued here, 7 may be the MoD's planning assumption that makes the figures add up nicely for the Treasury but out in the real world it's very much an inadequate force for what's being asked of it. The Russian Navy currently has 7 SSBNs, 3 SSGNs, 14 SSNs and 7 SSKs assigned to their Northern Fleet while the RN (on a good day) will have 2 SSNs and an SSBN in the Atlantic. Once you factor in a boat to guard the carrier group when it's fully worked up and in service that number sinks to more like 1 on a regular basis. One submarine. For a very long time people cautioned about putting all our warship eggs into a few extremely expensive baskets that we can't, under any circumstances, afford to lose. Well now it's all but happened with the SSN fleet. HMG and the MoD have, for a very long time now, made a series of wholly unrealistic and dangerous assumptions about what is an acceptable and effective level of defence for this country to have. I would rather we face up to the problem and put it right before our chickens come home to roost and a lot of good people probably die.

If you go back to my previous post, you would see that i say it would be nice if we had extra SSN's to play with - there's no denying it. But, without intending a pun, the ship has sailed from where i am standing. Short of an actual inter-state war breaking out there isn't a snowball's chance in hell that we will be putting more SSN's in the water between now and whenever the Astute gets replaced.
There is no point dreaming about more SSNs – it’s simply an exercise in fantasy fleet making all the while we are stuck with the political realities we face – which is my whole point.

This line of argument completely ignores the simple fact that defence capacity and capability doesn't scale with economic strength in a linear fashion. It's more a matter of national will than anything else. Look at Russia, a country with an economy less than half the size of Britain's but able to build and sustain and use large and relatively modern armed forces because the political will exists to do so. Yes, there is some degree of coasting on old Soviet equipment going on, but in key areas like submarine and warship production and refurbishment they're serious about modernisation and are funding it properly. For another example look to Denmark, a country that spends a tiny proportion of it's budget on defence (~1.3% GDP) yet has a reputation for punching well above it's weight (to coin that awful phrase) because what they bring to the party is good kit, properly resourced, and the determination to use it. We need to stop thinking about defence in terms of inputs and start thinking in terms of what we need our forces to be able to do, then pay the money to get the people and kit to achieve that.

Moot point because we aren't willing to pay for it. Can't see a massive change of culture on the horizon anytime soon either. Even the 2015 SDSR, for all its supposed seriousness in rhetoric about the darkening of our world and the government's commitment to defence, has failed, in significant areas, to back words with actions - the fudging of the budget numbers speaks volumes about just how 'serious' this administration is about defence.

The key point there is "in recent years". In recent years we've lived through a brief period of near-total US defence hegemony that is increasingly looking like it's ever more speedily coming to an end. In recent years we had a weak and pacific Russia and China. In recent years another conventional war in Europe was unthinkable. See where I'm going with this? The world is changing rapidly and if we don't adapt we run the very real risk of getting caught with our trousers down and something really serious happening, by accident or by design, the likes of which we haven't seen since 1945.

We both come have background in historical academia so you should know as well as i that this nation has a pitiful record when it comes to preparing to face future threats. Who says it'd be any different next time round? I don't like it any more than you do, but since neither of us have the power to change our national/political culture towards defence matters, this country will continue to do what it has always done in the past, stick its head in the sand until it is too late and pay for it dearly later.

If we did change, it'd be a first - but I’m not hopeful.

That's my exact point, we've already seen a marked and very serious deterioration in the global security situation. A United States that if flirting with an isolationist Presidential candidate, a resurgent and revanchist Russia, an increasingly expansionist and assertive China, a crescent of instability in the MENA region. In six years since 2010 all the assumptions made in that defence review have been shredded and thrown to the four winds, we need to be a lot stronger than we currently are; otherwise we run the risk of marching blindly towards a threat that we can't deal with militarily, and after we've passed that point who knows what the world will look like.

Coming back to what i said above, even with all this change, what has been the government's response? Rhetoric largely unsupported by words and a continued desire to stick one's head in the sand; all the while paying lip service to security matters to keep the otherwise ignorant public happy.

Sure, some changes were realised and i think everyone would agree that SDSR 2015 was better than a poke in the eye with a sharp stick, but i see no sign that the government is truly serious about the defence of this nation. You, i, and everyone else here knows that it'd require a lot more investment that what has been afforded to truly bring us back to a level of comfortable, war winning capability.

This is the reality we live with. We may want to see it changed, but you can't argue that it doesn't exist all the same.

[Opinion3]

@UJ

I am really not in agreement. I believe that EngagedStrategy has just independently made the same basic point I have made on the CVF thread.

In summary, the world is different and it might suit the politicians to say there is a peace dividend to be taken, but it is like the 'Pension Holiday' companies have been taking for yonks. Look where we are now. They were sprouting rubbish.

The threats look real, namely being asked to stand up against Russia on our own two feet (with maybe our European comrades besides us). The US has being forking out in excess of $170bn per annum for foreign bases, Obama, Trump and quite possibly the American people want this cut big style.

The numbers we have are insufficient PERIOD.

The ability to regenerate capability in a war is only possible if you have that option. France had Marseilles, Saint-Nazaire, Cherbourg as major warship shipyards (plus Brest as a repair yard). All gone in what was one quick invasion. Yes we have to make decisions, yes we have to find money and prioritise how we spend it, but we also have to stop and access the threats and needs. We aren't doing that. EngagingStrategy has offered his take on a small part of our Armed Forces. It isn't fantasy fleets, it is a threat analysis.

[Opinion3]

@UJ

"We both come have background in historical academia so you should know as well as i that this nation has a pitiful record when it comes to preparing to face future threats. Who says it'd be any different next time round? "

Historically the RN at the turn of the previous century was very forward thinking. Pax-Britannia was also not a sign of head in the sand, I believe the strategy was the RN needed to be larger than all adversaries added together

[Engaging Strategy]

If you go back to my previous post, you would see that i say it would be nice if we had extra SSN's to play with - there's no denying it. But, without intending a pun, the ship has sailed from where i am standing. Short of an actual inter-state war breaking out there isn't a snowball's chance in hell that we will be putting more SSN's in the water between now and whenever the Astute gets replaced. Theirs is no point dreaming about more SSNs – it’s simply an exercise in fantasy fleet making all the while we are stuck with the political realities we face – which is my whole point.

So that's it then, we're stuck in a position of tremendous weakness with wholly inadequate defences due to "political realities" (read: Treasury fantasies). My point isn't that the UK government plans to make a change, it's that it needs to do so. We're a rich country, we just lack the will to pull our weight and defend ourselves.

Moot point because we aren't willing to pay for it. Can't see a massive change of culture on the horizon anytime soon either. Even the 2015 SDSR, for all its supposed seriousness in rhetoric about the darkening of our world and the government's commitment to defence, has failed, in significant areas, to back words with actions - the fudging of the budget numbers speaks volumes about just how 'serious' this administration is about defence.

Exactly, now we're committed to the 2% minimum we can start by not fudging the numbers and getting a bit more meat on the bones. Baby steps. This government may not be serious, but if it comes to the US bluntly telling us to pull our weight or they start thinking about leaving NATO then things may start to change. Washington has handled Europe with kid gloves on their reluctance to spend on defence properly, I can see attitudes shifting on the other side of the pond that are far more likely to push us to spend more than the threats of Russia or MENA instability!

We both come have background in historical academia so you should know as well as i that this nation has a pitiful record when it comes to preparing to face future threats. Who says it'd be any different next time round? I don't like it any more than you do, but since neither of us have the power to change our national/political culture towards defence matters, this country will continue to do what it has always done in the past, stick its head in the sand until it is too late and pay for it dearly later.

If we did change, it'd be a first - but I’m not hopeful.

Not true, from the 17th through to the mid 20th century the UK was well prepared to defend itself and deter its enemies, with military force when necessary. The entire 19th century from the perspective of the UK is a lesson in what can be achieved by strong conventional deterrence backed by real political will. Even before the Second World War, during the "appeasement" period and very hard economic times we walked with our eyes open-the RN remained vast and capable of defending the UK from invasion and we had serious planning and preparation go into the development of the critical war industries and conscription processes that would see us through. Throughout the Cold War as well, while we cut back (often harshly and foolishly) there was always the clear cast iron commitment of serious forces to the central front: BAOR, the GIUK Gap, RAF Germany and Trident. What we have now is single Division (only available at 6+ months notice due to reliance on reserves), a small and widely scattered surface and sub-surface fleet and an RAF that comprises probably ~80 front-line aircraft. We've never been this poorly prepared before. In the past, even when it was bad, there was always some slack to draw from. Not anymore.

Coming back to what i said above, even with all this change, what has been the government's response? Rhetoric largely unsupported by words and a continued desire to stick one's head in the sand; all the while paying lip service to security matters to keep the otherwise ignorant public happy.

Sure, some changes were realised and i think everyone would agree that SDSR 2015 was better than a poke in the eye with a sharp stick, but i see no sign that the government is truly serious about the defence of this nation. You, i, and everyone else here knows that it'd require a lot more investment that what has been afforded to truly bring us back to a level of comfortable, war winning capability.

This is the reality we live with. We may want to see it changed, but you can't argue that it doesn't exist all the same.

I never purported to argue that it doesn't exist, I'm arguing that it's a bloody dangerous state of affairs that we can ill afford to continue with. Governments can afford to play fast and loose with defence because the public don't see the problems until they're catastrophically revealed when inadequate forces are sent to war or an awful accident occurs because something critical was cut. I'm not even talking about a comfortable capability here, I'm talking about having more than one bloody submarine available to protect the UK. I'm talking about having an army that (whatever size we decide it needs to be) isn't hollowed out so half the formations are on-paper only to make our Wikipedia page look nice. We can choose to do less and have smaller armed forces if we want, but when we decide they are to do something we need to resource them properly. This is what Denmark does, it can't afford full spectrum capability so it focuses and does a few things very well.

[~UNiOnJaCk~]

It seems that no-one is actually reading a damn thing i have written...i have not argued that our position is sufficient, i have said the complete opposite - our position is entirely unacceptable, in that there is no dispute. What i am trying to point out is that the reality we face dictates that this is a position we are likely to be stuck with some time yet, if not indefinitely. That is the basic point in all this, there is very little else to it. You may not like the message, but don't shoot the messenger. You are presently arguing against positions i am not responsible for or in favour of. If we all want to pretend that that all we have to do is turn on the tap and hey presto, capability in abundance, you can do so - but it in no way reflects the set of circumstances we presently find ourselves with. I don't like it anymore than you guys, but there it is.

We need the extra capability, yes. Are we likely to get it? No, not in my opinion.

As for the historical points, I have things I would like to mention on that note but it would only derail the thread.

[Opinion3]

@UJ

Insufficient is your usual line, and yes I understand there is no argument on acceptability. But just recently we have ALL gone along with the line "but it's all fantasy" "MOD isn't gonna change" "There is no money". Right now, I for one am turning......

It isn't good enough and therefore should no longer we used as an explanation.

There is no gap to build Astutes isn't a good enough excuse in other words. (By the way, I haven't referenced back to what you said, so please de-personalise my line of argument).

[Repulse]

Everyone has also ignored the fact that more SSNs can be afforded by changing the SSBN plans. Even going for a more modest hybrid design with 4 tubes could be a way to increase the number of available SSNs.

[shark bait]

Everyone has also ignored the fact that more SSNs can be afforded by changing the SSBN plans. Even going for a more modest hybrid design with 4 tubes could be a way to increase the number of available SSNs.

The SSBN plans cant be changed unless we relinquish our nuclear deterrent, they must go ahead as planned if we want to maintain our ultimate guarantee of security. As such the capacity at barrow will be full for the next 2 decades leaving to wiggle room to increase numbers.

Beyond then there is the possibility of an increase, if there is the political support.

What i am trying to point out is that the reality we face dictates that this is a position we are likely to be stuck with some time yet, if not indefinitely

We are certainly only stuck with 7 nuke boats for "some time yet", but I will dispute we will be stuck with that indefinitely.

Slowly defence spending has been eroded since the second world war, and will the end of the cold war we have been through a period of US and to some extent european dominance that has led to what is possibly the most peaceful period of human civilisation since we industrialised.

The peace combined with increasing living standards and state welfare has created the conditions for a reduced level of defence spending. Top that off with a recession and a government whose primary mandate is to remove the deficit, and we end up in the position we are in, with defence at rock bottom. 2% is the minimum.

Now we are beginning to see those conditions reversed, Russia is returning and China is coming of age, which challenges the past decades of US and European dominance. Meanwhile the economy is growing, the deficit is shrinking which is creating more favourable conditions for defence.

We like our western partners have begun increasing spending for the first time in a long time in response to this change. The effect is slow at first, but it is expected to accelerate as US sponsored security is challenged further.

What does this mean for subs? I think it means it is reasonable for us to continue on this upward trend, the next government wont be so focused on deficit reduction, and its possible defence will be prioritised differently. I don't think we can say we will be stuck in this glut indefinitely, and the prospect of more subs in 20 years time does not seem impractical.

The upward trend may only be modest, but the reaction to modest change by the 5th biggest economy can still be pretty large.

I would say the biggest challenge to defence is a Corbyn government. If we can avoid that I remain cautiously optimistic, as the trends of the past 20 years are being reversed.

[Opinion3]

Sharkbait

Either Russia is an increasing threat / it is a threat or it isn't. If it isn't the the build status quo is OK, but if it is a threat then thinks need to change. It looks to me that there is a big change on the Russia front and we need to respond accordingly.

Building more Astute is the most logical step, they are a known quantity and we probably can fit it in

[shark bait]

Russia is an increasing threat, but it isn't the sole threat. Capable submarines are proliferating around regional powers, many of which are not the most stable. Whist they aren't going to be challenging us globally like the Russians may, the ability for small states to deny us access is increasing, which would seriously limit our ability to respond from the sea.

Looking at the schedule there is a gap, but successor will be over twice the size of Astute, and thus requiring more time to build, making that gap look smaller.

Successor cant stop, and it is too big to introduce changes or additional risk into the programme.

Unfortunately we are stuck with 7, unless we fancy an adventure with SSK's.

[seaspear]

It is difficult for democracies to outspend totalitarian regimes on defense, that are not answerable for poor health services and reduced life spans of their citizens ,last time I looked up Russias for instance it was twenty years fewer than most European countries ,Chinas not any better

[Repulse]

The SSBN plans cant be changed unless we relinquish our nuclear deterrent, they must go ahead as planned if we want to maintain our ultimate guarantee of security

Looking at the schedule there is a gap, but successor will be over twice the size of Astute, and thus requiring more time to build, making that gap look smaller.

Successor cant stop, and it is too big to introduce changes or additional risk into the programme.

The cost of introducing a few SSKs would greatly outweigh the benefits. Changing the SSBN design is still possible and I'd argue absolutely necessary to avoid a similar car crash as has happened in the surface fleet with the CVFs. I'd argue a smaller more numerous hybrid class with say 4 rather than 8 tubes to build 5 ships would ease as well as using the design gap to build an 8th Astute.

BTW, I thought Russia no longer had a CASD?

[Pseudo]

The cost of introducing a few SSKs would greatly outweigh the benefits. Changing the SSBN design is still possible and I'd argue absolutely necessary to avoid a similar car crash as has happened in the surface fleet with the CVFs. I'd argue a smaller more numerous hybrid class with say 4 rather than 8 tubes to build 5 ships would ease as well as using the design gap to build an 8th Astute.

If you then adapt the CMC to accept something like the CWL 'six-shooters' on Virginia block III you'd have a nice mini-SSGN in the same boat.

[Engaging Strategy]

The cost of introducing a few SSKs would greatly outweigh the benefits.

The argument isn't that the SSKs would be as operationally useful as the SSNs, but that they would free-up SSNs for the tasks that they're needed for. Currently UK SSN numbers are awfully low, with 4 boats available at any time for tasking. One of which will likely be in the North Atlantic, one East of Suez and one on training/Perisher around the UK. That leaves us with around 1 boat "spare" for crisis response. With the additional pressure of task group escort once the QE comes into service that leaves us with, er... no spare SSNs at all. Now introduce a class of, say, five reasonably modest ~3,000t SSKs into the picture (with 2-3 available for tasking) and suddenly the whole picture changes. Now you can remove the Atlantic SSN and the SSN needed for training/Perisher duties and put them elsewhere (or, more sensibly, hold one or both of them as a high-readiness reserve/contingency force). Considering that modest SSKs, on average, cost about half of what the RN's SSNs do it's far easier to make the sums add up (presuming an uplift in the defence budget) with 5 more SSKs than 5 more SSNs. Smaller boats would also be quicker to build, limiting their impact on an otherwise tight submarine build schedule.

Changing the SSBN design is still possible and I'd argue absolutely necessary to avoid a similar car crash as has happened in the surface fleet with the CVFs.

Make no bones about it, the cuts to the surface fleet's escort numbers (I presume that's what you're talking about) weren't because of the money spent on the carriers. Manpower was the critical issue, and simply put the RN couldn't crew all the ships it had with 5,000 less people. Instead of having the embarrassment of having the B3 Type 22s placed in mothballs, likely never to have been re-activated, they were cut up for razor blades.

I'd argue a smaller more numerous hybrid class with say 4 rather than 8 tubes to build 5 ships would ease as well as using the design gap to build an 8th Astute.

There are very good reasons why the hybrid SSN/SSBN concept has never actually been tried. It was considered by the UK back in the 60s and dismissed for for very good reasons.

1. Their operational utility as "SSNs" would be severely compromised-you couldn't send the duty "Hybrid bomber" East of Suez because you'd compromise deterrence vs Russia.

2. You couldn't use them offensively for fear that losing a boat would cripple your deterrent.

3. Deploying a nuclear-armed submarine in offensive SSN operations would run the risk of onlookers fearing that it's a prelude to the use of nuclear weapons.

4. Similarly you couldn't use it as a conventional deterrent in the same way that you can use an SSN in that manner, spreading "rumors" that it's in the South Atlantic for example could lead to a diplomatic crisis because its deployment is perceived as a veiled nuclear threat.

5. 4 Trident II D5 missiles at sea at all times aren't a credible deterrent and don't fulfill the "Moscow Criterion". An SSBN armed with 12 Trident II D5 missiles can.

There are good reasons that the SSN and SSBN roles have been separated out. Hybrid boats have been considered in the past on numerous occasions and ruled out as impractical. Simply put: they don't work well in either role.

BTW, I thought Russia no longer had a CASD?

You've got to be kidding! They've got 11 SSBNs, 7 of which are assigned to the Northern Fleet and 7 cruise missile submarines that are also likely nuclear-capable.

[Ron5]

5 new 3k ton SSK designed, built and entered into service at half the cost of 5 Astutes i.e. under 2 billion pounds?

Good luck with that.

[Engaging Strategy]

5 new 3k ton SSK designed, built and entered into service at half the cost of 5 Astutes i.e. under 2 billion pounds?

Good luck with that.

Build a licence version of an existing design, saves on the design phase substantially. Others have built small SSKs for cheap: Japan & Germany.