Royal Navy Dido class Light Crusiers

[bengtsson]

I was reading over on another warship site the general trashing of the Royal Navy's Dido class Light Cruisers of WWII. Being as the Didos are favorite ships of mine, I wonder does all that criticism really stack up to reality in the context of World War Two? Now I'm not sure how to take the posters on that thread, as they trashed the Atlanta Class Light AA Cruisers of the USN as well. The IJN Akitsuki, though large DDs, were also commented on though some little less criticism was thown their way at least.
We all know the short coming of the 5.25 main armament of the Didos as regards their AA performance and the lack of a good AA director in RN service. But given the type of war the RN was fighting in the Medit, wasn't the Dido class a darned welcome addition to the RNs naval forces? I can think of plenty less useful designs to have in operation in 1941-42 in the medit. They gave up some AA performance because a gun heavy enough to give good surface performance was wanted. Would the Didos have been better of being all completed with the eight 4.5 in DP guns of Charybdis and Scylla?
Some sources say that a Dido was less effective in the AA role than a standard RN 6in Gun LC armed with the secondary armament of 8 4in AA. If that's the case, were the Didos a bad decission? On the Atlantas, how can anyone fault them as AA ships? Especially as part of Carrier groups?
Was a vessel of the size of a Dido or Atlanta set aside as a design for AA use a good idea. Or was a smaller design like the Japanese Akitsuki a better more cost effective option?


Bob B.

[RNfanDan]

I believe it's true that these ships were somewhat less than they could have been, given that they embodied no obvious technological advancements in and of themselves, and that they were an expediency brought about by external pressures of their day, rather than a design carefully considered and developed with an eye toward long-term requirements.

At the same time however, they were not in gross violation of any then-prevalent design parameters, either "tactical or practical", and certainly were no more flawed than, say the Hunt-class destroyers, whose designs were similarly hampered by pressures of expediency and the perceived immediate requirements of their day. Few warships have been truly successful, that were designed under such conditions; nor were these ships alone--by any means--in suffering from their early stability and structural problems.

Given the fact that almost no navy on Earth in the 1930s would dare order a cruiser design completely without surface-combat capabilities, even one intended primarily for AA, the Didos could not be considered worthless (as many in hindsight regard them).

As to the issue of the earlier light cruisers with twin 4" being more effective designs--remember that most of these originally carried single 4" HA guns, which were later replaced. Retro-fitting of the excellent 4" twin in place of these obsolete weapons does not qualify those cruisers as "superior" designs; in fact, some of those ships had their AA magazines located more than sixty yards away from the gun mountings, themselves--not exactly innovative!

Remember too, that WW2 was a rude shock to the "gun lobbies" of almost every navy. Even the IJN--with arguably the most advanced air fleet and tactical strike capabilities in existence in those times--was still a "gun navy" in terms of its overall doctrines and strategy. Trashing of the Dido design by revisionist historians and post-facto pundits is unnecessarily severe when everything above, is given its due consideration.



My har-penny's worth.....

[bengtsson]

Given the fact that almost no navy on Earth in the 1930s would dare order a cruiser design completely without surface-combat capabilities, even one intended primarily for AA, the Didos could not be considered worthless (as many in hindsight regard them).



Remember too, that WW2 was a rude shock to the "gun lobbies" of almost every navy. Even the IJN--with arguably the most advanced air fleet and tactical strike capabilities in existence in those times--was still a "gun navy" in terms of its overall doctrines and strategy. Trashing of the Dido design by revisionist historians and post-facto pundits is unnecessarily severe when everything above, is given its due consideration.



My har-penny's worth.....

I'de really agree with those statements. All in all, you put the Didios into their proper context. I use hindsight as much as the next man, but when I consider a warship and it's place in the real world of the 1930s and on into the war I like to think context matters. The fact that the Didos were at least designed to put up a full main armament barrage against air attack was a step forward. The fact that they were not 6in gunned, became less important as Cruiser against Cruiser surface actions became a rare exception rather than the norm. When they arrived in the Medit Fleet, they were most welcome additions.
The fact that the same Dido trashers were also finding reasons to trash the Atlantas says alot about trashing designs for trashings sake. Atlantas were about as ideal as an AA Cruiser design could be for it's time.
I wonder about the question of using a Cruiser size ship in the primarily AA role. Would not the Akitsuki size ship be more ideal? When I think of an AA ship I am thinking on the lines of a ship to either be an escort to a Carrier force or provide AA cover for a convoy like the Malta and Arctic convoys. In those roles the Cruiser size may not be necessary.
Still, I like the Didos and think they were a good addition to the Royal Navy in very difficult times. Though it's clear the Didos suffered from being a design caught between two roles. AA Cruiser and conventional Light Cruiser.

Bob B

[ar]

Generally good ships once the structiral and vibration problems were worked out, which was by the end of 1941.
Those that served as command vessels did well in the latter part of the war.
Difficult to compare to the Atlantas as they served mainly as escorts to carrier groups which the Didos did not.

[Chuck~]

I was reading over on another warship site the........

Would that other site be Warship Projects?

Whom might you be on that site?

[bengtsson]

I was reading over on another warship site the........

Would that other site be Warship Projects?

Whom might you be on that site?

It was the Warships1 discussion boards. I haven't posted there for a year or more. I like to read the posts there sometimes. One guy over there is too much for anyone ,with a serious desire to learn and share information about warships, to handle.

Bob B.

[RNfanDan]

Interesting...I found a similar post at KBismarck.com--with similar bashing.

The usual suspects.

'Nuff said...

[Tiornu]

Would the RN have benefited by foregoing Didos and sticking with an Arethusa-type ship?

[Werner]

Were the defects in train of the 5.25" mountings ever rectified?

They seem to have had the potential to be quite successful, weatherly ships.

[Jack Ray]

Despite the purported defects of the Didos and Atlantas, the AA cruiser concept was obviously not dismissed as is proven by the postwar Worcester class large AAA cruisers mounting six fully automatic twin 6" turrets. The RN planned similar ships with the same armament, but these were cancelled (the Cold War Lion Class ships mounted similar-if not the same-weapons).

Jack

[bengtsson]

Would the RN have benefited by foregoing Didos and sticking with an Arethusa-type ship?

I think not, and that is just based on the need for a dedicated AA ship of sufficient size and speed to run with a Carrier. The way naval warfare was changing, Carriers were clearly in need of heavy AA cover. That the Didos didn't prove ideal at this would probably not have made Arethusa any better at it. The RN BBs themsleves were in need of heavy AA cover as much as the Carriers. I'de say all the AA ships were necessary in WWII. For what it's worth, the very heavy and rapid fire a Dido could put down in the LA role, did make them useful in warding of any torpedo attacks by hostile destroyers and Torpedo boats. So they surely had their uses. So did Arethusa class ships. I'de prefer to have them both

Bob B.

[Tiornu]

Can't you buy four Arethusas for three Didos?

[Werner]

Can't you buy four Arethusas for three Didos?

I think the question ought to be 'can four Arethusas be built in the same time with the same industrial plant that built three Didos?' When discussing cruisers delivered after the start of the war, delivery timing and industrial base is as important, if not more important, than the economies of scale.

Three Didos require 25% fewer reduction gears and turbines, and one less slipway, with the thousand or so artisans who work there.

[Tiornu]

Was there in fact a production bottleneck, other than the one regarding 5.25in weaponry?

[Werner]

Assuming there was no surplus of machinery makers or dockyard hands standing idle, adding one cruiser would probably require you to defer about two destroyers.

In certain "critical path" areas like casting for foundations, bow and stern shapes, armor and reduction gears, the cost in time might even be more severe.

[Tiornu]

I suppose the British capacity for building cruisers was maxed out by 1937, but it seems unlikely.

[Dick J]

Was there in fact a production bottleneck, other than the one regarding 5.25in weaponry?

The twin 4" AA mounts were in almost as short supply as the 5.25" mounts. Or, more accurately, the demand was so high for the 4" that supply simply couldn't keep up. The twin 6" mounts were not in production after the Arethusa's were completed, and I don't know if the British had the capacity to start the line back up without disrupting other projects.

[RNfanDan]

I suppose the British capacity for building cruisers was maxed out by 1937, but it seems unlikely.

I tend to agree, but if so, such a saturation seems more likely attributable to over two decades of declining armaments-production capacity, than any lack of shipyard efficiency. I regard British yards as simply amazing in their response to the war effort. They could not be held accountable for an armaments industry that was pressed by the needs of all service branches, not just the navy.

[jjb]

People tend to forget the bottlenecks weren't only in armament, there were also bottlenecks in turbine engines and machinery, and competition for materials and resources from the army and especially air force which was re-arming rapidly in the run up to war.

[ar]

Were the defects in train of the 5.25" mountings ever rectified?

They seem to have had the potential to be quite successful, weatherly ships.

The proble was caused by the ships being heavily loaded at the fore end, and by driven hard in heavy weather in Northern waters during the winter of 40/41.
The cure was to strengthen internally by extra pillars and brackets. This worked.

In the case of Bonaventure's problem, the ship was going at around 30knots, made a sharp turn with the turrets traing at the same time. This in order to keep the guns trained on the Hipper. It appears that the Captain of the Bonaventure was flinging the ship around.
The vibration problem lasted longer but was not very serioius but had to be addressed, which it was.
By the end of 42, it was realised that the AA cruiser as a dedicated type was obsolete. The modified Didos reflected this, being command ships in service.
One of the problems with small cruisers was the lack of internal space for all of the new stuff that was needed during the war, beginning with radar in 1940. Even the County class cruisers had to have X turret removed, not for reasons of topweight but to give apace for more equiptment.
I have not seen any figures, but I would very much doubt that the main armament of cruisers shot down many aircraft. The effectiveness of the twin 4" and the 5.25" would have been in breaking up attacks at long, to medium range. A significant advance was made when ships were fitted with barrage directors coulpled with type 283 radar. Named the Auto Barrage System.
The Didos had good seakeeping qualities, but you can drive a 6000 ton ship only so much in heavy weather before things start to bend. The Atlantas were no exception. Although the Atlantas were a little larger, they were wetter in heavy weather due to the pronounced sheer. They too suffered from vibration.
The Didos performed well in the Med, with perhaps their finest moment being in the 2nd Battle of Sirte. A gale was blowing during that engagement.