# RN, US, IJN Cruisers.



## Chouan

Looking at contemporary 10,000 ton cruisers of the 3 major Navies, I can't help but notice how much more effective the US and Japanese ones seem to look. 
More guns, more armour, aircraft, and a general air of modernity that the RN ones seem to lack. 
For example 10 8" guns, or 15 6" guns etc as well as 4 aeroplanes.
As a non-expert, am I missing something?


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## Peter4447

Interesting topic Chouan and I am sure we have some knowledgeable members onboard who can provide the answer. 
There were so many things that have to be taken into consideration not least the Washington Treaty that put strict limits on new builds.
Then of course the RN had a very specific task of protecting the sea lanes and the 'Empire' - a global committment where Cruisers replaced the Frigates that were so often used for this purpose in Napoleonic times.
Although the County Class with their 3 funnels may have looked archaic they were, I understand, superb sea-boats that could be fought in all weathers. Later classes such as the Southamptons were generally well-equipped and showed remarkable powers of resistance due to such invisible assests as strong construction embraced in a seaworthy hull.
As you say it would, however, be interesting to see the comparisons.
Peter4447(Thumb)


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## fred henderson

*WW2 Cruisers*

It is mainly a factor of the size of the ships, Chouan. The Washington Naval Treaty of 1922 limited the maximum fleet tonnage for each nation and the maximum tonnage and gun size of each type of vessel. For cruisers the limits were 10,000 tons and 8 inch guns.

The Treaty expired in 1935 but Britain still aimed to build effective and economical ships within the treaty limits; Japan initially tried to comply with the treaty tonnage limit but failed and quickly ignored it. Both the USA and Japan were able to gain some advantage by using welded construction to reduce hull weight. 

The 12 RN County Class were laid down from 1924 to 1927 and were Britain's heavy cruisers. All were about 9,975 tons with eight 8 inch guns. The Exeter & York of only 8,300 tons were economy versions with six 8 inch guns, which were laid down in 1927/28. The RN came to realise that the 8 inch gun had too slow a rate of fire to be an effective cruiser weapon and was too heavy. All subsequent British cruisers were fitted with 6 inch guns and the weight saving used to provide better armour protection. 

The 8 RN Town Class cruisers, laid down 1935/36, were 9,100 tons and the 11 Fiji Class were only 8,530 tons. The largest RN cruisers were Belfast and Edinburgh of 1936, which were 10,550 tons. The standard RN armament was twelve 6 inch guns.

The US Navy tried to keep within the treaty limits by fitting very limited armour on their Washington Treaty heavy cruisers. The following 9 Brooklyn Class 6 inch cruisers had 15 main guns, but were very lightly constructed and prone to storm damage. The Brooklyn design was improved in following classes, with steady weight growth and continuing problems from the original Washington Treaty limitations. The standard wartime US light cruiser design was the Cleveland Class, with twelve 6 inch guns on 11,744 tons. Twenty-nine of these ships were built but they were considered to be badly top-heavy by the end of the War. The 18 Baltimore Class cruisers were an enlarged and strengthened design and much better ships with nine 8 inch guns, but were 14,472 tons. 

The US Navy considered all of its wartime cruisers were unsatisfactory and commissioned two completely new designs – the 6 inch Worcester Class (14,700 tons) and the 8 inch Des Moines Class (17,255 tons). Both classes were splendid ships but were too expensive and produced too late to be of value in the age of guided missiles.

The Japanese had relatively few cruisers. The first Japanese Washington Treaty heavy cruisers were the four Nachi Class laid down in 1924/5. They were intended to be 10,000 ton ships but the actual weight turned out to be 10,980 tons. The USN had a similar problem, which it resolved by reducing the ships’ secondary armament. The Japanese ignored the excess weight. The Nachi Class had ten 8 inch guns. The four follow-on Takao Class had the same armament but their actual weight was 11,350 tons. The final Japanese heavy cruisers were the two Tone Class, fitted with eight 8 inch guns on 11,215 tons. 

The only Japanese large 6 inch cruisers were the four ships of the Mogami Class. These ships provide a classic example of the perils of fitting too great an armament in a light weight hull. These ships had fifteen 6 inch guns and were intended to be 8,500 tons, but when the first two ships were completed in July and August 1935 their trials revealed considerable problems. They both had doubtful stability and hull distortions prevented the training of the turrets. Both ships were extensively modified and re-emerged at 11,200 tons. The remaining two ships in the class were constructed to the revised design. 

Fred(Thumb)


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## John Cassels

Fred , thought the Mogami and Mikuma were upgraded to 8" main rifles.


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## fred henderson

*Mogami Class*

John

I confined my comments to the as-built ship specifications. You are correct of course that all 4 Mogami class were rebuilt again in 1939/40, with ten 8 inch main guns and their standard tonnage increased to 12,400 tons.

I also failed to mention the four Agano class cruisers that were laid down between 1940 and 1942. These were the final Japanese cruisers. They were only 6,652 tons and had a main armament of six 6 inch guns. Sakawa of this class and the training cruiser Kashima were the only Japanese cruisers to survive the war.

It seems to me, that as the Japanese only built a small number of "Super Cruisers" and did not include any in their building schedules after the 1931 Programme, they concluded that ships of this type were of little practical value.

Fred(Thumb)


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## John Cassels

Apologies Fred , did not realise you were referring to original specs.

Perhaps one reason for the IJN not putting more more emphysis on large
cruisers lies in the upgrading of the "Kongo"class battlecruisers .
Extremely fast ships ( and very beautiful ships if I may say so ) .

The "Haruna "was a lovely example of this type.


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## Steve Woodward

The washington Treaty was meant as an early arms limitation treaty, one of the specs was a heavy cruiser of up to 10,000 tons and eight inch rifles, What the treaty did was start a race to build cruisers right up to and in the case of some navies deliberately beyond that limit, so instead of creating a limit it started a building race.
What Britain needed for protection of it's far flung trade routes and interests was not a smaller number of large and expensive heavy cruisers but large numbers of cheap to build smaller cruisers, as has been proved in history a number of agressively handled small ships can overcome a much larger ship.

The County class cruisers, actually three subclasses - Kents, Londons and the Norfolk's - have been called white elephants and much worse but talking to people who sailed in them usually reveals a different side, that large high-sided hull gave plenty of space and (relatively) good living quarters, an important thing when on a long voyage. They were indeed lightly armoured but even the heavy armour of the Graf Spee did not stop an eight-inch shell from Exeter, the counties hull was very well subdivided and could absorb a lot of damage and the armour could not have been that bad ,Berwick was hit by an eight inch shell from the far bigger Admiral Hipper and the four inch armour of the magazine defelected it . Another plus for these ships was their range, over 13,000 miles at 12 knots was easily the best on the market when they were built, a Takao could manage 8,000 miles.
A parsimonious government and a navy strapped for cash prevented Britain improving on her heavy cruiser designs but had the money been available the follow-on Surrey class would have been somewhat better, these were enlarged Cathredral class ( Exeter and York) reverting to eight main 8" guns with significantly heavier protection.
Of course it easy to answer what were the best cruisers ever and of course they were the ultimate development of the type - the American Alaska class, even though they displaced almost 30,000 tons and had 12" guns and were called battle cruisers but they were in fact armoured as cruisers, they too possessed a very long range - 12,000 miles and could steam at just over 31 knots and would have a been a very unpleasant surprise for a commerce raider like a Deutchland class.
However when they appeared they were too late, the first two Alaska and Guam were only completed in 1944 by which time commerce raiding was a thing of the past, of the remaining ships Hawaii was scrapped when 85% complete and The Phillipines, Samoa and Puerto Rico were cancelled in June 1943


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## Chouan

Thanks everybody for your comprehensive and expert answers. I was pretty sure that the RN Constructors wouldn't have deliberately built inferior cruisers to the USN and IJN, despite what the reference books would have us believe.


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## Neil H

Can the Alaska class really be called cruisers? 34000 tons full load, 808ft long, 91ft beam, 9-12” guns, 6-9” belt armour, 4”deck (16% of total tonnage). Ship classification is a grey area, there are so many variables that broad generalisations have to be made otherwise there would be an infinite number of classes. From these statistics this class resembles a battlecruiser more than a cruiser. 

The armour percentage is similar to that of a cruiser and earlier types of battlecruiser (Repulse and Renown only had around 2-9” of side armour before refitting). The Baltimore class of heavy cruisers had 4-6” belt and 2.5” deck armour, the Italian Zara class had 3.9-5.9” belt and 2.75” deck armour but these were about the most heavily armoured cruisers and represent only a small fraction of the worlds heavy cruiser strength. The most common belt armour thickness used in the vast majority of heavy cruisers in all the worlds major navies was 3” to 4”. Some French, Italian and Japanese classes had only 2” to 3” belt armour, the Suffrens, Bolzanos and the Aobas for example. Even considering immediate post-war built cruisers like the USSR Sverdlov class which had 3.9-4.9” belt and 1-3” deck armour it can be seen that the Alaskas were significantly more heavily armoured than a standard sized heavy cruiser.

This is only half the equation though, a vessels sheer mass and its internal design must also be considered when comparing how damage resistant a ship is. In this case the Alaska class’s displacement and its physical size are clearly much greater than any heavy cruiser ever built. Their internal volume would allow an internal protection scheme similar to that of a battleship (compartmentalisation and sacrificial spaces). A standard sized cruiser just wouldn’t have the space. I don’t have the details of the Alaskas internal layout, anybody here know anything about that?

The design concept of the battlecruiser was to outrun anything it couldn’t outgun and outgun anything it couldn’t outrun. For this the vessel had to have improved speed compared to battleships and a better armament compared to cruisers. Two design branches were formed. The first was to reduce the armour protection to save weight and the second was to reduce the armament calibre. The Alaska class seem to be a hybrid of both branches, reduced armour and a slightly reduced main armament. Similar in concept to the original British battlecruiser classes of WW1 the Queen Mary class. Personally I find them an odd design for a navy that emphasises defence and protection in its ships.

A very interesting topic for discussion(Thumb)


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## Nihon Fan

Steve Woodward said:


> The washington Treaty was meant as an early arms limitation treaty, one of the specs was a heavy cruiser of up to 10,000 tons and eight inch rifles, What the treaty did was start a race to build cruisers right up to and in the case of some navies deliberately beyond that limit, so instead of creating a limit it started a building race.



I disagree. I'm writing from the vantage point of the United States and Japan.Right after World War II each of these countries already viewed the other as the most likely opponent in another war. The Washington Treaty apportioned strengths for Britain, the US and Japan at a ratio of 5:5:3 for battleships and heavy cruisers, which meant that for every 3 BBs or CA Japan had the US/Britain were allowed to have 5.

From the Japanese perspective they felt for them to win a war with either nation, their 3 ships had to be better than their 5 enemy counterparts; essentially a quality vs. quantity issue. In many instances they were, particularly with the haevy cruisers, largely in part because Japan did violate weight restrictions.

Wiser Japanese naval leaders, such as Admiral Yamamoto, wanted the treaty to continue because they knew Japan would never win a naval race and eventually even if their ships were qualitatively better, the superiors numbers that the Americans could produce would overwhelm this advantage. Not only that but the Americans and British would also no longer be bound by treaty restrictions and build bigger and better ships, so Japan would lose that qualitative advantage as well.

Unfortunately for Japan, most of the leadership did not view it this way and saw the treaty as an insult and withdrew from it out of pride, not fully comprehending the consequences. As it was, the US for most of the peace time period did not build to what it was entitled to.




Steve Woodward said:


> The County class cruisers, actually three subclasses - Kents, Londons and the Norfolk's - have been called white elephants and much worse but talking to people who sailed in them usually reveals a different side, that large high-sided hull gave plenty of space and (relatively) good living quarters, an important thing when on a long voyage.



From what I understand, Japanese quarters on almost all ships were quite spartan as they did not give as much consideration for comfort and rather focused on offensive capabilities.





Steve Woodward said:


> Of course it easy to answer what were the best cruisers ever and of course they were the ultimate development of the type - the American Alaska class, even though they displaced almost 30,000 tons and had 12" guns and were called battle cruisers but they were in fact armoured as cruisers, they too possessed a very long range - 12,000 miles and could steam at just over 31 knots and would have a been a very unpleasant surprise for a commerce raider like a Deutchland class.



For what it's worth, the Alaska-class ships were never designated battle cruisers by the USN but instead large cruisers. The USN didn't see them as quite large enough to be battlecruisers. They were essentially bigger than a heavy cruiser but smaller than a battlecruiser. Hood, the Renown-class, and the Kongo-class battlecruisers were older ships and already had bigger guns than the Alaskas. Supposedly they were designed to deal with a mythical Japanese commerce raider design called the Chichibu class.


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## Ribtikler

*Washinton Naval Treaty*

As I recall, this limited total tonnage of cruisers ...so the RN built more smaller sized ships.


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