Summary of Plans 1920
Summary of Designs – 1920

We’re going to be talking about ‘improved Rodneys’, ‘modified South Dakotas’, etc…, a lot over the next few instalments, so here’s a brief summary of what’s what in the story as regards the three major navies:

Royal Navy

HMAS Australia is a ‘Lion’ class ship.
4 x ‘Royals’ – Economy versions of Queen Elizabeth (so the RN has a total of nine 23½kt battleships with 8-15” guns)

Renown, Repulse – ‘Super Tigers’, 8-15”, 16-4”. Are being reconstructed to include a 9” armour belt. Normal Load to be 34,000 tons (28,500 as built), speed 29½ kts on trial, sea speed about 28 kts.

Furious – 6-18”, 24-4”, 12” belt (very narrow), 33½ kts
Hood – a little smaller than OTL. 8-15”, uniform 9” sloped belt to the upper deck, 31 kts.
Howe – as Hood but with 11” lower belt, thicker decks.
Rodney – fast battleship version of Hood with reduced machinery; 8-16” Mk.2, 12” sloped belt, heavy deck armour (but still layered), 28½ kts.

Drawings of some of these are in this post.

‘Hawkins’ class cruisers are as reality.
‘E-class’ cruisers are armed with 8-6” in twin ‘shielded gunhouses’, but are otherwise similar to reality.

United States Navy

Battleships up to and including the ‘Marylands’ are the same.

‘South Dakota’ – as OTL (12-16” Mk.2, 16-6”/53 , 13.5” belt, 3.5” armour deck, 23kts)
Two laid down in 1919. One laid down 1920. Three others due to be funded in ’21 & ’22.

‘Lexington’ – 8-16” Mk.1, 14-5”/51, 9” belt, 3” deck, 33kts
These are about halfway between the Lexingtons as laid down in reality and the original design of 1916. They have 5 funnels (3 in profile) and a three-layer TDS.
Two laid down in 1919. One laid down in 1920. Three others due to be funded in ’21 & ’22, but some debate as to whether these should be built to a new design.

‘Omahas’ – 10-6”/53, single fore/aft turrets instead of twins, otherwise very similar to OTL. Twelve ships under construction.
‘Newarks’ – 6-8” in twin turrets, light protective plating and decks, 32½ kts. Based on the Omahas, lengthened and widened to accommodate the heavier armament. Four ships under construction.

Imperial Japanese Navy

Settsu, Kongo, Ise, Fuso classes are the same.
Kawachi was sunk in 1918 due to magazine explosion (as OTL).

Nagato is about to be completed, Mutsu is further advanced and due to complete in mid-1921.

Kaga, Tosa – Design as OTL. Laid down Autumn 1919, expected to complete in 1922.

‘Amagi’ class – Broadly similar to OTL, with ten 16” guns, but with an 11” inclined belt, 3.7” armour deck. 41,500 tons (normal), with 30 knots hoped for. First two laid down in the spring of 1920.

-o-

Author’s note –

In reality from 1919 to 21, there were numerous British studies labelled ‘F’ thorough ‘O’ followed by a number, which covered many possible RN battleships and battlecruisers, including the famous ‘G3’ of 1920-21 (although be aware there were several variants of G3). Battleships were ‘L’ and onwards, while battlecruisers worked backwards from ‘K’.

To avoid confusion, I’ve used a slightly different reference system in the next few instalments. Any ships with ‘F to O’ designations are as in reality, while any adaptions have non-historic references (e.g. N-3 is the real thing, as in any reference book, while P-3 is fictional).
 
‘Amagi’ class – Broadly similar to OTL, with ten 16” guns, but with an 11” inclined belt, 3.7” armour deck. 41,500 tons (normal), with 30 knots hoped for. First two laid down in the spring of 1920.

At least know they got a decent armour scheme, I like it . Although I think that it would be better if the central turret is deleted, maybe that gives a better speed.
 
‘Lexington’ – 8-16” Mk.1, 14-5”/51, 9” belt, 3” deck, 33kts
These are about halfway between the Lexingtons as laid down in reality and the original design of 1916. They have 5 funnels (3 in profile) and a three-layer TDS.
Two laid down in 1919. One laid down in 1920. Three others due to be funded in ’21 & ’22, but some debate as to whether these should be built to a new design.

do you have a diagram or did you uploaded one before already?, I didn't notice.
 
An inch of belt armor at that inclination is pretty significant. But, uh, no way is that only 300 tons extra over the original design.

The bigger gain is that they're being laid down six months early.
Being laid down earlier is good for the Japanese. While the ships did gain an inch of belt armor, their deck armor is only 3.7" vs 5.5" OTL
 
Being laid down earlier is good for the Japanese. While the ships did gain an inch of belt armor, their deck armor is only 3.7" vs 5.5" OTL
Uh, it was only 5.5" OTL if you added up all the armored decks. The main deck was 3.7", adjoining the top of the belt.
 
I'd consider the completion of the Normandie or Caracciolo-class battleships unlikely, unless they were never suspended in the first place and construction continued as planned through the Great War.


Both navies, OTL, had an opportunity to pause and re-evaluate their designs in the period between the end of WWI and the WNT conference of 1921-1922, which they spent evaluating their designs and judging if they could be completed or not. Both returned a nay. Though the Italians worked to find a solution to address Caracciolo's pre-Jutland heritage of poor deck armor, this ended up being besides the point as nothing could change the fact the design was horrifically vulnerable to any modern torpedoes, and this was fairly damning. Normandie fared little better in the eyes of the Marine Nationale, with a horrifically vulnerable armor scheme, even by pre-Jutland standards, and its torpedo protection, or rather lack thereof, made the design untenable in the 'modern' era anyways.

More likely than not both classes still end up being scrapped - though, if the Regia Marina really had the cash to spare to consider completing the Caracciolo-class, one or more, they'd be more likely to spend it on converting it into an aircraft carrier (designs Pg 579 to 582) and reconditioning Leonardo da Vinci, which has since been raised and was likewise under consideration for conversion (dropped, the hull was totally unsuitable for it) or repair and refurbishment as a battleship once more (though I would still consider this unlikely, there were other things that had a higher priority for the RM at the time. She'd likely be scrapped as she was historically). A carrier conversion for Caracciolo would likewise be more politically tenable if France continues on their OTL path by scrapping the Normandie-class and completing Béarn as a carrier, as this does not upset the balance of power between France and Italy (as would result from one party having 15" battleships and the other not).

Though, of course, that would depend on whether or not Italy sees the rise of fascism or not, since that was decisive in the crippling of the RM's air arm over the course of the 1920s. Without the rise of the heavily political Regia Aeronautica, the plans for the development of the RM's Forza Aerea will be free to grow without the malicious opponent of the fascist-aligned RA. Given the hundreds of millions of lire per annum that the Regia Aeronautica ate up in spending in the interwar period, rising to billions by the latter half of the 1930s, one can only imagine how much more freedom the Regia Marina would have in its own spending. Even if, for example, we only gave the RM a third of the RA's budget allocation in FY 1925/26, that'd still be a 17.2% increase in the RM's budget.

----

If France is serious about matching foreign construction, now armed with 16" and 18" guns, then they'll likely skip all their 340mm battleship plans and move directly to the prospective 40,000-ton, 450mm-armed (17.7") battleships - though since they'd have to be over 200 meters in length, France is going to have to spend time investing in infrastructure upgrades before they can hope to get back into the battleship-building game. Otherwise, they'll have to keep building too-small, compromised designs. The OTL plan, pre-WNT of course, in 1921 called for eleven such ships to be completed by 1940, along with fifteen 12,000-ton cruisers, and acknowledges that no battleships could have been laid down until 1925.


The key thing to remember for both France and Italy, however, is that both their navies were very concerned about their lack of modern light units, especially cruisers. The RM is still slightly better off thanks to their esploratori (scouts), but still lack anything approaching a true modern light cruiser, and the MN is in an even worse position. In the short term (1920s), I'd be seriously skeptical of any navy attempting to lay down battleships. Rather, I'd expect them to focus on cruisers and destroyers, plus their respective carrier conversions and infrastructure projects. France will, as they did historically, still probably place a great weight on their submarines and build them as aggressively as they can manage (basically, the same rate as irl), and Italy likewise will still maintain their relatively slow and methodical approach to submarine construction (which saw prototypes for modern classes start construction only in 1925). Likely, the considerable focus in this era for the RM (again, assuming no rise of fascism) is the development of their naval air arm, namely to fill the outlines established in 1920; general and specific reconnaissance (the latter in direct support of the fleet), protection of the fleet from air attack, and the attacking of enemy forces and shipping by torpedo bombers.
 
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Deleted member 94680

Being laid down earlier is good for the Japanese.

It will be interesting to see which way “this” Japan goes. They seem to have had a better war, they’re building heavy units earlier, less American influence on world events is good for them too.
 
do you have a diagram or did you uploaded one before already?, I didn't notice.
I don't, but CV12Hornet posted one of the Springstyle schemes here:

The Lexingtons of the story aren't quite that design (they're not as well armed, but slightly better armoured). Visually they would be almost identical.
 
At least know they got a decent armour scheme, I like it . Although I think that it would be better if the central turret is deleted, maybe that gives a better speed.
An inch of belt armor at that inclination is pretty significant. But, uh, no way is that only 300 tons extra over the original design.

The bigger gain is that they're being laid down six months early.
Well spotted.
An extra inch of 450' of armour belt, 13' deep is only about 220 tons, and the deck is slightly thinner than the real ones.

I won't go further for now, as there's more to come on the Amagis and why they are that little bit different.

Edit - I find conflicting data.
The version of Conway's quoted by Wikipedia (and others) gives these ships a 3.7" armour deck (at main deck level atop the belt). They also had other, thinner decks.
The version version of Conway's I have gives them 3.9", which I reduced to 3.7", thereby saving weight (amongst other things that you'll have to wonder about for now...)

It's entirely possible there were several subtle variations, plus the Japanese went metric at about this time, which probably further confused matters.
 
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I'd consider the completion of the Normandie or Caracciolo-class battleships unlikely, unless they were never suspended in the first place and construction continued as planned through the Great War.

The thing is the never was a Jutland in this tl and slightly different lessons were learned.

First of all the speed is vital, at Dogger Bank and Stavanger the German Battlecruisers escaped at the former and the fast wing of the RN avoided annihilation at the latter due to speed. I can't see the RN or anyone who listens to them laying down anything with a top speed of less than 25 knots and everything the RN has built since Stavanger has been at least 28 knots. That is a major mark against the 21 knot Normandie's but is a an argument in favour of the 28 knot Caracciolo's.

At Stavanger there were a large number of turret fires and thanks to better than OTL flash protection on the British side ships kept fighting and dealing damage. That is a strong argument in favour of more, smaller turrets. Once again the Caracciolo's with their 4x2 15" layout look fairly sensible, the Normandie's with their 3x4 13.4" look like a dead end.

Hits outside of the armoured centre of a ship could cause significant problems. No British ship was directly sunk due to such hits, but the loss of speed and seakeeping abilities led to close calls for Lion, Warspite and Barham and undoubtedly contributed to the swift capsize of Royal Oak. Thin armour to the stem or stern seemed to be of little value, but steering gear and shafts needed greater protection from shrapnel.

- Deck protection would need to be increased over vital areas. In several ships, engine or boiler rooms suffered damage as a result of splinters from hits higher up in the ship, and the DNC’s staff suggested that such an event also represented an alternative mechanism for triggering the magazine fire that led to the loss of the Queen Mary.

- Watertight bulkheads needed to run as high as possible and greater attention should be paid to avoiding any penetrations for trunking or steam lines low down in the ship. Subdivision outside of the main armoured areas should be increased, perhaps in place of thin armour.

Then you've got the armour lessons, now both the French and Italian ships have armour that is too thin and not optimally distributed but the case in favour of all or none is weaker in this tl so they look less outdated.

On the question of torpedo defence the Carocciolo's urgently need bulges but that puts them in the same category almost every capital ship afloat.

All in all the French need to cancel the Normandie's ASAP but the Italians should probably persevere with the Caracciolo's.
 
Much like the Maryland’s went from a triple turret, 3x14”, to a double, 2x16”, could the South Dakota’s go from a triple 16” to a twin 18” turret?
 
Much like the Maryland’s went from a triple turret, 3x14”, to a double, 2x16”, could the South Dakota’s go from a triple 16” to a twin 18” turret?
Yes, but:

They wouldn't what an American designer would regard as a balanced ship.
 
The thing is the never was a Jutland in this tl and slightly different lessons were learned.

First of all the speed is vital, at Dogger Bank and Stavanger the German Battlecruisers escaped at the former and the fast wing of the RN avoided annihilation at the latter due to speed. I can't see the RN or anyone who listens to them laying down anything with a top speed of less than 25 knots and everything the RN has built since Stavanger has been at least 28 knots. That is a major mark against the 21 knot Normandie's but is a an argument in favour of the 28 knot Caracciolo's.

At Stavanger there were a large number of turret fires and thanks to better than OTL flash protection on the British side ships kept fighting and dealing damage. That is a strong argument in favour of more, smaller turrets. Once again the Caracciolo's with their 4x2 15" layout look fairly sensible, the Normandie's with their 3x4 13.4" look like a dead end.

Then you've got the armour lessons, now both the French and Italian ships have armour that is too thin and not optimally distributed but the case in favour of all or none is weaker in this tl so they look less outdated.

On the question of torpedo defence the Carocciolo's urgently need bulges but that puts them in the same category almost every capital ship afloat.

All in all the French need to cancel the Normandie's ASAP but the Italians should probably persevere with the Caracciolo's.

Reading through the actions mentioned, though the battles are different, the lessons key to the demise of Caracciolo and Normandie still ring plenty true. The lesson of weak deck armor and longer engagement ranges is strongly enforced by the 20,000-yard ranges at Dogger Bank, and fire control developments were pushing longer engagement ranges anyways, even among the less advanced navies. The Adriatic dreadnought clash in this timeline actually has the Austrian and Italian dreadnoughts firing at longer ranges than either had the fire control technology or doctrine for during WWI.

The attention to torpedo defense came from wartime experience independent of the North Sea, and home development of torpedoes with increasing strength. TDS among the ships, or the lack thereof at all (Normandie), became a major concern. The condition of the underwater protection was worse still than their British counterparts (Normandie is just a lost cause, while Caracciolo's TDS, though generally better, becomes similarly poor abreast the No.3 main battery turret). Simply adding bulges isn't going to do nearly as much for these ships as it would for the British ships, due to insufficient depth, and it will likewise cost them speed - there's no way Caracciolo is maintaining 28 knots if the design adds bulges. The designs are simply too much of a dead-end, and even with the different experiences in the North Sea of the British and Germans, that's not going to change much about the conclusions of the French and Italians about their designs.
 
Alphabet Soup
Alphabet Soup

At the end of the war, the Royal Navy could outgun every other fleet on the planet put together. However, other nations had building programmes underway, and so that situation would not last for long, even without the rapid process of demobilisation.
In 1919, design teams turned towards producing concepts for the next generation of capital ships that would be built in the 1920s. There were numerous lessons that had to be learned from the experience of war, and particularly from the magazine fires and explosions at Stavanger and in the Adriatic. Torpedo protection was better in war-built ships such as Hood, but there was always room for further improvement.
Any new ships would have to be at least as good as the latest opposition. The naval mission to the USA in the last months of the war had provided a much better understanding of what was being built under the 1916 US Naval Bill, while the alliance with Japan had given relatively clear indications of what the IJN wanted over the next decade.

If nothing were done, by 1925 the RN would be outgunned at the front of the battle-line, although in the middle and rear the picture was less gloomy. The ‘Royal’ and ‘Queen Elizabeth’ class ships were effectively as powerful and were faster than their contemporaries, while the five newest battlecruisers were more powerful than anything yet completed abroad. However, both the USA and Japan were known to be building 16” gunned battleships and battlecruisers, while the RN would have only Furious and Rodney equipped with guns larger than 15”.

Despite the losses and damage during the war, there was no reduction in enthusiasm for fast ships, and in fact the performance of the battlecruisers seemed to confirm their usefulness in hunting, scouting and fighting roles. However, any future fast ships would need better protection than the unfortunate Queen Mary or Inflexible.
The battlefleet consisted of 21-knot, 23½-knot, 27-knot and 31-knot ships (discounting some obsolete 25-knot battlecruisers lying in reserve, and the 33-knot Furious). Some strategists argued for a uniform fleet of ‘very fast’ battleships similar to Rodney, capable of 27 knots and with battleship levels of protection. Others argued that new battleships should be tactically compatible with the more modern 23½-knot vessels (which were likely to be in service for at least another decade), and that faster, less-heavily armoured battlecruisers still had their place in future plans.
Starting at the top, with the C-in-C Atlantic Fleet, Admiral Beatty, there was no shortage of senior officers who believed in the value of vessels capable of well over 30 knots, while simultaneously arguing that battleships should also be as swift as possible. In an ideal world, they might even want 27-knot battleships and 33-knot battlecruisers, but the world of 1919 was far from being an ideal one.

Capital ship studies therefore fell into two categories, with conceptual designs over the following years that started with ‘A’, but which skipped about in a way that appeared to defy logic. In fact, the DNC appears to have allocated different concepts to design teams, and some of the letters appear to be associated with names rather than the ships themselves; for instance ‘J’ was a design worked on by a team working under a future DNC, Arthur Johns.

Studies into both types began with HMS Rodney, due for completion in early 1921. She was the RN’s newest capital ship design, and as a derivative of Hood she also had battlecruiser lineage.

The ‘A-series’ battleships were comparatively conventional, based on a deepened version of Rodney’s hull. A-2 mounted eight 18” guns, with 90,000shp for 27 knots at a load displacement of 44,000 tons. However, she had only a 12” armour belt and a 4” upper armoured deck – an improvement on Rodney’s layout, but not in terms of total armour protection.
A-3 attempted to do the same with nine guns in triple turrets, but work was stopped once it became clear that the armour protection could never be brought up to the standards that would be required of future battleships.

Work on battleships then slowed, while their faster cousins took priority, and it was not until 1920 that studies resumed with the ‘M-series’, which resulted from concerns over displacement, the possibility of plunging shells reaching the magazines through funnel or ventilator openings, and the need to increase torpedo protection. All guns were mounted forward, grouped fore and aft of a towering bridge structure. The hull was a totally new form, which dispensed with the inclined sides of Hood and brought the belt inboard, allowing it to be more steeply sloped than the 10-12 degrees of the earlier ships. Beneath the belt, the curved external form of the bulges was gone, replaced by a near-vertical side with a broad torpedo protection system inboard.
A few years earlier, American designers had found that alternating layers of liquids and voids were effective in stopping torpedo fragments and in limiting underwater damage. USN battleships had been constructed accordingly, with broad beams and a series of vertical bulkheads near their sides.
The layout of this system had been noted by British engineers during the war, and since then a series of explosive tests on full-scale mock-ups of bulges and ships’ sides had shown that these layers could be at least as effective as Hood’s system of crushing tubes and timber-clad bulkheads. There was also a bonus; if oil were stored in the liquid layers, fuel capacity could be increased without needing room elsewhere in the ship.

M-2 would carry eight 18” Mk.2 guns (a new design of 45-calibres length) on 47,500 tons and would be capable of 23 knots, while M-3 would have nine guns in triple turrets on 46,000 tons, with 23½ knots being practical due to the lighter displacement.
The grouping of guns forward also allowed for very heavy armour; there was a 15” belt over the magazines, sloped at 25 degrees. Tests had shown that this would provide immunity against the older 18” Mk.1 gun down to under 12,000 yards, while decks up to 8” thick would protect the magazines against ‘plunging fire’ out to effective maximum range.
A 14” belt and 7” deck over machinery spaces would provide equivalent protection against the RN’s new 16” Mk.2 gun (as was fitted to Rodney).

Another remarkable improvement with ‘M’ was the incorporation of a transom stern, which resulted from the Chief Constructor noting that the long, fine stern of ships such as Hood and the ‘A’ designs barely touched the water. Model tests soon confirmed that cutting 15’ or even 25’ off the stern had virtually no effect on resistance at high speed.

The ‘N-3’ of late 1920 was a development of ‘M’, with refinements based on new calculations regarding weights and stresses. Displacement increased to 48,500 tons, but it was effectively just a more precisely worked-out version of M-3, with a slightly less sloped belt to help increase the size of the citadel, improving stability in a damaged condition and providing better protection against shells missing the bottom of the belt (for instance, as the ship rolled).

In turn, this design fed into a series of possible derivatives with the ‘P-series’.
P-34 included twelve 16” Mk.2 guns in four triple turrets (hence the ‘34’), requiring length to be increased to 855’. Normal displacement was 52,000 tons, and it had the distinction of being the first RN design with a Deep Load over 60,000 tons. Power was unchanged, but the longer hull allowed speed to be maintained at 23½ knots.
Although broadside weight decreased from 30,000 to 28,000 pounds, the new 16” gun had been shown to be only slightly less effective than the 18” Mk.1 against vertical armour, partly due to its higher muzzle velocity. Hitting the enemy quickly and repeatedly was important, and there was an argument that having twelve ‘very good’ guns was perhaps preferable to having nine ‘excellent’ ones.

P-3 blended the two earlier design, using nine of the 18” Mk.2 45-calibre guns in the same hull as P-34. This allowed machinery power to be increased, with eight large boilers delivering steam for 80,000shp through two shafts. The relatively full hull wasn’t optimised for speed, but the combination would deliver 26 knots at a normal load of 51,000 tons.

However, in design terms none of these massively powerful battleships were pursued so aggressively as their battlecruiser cousins, in part because of the influence of the wartime leaders Admirals Beatty and Jellicoe, who both regarded fast ships as more useful. By 1920, Beatty had reached the position of First Sea Lord, while Jellicoe’s 1919 report into Imperial Defence requirements supported his wartime observations that fast capital ships were more valuable than slow ones.
 
Alright, so broadly as OTL, at least for the battleships. Hopefully these don't have the closely-spaced secondary battery and short, low-volume citadel of the OTL Nelsons...
 
In an ideal world, they might even want 27-knot battleships and 33-knot battlecruisers,

The best.

Some strategists argued for a uniform fleet of ‘very fast’ battleships similar to Rodney, capable of 27 knots and with battleship levels of protection.

Good enough for the next decade.

P-3 blended the two earlier design, using nine of the 18” Mk.2 45-calibre guns in the same hull as P-34. This allowed machinery power to be increased, with eight large boilers delivering steam for 80,000shp through two shafts. The relatively full hull wasn’t optimised for speed, but the combination would deliver 26 knots at a normal load of 51,000 tons.

P-3 seems like a very a good idea and is not OTL. With a bit of tweaking to the hull form it might be able to make 27 knots which would be ideal.

However, in design terms none of these massively powerful battleships were pursued so aggressively as their battlecruiser cousins

Not good, since the RN last commissioned a battleship it has produced 6 battlecruisers (Renown, Repulse, 3 Admirals and Furious) and 2 large light cruisers, even if one of those battlecruisers has turned into a fast battleship in practise. The battleline can't be neglected and it needs some new steel.
 
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Not good, since the RN last commissioned a battleship it has produced 6 battlecruisers (Renown, Repulse, 3 Admirals and Furious) and 2 large light cruisers, even if one of those battlecruisers has turned into a fast battleship in practise. The battleline can't be neglected and it needs some new steel.
A G3 battleline wouldn't be the worst thing, it's armored well enough to take 18" guns, though its firepower might not be enough
 
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