The G3 Battlecruiser after WW2

[uk 75]

As we have looked at various options for RN battledhips after WW2 I cannot resist wondering what would have happened if instead of Nelson and King George V class ships the RN had built four G3 battlecruisers in the years up to 1939.

Rather like Queen Mary and Queen Elizabeth the ships are on and off again because of various financial crises. The last of the four enters service in 1937.

The N3 battleship might then have followed as Germany's Z plan unfolds and Japan threatens war in the Pacific.

The above is only a flimsy excuse to encourage some artwork and ideas from folk here.

 

[Dilandu]

RN had built four G3 battlecruisers in the years up to 1939.

It basically means that Washington Naval Treaty allowed such ships to be completed. Which means rather... different power balance in post-1919 world. The G3 are so much more powerful than any other units around, that everyone - US, Japan, France, Italy - would demand either a right to build their own advanced units, or increase of their allowed quotas.

 

[Dilandu]

The last of the four enters service in 1937.

Impossible. No one would build in 1937 a ship, designed in 1921. Technology marched on, after all.

 

[zen]

I think evolution would have happened. For which real world gives us indications of what.

 

[Dilandu]

The only scenario I could imagine for G3 to exist is for Washington treaty to be delayed to, say, 1925 - so the construction of new battleships and battlecruisers progressed far enough for all maror parties to be reluctant to abandon them. So the 40.000-45.000 tons of standard displacement is agreed upon as upper limit, and each side could complete, say, four already-laid up warships (France and Italy could build new ones).

 

[Lascaris]

The only scenario I could imagine for G3 to exist is for Washington treaty to be delayed to, say, 1925 - so the construction of new battleships and battlecruisers progressed far enough for all maror parties to be reluctant to abandon them. So the 40.000-45.000 tons of standard displacement is agreed upon as upper limit, and each side could complete, say, four already-laid up warships (France and Italy could build new ones).

Actually the American and Japanese negotiators were willing to accept a pair of G3s at the time in exchange of Britain retiring a fifth battleship, from memory HMS Tiger when they were completed. Apparently neither knew what G3 truly represented. But it looks to me neither did the British foreign minister who failed to grab on this with both hands.

Well say he does. Has everyone else realized what the G3s are by 1931? If yes say goodbye to the building holiday extending to 1936 and the 35,000t limit.

 

[Dilandu]

Well say he does. Has everyone else realized what the G3s are by 1931? If yes say goodbye to the building holiday extending to 1936 and the 35,000t limit.

They would realize it much sooner - because Washington treaty reqiured all sides to provide basic data about their warships. As soon as US and Japan realize that Britain build ships more powerful than they anticipated, they would either demand further reduction of RN (like scrapping all 13.5-inch units) or the right to complete a pair of modern battlecruisers of their own. France and Italy would also demand more rights.

 

[CV12Hornet]

Okay, going with Lascaris' scenario - well, to answer the question in the title they'd be in a similar situation to the Nelsons, postwar. Namely, worn out, obsolescent, and in need of a modernization to continue to serve that the Royal Navy can't afford to fund. Likely one would be in worse condition than the other.

Now, being fast 30-knot ships they'd be more seriously considered than the 23-knot Nelsons were, but I expect that just means they get to a serious design stage before being canned. See, again, Britain's money issues in the immediate postwar period. Refitting two twenty-year-old battleships is going to be very low on the priority list.

 

[Dilandu]

Okay, going with Lascaris' scenario - well, to answer the question in the title they'd be in a similar situation to the Nelsons, postwar. Namely, worn out, obsolescent, and in need of a modernization to continue to serve that the Royal Navy can't afford to fund. Likely one would be in worse condition than the other.

Important point - they would likely NOT get any mid-war refits in 1930s. The RN policy was to spend what limited money were available on the oldest ships with lasting value - Renown-class and QE-class - so G3's would almost certainly be considered "sufficient as they are". By WW2, they would likely be in the same situation as Nelson's were: worn-out, semi-obsolete, with inadequate air defense and many design flaws not remedied. The only difference, perhaps, is that Americans may be more willing to repair and refit them.

 

[nl4real]

If the restrictions are loose enough for the G3s, then presumably The USN and IJN capital ships constructed around this time are in play as well.

1. What happens after Amagi's construction is aborted by the Kanto Earthquake? Is a replacement allowed?
2. What happens to the N3s? Does the 16in/406mm limit still happen? If so, how are they modified? If not implemented, what response does that draw from Japan and the US?
3. What are Italy and France up to at this time?

All of these affect the context into which the G3s would enter service.

Plan Z was always a pipe dream given Germany's situation. The real action is likely in the Pacific.

 

[meeware]

Important point - they would likely NOT get any mid-war refits in 1930s. The RN policy was to spend what limited money were available on the oldest ships with lasting value - Renown-class and QE-class - so G3's would almost certainly be considered "sufficient as they are". By WW2, they would likely be in the same situation as Nelson's were: worn-out, semi-obsolete, with inadequate air defense and many design flaws not remedied. The only difference, perhaps, is that Americans may be more willing to repair and refit them.

Those are good arguments, but there are counter arguments too. For one thing the Nelrods were highly compromised designs, which wore out fast due to lighter than ideal fittings, and which had little capacity for additional topweight, and very little space for a reconfigured AA fit. They were also slower, less long ranged, and hence less useful in a changing global threat posture.

It's therefore conceivable (though I'll grant still not nailed on) that if there had been 4 G3s in service, then by the late 30's at least one or two would have been candidates for modernisation. One would hope that the secondary battery would be the priority with the 6inch turrets replaced with 5.25DP mounts. Designed in the mid 30s they came into service on the KGV class in 1940, but it must be admitted that they were slow to produce, had varying degrees of reliability at first, and really only evolved into truly excellent mounts in the Vanguard class. Historically it would have been more likely that the QF4.5inch twin, as seen on the refit of Renown and some of the QE class, would have been used. These too were scarce beasts, and considerably lighter than the 6 inch twins they'd replace, so it's not inconceivable that you'd have seen a partial replacement. Perhaps the upper of each pair of mounts being replaced (though that would play havoc with magazine arrangements!) or alternatively an echelon replacement seeing (for example) the forward port and aft starboard secondary armament being replaced.

One advantage of swapping out all the 6 inch turrets for 4.5 in ones would be a reduction in topweight - the 6 inch turrets were about 75 tons each, and the 4.5s are around 38 tons. 300 tons of weight saved is something to play with!

 

[Dilandu]

Those are good arguments, but there are counter arguments too. For one thing the Nelrods were highly compromised designs, which wore out fast due to lighter than ideal fittings, and which had little capacity for additional topweight, and very little space for a reconfigured AA fit. They were also slower, less long ranged, and hence less useful in a changing global threat posture.

The counter-counter argument is, that same logic was applied to Hood; she was also viewed as "good enough as it was" and not given any major refits interwar. Considering that G3 ships would be far more capable than both Hood and Nelson's, I just can't see how Navy would be able to justify any kind of major refit given to them, while older ships would be in much more desperate need of such.

Even if some refit would be given, it would almost certainly be limited to fire control (HACS) & additional Pom-Pom's installations. Maybe the upper rear 6-inch turrets would be removed to put a few more AA cannons. Definitedly no large scale re-armament; simply not enough weapons or capabilities for that.

 

[meeware]

Very fair.

But, Renown DID get a refit, so clearly ships of that era _could_ be considered worth refitting. This is all hugely hypothetical, but the arguments for and against refits for Hood and a putative class of G3s are not 100% aligned.

For instance, one reason against refitting hood is that you loose the biggest ship in the fleet for 3 years. If you've a load of G3s then a program of refitting them has a less deleterious effect on the fleet.

Also... and this is way out of left field... maybe if you have 4 G3s, maybe the KGV class aren't quite such a priority, and instead a refit of these beasts is seen as a better investment? And we see something like a Lion hitting the slips later in the war? Or maybe a second Ark Royal class carrier?

 

[CV12Hornet]

If the RN has four G3s the KGVs aren't even going to be a glimmer in their eye. 4 G3s means no treaty regime.

Those are good arguments, but there are counter arguments too. For one thing the Nelrods were highly compromised designs, which wore out fast due to lighter than ideal fittings, and which had little capacity for additional topweight, and very little space for a reconfigured AA fit. They were also slower, less long ranged, and hence less useful in a changing global threat posture.

Most of those flaws would not be present on the much larger, heavier, and faster G3s.

 

[Dilandu]

But, Renown DID get a refit, so clearly ships of that era _could_ be considered worth refitting. This is all hugely hypothetical, but the arguments for and against refits for Hood and a putative class of G3s are not 100% aligned.

Renown & Repulse got a major refit because their original design was deemed too deficient from post-Jutland experience. Britain even specifically bargained a cause in Washington Treaty that allowed Royal Navy to finish their already-started reconstructions. The G3 battlecruisers would hardly be viewed as deficient to the point that they would need major refit.

Also... and this is way out of left field... maybe if you have 4 G3s, maybe the KGV class aren't quite such a priority, and instead a refit of these beasts is seen as a better investment? And we see something like a Lion hitting the slips later in the war? Or maybe a second Ark Royal class carrier?

I'm seriously not sure. First of all, if Britain got four G3, then it means that Washington Treaty is negotiated on significantly different terms. Most likely it means that US and Japan were allowed to finish their 16-inch battlecruisers too, and Italy and France have rights to construct comparable units. So Royal Navy would actually be quite desperate to replace its older units with new construction - because comparing to G3 (and their foreign opponents), the older units have less relative value than comparing to Nelson's.

If the RN has four G3s the KGVs aren't even going to be a glimmer in their eye. 4 G3s means no treaty regime.

Or more likely, Treaty being negotiated later - say, in 1924-1925 - where more new ships were either in service or close to completion, and Washington limits would be set higher.

 

[meeware]

If the RN has four G3s the KGVs aren't even going to be a glimmer in their eye. 4 G3s means no treaty regime.


Most of those flaws would not be present on the much larger, heavier, and faster G3s.

Yes, that's exactly my point. They don't wear out so fast, their hulls and main batteries don't wear out so fast, so refitting secondary batteries and upgrading fire control and AA is a better investment.

 

[meeware]

Renown & Repulse got a major refit because their original design was deemed too deficient from post-Jutland experience. Britain even specifically bargained a cause in Washington Treaty that allowed Royal Navy to finish their already-started reconstructions. The G3 battlecruisers would hardly be viewed as deficient to the point that they would need major refit.


I'm seriously not sure. First of all, if Britain got four G3, then it means that Washington Treaty is negotiated on significantly different terms. Most likely it means that US and Japan were allowed to finish their 16-inch battlecruisers too, and Italy and France have rights to construct comparable units. So Royal Navy would actually be quite desperate to replace its older units with new construction - because comparing to G3 (and their foreign opponents), the older units have less relative value than comparing to Nelson's.


Or more likely, Treaty being negotiated later - say, in 1924-1925 - where more new ships were either in service or close to completion, and Washington limits would be set higher.

As we wade deeper into hypotheticals the landscape is less clear, but yes, G3s means a radically different treaty set up, and a far more intense arms race. I mean you could reach the point where this starts to impact other areas, like the balance of investment in the UK on air and sea power. WHich (in spite of almost everyone apart from Park, Coningham, Tedder, and Dowding being useless or worse, I'd rather not see chain home sidelined).

 

[pathology_doc]

Four G3s means you can have one constantly in refit, so they get the regular service they need, the little things never get a chance to gang up on them, and they are mostly in full fighting trim when the war breaks out.

I would be prepared to bargain the entire R class away to have four G3s in the fleet.

 

[Dilandu]

Four G3s means you can have one constantly in refit, so they get the regular service they need, the little things never get a chance to gang up on them, and they are mostly in full fighting trim when the war breaks out.

Question is, what would the others have? USN would clearly have fourth "Maryland"-class battleship, and likely two or three "Lexington"-class battlecruisers. Japan would have "Amagi" and "Akagi". France would likely build a pair of comparable battleships close to 1930s.

 

[pathology_doc]

Japan would have "Amagi" and "Akagi"

Probably Kaga and Akagi, since the Great Kanto Earthquake is still going to have something to say about the Amagi. However, having them as battleships means they won't be at Pearl or Midway as carriers. Granted, the Americans won't have Lexington or Saratoga either.

 

[Dilandu]

Probably Kaga and Akagi, since the Great Kanto Earthquake is still going to have something to say about the Amagi.

Hm, not likely. Without works being halted in early 1922, by September 1923 both would be already launched. So they would likely both be completed as battlecruisers.

However, having them as battleships means they won't be at Pearl or Midway as carriers.

There were Atago and Takao of the same class.

However, having them as battleships means they won't be at Pearl or Midway as carriers. Granted, the Americans won't have Lexington or Saratoga either.

One point. For G3 being advanced enough for being included into Treaty, the Treaty itself should be pushed to early 1924 at best.

 

[Dilandu]

Hm, I just thought. For G3 battlecruisers to be in advanced enough stage of construction to validate their completion, the Treaty should be pushed to either 1923 or 1924.

Which means, that IJN would already have Akagi and Amagi up & running, Atago and Takao likely launched, and Tosa & Kaga completed, or nearly completed. Counting Nagato and Mutsu, it would give Japan eight 16-inch capital ships in total.

The USN by this time would clearly complete all four Colorado-class battleships, and likely South Dakota & North Carolina (the two of first South Dakota-class) launched & fitting out. Lexington and Saratoga would likely be launched and reasonably progressed too.

Britain with its four G3 battlecruisers merely launched would looks... well, not exactly great. They would have four 16-inch battlecruisers - arguably of greater fighting power, but still - against 6-8 battleships and battlecruisers with 16-inch guns that IJN and USN would possess. At best, Britain might bargain for another pair of 16-inch ships, but RN would be very clearly pushed into second rate.

 

[TorpedoJ]

To try to engage with the spirit of the thread, rather than the detail:
The G3s as designed had no aviation facilities. As all of the QEs were fitted with the trademark sideways catapult and hangar between the wars, wouldn't that have been a priority in the 1930s? It could have replaced the boat handling facilities, or maybe that big empty stern could have been built up with a hangar and more conventional stern catapults.
Or, would the long G3 hull have been any good for conversion to carrier in the way the Japanese and USN did, had [their build] been more advanced? Having the funnels and therefore the island further aft would have given them a very interesting profile a bit more like a modern US carrier, though they would of course have been too [early] for angled decks and all that.
Or post-WW2, that central turret would have looked really good for conversion to missile battleship. Just saying...

 

[Dilandu]

The G3s as designed had no aviation facilities. As all of the QEs were fitted with the trademark sideways catapult and hangar between the wars, wouldn't that have been a priority in the 1930s? It could have replaced the boat handling facilities, or maybe that big empty stern could have been built up with a hangar and more conventional stern catapults.

Well, for G3 it won't exactly be a major problem. Their rear superstructure have more than enough space to accomodate any kind of hangar required.

 

[TorpedoJ]

Well, for G3 it won't exactly be a major problem. Their rear superstructure have more than enough space to accomodate any kind of hangar required.

That's what I thought, the pom-poms could always be relocated to the hangar roof. Dunkerque had quite a good arrangement, though I think the G3's size could extend to twin catapults and maybe 4-5 Walruses.

 

[pathology_doc]

There were Atago and Takao of the same class.

I thought those were cruisers.

 

[pathology_doc]

Or post-WW2, that central turret

That extensive aft superstructure.

 

[Dilandu]

I thought those were cruisers.

Initially those were two Amagi-class battlecruisers; after the class cancellation, the names were later re-used for heavy cruisers.

 

[pathology_doc]

Initially those were two Amagi-class battlecruisers; after the class cancellation, the names were later re-used for heavy cruisers.

Interesting. I didn't know that.