Design "feature" of R-class

General naval discussions that don't fit within any specific time period or cover several issues.
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marcelo_malara
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Re: Design "feature" of R-class

Post by marcelo_malara »

Yes guys, after a little calculation I agree.

sine 20° = .34

That means that a shell coming with angle of fall of 20°, after piercing the upper belt and flying 10 m into the hull, will impact what it finds 3.4 m lower than point of penetration. After flying 20 m will impact 6.8 m lower. That means that even if impacting the slope is a remote possibility (at least for me) impacting the armoured deck will be the norm for upper belt penetration. This would need a thicker armoured deck, but this seems unfeasible in the ship size and weight already devoted protection (8200 t). Another mean will be lowering the armoured deck one deck, as already proposed by you. Only question that remains is to know if this would be possible due to boiler height. I am on holidays and far from my volumes of R. Burt, would like to see the sections of the ships to see if I can find out this.

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hans zurbriggen
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Re: Design "feature" of R-class

Post by hans zurbriggen »

Hello Mr. Malara,
I agree with you, however hit on the slope (20°+ steepness of slope, in the drawing around 50° --> 20° inclination from normal to plate) are far more dangerous than on flat deck (70° inclination from normal). This is IMHO the real weakness of such scheme, while flat deck parts look anyway better positioned to defeat shells.

hans
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marcelo_malara
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Re: Design "feature" of R-class

Post by marcelo_malara »

Hi Hans. Yes, I agree, you have a lower probability hit on the slope with almost certain penetration, or a higher probability impact higher in the belt with a less easy penetration on the flat. It remains me of the step in the armoured deck of Scharnhorst.
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marcelo_malara
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Re: Design "feature" of R-class

Post by marcelo_malara »

It seems as the designers did not deem possible an impact at that distance, an 20° angle of fall would be at a range around 17/18000 yards.
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marcelo_malara
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Re: Design "feature" of R-class

Post by marcelo_malara »

One question. QE class BB had an armoured deck of 100 lb on 40 lb (2.5" on 1"), total 3.5". How can it be that two classes of almost the same size and displacement, with weight devoted to protection almost the same too, one can have a 3.5" thick deck and the other only 1"/2"?
wmh829386
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Re: Design "feature" of R-class

Post by wmh829386 »

Hi Marcelo,


The 100 lb on 40 lb is added after the reconstruction of the QEs in the late 1930s. Originally QEs only have 40 lb of deck and slope at the middle deck.

HMS Royal Oak received the same thickness after her 1936 refit, however nothing was done to the 2 inch slope. The addition is possible because of the increased stability offered by the torpedo bulge.
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Re: Design "feature" of R-class

Post by wmh829386 »

marcelo_malara wrote: Tue Jan 31, 2023 2:12 am It seems as the designers did not deem possible an impact at that distance, an 20° angle of fall would be at a range around 17/18000 yards.
The problem is deeper than that. We are only considering 12 inch shell thus far. A 13.5 inch / 15 inch shell exploding directly above the 1"/ 2" deck is also extremely dangerous. Example from Jutland shows that the 1" middle deck is unable to keep out all shell fragments from 12" German shells.
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marcelo_malara
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Re: Design "feature" of R-class

Post by marcelo_malara »

wmh829386 wrote: Tue Jan 31, 2023 4:54 am Hi Marcelo,


The 100 lb on 40 lb is added after the reconstruction of the QEs in the late 1930s. Originally QEs only have 40 lb of deck and slope at the middle deck.

HMS Royal Oak received the same thickness after her 1936 refit, however nothing was done to the 2 inch slope. The addition is possible because of the increased stability offered by the torpedo bulge.
Thanks!
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marcelo_malara
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Re: Design "feature" of R-class

Post by marcelo_malara »

Bear in mind that the armoured deck is the heaviest of the individual protection areas. For example, a deck:

127 m long x 30 m wide x 88.9 mm thick (140 lb) = 2733 tons

May be that a thicker deck is simply impossible in a ship 27 000 t dspl.
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Re: Design "feature" of R-class

Post by wmh829386 »

marcelo_malara wrote: Tue Jan 31, 2023 4:06 pm Bear in mind that the armoured deck is the heaviest of the individual protection areas. For example, a deck:

127 m long x 30 m wide x 88.9 mm thick (140 lb) = 2733 tons

May be that a thicker deck is simply impossible in a ship 27 000 t dspl.
It is all about sacrifices. If we consider the change armour scheme from Dreadnought to R-class, there is a clear trend of distributing the armour to more areas.

In Dreadnought, the belt armour only reached the main deck, while on Iron duke, the side armour reached the forecastle deck!
It will be a simple exercise to increase the thickness of middle deck armor on the original QE by sacrificing armour of the 6 inch battery. (6 inch side + 1 inch roof)

The same could be said for the R-class, with the caveat that the slope will always be a weak spot unless the main deck is extended to the top of the belt.
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marcelo_malara
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Re: Design "feature" of R-class

Post by marcelo_malara »

wmh829386 wrote: Thu Feb 02, 2023 3:03 am

It is all about sacrifices. If we consider the change armour scheme from Dreadnought to R-class, there is a clear trend of distributing the armour to more areas.

In Dreadnought, the belt armour only reached the main deck, while on Iron duke, the side armour reached the forecastle deck!
It will be a simple exercise to increase the thickness of middle deck armor on the original QE by sacrificing armour of the 6 inch battery. (6 inch side + 1 inch roof)

The same could be said for the R-class, with the caveat that the slope will always be a weak spot unless the main deck is extended to the top of the belt.
I don´t think it would suffice. Look at this calculation, the weights of the main deck 1" thick along with the lower and upper belts (both sides counted), and below the same with the deck thickened to 4". 1800 tons are needed to be added to thicken to deck, and for sure can not be compensated with the battery protection, look at the weight of the upper belt which is much longer than the battery.

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Re: Design "feature" of R-class

Post by wmh829386 »

marcelo_malara wrote: Thu Feb 02, 2023 3:39 pm
I don´t think it would suffice. Look at this calculation, the weights of the main deck 1" thick along with the lower and upper belts (both sides counted), and below the same with the deck thickened to 4". 1800 tons are needed to be added to thicken to deck, and for sure can not be compensated with the battery protection, look at the weight of the upper belt which is much longer than the battery.
Oh, that is a misunderstanding. I don't mean increasing the deck thickness to 4".
But the 1" forecastle roof and 6" battery armor can be traded for a uniform 2" middle deck on the flat. Thinning the upper deck can also be allocated to the middle deck/main deck.

This kind of scheme is not some fantasy either, this type of scheme is similar to the 12 inch dreadnoughts of RN.
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marcelo_malara
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Re: Design "feature" of R-class

Post by marcelo_malara »

wmh829386 wrote: Thu Feb 02, 2023 10:49 pm
Oh, that is a misunderstanding. I don't mean increasing the deck thickness to 4".
But the 1" forecastle roof and 6" battery armor can be traded for a uniform 2" middle deck on the flat. Thinning the upper deck can also be allocated to the middle deck/main deck.

This kind of scheme is not some fantasy either, this type of scheme is similar to the 12 inch dreadnoughts of RN.
Ok, but those ships did not have a secondary battery of 6" guns, just 4" mountings. The 6" battery handles cordite bags, so you have to protect them, from an exploding shell above and from an impact in front. If you renounce to that protection you have to renounce to the secondary battery too, which is not bad, it was done with Hood in the 30s, but was not part of the specifications for the R class.

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Re: Design "feature" of R-class

Post by wmh829386 »

marcelo_malara wrote: Fri Feb 03, 2023 2:12 am
wmh829386 wrote: Thu Feb 02, 2023 10:49 pm
Oh, that is a misunderstanding. I don't mean increasing the deck thickness to 4".
But the 1" forecastle roof and 6" battery armor can be traded for a uniform 2" middle deck on the flat. Thinning the upper deck can also be allocated to the middle deck/main deck.

This kind of scheme is not some fantasy either, this type of scheme is similar to the 12 inch dreadnoughts of RN.
Ok, but those ships did not have a secondary battery of 6" guns, just 4" mountings. The 6" battery handles cordite bags, so you have to protect them, from an exploding shell above and from an impact in front. If you renounce to that protection you have to renounce to the secondary battery too, which is not bad, it was done with Hood in the 30s, but was not part of the specifications for the R class.

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The 6 inch secondaries were given up on the Renown and Repulse, which uses a silly triple mount :lol: . And the reason probably has a name: Jacky Fisher.

Furthermore Warspite did end up running a 6 inch battery without armour after 1936 refit anyway. And the reason is simple: the 6 inch side + 1 inch roof are completely useless against any reasonable threat.

There is really no necessity to mount armour for 6 inch guns: The contemporary light cruisers use the same 6 inch guns with minimal armour.
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Re: Design "feature" of R-class

Post by paul.mercer »

Gentlemen,
I admit I do have a soft spot for the QE's, my father served on both QE and Valiant in the early 30's first as a Midshipman and later as a Lieutenant and I still have some of the photos he took at the time (somewhere!) While I bow to everyone's superior knowledge of the armour layout etc, perhaps we should not forget that Warspite in her original form took one hell of a lot of punishment at Jutland after her rudder jammed but still survived, so the QE's as a class and in particular the rebuilt ones, could not have been too bad bearing in mind their age in WW2. While I'm not suggesting that they could have gone up against a ship like Bismarck with any serious chance of success, with their 8 x15" guns they were still formidable opponents.
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