Age of large ships over

[johnpjones1775]

How many times have we heard that in the last 200 years? Particularly about surface combatants specifically?

Introduction of the torpedo and torpedo boat, ‘it’s the end of the battleship!’
Battleships continued on for another century or so.
Introduction of submarines, ‘it’s the end of large ships!’ Well over a century large ships still exist.
Introduction of naval aviation ‘it’s the end of surface combatants!’ Well over a century later large surface combatants are still integral parts of every fleet, if not the most important part.

 

[Byeman]

How many times have we heard that in the last 200 years? Particularly about surface combatants specifically?

Introduction of the torpedo and torpedo boat, ‘it’s the end of the battleship!’
Battleships continued on for another century or so.
Introduction of submarines, ‘it’s the end of large ships!’ Well over a century large ships still exist.
Introduction of naval aviation ‘it’s the end of surface combatants!’ Well over a century later large surface combatants are still integral parts of every fleet, if not the most important part.

There are no large ships (cruisers and battleships) anymore. Just destroyers and carriers.

 

[EmoBirb]

There are no large ships (cruisers and battleships) anymore. Just destroyers and carriers.

So +10.000t ships and +100.000t super carriers aren't large ships?

Ships as a whole have become bigger over the past several decades. Just look at the Zumwalt, Sejong, ASEV or Type 055. These ships are utterly massive for "destroyers".

So while ships (mostly) shrunk following WW2 over the course of the cold war and modern era they grew in size again. Today destroyers rival battle cruisers of old.

 

[Dilandu]

Well, by now large warships - if modern and fully functional - seems to be surprizingly resistant to everything thrown against them. The Red Sea campaign demonstrated, that modern destroyers could fight off missile attack that would be overwhelming by Cold War means.

 

[johnpjones1775]

There are no large ships (cruisers and battleships) anymore. Just destroyers and carriers.

The zumwalt is literally the size of a pre-dreadnought battleship.
Burkes are the size of WWII light cruisers.

Modern corvettes are the size of frigates from the 60s-70s frigates are the size of destroyers from the same period (or larger). Destroyers are the size of WWII cruisers or pre-dreadnought battleships.

But even from the perspective of classification only the US and russia both still have cruisers in their fleets, the Russians still have very large cruisers in their fleet, so you’re wrong by every metric.

 

[johnpjones1775]

So +10.000t ships and +100.000t super carriers aren't large ships?

Ships as a whole have become bigger over the past several decades. Just look at the Zumwalt, Sejong, ASEV or Type 055. These ships are utterly massive for "destroyers".

So while ships (mostly) shrunk following WW2 over the course of the cold war and modern era they grew in size again. Today destroyers rival battle cruisers of old.

I’m not even sure ships really shrank post WWII necessarily.

The Atlanta class was 530ft long and 7400tons compared to a tico, 567ft and 9800 tons.

Cruiser Truxtun was 564ft long 8500tons.

Cold War ships might have been fewer tons when compared to heavy cruisers, but Cold War era cruisers were generally of similar overall size as WWII CLs (at least in the American fleet)

For destroyers the gearings were 3500tons at 390ft while forest Sherman class is 4000 tons and 418ft.

 

[Josh_TN]

One thing that does seem to be changing (and not just for ships) is prolific and persistent ISR. Regardless of the invention of new platforms and weapons, scouting was always still difficult. The AV-MF still had to eyeball a ship to identify it, if it was not radiating.

At this point there are enough remote sensing satellites and long endurance UAVs that I question if task forces can conceal their position and/or composition anymore.

 

[johnpjones1775]

One thing that does seem to be changing (and not just for ships) is prolific and persistent ISR. Regardless of the invention of new platforms and weapons, scouting was always still difficult. The AV-MF still had to eyeball a ship to identify it, if it was not radiating.

At this point there are enough remote sensing satellites and long endurance UAVs that I question if task forces can conceal their position and/or composition anymore.

No they cannot conceal their position or composition any more, but that came around a while ago

 

[Deleted member 29851]

I’m not even sure ships really shrank post WWII necessarily.

Modern ships require more volume, so if anything, they got larger.

 

[EmoBirb]

Modern ships require more volume, so if anything, they got larger.

Large surface combatants immediately after WW2 became smaller, compared to battleships and battlecruisers. Following several cruiser and destroyer developments in the cold war ships began to grow again and that growth continues to this day. Endurance, more capable subsystems etc. simply lead to size and weight bloat.

 

[johnpjones1775]

Large surface combatants immediately after WW2 became smaller, compared to battleships and battlecruisers. Following several cruiser and destroyer developments in the cold war ships began to grow again and that growth continues to this day. Endurance, more capable subsystems etc. simply lead to size and weight bloat.

well Duh, surface combatant capital ships were much larger than non-capital ship surface combatants…go figure.

But still your statement isn’t 100% true. Russian ‘battle’cruisers, are very much in the same ballpark of size as WWII large cruisers/battlecruisers. (Not that any battlecruisers existed by WWII any way.)

 

[shin_getter]

Ships are more efficient the bigger they are, look at 500k ton tankers and all the paramax 120k ton roaming around. Navy ships are actually pretty small compared to cargo in this era.

With diminishing returns on speed and stable survivability gains from sheer bulk, perhaps Habakkuk have the right idea.

Well over a century later large surface combatants are still integral parts of every fleet, if not the most important part.

If it ain't got large surface combatants it ain't a fleet.

But there is more to power over water than fleets, as land and air forces both have vastly greater reach. One wouldn't need a fleet if land based power projection spans the body of water like a lake.

I believe a lot of ships are procured using the same logic of the high seas fleet.

Well, by now large warships - if modern and fully functional - seems to be surprizingly resistant to everything thrown against them. The Red Sea campaign demonstrated, that modern destroyers could fight off missile attack that would be overwhelming by Cold War means.

Missile tech itself have become much cheaper and accessible as a result of moore's law. I mean, this is Yeman after a civil war we are talking about here.

 

[Josh_TN]

No they cannot conceal their position or composition any more, but that came around a while ago

I would argue it is a relatively recent development, and that it complicates survival against every other class of weapon.

That said, the only thing more vulnerable than a large ship is a small one, and I think the direction navies will go in is a mix of USVs, lightly/optionally manned ships, and modern combatants.

 

[a5mg4n]

It going As long as Economic of most country rely on sea transport,
and as long as systems protecting merchant ships required large platform.
(says size needed for anti-ASBM system/LAMPS/...)

 

[Scott Kenny]

The big radars needed for AShBM and high end AShCM defense require a large ship, hence the very large for a "low end Frigate" Constellation class. Larger ships also allow operating more and more capable ASW helicopters, this is one of the reasons I like the Independence-class LCS with their huge flight deck so much.

Zumwalts are heavier than the post-treaty cruisers like Baltimore-class (~13,600 tons standard). Zs are 15,700tons standard!

I fully expect the DDG(X) Burke replacement to be in the same size class as Zumwalts. The Japanese ASEV is supposed to be the same kind of size, though ASEVs are intended to be a replacement for Aegis Ashore so they have more VLS cells and may not have the Flag space like all the other "Japanese Burkes" do.

I would not be surprised if the CG(X) Tico replacement ends up at Salem-class size, 18,000tons standard/21K full load. Even if the hull is literally just a DDG(X) stretched fore and aft to allow more missiles to be packed inside (like 93 cells at each end).

 

[johnpjones1775]

Ships are more efficient the bigger they are, look at 500k ton tankers and all the paramax 120k ton roaming around. Navy ships are actually pretty small compared to cargo in this era.

With diminishing returns on speed and stable survivability gains from sheer bulk, perhaps Habakkuk have the right idea.

If it ain't got large surface combatants it ain't a fleet.

But there is more to power over water than fleets, as land and air forces both have vastly greater reach. One wouldn't need a fleet if land based power projection spans the body of water like a lake.

I believe a lot of ships are procured using the same logic of the high seas fleet.


Missile tech itself have become much cheaper and accessible as a result of moore's law. I mean, this is Yeman after a civil war we are talking about here.

Even when you can project power over bodies of water there have still been the need for naval assets. Artillery and small arms have long been able to reach across rivers, and in the case of artillery across most lakes for a century or so now, yet we’ve still river and lake battles going back throughout that time.
Navy ships are the boots on the ground so to speak. Just like air power and artillery still havent removed the need for boots on the ground ashore.

 

[johnpjones1775]

I would argue it is a relatively recent development, and that it complicates survival against every other class of weapon.

That said, the only thing more vulnerable than a large ship is a small one, and I think the direction navies will go in is a mix of USVs, lightly/optionally manned ships, and modern combatants.

I mean it’s been at least 2 decades now.

Relative to the history of naval combat yes it’s recent, but relative to modern navies it’s been around a while.

 

[johnpjones1775]

The big radars needed for AShBM and high end AShCM defense require a large ship, hence the very large for a "low end Frigate" Constellation class. Larger ships also allow operating more and more capable ASW helicopters, this is one of the reasons I like the Independence-class LCS with their huge flight deck so much.

Zumwalts are heavier than the post-treaty cruisers like Baltimore-class (~13,600 tons standard). Zs are 15,700tons standard!

I fully expect the DDG(X) Burke replacement to be in the same size class as Zumwalts. The Japanese ASEV is supposed to be the same kind of size, though ASEVs are intended to be a replacement for Aegis Ashore so they have more VLS cells and may not have the Flag space like all the other "Japanese Burkes" do.

I would not be surprised if the CG(X) Tico replacement ends up at Salem-class size, 18,000tons standard/21K full load. Even if the hull is literally just a DDG(X) stretched fore and aft to allow more missiles to be packed inside (like 93 cells at each end).

The current DDG(X) program is the Tico replacement. The term cruiser seems to be dead going forward as there is no CG(X) program planned or even being whispered about in the USN right now.

 

[Josh_TN]

I mean it’s been at least 2 decades now.

Relative to the history of naval combat yes it’s recent, but relative to modern navies it’s been around a while.

I think the proliferation of space based assets is far more recent. China put up something like a hundred remote sensing satellites in 2022 and 2023, and presumably in 2024 again. The NRO just put up 180 in nine launches in under 12 months. Those kind of quantities are much more recent.

But in any case, I think we agree ships can no longer hide in open water anymore, let alone the littorals. That is new, or at least new ish, and that has a much greater impact than any previous technology that was largely weapons based rather than sensors. Even radar, while a huge change, provided little information initially. Now adays you can get potential a rough picture of the target.

 

[Scott Kenny]

The current DDG(X) program is the Tico replacement. The term cruiser seems to be dead going forward as there is no CG(X) program planned or even being whispered about in the USN right now.

If true, DDGX had better include flag space in the base design.

Else someone is going to have to build a flight with flag space, which may-or-may-not involve changes to superstructure or even overall ship's length. It was not unusual to build a couple ships of a class with flag space while the others were built without flag space. Only the Iowas were all built with flag space up through WW2.

I still think that the Tico replacement should get a stretched hull versus the base DDGX, to allow at least 93 Mk41 cells at each end. I'd also like to stick a row of Mk57 PVLS down the sides of the helo deck. Oh, and each end should have space for either a gun or the big-tube install that the Zumwalts are getting. Not sure how far down the 5"/62 sticks versus the big-tube install, but I'm sure the big-tubes are 3 decks deep, maybe 4.

So it may end up that the gun on the design ends up at the stern, so that there's space for the big tubes up front.

 

[Josh_TN]

If true, DDGX had better include flag space in the base design.

Else someone is going to have to build a flight with flag space, which may-or-may-not involve changes to superstructure or even overall ship's length. It was not unusual to build a couple ships of a class with flag space while the others were built without flag space. Only the Iowas were all built with flag space up through WW2.

I still think that the Tico replacement should get a stretched hull versus the base DDGX, to allow at least 93 Mk41 cells at each end. I'd also like to stick a row of Mk57 PVLS down the sides of the helo deck. Oh, and each end should have space for either a gun or the big-tube install that the Zumwalts are getting. Not sure how far down the 5"/62 sticks versus the big-tube install, but I'm sure the big-tubes are 3 decks deep, maybe 4.

So it may end up that the gun on the design ends up at the stern, so that there's space for the big tubes up front.

When says DDGX is the Tico replacement, he means 1:1 is probably the buy rate. Ie, they will not be replacing Burkes.

The tenders I’ve seen have basic bitch mk41s. Any long tubes would be in a hull plug amidship most likely.

 

[Scott Kenny]

When says DDGX is the Tico replacement, he means 1:1 is probably the buy rate. Ie, they will not be replacing Burkes.

I'd expect them to be replacing early Burkes as well. The oldest Burkes were commissioned in the early 1990s. The Flight IIs started commissioning in the late 1990s. Flight IIA did not start commissioning until 2000, and ran until 2012. The Flight IIA Restart commissioned in 2017. And the first Flight III was commissioned in 2023.

After all, there's only 9x Ticos left in service, and they're decommissioning fast. Zero Ticos left by 2030.

I'm expecting some 12-24x DDGX as a minimum. Assuming that they have AAW flag space, you need at least one per carrier group, that's 12. Then you need a bunch for convoy leaders, I'm just going to say another 12.

Then you need the rest of the formal carrier battle group: At least one cruiser (for AAW flag), at least two destroyers, and a couple of FFGs for ASW. When cruisers were more available: 2 cruisers, 2-3 DDGs, and 2-3 FFGs.

 

[shin_getter]

Navy ships are the boots on the ground so to speak. Just like air power and artillery still havent removed the need for boots on the ground ashore.

Boots on the ground works because boots gets underground in cover and become very difficult to dig out.

No one cares about boots on the ground if it is a desert or something. In the same sense almost no one care about river boats even if they are useful some of the time.

Frankly the likes of Russian or German naval experience have show how worthless surface ships can be, but that is timeless and can be figured out by looking at a map. The fact that such states still invest in them shows that such assets are often not serious warfighting assets with strategic relevance.

The big radars needed for AShBM and high end AShCM defense require a large ship

I wonder if modern warships are evolving towards a "H-44", in the sense that ship sizes increases massively just to fit defensive systems to make it "survivable" against currrent (to be previous by the time it gets built) gen threats.

In the mean time submarines should become cheaper and better with battery tech improving under massive investment, small modular reactors on the horizon and autonomous tech reducing need for large pressure hulls.

Increase in aircraft and missile range is also clear. It is now possible to fight a war in the pacific with rotorcraft island hopping, no ship needed. I am not sure how warfare would work if starship just gets used as a bomber and drop a hundred tons of munitions per ship on any task force anywhere, do ships even have enough magzine?

 

[johnpjones1775]

If true, DDGX had better include flag space in the base design.

Else someone is going to have to build a flight with flag space, which may-or-may-not involve changes to superstructure or even overall ship's length. It was not unusual to build a couple ships of a class with flag space while the others were built without flag space. Only the Iowas were all built with flag space up through WW2.

I still think that the Tico replacement should get a stretched hull versus the base DDGX, to allow at least 93 Mk41 cells at each end. I'd also like to stick a row of Mk57 PVLS down the sides of the helo deck. Oh, and each end should have space for either a gun or the big-tube install that the Zumwalts are getting. Not sure how far down the 5"/62 sticks versus the big-tube install, but I'm sure the big-tubes are 3 decks deep, maybe 4.

So it may end up that the gun on the design ends up at the stern, so that there's space for the big tubes up front.

Makes no sense to put the the big missiles up front if it blocks a gun on the bow. The missiles go straight up and then turn whatever direction they need to, a gun needs to point at its target.

We probably just need an all new GP VLS, that can accommodate the new hypersonics, while allowing at least dual packing things like standard missiles and octo-packing ESSMs rather than building a ship with multiple sized VLS like the Russian, Chinese, and the NORKs have.

 

[johnpjones1775]

Boots on the ground works because boots gets underground in cover and become very difficult to dig out.

No one cares about boots on the ground if it is a desert or something. In the same sense almost no one care about river boats even if they are useful some of the time.

Frankly the likes of Russian or German naval experience have show how worthless surface ships can be, but that is timeless and can be figured out by looking at a map. The fact that such states still invest in them shows that such assets are often not serious warfighting assets with strategic relevance.

I wonder if modern warships are evolving towards a "H-44", in the sense that ship sizes increases massively just to fit defensive systems to make it "survivable" against currrent (to be previous by the time it gets built) gen threats.

In the mean time submarines should become cheaper and better with battery tech improving under massive investment, small modular reactors on the horizon and autonomous tech reducing need for large pressure hulls.

Increase in aircraft and missile range is also clear. It is now possible to fight a war in the pacific with rotorcraft island hopping, no ship needed. I am not sure how warfare would work if starship just gets used as a bomber and drop a hundred tons of munitions per ship on any task force anywhere, do ships even have enough magzine?

Your analogies are horrible, and you clearly don’t know what you’re talking about.

 

[johnpjones1775]

I'd expect them to be replacing early Burkes as well. The oldest Burkes were commissioned in the early 1990s. The Flight IIs started commissioning in the late 1990s. Flight IIA did not start commissioning until 2000, and ran until 2012. The Flight IIA Restart commissioned in 2017. And the first Flight III was commissioned in 2023.

After all, there's only 9x Ticos left in service, and they're decommissioning fast. Zero Ticos left by 2030.

I'm expecting some 12-24x DDGX as a minimum. Assuming that they have AAW flag space, you need at least one per carrier group, that's 12. Then you need a bunch for convoy leaders, I'm just going to say another 12.

Then you need the rest of the formal carrier battle group: At least one cruiser (for AAW flag), at least two destroyers, and a couple of FFGs for ASW. When cruisers were more available: 2 cruisers, 2-3 DDGs, and 2-3 FFGs.

You’re very optimistic. I’ll be surprised if we get 10 DDG(X) at least in the first batch I’ll be surprised.

 

[Josh_TN]

Makes no sense to put the the big missiles up front if it blocks a gun on the bow. The missiles go straight up and then turn whatever direction they need to, a gun needs to point at its target.

We probably just need an all new GP VLS, that can accommodate the new hypersonics, while allowing at least dual packing things like standard missiles and octo-packing ESSMs rather than building a ship with multiple sized VLS like the Russian, Chinese, and the NORKs have.

The problem with CPS is not just diameter but depth: they are dramatically longer than mk41. So it makes sense to have dedicated cells, since they will penetrate another deck or so into the ship. This is another reason forward mounting may be difficult. DDGX renders seemed to have some dead space between the two stacks, likely to make the engine rooms more widely spaced. This area seeto be where they are thinking the deep tubes should go.

Zoomies have the missiles forward because there was a lot of empty forward below deck space where the 155mm automated magazines were.

 

[Josh_TN]

You’re very optimistic. I’ll be surprised if we get 10 DDG(X) at least in the first batch I’ll be surprised.

Agree, two dozen total on the high end - Tico replacement. Burkes will be replaced by Connies.

 

[Ozair]

Agree, two dozen total on the high end - Tico replacement. Burkes will be replaced by Connies.

With the bulk of the VLS tubes provided by accompanied unmanned assets.

Controversial but if unmanned surface vessels do get traction then perhaps the ship sizes will decrease and onboard weaponry will move towards self defence over requiring each vessel to have to be equipped to fight essentially independent of any support.

 

[johnpjones1775]

The problem with CPS is not just diameter but depth: they are dramatically longer than mk41. So it makes sense to have dedicated cells, since they will penetrate another deck or so into the ship. This is another reason forward mounting may be difficult. DDGX renders seemed to have some dead space between the two stacks, likely to make the engine rooms more widely spaced. This area seeto be where they are thinking the deep tubes should go.

Zoomies have the missiles forward because there was a lot of empty forward below deck space where the 155mm automated magazines were.

Deck penetration doesn’t change anything about a new GP VLS…

 

[johnpjones1775]

Agree, two dozen total on the high end - Tico replacement. Burkes will be replaced by Connies.

I’ll be equally surprised if we get a second batch.
Gotta remember this will likely be no less than $5b
Also don’t think Connies are replacing the Burkes. They’re meant to grow fleet numbers not maintain them.
We won’t see a burke replacement hit the drawing board for at least another 8 years, maybe a decade. Navy seems to like to put off coming up with new ideas until it’s way too late these days. Combine that with Burkes being the last truly successful program we’ve had, the navy will be very hesitant to try to create a replacement.

We should have started the FFG(X) program a decade ago when it was clear china was well into its ascendancy, and russia was looking to rebuild its old empire.

The current DDG(X) should have been started around the same time as well tbh, with a burke replacement about the time we started the FFG(X) program.

 

[Josh_TN]

Deck penetration doesn’t change anything about a new GP VLS…

It makes it a big waste of space when it isn’t caring an CPS.

 

[Josh_TN]

I’ll be equally surprised if we get a second batch.
Gotta remember this will likely be no less than $5b
Also don’t think Connies are replacing the Burkes. They’re meant to grow fleet numbers not maintain them.
We won’t see a burke replacement hit the drawing board for at least another 8 years, maybe a decade. Navy seems to like to put off coming up with new ideas until it’s way too late these days. Combine that with Burkes being the last truly successful program we’ve had, the navy will be very hesitant to try to create a replacement.

We should have started the FFG(X) program a decade ago when it was clear china was well into its ascendancy, and russia was looking to rebuild its old empire.

The current DDG(X) should have been started around the same time as well tbh, with a burke replacement about the time we started the FFG(X) program.

FFGX will effectively be Burke I replacement, and likely unupgraded Burke II replacement as well, then if enough get built fast enough they will grow total fleet numbers.

 

[Scott Kenny]

I wonder if modern warships are evolving towards a "H-44", in the sense that ship sizes increases massively just to fit defensive systems to make it "survivable" against currrent (to be previous by the time it gets built) gen threats.

Sorta, IMO.

Large ships due to sensors needed, which gives space for lots of defenses.

In the mean time submarines should become cheaper and better with battery tech improving under massive investment, small modular reactors on the horizon and autonomous tech reducing need for large pressure hulls.

Disagree, IEP enginerooms are large. Even stuffing the drive motor outside the pressure hull to reduce hull penetrations doesn't really help reduce the size of the engineroom.

The torpedo room on a Virginia-class makes up roughly half the forward compartment, and proportionally more for Barbel-derivatives and Soryu-class.

I am not sure how warfare would work if starship just gets used as a bomber and drop a hundred tons of munitions per ship on any task force anywhere, do ships even have enough magzine?

Depends on how exactly those munitions are guided and how heavy they are individually.

Makes no sense to put the the big missiles up front if it blocks a gun on the bow. The missiles go straight up and then turn whatever direction they need to, a gun needs to point at its target.

Guns do not have to go on the bow. 5" on the stern works fine for almost all situations.

And honestly I was considering a 57mm or 76mm far forward, where the bow doesn't have room for VLS.

We probably just need an all new GP VLS, that can accommodate the new hypersonics, while allowing at least dual packing things like standard missiles and octo-packing ESSMs rather than building a ship with multiple sized VLS like the Russian, Chinese, and the NORKs have.

As I understand it, the hypersonics are some 34" diameter tubes, and are 4 decks deep. They're basically the same size as a Polaris missile!

 

[Archibald]

Reminds me of this novel.

The Ministry for the Future - Wikipedia

en.wikipedia.org

Drone swarms (kinda flying hive mind) makes airliners and warships relics of the past.

 

[johnpjones1775]

It makes it a big waste of space when it isn’t caring an CPS.

Not really. I’d say dedicated cells that can only be used for one mission set is a bigger waste of space tbh

 

[johnpjones1775]

Sorta, IMO.

Large ships due to sensors needed, which gives space for lots of defenses.



Disagree, IEP enginerooms are large. Even stuffing the drive motor outside the pressure hull to reduce hull penetrations doesn't really help reduce the size of the engineroom.

The torpedo room on a Virginia-class makes up roughly half the forward compartment, and proportionally more for Barbel-derivatives and Soryu-class.



Depends on how exactly those munitions are guided and how heavy they are individually.




Guns do not have to go on the bow. 5" on the stern works fine for almost all situations.

And honestly I was considering a 57mm or 76mm far forward, where the bow doesn't have room for VLS.




As I understand it, the hypersonics are some 34" diameter tubes, and are 4 decks deep. They're basically the same size as a Polaris missile!

That’s fine, just means you can fit more normal missiles in each cell.

 

[johnpjones1775]

Think of it this way.
Would you really prefer 120 mk41 and a dozen CPS VLS, or would you prefer 96-100 VLS(X) that can operate any missile we have meaning we could potentially have 80 CPS onboard and 16-20 cells for SAMs?

SM2 and 6 are less than 14” diameter so double packing them should be feasible into this new theoretical VLS, meaning 16 cells gives you 32 mid-long range SAMS.

Even at a split of 12 CPS and 84 cells for everything else you can still get more of our conventional missiles overall. Say 4 for TLAM, meaning 160 Standard Missiles assuming no ESSMs.

 

[Scott Kenny]

As-is, the CPS tubes are able to hold 6x 21" weapons because they're using the same inserts as the Virginia Payload Modules. So a sub or ship could carry 3x(?) CPS per tube, and swap that out quickly for a 6x21" insert. This makes the inserts cheaper due to large production runs.

Also, I believe that the CPS tubes more or less replace a single 8-cell block of Mk41s dimensionally, barring the extra deck of depth even over the Strike-length cells.

Think of it this way.
Would you really prefer 120 mk41 and a dozen CPS VLS, or would you prefer 96-100 VLS(X) that can operate any missile we have meaning we could potentially have 80 CPS onboard and 16-20 cells for SAMs?

SM2 and 6 are less than 14” diameter so double packing them should be feasible into this new theoretical VLS, meaning 16 cells gives you 32 mid-long range SAMS.

Even at a split of 12 CPS and 84 cells for everything else you can still get more of our conventional missiles overall. Say 4 for TLAM, meaning 160 Standard Missiles assuming no ESSMs.

If the USN had an unlimited budget? absolutely go for the ~48" VLSX that can single-pack CPS, quad-pack Tomahawks or SM3s/6x, 9-pack SM2s, and 16pack ESSMs.

But we don't have an unlimited budget.

So I think DDGX is going to end up with a mix of Mk41, Mk57, and CPS tubes/cells. Mk57 specifically because it can be placed at the edge of the helo deck, mostly out of the way. If we go with a widened hull compared to a Burke like the Japanese ships, it'd be possible to get the PVLS in place without reducing the size of the landing area. Burke landing area is ~43'x54', tough there are some cleats and bollards around the edge to get in the way.

Maybe a flight II DDGX would get a VLSX instead of the mix, but the first dozen are needed much too soon to develop a whole new VLS for them.

 

[DWG]

Large surface combatants immediately after WW2 became smaller, compared to battleships and battlecruisers.

Only if you compare post-war cruisers to WW2 era battleships. If you compare post-war cruisers to WW2 era cruisers, growth continued, or size was held consistent with late war designs and armament dropped because of the other demands on volume. The UK's first post-war looks at truly new light cruisers in 1951 came in at 17,350t deep and 19,000t deep for 4x2x6" or 5", they had to halve the armament to get down to 10,000t