Mini BEF to Poland, April 1939

[GrauGeist]

The wonder weapons were a last ditch hope.

They had a good start with the Graf Zeppelin and Peter Strasser, but didn't stay focused on their construction.

If you're going to start a world war, at least commit to building the stuff you'll need to fight it.

 

[EwenS]

On 3rd Sept 1939 Graf Zeppelin was 85% complete and Raeder ordered that work on her should continue.
"Freedom of the Seas. The story of Hitler's Aircraft Carrier - Graf Zeppelin"

The Admiralty considered her a bigger threat than even Bismarck. From ADM 1/10617 29 Jan 1940.

"...it is the aircraft carrier GRAF ZEPPELIN which is likely to provide our most disagreeable problem."

"The conclusion is that the BISMARCK herself is not likely to prove the menace that would at first seem likely. It is the aircraft carrier which is going to turn the scales in favour of any raider."

By the end of March 1940, Admiralty intelligence reports (which proved to be incorrect) believed that the GZ had begun her trials and would be complete as soon as April or May 1940. In fact work on her ceased in April 1940 and before being sent east to safety in July 1940 she had been stripped of her armament to reinforce Coast defences in newly captured ports in France.

In March 1942 work on her was authorised to begin again, with a modified design, but it was Nov 1942 before it did. And it ceased in April 1943.

Carrier B (only ever unoffially Peter Strasser) was laid down in 1938, two years behind GZ. Work on her stopped in Sept 1939 and she was broken up on the slip from Feb 1940.

 

[Admiral Beez]

All those wonder weapons and they couldn't finish Graf Zeppelin.

They should have just bought the plans for a Shōkaku-class and hired some designers to come to Deutsche Werke to drive the design and build.

If this were the case, how would France and Britain view the Soviet attack on Poland?

If the Russians don't stop at Poland we may see Britain, France and Germany join forces.

 

[EwenS]

They should have just bought the plans for a Shōkaku-class and hired some designers to come to Deutsche Werke to drive the design and build.

Except Graf Zeppelin's design predates that of the Shokaku class by about a year. (GZ laid down Dec 1936. Shokaku laid down Dec 1937). The Shokakus didn't complete until Aug/Sept 1941.

Time wise, a better comparison is with the Soryu. But in 1934/36 the Japanese were having their own problems with ship design, these were principally around stability (trying to do too much on a limited tonnage). Soryu had to be modified in 1936/37 after launch and before completion. Hiryu was even more heavily modified during her construction 1936-39.

So given these problems and the amount of work in hand, I doubt that the Japanese could have spared anyone even had they wished to.

 

[Shortround6]

Germans needed to figure out what the Graf Zeppelin was supposed to do.

They saddled her with more guns than US Brooklyn class cruiser and about 4in of belt armor. More suited to a North Sea gun fight than carrier opps.
40-42 aircraft was ludicrous for a carrier of her size.

For some reason a number of navies, over a number of decades, built ships to "match" an opponent's ship one for one like a dual. Some navies, like the Germans, were never going to have the number of ships needed to do straight up fights with their enemies. One Bismarck was not going to win a fight with four old QEs that had modern fire control. Sinking two of then or even 3 before getting sunk leaves the Germans with no battleship (or one building) while the British have another dozen left, for example.
The Graf Zeppelin was old thinking. Carriers should not be self supporting (not need escorts or minimal escorts). They should concentrate on flying operations and have enough sacrificial escorts ,destroyers and light cruisers, to handle surface attacks from less than the enemies main fleet.
If the enemies main battle fleet is within gun range of your carrier somebody has really screwed up.

 

[Peter Gunn]

No carriers.

A fair point, I would get into carrier warfare more but no Mustangs.

 

[Admiral Beez]

It is it all politics. Does it convince Hitler that the British and French are serious or do they take a good look at what was sent and after laughing, they delay the invasion by one week.

It's certainly a move entirely out of character for both Britain and France. One that must challenge whatever Hitler was telling his general staff about the likely ease of success. Imagine if in June 1990, one thousand USMC troops land and encamp in Kuwait, just as Saddam is planning his invasion that August. Surely this tiny force would throw a wrench into any assumptions of an easy win for Iraq? It's not the one thousand Marines that's the concern, it's the hammer that comes if you touch them. Britain and France need to convey that this is a trip wire force, if our guys are scratched, we will roll into Germany. For this to play, both Britain and France need to have boots on the ground on the German border, and not just behind defensive works, but ready to move forward.

This also gives a good opportunity for Britain and France to change relations with the USSR. Chamberlain and someone from France (Lebrun seems to be a bit of a wet noodle) after visiting the troops in Poland could sail for Leningrad and then meet with Stalin on the issue of mutual defence against Germany. Stalin might throw him out, but again, Chamberlain meeting with Stalin would challenge Hitler's assumptions and plans for the upcoming Sept 1939 agreement with Stalin to divvy up Poland.

 

[Thumpalumpacus]

For this to play, both Britain and France need to have boots on the ground on the German border, and not just behind defensive works, but ready to move forward.

Therein lies the rub. Even after war broke out the lack of offensive willpower from the Western allies allowed the Sitzkrieg to unfold. Would it be responsible to put a tripwire force of ten thousand in Poland when the hammer behind it is so timid?

ETA: After Munich, Stalin was deeply suspicious of he Western Allies, especially after (at Poland's behest) they rebuffed his proposal for a formalized security arrangement in summer of 1939. A visit to Leningrad may have done some good if the emissaries were empowered to sign a deal. If they weren't so empowered, I bet Stalin would simply have seen it as mere posturing and gone ahead with the Molotov-Ribbentrop pact once the Germans made that demarche.

 

[EwenS]

There are a few things to unpick here and you seem to be applying a lot of hindsight.

Germans needed to figure out what the Graf Zeppelin was supposed to do.

This was the 1930s. Less than 20 years since the first flat deck carrier (Argus) had appeared. Everyone, the US included, were still trying to figure out what a carrier could and couldn't do.

They saddled her with more guns than US Brooklyn class cruiser and about 4in of belt armor. More suited to a North Sea gun fight than carrier opps.
40-42 aircraft was ludicrous for a carrier of her size.

Everyone at least looked at putting big guns on carriers. Partly it was because the Washington Treaty of 1922 specifically permitted it. So why wouldn't you!

Look at the USN 8x8" guns on the Lexingtons only completed in 1927. In Nov 1940 BuAer (that is the USN Bureau of Aeronatics) resisted the proposal to remove them. It was 1942 before they were removed. A few months previously they had actually argued for 8" guns on a new batch of carriers to follow the first batch of Essex class. It was being influenced by the USN being potentially hard pressed to provide enough cruiser escorts and by the loss of Glorious. Japan did likewise with Akagi & Kaga, retaining some of these guns into WW2.

In the early 1930s the US looked at flight deck cruiser designs with guns forward and flight deck aft. So did the Japanese in early design proposals for the Soryu in 1934.

Britain only dropped the big gun idea in the late 1920s reconstructions of C&G, preferring smaller 4.7"DP weapons instead.

The US expected that its carriers, operating individually at this time not in multi-carrier Task groups, might well bump into Japanese 8" cruiser forces trying to sink them. And if the presence of not enough USN 8" cruiser support could be relied on (the USN was only permitted 18 by Treaty and was generally allocating 3 to each carrier) a carrier would have to defend itself.

As for side armour, it was seen as an essential defence against torpedoes over a ship's vital machinery compartments. Ark and the armoured carriers 4.5". The Essex class had 2.5-4" belt armour, the Midways 7-7.6". So why shouldn't the Germans put belt armour on GZ.

And again Treaty limits meant you could only do so much in the tonnage available. It was guns or aircraft in the 1930s. The USN and IJN took advantage of specific provisions allowing them to build large ships like the Lexingtons. But that meant fewer carriers.

As for GZ size, that was affected by the Anglo German Naval Agreement of 1935 which limited the KM to 35% of the British fleet (except for submarines), itself still limited by the Washington Treaty. This was applied Warship type by Warship type, even though it strictly didn't need to be. So Germany had 47,250 tons of carrier tonnage to play with or 23,625 tons for each of the ships it wanted. As originally designed GZ was just over 23,000 tons. After her redesign and bulging in WW2 she grew in size. It also explains why she was laid down before the end of 1936.

For some reason a number of navies, over a number of decades, built ships to "match" an opponent's ship one for one like a dual. Some navies, like the Germans, were never going to have the number of ships needed to do straight up fights with their enemies. One Bismarck was not going to win a fight with four old QEs that had modern fire control. Sinking two of then or even 3 before getting sunk leaves the Germans with no battleship (or one building) while the British have another dozen left, for example.

The 1922 Treaty laid down limits on ship and gun size. And on replacement intervals. Why build anything other than the max permitted in case you found your opponent built something bigger. The French tried it with Dunkerque & Strasbourg to match the Italian Cavour rebuilds only to find the Italians then building the Littorios, forcing them to build the full size (35,000 tons) Richelieus.

The Graf Zeppelin was old thinking. Carriers should not be self supporting (not need escorts or minimal escorts). They should concentrate on flying operations and have enough sacrificial escorts ,destroyers and light cruisers, to handle surface attacks from less than the enemies main fleet.

It was only old thinking if you apply hindsight. No one had ever fought a carrier war in the 1930s. WW2, and particularly the war in the Pacific changed much thinking.

If the enemies main battle fleet is within gun range of your carrier somebody has really screwed up.

I would agree but it happened in WW2. Glorious in 1940 and Formidable at night during the Matapan action for different reasons. In Oct 1944 the USN cruisers set about chasing down the remaining Japanese carriers after Leyte, finishing off the damaged and immobile Chiyoda. As usual the enemy gets a say in what happens.

 

[Shortround6]

There are a few things to unpick here and you seem to be applying a lot of hindsight.

Well, some hindsight

This was the 1930s. Less than 20 years since the first flat deck carrier (Argus) had appeared. Everyone, the US included, were still trying to figure out what a carrier could and couldn't do.

It was only 50 years since smokeless powder appeared and about 25 years since oil fuel showed up. 10 years could cover a lot of change. The Akagi had some of her boilers taken out/replaced in her 1935-38 reconstruction.

Look at the USN 8x8" guns on the Lexingtons only completed in 1927.

Like I said, a lot changed in 10 years even without shooting war. Akagi was built with ten 8in guns but four were taken out during the rebuild. Unfortunately for the Germans they had a team visit her during the 1935 Naval week just before her return to Japan for the Rebuild. Akagi was also around 30,000tons standard (and more at full load) rather than the "legend" displacement.

So Germany had 47,250 tons of carrier tonnage to play with or 23,625 tons for each of the ships it wanted. As originally designed GZ was just over 23,000 tons. After her redesign and bulging in WW2 she grew in size.

And here comes the problem, The Lexington was closer to 36,000 tons, Her 33,000 ton figure doesn't count around 3,000 tons of "improvements" the US figured she was entitled to as a converted battleship/battlecruiser. Trying to match the two big American carriers and the two big Japanese ones on a much smaller displacement ship meant something had to go.
Germans chose aircraft and kept guns.

The French tried it with Dunkerque & Strasbourg to match the Italian Cavour rebuilds only to find the Italians then building the Littorios, forcing them to build the full size (35,000 tons) Richelieus.

Most histories say that the Dunkerque & Strasbourg were built to counter the Deutschland class. The Dunkerque was laid down in the last days of 1932 and the Cavour didn't start rebuild until Oct 1933. I have no idea how leaky the Italian design offices were to French spies.
The French and Italians were trying to one up each other with Destroyers and Cruisers and came up with some of the worst designs possible. Egg shells armed with hammers may have been borrowed from the British WW I battlecruisers but some of these ships were even less balanced.

It was only old thinking if you apply hindsight. No one had ever fought a carrier war in the 1930s. WW2, and particularly the war in the Pacific changed much thinking.

The whole idea of screening the main fleet units went back to before 1900 if not into the age of sail. The problem was not viewing the carriers as main fleet units despite their cost, size and building times (not much quicker than a battleship).

I would agree but it happened in WW2. Glorious in 1940 and Formidable at night during the Matapan action for different reasons. In Oct 1944 the USN cruisers set about chasing down the remaining Japanese carriers after Leyte, finishing off the damaged and immobile Chiyoda. As usual the enemy gets a say in what happens.

You could have had a 15 in turret on the Glorious and it wouldn't have made any difference. Stupidity can't be solved with a few extra guns.
Chiyoda is a bad example. Damaged and immobile no gun armament would have saved her. At around 12,000 tons she simply had no chance.
Even a Tone class cruiser hit by four bombs and immobile wouldn't have lasted much longer against two Cleveland's, two 8in cruisers and 9 destroyers.

 

[GrauGeist]

If the enemies main battle fleet is within gun range of your carrier somebody has really screwed up.

USS Gambier Bay (CVE-73) did try and defend itself with it's sole 5" gun at Samar.

 

[Shortround6]

The tin cans and junior tin cans tried their best.

But no matter what you stuck on a CVE you weren't going to defend against Battleships and Cruisers in a gun fight.

What saved the rest of Taffy 3 was the 400 planes from the rest of task force.
Think about the result if TF had only 200 planes. Each escort carrier had a pair of 6in guns and several 5in but 1/2 the number of planes.
Would the US losses have been less or greater and would the Japanese losses have been greater or lesser?

USS Gambier Bay (CVE-73) did try and defend itself with it's sole 5" gun at Samar.

If the enemies main battle fleet is within gun range of your carrier somebody has really screwed up

And sometimes the screw up was at a much higher pay grade than the captain of the ship/s that paid the price.

 

[Shortround6]

It's not the one thousand Marines that's the concern, it's the hammer that comes if you touch them. Britain and France need to convey that this is a trip wire force, if our guys are scratched, we will roll into Germany.

The situation is a bit different.
The US had been (rightly or wrongly) playing world policeman for sometime. The French and British (and the rest of the world ) couldn't stop the Italians in Abyssinia. Let alone Japan in China. The threat was not credible, trip wire force or not.

The hammer was just minutes away. Not days or weeks. Two or three US Carriers can drop a large hammer in a very short period of time.

France took hours just get a phone call through, let alone get squad across a border check point.

 

[EwenS]

Most histories say that the Dunkerque & Strasbourg were built to counter the Deutschland class. The Dunkerque was laid down in the last days of 1932 and the Cavour didn't start rebuild until Oct 1933. I have no idea how leaky the Italian design offices were to French spies.
The French and Italians were trying to one up each other with Destroyers and Cruisers and came up with some of the worst designs possible. Egg shells armed with hammers may have been borrowed from the British WW I battlecruisers but some of these ships were even less balanced.

Yes that is the way it is portrayed in most histories. But that puts the focus on Germany and ignores what was going on between Italy & France at the time. It is more complicated than portrayed. The appearance of the Deutshland class has some influence on the French ships but they were not built simply to counter them.

And on looking back I have laid out the order of the Franco / Italian battle less than clearly.

Go back to the Washington Conference negotiations in 1921/22 and you will see that the original proposals would have left the French and the Italians with 7/6 old pre-Jutland dreadnought battleships of limited use plus a few pre-dreadnoughts that were already useless. As a result they secured the ability to lay down replacement tonnage before other nations. Each got an entitlement to 35,000 tons in 1927 & 1929.

The French began to study new battleship designs in 1926, with proposals ranging from 17,500 tons in 1926 through 37,000 tons in in 1927/28 to 23,333 tons in 1930. They faced 3 limitations:-
1. Technical - the larger designs would exceed then current building facilities. As it was Dunkerque was built in two parts and joined after launch. Richelieu was built in 3 parts.
2. Financial - the Govt was limiting expenditure
3. Political - this was an era of disarmament. As a principal proponent of disarmament she could not have been seen to start building a new batch of super battleships up to the tonnage limits allowed (35,000 tons). At the same time by 1930 Britain was proposing a 25,000 ton /12" gun limit on battleships ahead of the 1930 London Conference, which France wanted to support. Both France and Italy came out of London retaining the right to build that new tonnage while the battleship holiday for other nations was extended until the end of 1936.

So with aging tonnage France needed to begin building new ASAP. But what size? 23,333 tons gave them 3 ships with 305mm guns within their 70,000 ton allowance. But they needed to future proof the design and this is where the influence of the Deutschland becomes apparent. The decision to increase to 26,500 tons allowed an increase in gun calibre to 330mm from 305mm v the 280mm of Deutschland and an increase in protection against the German weapon. Until that point Jordan & Dumas make no mention of Deutschland as an influence in French designs.

But you are still talking about a ship that is 26,000 tons / 29.5 knots v a Deutschland of c12,000 tons / 26 knots. So they were clearly intended to be much more than simply a "counter" to the heavy cruiser sized / panzerschiffe Deutschland. Dunkerque was laid down in Dec 1932. Before a second identical ship could be ordered Italy had announced her decision to proceed with the Littorios and the Germans had announced plans for Deutschland number 4 (it became Scarnhorst in due course). In order not to suffer delays by designing a new vessel, the Dunkerque design was beefed up and Strasbourg (27,300 tons) laid down in Nov 1934.

Meanwhile over in Italy, the focus in the 1920s was on naval spending to create a fleet to match France, so it was the end of the 1920s before thoughts turned to replacement battleship tonnage at which point 23,000 ton designs were considered. Because of ongoing political uncertainties in the early 1930s the Italians decided to hang fire on new construction and in Oct 1933 adopted the interim solution of rebuilding Cesare & Cavour. At this point there was a lot of negotiations going on between Italy & France following the London Conference brokered at least some of the time by Britain & America, to prevent the two nations getting into an arms race, which might then have forced the collapse of the Treaty system.

In mid-1934 the Italians opted for a full 35,000 ton design, the Littorios, laying down 2 ships on 28th Oct 1934. Even after this Franco - Italian negotiations continued with a view to reversing this but ultimately nothing happened. The Italians then looked towards building a fleet of 8 battleships (4 Littorios & 4 reconstructions). So in 1935 began the reconstruction of Doria & Duilo and in 1938 the construction of a second pair of Littorios.

Following the Italian decision to proceed with the first pair of Littorios, France immediately began the design of a ship to match them. That became the Richelieu class. With Richelieu laid down in Oct 1935 the French were technically in breach of their Treaty limits and even more so after Jean Bart was laid down 3 weeks before the Washington Treaty expired at the end of 1936. But it was complicated by France onlysigning up to bits of the 1930 London Treaty and again politics was playing its part because the French were annoyed by the Anglo-German Naval Agreement of 1935 allowing Germany to build up to 35% of the RN tonnage.

After that French attention seems to shift focus more towards Germany than Italy. With Germany changing the design of Deutschlands 4 & 5 to the larger Scharnhorst class (laid down mid-1935 after the Strasbourg) to match the Dunkerques and then the Bismarcks in 1936, France then follows up with plans for another pair of 35,000 tonners based on the Richelieu design in 1938. By then France is having to face the prospect of potential enemies in both the Atlantic & the Med.


Sources:-
"French Battleships 1922-1956" by John Jordan & Rubert Dumas
"Littorio Class Italy's Last & Largest Battleships 1937-1948" Erminio Bagnasco & Augusto de Toro

The second of these goes into detail about the various negotiations between the French & Italians about naval construction between 1930 & 1935.

 

[EwenS]

What I omitted from my previous post was any comment about the German Navy, the Reichsmarine, in the period up to the mid-1930s. Remembering of course that Germany suffered financially in the period between reparations and recession and that Hitler didn't come to power until 1933.

Under the Treaty of Versailles the RM was severely limited in size. Manpower was limited to 15,000. It was limited to 6 pre-dreadnoughts (plus 2 in Reserve) all built 1904 to 1908, 6 cruisers (plus 2 in reserve), 12 destroyers and 12 torpedo boats.

Replacements for the old battleships were to be limited to 10,000 tons. That emerged in 1922 at Washington as the lower limit for a capital ship. And gun size was effectively limited to what existing machinery could produce (11") by virtue of close Allied oversight and virtual control of the armaments industry. On that tonnage it was expected that you could get a fast heavy cruiser type vessel with little armour, like many nations built in the 1920s, or a slow coast defence type vessel with heavy armour & larger guns, as developed by various Nordic countries. The Swedish Sverige is often quoted as the example everyone had in mind at the time.

HSwMS Sverige - Wikipedia

en.m.wikipedia.org

Neither type of vessel was considered a match for the much larger capital ships of the major powers.

By the mid-1920s the old RM pre-dreadnoughts badly needed replaced. By adopting radical design features the RM managed to get big guns, together with better armour than most heavy cruisers of the period, good range and a reasonable, but not cruiser, speed. So all diesel power and extensive use of welding saved weight for guns and armour. And all that was achieved without excessively exceeding the tonnage limit, at least in the first ship. Deutschland was about 10,600 tons when completed. The design evolved with the second and third ships being a bit larger & heavier. Plans for more ended with Hitler's rise to power.

So they were ships that could outrun most vessels they could not outfight, at least on a 1 to 1 basis. And, assuming the Germans kept to the terms of Versailles, there were only going to limited numbers of them. Therefore not an insurmountable problem.

In the 1920s the RM also set about replacing its cruisers, first with the Emden developed from WW1 designs, to be followed by the 3 Koln class and slightly larger Leipzig and Nurnberg. These all carried 5.9" guns.

But it was only after Hitler's rise to power in 1933 followed by the 1935 Anglo-German Naval Agreement that the German Navy, renamed the Kriegsmarine in 1935, began to expand with significantly increased building programmes that included larger capital ships, aircraft carriers, heavy cruisers and new larger destroyers

 

[Shortround6]

Under the Treaty of Versailles the RM was severely limited in size. Manpower was limited to 15,000. It was limited to 6 pre-dreadnoughts (plus 2 in Reserve) all built 1904 to 1908, 6 cruisers (plus 2 in reserve), 12 destroyers and 12 torpedo boats.

I believe there were also tonnage restrictions on the smaller classes, 6,000 tons for cruisers comes to mind and similar Pre WW I sizes for the Destroyers and torpedo boats. The German light cruisers were more North Sea/Baltic cruisers than Atlantic cruisers. Some did make very long cruises but at least one needed hull repairs along the way after dealing with heavy seas.

The Washington treaty cruisers started showing up pretty quick considering the design work.
Laying down dates.
Kent.........................Sept 1924
Nachi........................Oct 1924
Duquesne...............Oct 1924
Trento.......................Feb 1925
Pensacola...............Oct 1926
Deutschland..........Feb 1929

Sometimes the 3rd class of a navy was being laid down before the 1st class was doing sea trials so a lot of errors were carried over.

 

[EwenS]

The Washington treaty cruisers started showing up pretty quick considering the design work.
Laying down dates.
Kent.........................Sept 1924
Nachi........................Oct 1924
Duquesne...............Oct 1924
Trento.......................Feb 1925
Pensacola...............Oct 1926
Deutschland..........Feb 1929

Sometimes the 3rd class of a navy was being laid down before the 1st class was doing sea trials so a lot of errors were carried over.

Which ignores what had been the trajectory in cruiser design prior to Washington Conference which ended in Feb 1922. And ships in those days were a lot simpler than they became by the end of WW2 (no radar, minimal secondary and tertiary AA, fewer electronics etc) so took far less time to design and then, generally, one class design could serve as the basis for the next with little modification to the basics. Who proposed the Washington cruiser limits seems lost in time but the principal nations were all thinking along the same lines.

Britain went to Washington seeking to retain the 4 Hawkins class cruisers designed in WW1 which completed 7/19 to 7/25 (c9,600 tons 7.5" guns). So already had some idea of the possibilities.

In 1920 the USN had begun to design a new generation of cruisers. By 1921 these were emphasising speed & endurance, for Pacific operations (meaning size), over firepower and that over protection. That required a large ship (8,000-12,000 ton designs were examined in this period). But all were designed around the 8" gun usually in twin turrets.

In 1921 Japan was working on a new class of cruiser of 7,500 tons armed with 6x7.9" guns. These were to act as a counter to the Hawkins class and the US Omahas. Their construction was authorised by the IJN in Feb 1922 and they were laid down in Dec that year even before the Japanese Govt had authorised them! These were the 2 Furutaka class, which were followed by the 2 modified Aoba class. These were classed as Pre-Treaty ships but again showed the thinking.

The French had been considering large cruisers for overseas service before 1920 before reverting to the smaller 8,000 ton / 155mm Duguay-Trouin class laid down in 1922.

So the 10,000 ton / 8" limits were fairly easy to agree by the various participants. And the three principal participants all had some idea of what could be achieved, while the French had a more modern design that they initially thought they could scale up. It rapidly became clear that everyone, for their own reasons, would be building ships designed to the new limits.

The IJN got the ball rolling. In July 1922 they announced a new warship building programme which included the 2 Aoba class and the 4 Myoko class. By the end of the year draft designs for the Myoko had been produced, allowing the first pair to be ordered in Spring 1923, before the design being finally approved in Aug 1923. The first pair had their laying down delayed until Oct/Nov 1924 due to the Great Kanto Earthquake in Sept 1923.

That announcement spurred the RN into action, especially when they had decided that they needed a fleet of 70 modern cruisers to patrol the worldwide shipping lanes. Proposals for a new 8" gun and mount began around Nov 1922 and the design of the Kent class was approved in Dec 1923. The USN continued its path still trying to reconcile the various cruiser qualities before finalising the Pensacola design in 1925. The French eyed the limits as an opportunity to make up for their lack of capital ships vis a vis Britain & the USA and Italy wanted to maintain some kind of parity with the French. And so a new naval arms race began, remembering that cruiser numbers at this time were unlimited (that limit was the outcome of the 1930 London Treaty). The only restriction on numbers was a financial one as these ships proved to be a lot more expensive than previous generations.

The biggest difficulty facing the designers of these new cruisers was figuring out how best to build a ship to the Washington Conference definition of "standard displacement" while trading armament, speed, range and protection. That definition included some things but not others and no one had tried designing a ship to such a limit before, so everyone was on a learning curve. So what is, with hindsight, seen as "errors" was part of the evolving learning process. The alternative would have been to delay starting to build new vessels, something which against the political background of a capital ship holiday would have been unacceptable to all 5 Washington signitories.

"STANDARD DISPLACEMENT
The standard displacement of a ship is the displacement of the ship complete, fully manned, engined, and equipped ready for sea, including all armament and ammunition, equipment, outfit, provisions and fresh water for crew, miscellaneous stores and implements of every description that are intended to be carried in war, but without fuel or reserve feed water on board."

So a design would be drawn up and, as everyone was in a hurry, it would be ordered & laid down. Meanwhile the ships designers were beavering away in the background taking the design and seeking to improve on it before the first ships even completed. For example all the Counties were under construction before the first ship completed. So efforts were made to save weight to allow heavier armour as each class .

As a result a number of the earliest designs came out underweight. For example the Kents were 130-250 tons lighter than planned, even though the gun turrets turned out heavier than initially thought. The Pensacolas weighed in at 9,100 tons and the Northamptons at 9,400 tons. Others came out heavy to varying degrees like the Japanese Myokos & Takaos and Italian Trentos & Zaras with designers trying to cram that quart into the pint pot. In order to free up weight for more protection the USN first sacrificed a gun when moving to the Northamptons and then abandoned the unit machinery layout when they designed the New Orleans class, the last in order to stay with the Treaty limits (or at least reasonably close to them - estimating weights was not an exact science - no one quibbled about a couple of hundred tons over the limit).