Cruiser designs if the LNT/WNT never happened

[40902nd]

Personally, I think the concept of 'Light' and 'Heavy' Cruisers won't exist, and we would see a greater spread of warship sizes. The stair-step jumps we see in categories is a function of the Treaty system. Without it, and depending on the need of the nation in question, I believe we would see much blurrier designs. I also believe we'd see smaller cruiser forces overall, as the naval budgets get eaten by the naval arms race that was developing and that the treaties were specifically instituted to kill.

Still, when it comes to the cruisers that were built, I believe the USN would prefer fast (35-kt), 8-inch armed cruisers with high endurance (10,000nm cruising), with proper IZ against their own guns. The arrangement would likely be AB-XY with either 8, 10, or 12 guns. Given enough time, these might evolve into 10-inch gun cruisers, depending on developments of other nations.

The Royal Navy would prefer lighter 5,000 to 7,500 ton designs for trade productions. If they have the budget for it, they might have some heavier cruisers armed 7.5" or 9.2" guns, though the G3 and N3 would devour large portions of their budget.

I imagine that the Japanese would focus more on battleship and battlecruisers to maximize resources, and so cruisers would be kept small and relegated to destroyer leaders.

I don't know what France or Italy would do.

Germany would cry in the corner, and then probably build coastal monitors.

Of course, this is all just my speculation.

 

[CV12Hornet]

The Royal Navy would prefer lighter 5,000 to 7,500 ton designs for trade productions. If they have the budget for it, they might have some heavier cruisers armed 7.5" or 9.2" guns, though the G3 and N3 would devour large portions of their budget.

Again, no, they won't. We know what the RN was looking at in 1921 and it's 8" cruisers around 10,000 tons.

I imagine that the Japanese would focus more on battleship and battlecruisers to maximize resources, and so cruisers would be kept small and relegated to destroyer leaders.

Also no - the Furutakas predate the Washington Treaty and show where the IJN's thinking was regarding counter-scout assets.

Also, they after 1923 they won't be able to build capital ships for a while for financial reasons.

 

[Owens Z]

One result of WNT was not only was cruiser size capped, but that cap became a de facto minimum. My suspicion is that cruisers would not all become 20000 ton monsters, but most cruisers would remain in the 7,500 ton range, armed with guns in the range of 15 cm...

Seen in hindsight, the US Navy's fast-firing and fast-training six-inch guns with 'super-heavy' 130-lb APHE projectiles were more effective for the ferocious 1942-43 Pacific naval battles than the much slower eight-inch guns which Scott Kenny prefers, whose own super-heavy projectiles did not enter service until later. But 7.5kt standard displacement ('standard' would not exist in the absence of the Washington Naval Treaty)—although British light cruisers and the German Leipzig class were near this—seems somewhat tight for distant waters. 10kt standard, like the Brooklyn class or Soviet Chapayev class light cruisers, is more reasonable.

Personally, I think the concept of 'Light' and 'Heavy' Cruisers won't exist, and we would see a greater spread of warship sizes. The stair-step jumps we see in categories is a function of the Treaty system. Without it, and depending on the need of the nation in question, I believe we would see much blurrier designs. I also believe we'd see smaller cruiser forces overall, as the naval budgets get eaten by the naval arms race that was developing and that the treaties were specifically instituted to kill...

Agreed; the legal distinction between heavy cruisers and light cruisers was an artificial product of the interwar naval treaties.

 

[TorpedoJ]

Not strictly related to a 'not-WNT' scenario, but was there ever any consideration given to creating shells with increased performance while maintaining the same calibre at treaty limits?
For example, by creating an 8" shell that is longer and uses a larger charge than standard shells for more range and penetration, in a similar fashion to the trends in MBT shells.

 

[Scott Kenny]

Not strictly related to a 'not-WNT' scenario, but was there ever any consideration given to creating shells with increased performance while maintaining the same calibre at treaty limits?
For example, by creating an 8" shell that is longer and uses a larger charge than standard shells for more range and penetration, in a similar fashion to the trends in MBT shells.

The USN built super-heavy AP shells, some 25-30% heavier than "standard" but fired them at a lower velocity. This relied on the better ballistic coefficient of those heavier shells to preserve velocity downrange.

• 6" shells were 105lbs for the HE and 130lbs for the AP. 6" superheavy AP shells hit at a higher velocity than the HE shells did at all measured ranges, despite a 165fps lower muzzle velocity.
• 8" shells were 260lbs for HE and early AP, 335lbs for superheavy AP. The superheavy AP shells hit at a higher velocity than the HE shells did at ranges beyond 10,000 yards.
• 14" shells don't appear to have had a specific superheavy shell developed, 14" armed battleships were obsolescent in WW2.
• 16" shells were 1900lbs for HE, 2240lbs for the light AP, and 2700lbs for the superheavy AP. 16" superheavy AP hit at higher velocities than the HE or light AP shells did at ranges beyond 10,000 yards.

 

[40902nd]

Again, no, they won't. We know what the RN was looking at in 1921 and it's 8" cruisers around 10,000 tons.

I'll admit the bulk of my research has been down in USN and German Naval designs, so I don't know about all of the proposals that the British Admiralty was floating around at the time, but I do know that the British were more concerned, especially later into the treaty-era, with lighter units to protect trade. Now, admittedly, the preference for lighter ships could have been to maximize the number of hulls within a limited tonnage maximum, and relying on the compromised nature of treaty designs to allow weaker cruisers to threaten heavier ones.
Anyway, the last 8" cruisers built by the Royal Navy were the Yorks, and even then, those were cancelled early.

Also no - the Furutakas predate the Washington Treaty and show where the IJN's thinking was regarding counter-scout assets.

The Japanese were well aware that they could not match the USN ship-for-ship, and so opted for superiority of quality, hence an 8-inch (technically 20cm) armed cruiser to counter the 6" Omaha and 7.5" Hawkins. As the USN was planning their next scout cruiser to be between 8.25k and 12k tons, between 33kts and 36 kts, and armed with between six and eight 8-inch guns in centerline turrets, you can bet that the IJN could want something bigger, faster, and better armed and armored.

Also, they after 1923 they won't be able to build capital ships for a while for financial reasons.

The Amagi-Class, Tosa-Class, Kii-Class, and No. 13-Class showed that the IJN thought differently. All of these were planned, but killed by the WNT. The depression won't be for another decade-ish, depending on when you are counting.

Not strictly related to a 'not-WNT' scenario, but was there ever any consideration given to creating shells with increased performance while maintaining the same calibre at treaty limits?
For example, by creating an 8" shell that is longer and uses a larger charge than standard shells for more range and penetration, in a similar fashion to the trends in MBT shells.

There is a limit to how long you can make a spin-stabilized shell, which I believe is around 7 calibers, and longer and you need to move to fin-stabilized.
As for faster shells, you start to run into excessive barrel wear and the higher chamber pressures means guns must be more heavily built. The British 16"/45 Mk I was designed to fire a lightweight projectile at high speeds (823mps), but the wear was such that the barrel life was only 180 rounds. The speed was later reduced to 788 mps, which helped increase barrel life to 200-260 rounds, and new rifling allowed them to bring the projectile speed up to 797.
Another example would be USN 16"/56 Mk 4, which was the experimental 18"/45 Mk 1 with a liner to reduce the diameter down. Until very recently, there wasn't much known about this gun, but someone who had preserved the data (as well as plans for a notional 18" lightweight gun and turret that could fit an Iowa's barbette) were recently donated to the USNI, and among the data is performance results for the 16"/56.
Here is a link to the video.
Other US projects include a 9"/98 made from a 14"/50 gun barrel that was never completed, and a 3"/105 that was and was used to test different projectiles at very high speed (4 caliber and 4.5 caliber shells were stable with RH 1 in 45 rifling, while 5 caliber tumbled).

The Italian Navy had very short barrel lives on their 15-inch guns, 110-130 rounds, but this was seen as acceptable, as the ships would never be far from allied ports, where the guns could be relined.

 

[A Tentative Fleet Plan]

Personally, I think the concept of 'Light' and 'Heavy' Cruisers won't exist, and we would see a greater spread of warship sizes. The stair-step jumps we see in categories is a function of the Treaty system. Without it, and depending on the need of the nation in question, I believe we would see much blurrier designs. I also believe we'd see smaller cruiser forces overall, as the naval budgets get eaten by the naval arms race that was developing and that the treaties were specifically instituted to kill.

We will see light and heavy cruisers, simply because navies will not be able to afford sufficient numbers of 10,000 ton plus heavy cruisers (especially if large 40,000 ton plus battleships are also competing for funding), so larger numbers of smaller cruisers will be required to make up numbers. In addition to numbers, the Royal Navy also required fleet cruisers with minimally-sized silhouettes to work in concert the fleet's destroyers, which drove the procurement of the Leander, Arethusa and Dido classes.

 

[A Tentative Fleet Plan]

The Amagi-Class, Tosa-Class, Kii-Class, and No. 13-Class showed that the IJN thought differently. All of these were planned, but killed by the WNT. The depression won't be for another decade-ish, depending on when you are counting.

Planning to build ships, and actually being able to afford them are two different questions. I assume the reference to 1923 is not the Great Depression, but instead the Great Kantō earthquake.

 

[TorpedoJ]

There is a limit to how long you can make a spin-stabilized shell, which I believe is around 7 calibers, and longer and you need to move to fin-stabilized.
As for faster shells, you start to run into excessive barrel wear and the higher chamber pressures means guns must be more heavily built. The British 16"/45 Mk I was designed to fire a lightweight projectile at high speeds (823mps), but the wear was such that the barrel life was only 180 rounds. The speed was later reduced to 788 mps, which helped increase barrel life to 200-260 rounds, and new rifling allowed them to bring the projectile speed up to 797.
Another example would be USN 16"/56 Mk 4, which was the experimental 18"/45 Mk 1 with a liner to reduce the diameter down. Until very recently, there wasn't much known about this gun, but someone who had preserved the data (as well as plans for a notional 18" lightweight gun and turret that could fit an Iowa's barbette) were recently donated to the USNI, and among the data is performance results for the 16"/56.
Here is a link to the video.
Other US projects include a 9"/98 made from a 14"/50 gun barrel that was never completed, and a 3"/105 that was and was used to test different projectiles at very high speed (4 caliber and 4.5 caliber shells were stable with RH 1 in 45 rifling, while 5 caliber tumbled).

The Italian Navy had very short barrel lives on their 15-inch guns, 110-130 rounds, but this was seen as acceptable, as the ships would never be far from allied ports, where the guns could be relined.

Thanks for the info, I think your first paragraph answers my initial question about 'getting around' treaty calibre limits very nicely.
However, I now want someone to make an 8" fin-stabilized smoothbore cannon and round, optionally with laser guidance!

 

[CV12Hornet]

I'll admit the bulk of my research has been down in USN and German Naval designs, so I don't know about all of the proposals that the British Admiralty was floating around at the time, but I do know that the British were more concerned, especially later into the treaty-era, with lighter units to protect trade. Now, admittedly, the preference for lighter ships could have been to maximize the number of hulls within a limited tonnage maximum, and relying on the compromised nature of treaty designs to allow weaker cruisers to threaten heavier ones.
Anyway, the last 8" cruisers built by the Royal Navy were the Yorks, and even then, those were cancelled early.

No, the preference for lighter units came about because the Treasury refused to pay for the 8" cruisers the RN actually wanted in the numbers they thought they needed. The inflection point seems to have come around the mid-1920s as cruiser programs start getting cut.

The Japanese were well aware that they could not match the USN ship-for-ship, and so opted for superiority of quality, hence an 8-inch (technically 20cm) armed cruiser to counter the 6" Omaha and 7.5" Hawkins. As the USN was planning their next scout cruiser to be between 8.25k and 12k tons, between 33kts and 36 kts, and armed with between six and eight 8-inch guns in centerline turrets, you can bet that the IJN could want something bigger, faster, and better armed and armored.

Probably. Unfortunately, we don't have much data on what the Japanese were thinking of building between the Furutakas and the WNT. Could they go to a big 10" cruisers? Quite possibly! Could they go for a larger 8" cruiser? Also quite possible, especially in a post-earthquake funding environment.

The Amagi-Class, Tosa-Class, Kii-Class, and No. 13-Class showed that the IJN thought differently. All of these were planned, but killed by the WNT. The depression won't be for another decade-ish, depending on when you are counting.

Bluntly, the IJN was at best far too optimistic. The Kii class, for example, were supposed to be built in two years, a hilariously unrealistic build schedule for such large, complex ships. And even before Washington runaway inflation had doubled the cost of their capital ships, forcing the IJN to go hat in hand to the Diet for more funding.

Once the Great Kanto Earthquake levels most of Tokyo (and wrecks what little of Owari they've managed to assemble) the build program is dead - the economy is in the shitter and government finances need to be redirected to rebuilding.

 

[Scott Kenny]

Probably. Unfortunately, we don't have much data on what the Japanese were thinking of building between the Furutakas and the WNT. Could they go to a big 10" cruisers? Quite possibly! Could they go for a larger 8" cruiser? Also quite possible, especially in a post-earthquake funding environment.

With the funding environment, I suspect that the Japanese would have ended up with bigger 8" cruisers.

Basically, the Mogami, etc cruisers but built up to a much more reasonable total displacement for all the weapons installed. I'm guessing ~13k or so, but maybe 15k if they went with more armor. "Baltimore-chan," basically.

 

[A_Random_Guy]

Thanks for the info, I think your first paragraph answers my initial question about 'getting around' treaty calibre limits very nicely.
However, I now want someone to make an 8" fin-stabilized smoothbore cannon and round, optionally with laser guidance!

Already done. This was the (rough) plan for the SAM-N-8 Zeus. It was a fin stabilized 4 inch subcaliber shell with a deflection charge for anti-aircraft use. Testing of the concept ran from the late 40s to around the mid 50s. If you want a more contemporary design the 8"/55 Mk 71 lightweight was to use a laser guided shell with folding fins.

 

[DWG]

Not strictly related to a 'not-WNT' scenario, but was there ever any consideration given to creating shells with increased performance while maintaining the same calibre at treaty limits?
For example, by creating an 8" shell that is longer and uses a larger charge than standard shells for more range and penetration, in a similar fashion to the trends in MBT shells.

There were a bunch of improvement processes applied to the British 15", adopting longer-nosed shells for better ballistics and therefore range, from 4crh (calibre radius head) during WWI, to 6crh later (monitors had 8crh) , there was also super charge to increase muzzle velocity by using a large charge, and during the 1930s rebuilds the turrets were modified to increase the elevation, and therefore range, of existing guns. The problem with all of these is you need a parallel set of changes to the main battery director and fire control table (ballistic computer) to ensure shells go where you're aiming, and that was difficult because the ballistics calculations were done mechanically.

Mid-WWI the RN also switched from Lyddite as an explosive filler, to Shellite, as Lyddite was considered too sensitive to impact and responsible for the poor performance at Dogger Bank.

And as a non-penetrative improvement, for 15" all the way down to 6" in the late 30s, there was the adoption of die bags ('K shells'), to colour splashes for identification when multiple ships were firing.

 

[40902nd]

Thanks for the info, I think your first paragraph answers my initial question about 'getting around' treaty calibre limits very nicely.
However, I now want someone to make an 8" fin-stabilized smoothbore cannon and round, optionally with laser guidance!

So, one of the plans for Kentucky and Illinois was to turn them into Anti-Aircraft Battleships, armed with quad autoloading smooth-bore 8-inch dual purpose cannons based off of the Des Moines-Class autoloaders. One proposal had 3 turrets and a normal load out of 5" guns, another only had 2 such turrets, but 20 dual 5" mounts (can't recall if they were the 5"54, but I think they were the standard 5"/38).

Also, check the below, something along those lines was proposed.

HE-ER Mark 148 (Planned)
13.65 in (34.7 cm) diameter, extended-range (ER), sub-caliber cargo projectile with sabot. This projectile was to be ET-fuzed with a payload of about 300 M46 grenade sub-munitions. Experiments with this projectile were conducted during the 1980s, but development was cancelled in FY91 when the battleships were decommissioned. Projected range was to be in excess of 70,000 yards (64,000 m) at a muzzle velocity of 3,600 fps (1,097 mps). One of the dummy prototypes is currently on display at the USS Iowa (BB-61) museum.

USNFSA Concept (Proposed)
Advanced Gun Weapon Systems Technology Program 16/11-Inch Long Range GPS Concept with Sabot. This concept was developed by the United States Naval Fire Support Association (USNFSA). The proposal envisioned an 11 inch (28 cm) sub-caliber cargo projectile utilizing a sabot to fit into the 16"/50 (40.6 cm) gun barrel.

 

[Owens Z]

Some commenters here, naturally enough, believe that the distinction between light cruisers and heavy cruisers was their weight (displacement). Not so. The Leipzig-class light cruisers and Admiral Hipper-class heavy cruisers of Nazi Germany, for example, did manifest a considerable weight difference, and I think this was more or less the UK's and Italy's preference too. But as per the actual agreed terms of the interwar naval treaties, light and heavy only referenced the cruisers' main armament: lights restricted to a gun bore diameter of no more than 155mm, and heavys to no more than 203mm. Both types of cruiser had the identical displacement limit of ≤10,000 tons in the treaties. And in practice, US Navy light cruisers and heavy cruisers during WW2 were about the same weight and size (and cost). The Mogami-class light cruisers were of similar weight to Japan's heavy cruisers, until the Mogamis were upgunned to formally become heavy cruisers. Soviet Chapayev- and Sverdlov-class light cruisers weighed substantially more than their Kirov-class heavy cruisers did.

In any case, the light vs. heavy legal distinction, as with all other terms of the signed naval treaties, was mooted by the outbreak of WW2. Postwar, the main armament of cruisers became guided missiles instead of guns, so a gun distinction no longer mattered. To my knowledge, the sole de jure rule remaining today that regulates naval gun bore is the Montreaux Convention about the Turkish straits between the Black Sea and Med (Article 9 and Annex IIB).

With the USA's 10,000-ton Ticonderoga-class "cruisers", Japan's 10,000-ton Maya-class "destroyers", and the planned German 10,000-ton F126 "frigates", warship divisions have become blurred, partly for political reasons.

 

[Dilandu]

With the USA's 10,000-ton Ticonderoga-class "cruisers", Japan's 10,000-ton Maya-class "destroyers", and the planned German 10,000-ton F126 "frigates", warship divisions have become blurred, partly for political reasons.

It become blurred much earlier, during early missile era - when traditional classifications became dubious and unclear.

 

[Scott Kenny]

It become blurred much earlier, during early missile era - when traditional classifications became dubious and unclear.

Agreed.

Crud, the USN was attempting to completely redefine the types, going back to calling the big escorts "frigates" with the DL hull type and calling the small ASW escorts just "Ocean Escorts" with the DE hull type.

 

[Dilandu]

Crud, the USN was attempting to completely redefine the types, going back to calling the big escorts "frigates" with the DL hull type and calling the small ASW escorts just "Ocean Escorts" with the DE hull type.

USSR tried to do similar redefinition in late 1950s, by introducing fully functional classification - like "large missile-carrying ship", "large anti-submarine ship", ect. Didn't exactly worked well, and eventually reverted to the more traditional "cruiser, destroyer" albeit some definitions, like BPK, still stuck.

 

[Volkodav]

I think the assumption cruiser armament would converge on 8" is a fallacy. If that was the case why did everyone, literally everyone, keep building 6" cruisers, while building far fewer 8" cruisers. The point of a cruiser isn't to defeat enemy cruisers, it's to prevent enemy commerce raiding, and you can do that by shipping enough armament to threaten the other guy's chance of returning home, you don't have to sink him yourself.

6" lets you threaten damage to a raider while engaged in commerce protection, and blow destroyers out of the water while engaged in fleet work or functioning as a destroyer leader. You don't need anything more.

The RN considered the Hawkins a disaster because it caused the USN and IJN to focus on unaffordable 10,000t cruisers, where the RN needed the focus to be 6,000t to permit them the numbers needed worldwide.

I agree.

I see 10000 ton and 8", as set by the WNT, as a compromise, rather than a natural or ideal state, that would not have existed without the treaty.

Cruiser roles were basically split between fleet, and trade protection/presence work.

Fleet roles were screening and scouting, trade protection and presence are pretty self explanatory.

Pre WWI, the Town Class cruisers became the lighter end of trade protection and presence, with armoured cruisers being the heavy end and battle cruisers their planned replacement.

More specialised light cruisers were developed for scouting and screening for the battle fleet, evolving through the Arethusa class to the C and D classes.

The ultimate trade protection cruiser was the Hawkins/Frobisher, class, the Fleet cruiser this was the E Class, while the armoured cruiser had given way to the battle cruiser, perhaps the large light cruisers.

The 8" WNT cruiser was a compromise, arguably too big for the light end of fleet work and trade protection, and too small for the heavy end. What it was good at was presence and perhaps scouting, but then again the WWII Towns and the USN Brooklyns were as good or better in that role.

Without the WNT 15000 to 20000 ton 9.2 to 12" gunned large cruisers would likely have reappeared, supported by a larger number of smaller cruisers (Arethusa, Dido, Atlanta) and larger 6" cruisers.

 

[CV12Hornet]

I agree.

I see 10000 ton and 8", as set by the WNT, as a compromise, rather than a natural or ideal state, that would not have existed without the treaty.

Am I having an internal monologue?!

I've pointed out repeatedly that multiple countries were looking to buy 10,000-ton 8" cruisers in the runup to Washington, that's why those specific limits were set. Britain, the US, and France were all explicitly looking to buy such ships.

This type of cruiser would have absolutely existed without the Treaty. The difference is that it would not have kept being built for the next fifteen years.

 

[Volkodav]

Everything I have read in

Am I having an internal monologue?!

I've pointed out repeatedly that multiple countries were looking to buy 10,000-ton 8" cruisers in the runup to Washington, that's why those specific limits were set. Britain, the US, and France were all explicitly looking to buy such ships.

This type of cruiser would have absolutely existed without the Treaty. The difference is that it would not have kept being built for the next fifteen years.

Everything I have read indicates (if not outright states) that the 8" 10000 ton limit was derived from the Hawkins/Frobisher, which in turn came from the Atlantic cruiser, which was evolved from (or as a replacement for) the Towns. Designs and intentions to design by other navies were as a counter.

I am stretching my memory a bit here and will have to reread what I have on the Atlantic cruiser concept, but I believe that its origin was in a belief that Germany was building something of that ilk that needed to be countered.

Anyway, long story short, the Hawkins/Frobishers were not really that successful and battle cruisers were hideously expensive; it is doubtful that, even if built, the WNT style cruiser, as you have said, would not have lasted long, something bigger was needed and many something smaller were needed too. In fact, naval design being what it is, once everything that was required was incorporated, none of them would have been anywhere near as light as 10000 tons.

Pre WNT the RN was looking to an evolved Courageous-style large light cruiser, that carried multiple aircraft and possibly even torpedo boats for the China Station in particular. WNT led them to switch to a planned force of WNT cruisers instead.

To be honest, I skimmed many of the posts on this topic, only reading a number in detail, including the one I replied to, so I missed all of your points. If I hurt your feelings, or perhaps left you a little frustrated, I apologise. I was simply agreeing with a point in that other post, and elaborated as to why I agreed.

 

[Volkodav]

Personally, I think the concept of 'Light' and 'Heavy' Cruisers won't exist, and we would see a greater spread of warship sizes. The stair-step jumps we see in categories is a function of the Treaty system. Without it, and depending on the need of the nation in question, I believe we would see much blurrier designs. I also believe we'd see smaller cruiser forces overall, as the naval budgets get eaten by the naval arms race that was developing and that the treaties were specifically instituted to kill.

Still, when it comes to the cruisers that were built, I believe the USN would prefer fast (35-kt), 8-inch armed cruisers with high endurance (10,000nm cruising), with proper IZ against their own guns. The arrangement would likely be AB-XY with either 8, 10, or 12 guns. Given enough time, these might evolve into 10-inch gun cruisers, depending on developments of other nations.

The Royal Navy would prefer lighter 5,000 to 7,500 ton designs for trade productions. If they have the budget for it, they might have some heavier cruisers armed 7.5" or 9.2" guns, though the G3 and N3 would devour large portions of their budget.

I imagine that the Japanese would focus more on battleship and battlecruisers to maximize resources, and so cruisers would be kept small and relegated to destroyer leaders.

I don't know what France or Italy would do.

Germany would cry in the corner, and then probably build coastal monitors.

Of course, this is all just my speculation.

The RN would likely have three levels of cruiser for trade protection/presence, roughly equating to sloop, light cruiser and armoured/large cruiser, plus additional types for fleet work and special duties.

The fleet and special types would likely be small light cruisers as destroyer leaders, scouts (possibly evolving into the FADE role), AA and GP light cruisers. Fast minelaying cruisers are a possibility and also command ships for coastal forces, i.e. a surface warfare type to provide overwatch for the MTBs and MGBs in case hostile destroyers show up.

No WNT, there is also the likelihood that there would be escort and ASW groups built around sloops and small carriers that require an escort group leader.

 

[CV12Hornet]

Everything I have read indicates (if not outright states) that the 8" 10000 ton limit was derived from the Hawkins/Frobisher, which in turn came from the Atlantic cruiser, which was evolved from (or as a replacement for) the Towns. Designs and intentions to design by other navies were as a counter.

I am stretching my memory a bit here and will have to reread what I have on the Atlantic cruiser concept, but I believe that its origin was in a belief that Germany was building something of that ilk that needed to be countered.

Anyway, long story short, the Hawkins/Frobishers were not really that successful and battle cruisers were hideously expensive; it is doubtful that, even if built, the WNT style cruiser, as you have said, would not have lasted long, something bigger was needed and many something smaller were needed too. In fact, naval design being what it is, once everything that was required was incorporated, none of them would have been anywhere near as light as 10000 tons.

The Hawkins-class was unsuccessful mostly because it was woefully outdated, between the mixed-firing powerplant and the hand-swung pedestal mounts. A fully modern ship with oil firing and powered, enclosed mounts proved much more successful.

As for the 8" 10,000-ton limit being derived from the Hawkins class, yes, but actually no. Certainly the USN move to 8" was motivated very heavily by the Hawkins-class, which in turn motivated the British to move to 8" to match what the USN was doing. However, per Friedman the contemporary French move to a 10,000-ton 8" cruiser was motivated by what the Germans might build under Versailles restrictions, and the Japanese Furutakas were motivated entirely to outdo the Omaha-class in scouting action - and while it took a while for the details to come out on them, the Furutakas are mentioned as another factor driving development of the 10,000-ton 8" cruiser.

Even then, the Hawkins-class was only part of the calculus for the USN. The arguments of the effectiveness of 6" versus 8" guns in open-water action made by Dreyer below were repeated in the USN[sup]1[/sup], and both the USN and RN found that the combination of speed and range they wanted mandated a very large ship anyway.

Regarding larger ships, well, the USN did look at a 12,000-ton ship in their 1919 and 1921 studies. This was the opinion on it:

While providing desired capabilities, this design was considered too large to be affordable.

Fundamentally, heading into the early 1920s everyone needs cruisers en masse, and generally they need cruisers operating deep into the ocean away from basing, whether for trade protection or scouting; fleet roles were mostly covered by WW1-built ships. This mandates a large ship, that much is clear from the design studies of the period, just for the required speed and endurance - but it also demands affordability due to the sheer numbers involved.

You would get larger 8" cruisers later on as numbers get filled, the fleets get experience with the 10,000-tonners, and someone (probably Japan) escalates matters, but there's going to be a very large initial generation that is basically just the 10,000-ton Washington type.

Pre WNT the RN was looking to an evolved Courageous-style large light cruiser, that carried multiple aircraft and possibly even torpedo boats for the China Station in particular. WNT led them to switch to a planned force of WNT cruisers instead.

They were looking at this type of cruiser, but this was in addition to various 8" cruiser designs up to 10,000 tons. The Courageous-type large light cruiser, though, was probably not going to happen on cost grounds - despite attempts to keep them at 15,000 tons the RN was horrified to find they would be at 19,000 tons.

The following, per Friedman, was the outcome of design studies in 1920-1921:

On this basis, Dreyer suggested five alternatives:

A: 10,000 tons, 31 knots, eight 8" in twin splinter-proof
B: 8500 tons, 32 knots, five 8"
C: 7500 tons, 35 knots, four 8"
D: 7500 tons, 32 knots four 8"
E: 7500 tons, 25 knots, four 8"

Design A would counter the projected US 10,000-ton cruisers, if British finances permitted. It would not be desireable to go below 7500 tons, 'as this would is the smallest size now advocated by other countries'. ... No 6" cruiser could effectively fight an 8" cruiser. Dreyer preferred a 7500-tonner with four centerline 8" guns.

...

DCNS agreed that any new trade protection light cruisers would have to be armed with (at least) 7.5" guns, and would probably be comparable to the big Hawkins type. He doubted that a ship of smaller displacement could combine sufficient radius of action and armament.

More detailed DNC design studies reached similar conclusions to the USN vis a vis the effects of speed and endurance requirements, namely that it was going to be a struggle to fit everything desired into even 10,000 tons.

1. Note that the relative merits of the two guns were very different from what they were even by 1930 - for one, this was still before effective powered mounts for 6" guns, and an enclosed turret for a 6" gun had very real rate of fire penalties.

 

[Arjen]

the USN did look at a 12,000-ton ship in their 1919 and 1921 studies. This was the opinion on it:

While providing desired capabilities, this design was considered too large to be affordable.

The USN was not alone in facing that quandary. Which is where the WNT came in.

 

[Scott Kenny]

I'm still thinking that the big-gun cruisers would have ended up around 13k tons (Baltimores), at least for the Pacific nations: US, Japan, and maybe the UK.

Expensive, so hard to buy many of and maybe even preempting a battleship or three due to expense.

But it's literally what it costs to play in the Pacific. More fuel, more food, more spare parts, because you're more days away from a port.

Whether the Atlantic nations would have built up to 13k or remained around 10k because they didn't need the range is a debate we can have, so pass a beverage. If the Atlantic nations didn't build 13k cruisers, I suspect that the UK would have gone with a split fleet. Mostly consisting of the cheaper 10k cruisers for the Atlantic and Med, but with a class or two of 13k cruisers that more or less lived in the Pacific. And now that I'm thinking about it, I think the US would have gone with a split fleet as well.

 

[Cjc]

Personally I think the Alaska class, the b-65 class, and that 12 gun 9.2 inch gun british design show pretty well what the direction cursers were going to go in if the treaty hadn't existed, with a branch of much smaller trade protection cursers especially for Britain. So a much more extreme version of the heavy (maby in this time line they get the battlecruiser tag) and light (maby destroyer leader) cursers.