Hood v Vittorio Veneto

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Alberto Virtuani
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Re: Hood v Vittorio Veneto

Postby Alberto Virtuani » Sun Jun 05, 2016 8:02 am

@ Maciej,
Hi, first of all, thank you for fairly posting the values given by "Face Hard" for penetration above. It's a pleasure to discuss with a knowledgeable and polite person, even when being in disagreement..... :clap:

you wrote: "What I'm questioning is some extreme large advance of such structure over single plate."

Well, even according to "Face Hard" (and with all its limits) the advantage is quite clear giving a 16" equivalent thickness for the 13.8" combined plates of the array for "no penetration", more than justifying the complexity of the system.
So, an equivalent thickness of 406,5 mm vs 350 mm, based on the test results, that confirmed that the array plate "brilliantly resisted to the attacks" (and I suspect this estimation was cautionary).


you wrote: "Who evaluates whether the test results confirm the theory?"

I don't have any more details than the ones that are included in Bagnasco/De Toro same page that you mentioned already (I have the Italian version....). The tests were not done by Pugliese, but by another officer (Bianco di San Secondo) and final decision was taken by "Marinalles" (RM "Department for naval fittings"), according to the procedures of the RM.


you wrote: "My feelings....... is that designers expected in normal situation that some splinters, shell fragments will be thrown into the hull, so those bulkheads are placed to stop them. If splinters were not expected "

The first bulkhead (36mm) is clearly against splinters from the belt. The second (24mm) and the third one (19mm) are mainly against splinters coming from "plunging" fire hitting the outboard (weaker) part of the armor decks (or the upper belt plus the lower armor deck....). The third one is also part of the TDS. (please see scheme at pag. 12 of this thread).

The RM wanted clearly to (somehow) protect Littorio's also at very short ranges, possibly below 16 km, I would say up to 10-12 km, against guns less powerful than the Italian ones, so I would not consider "suspicious" the presence of a splinter bulkhead behind the belt, just additional protection in case of.....

If Italians really had doubts about the array functioning at that time, before starting the construction of the first two Littorio's, I think that Marinalles would have decided to build the ships with a (easier to build ) single plate of 350 mm steel, inclined 15°....... Instead, the same layout was confirmed, some time later, for the further two ships, with no change.....


Bye, Alberto
"It takes three years to build a ship; it takes three centuries to build a tradition" (Adm.A.B.Cunningham)

Thorsten Wahl
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Re: Hood v Vittorio Veneto

Postby Thorsten Wahl » Fri Jun 10, 2016 2:14 pm

larger AP-caps supress the turning moment during oblique impacts thus increasing oblique performance of capped shells(with cap attached) compared to ogival shaped non capped Shells. The supression is more pronounced the larger caps.

as can be seen on this high-speed recordings
Image

---------------------------------------------------------
The british tests did not correctly reproduce the italian armor scheme, as the concrete filling between the fore and main plate is missing. So the spacing was not sufficent to ensure complete removal of the amour piercing cap of a 14" Shell. But from the results on can conclude, that the decapping process was in formation, as the Ballistic Limit of the spaced arrangement was the same as a solid plate of same total thickness against the same projectile.

see scheme X
Image
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Re: Hood v Vittorio Veneto

Postby dunmunro » Sat Jun 11, 2016 6:38 pm

The RM didn't use a concrete filling as that would have increased weight too much, rather they used a lightweight water exclusion material which had minimal balistic effect.

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Alberto Virtuani
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Re: Hood v Vittorio Veneto

Postby Alberto Virtuani » Sat Jun 11, 2016 9:20 pm

I confirm, no "full" traditional concrete was used on Littorio's between the two plates.

In addition to its weight, concrete would have had a negative effect, preventing too much the nutation (and precession) motion of the shell between the plates. Thanks to Dave Saxton for clarifying the role of both different motions here.

After experimenting several solutions, Italians tried with the light, water-repellent component (it was called "cellulite") and, according to the final tests, it was the best choice, avoiding water to come in (by filling the inter-plates space) and providing a protection equivalent to a single plate able to defeat he Italian 381 mm gun from 16 km.

Bye, Alberto
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paul.mercer
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Re: Hood v Vittorio Veneto

Postby paul.mercer » Tue Jun 14, 2016 3:52 pm

Gentlemen,
We have discussed VV meeting up with Hood, a QE and a KGV, what about a fight against Nelson or Rodney one to one?

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Re: Hood v Vittorio Veneto

Postby Maciej » Tue Jun 14, 2016 6:42 pm

I would say - 6 knots speed difference
So if VV is not slowed down considerably, and fast, she can simply run away if something goes wrong.
Nelson had no such option.
In 1:1 and no any escort fight.

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Re: Hood v Vittorio Veneto

Postby paul.mercer » Wed Jun 15, 2016 7:20 pm

Maciej wrote:I would say - 6 knots speed difference
So if VV is not slowed down considerably, and fast, she can simply run away if something goes wrong.
Nelson had no such option.
In 1:1 and no any escort fight.

I was presuming that VV (or Littorio) would actually fight rather than run

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Re: Hood v Vittorio Veneto

Postby Maciej » Thu Jun 16, 2016 8:38 am

Quite short.
Both had inclined belt armour.
Littorio – 15 degree
Nelson – 18 degree
How good was spaced array of Littorio we had debate, so I’ll try to avoid repeat it now.
In Nelson belt was 14” over magazines and 12” over machinery.
Internal ( Littorio external ).
Both were shallow – in Nelson ~1 feet shallower, and thanks to internal position, there was larger chance of diving shell avoiding that belt and strike below.
In case of quality of armour – I have data that puzzles me.
Post WWII British tested plates removed from Nelson being scrapped, and compared them with actually produced plates.
Plates removed from Nelson – so actual fitted on ship.
General conclusion was that those Nelson’s plates could be accepted for Vanguard. They were just at the acceptance level.
But newer plates were accepted generally with better quality, and were more consiscent, but conclusion was that there is no large difference.

FaceHD gives significant difference in stopping power of Nelson’s and Vanguard’s plates. I don’t know reasons of such difference. Possibly averaged value differs so much? Or plates actually accepted for Vanguard ( and KGV ) were so better than required?

But still Italy’s armour was superior ( according to FaceHD ), when considering single plate of the same thickness as British.

Littorio’s sapaced array relative to single plate was poorer as shell calibre increases. For smaller shell – that space works better than single plate, for larger worse.
Where are more or less the same – we can discuss long and finish with nothing.

So to avoid confusion – lets say belts over magazines on both sides had more or less the same protection.
Belt over machinery of Littorio was better.

Deck – thickness more or less the same on both ships. Any data about quality of plates?

Artillery
I know how bad performance of British 16” shells are described in navweaps.com, calculated by Thompson F formula. And I repeated many times why results from that formula has no use in calculating performance of shells other than USA
According to FaceHD, Nelsons guns had better perforation power than Iowa’s. In low oblique impact worse than Littorio, in middle oblique better.
So to simplefy things say similar relative protection and perforation power ( with possible some advantage of Littorio ).
In case of turrets, barbettes and so one – things are similar.

So in case who can hurt who – more or less the same capabilities ( some fire control differences could be considered, and of course crew capability ), with some advantage of Littorio.
And Littorio was ~6 knots faster so could choose distance, and run away if needed, or close range at will, of situation requires it.

15 years and 7-8 000 tons difference weights something.

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Re: Hood v Vittorio Veneto

Postby paul.mercer » Thu Jun 16, 2016 5:14 pm

Maciej wrote:Quite short.
Both had inclined belt armour.
Littorio – 15 degree
Nelson – 18 degree
How good was spaced array of Littorio we had debate, so I’ll try to avoid repeat it now.
In Nelson belt was 14” over magazines and 12” over machinery.
Internal ( Littorio external ).
Both were shallow – in Nelson ~1 feet shallower, and thanks to internal position, there was larger chance of diving shell avoiding that belt and strike below.
In case of quality of armour – I have data that puzzles me.
Post WWII British tested plates removed from Nelson being scrapped, and compared them with actually produced plates.
Plates removed from Nelson – so actual fitted on ship.
General conclusion was that those Nelson’s plates could be accepted for Vanguard. They were just at the acceptance level.
But newer plates were accepted generally with better quality, and were more consiscent, but conclusion was that there is no large difference.

FaceHD gives significant difference in stopping power of Nelson’s and Vanguard’s plates. I don’t know reasons of such difference. Possibly averaged value differs so much? Or plates actually accepted for Vanguard ( and KGV ) were so better than required?

But still Italy’s armour was superior ( according to FaceHD ), when considering single plate of the same thickness as British.

Littorio’s sapaced array relative to single plate was poorer as shell calibre increases. For smaller shell – that space works better than single plate, for larger worse.
Where are more or less the same – we can discuss long and finish with nothing.

So to avoid confusion – lets say belts over magazines on both sides had more or less the same protection.
Belt over machinery of Littorio was better.

Deck – thickness more or less the same on both ships. Any data about quality of plates?

Artillery
I know how bad performance of British 16” shells are described in navweaps.com, calculated by Thompson F formula. And I repeated many times why results from that formula has no use in calculating performance of shells other than USA
According to FaceHD, Nelsons guns had better perforation power than Iowa’s. In low oblique impact worse than Littorio, in middle oblique better.
So to simplefy things say similar relative protection and perforation power ( with possible some advantage of Littorio ).
In case of turrets, barbettes and so one – things are similar.

So in case who can hurt who – more or less the same capabilities ( some fire control differences could be considered, and of course crew capability ), with some advantage of Littorio.
And Littorio was ~6 knots faster so could choose distance, and run away if needed, or close range at will, of situation requires it.

15 years and 7-8 000 tons difference weights something.


Thanks very much for all the info, i think I would put my money on a 'Nelson' primarily because the RN crew are likely to be better trained and have more experience at sea.
Re closing the range, I think the same answer would apply to that given about closing with a QE in earlier posts, but with 9 x16" being hurled at you every few minutes it would be an even riskier manoeuvre than doing the same with a QE - I wouldn't like to be on the Italian ship!

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Alberto Virtuani
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Re: Hood v Vittorio Veneto

Postby Alberto Virtuani » Thu Jun 16, 2016 6:39 pm

Paul Mercer wrote: "...I think I would put my money on a 'Nelson'... "

Hi Paul,
as Maciej has fairly posted, the advantage both in protection (clear belt advantage aside machinery even accepting the results of the British tests on various spaced arrays, much discussed already.....) and armament (slight, but still the Italian shell has a higher kynetic energy than the British one; also the 16" gun was not the best British gun in terms of precision, to say the least.....) is for a Littorio.

Added to a huge advantage in speed and being quite larger ships, I'm not so sure your money will eventually be back..... :wink:

I agree the training level (and the adoption of new technology) in the RN was higher than in RM, especially in "unconventional" situation (e.g. night fight), however we are here in a classical daylight broadside duel.

I would more see a situation where odds are favorable to Italians but a lucky hit on both sides can decide the fight, with the difference that a Littorio (if not dramatically slowed) can decide (in case of) to retreat while a Nelson cannot.


Bye, Alberto
"It takes three years to build a ship; it takes three centuries to build a tradition" (Adm.A.B.Cunningham)

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Re: Hood v Vittorio Veneto

Postby paul.mercer » Sun Jun 19, 2016 3:25 pm

Alberto Virtuani wrote:
Paul Mercer wrote: "...I think I would put my money on a 'Nelson'... "

Hi Paul,
as Maciej has fairly posted, the advantage both in protection (clear belt advantage aside machinery even accepting the results of the British tests on various spaced arrays, much discussed already.....) and armament (slight, but still the Italian shell has a higher kynetic energy than the British one; also the 16" gun was not the best British gun in terms of precision, to say the least.....) is for a Littorio.

Added to a huge advantage in speed and being quite larger ships, I'm not so sure your money will eventually be back..... :wink:

I agree the training level (and the adoption of new technology) in the RN was higher than in RM, especially in "unconventional" situation (e.g. night fight), however we are here in a classical daylight broadside duel.

I would more see a situation where odds are favorable to Italians but a lucky hit on both sides can decide the fight, with the difference that a Littorio (if not dramatically slowed) can decide (in case of) to retreat while a Nelson cannot.


Bye, Alberto


Thanks for that Alberto.
I suppose any one hit that causes a ship to sink or become disabled could be considered 'lucky' I know this has been discussed before, but I suppose one could say that the hit on 'Hood' was lucky the same as the torpedo into Bismarck's rudder or the hit from Rodney that disabled her front turrets was lucky. Even if the RN 16" was not known for its precision that would surely be nullified if the Italian ships closed the range. I realise that Bismarck was pretty well a 'sitting target', but it would seem that it was Rodney's did most guns were the ones did the most damage particularly as the range closed and I still think if a 'Nelson' still had all her guns working that for the Italian ship to close the range would be very risky.

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Re: Hood v Vittorio Veneto

Postby Alberto Virtuani » Sun Jun 19, 2016 8:30 pm

Hi Paul,
I do agree with you. Rodney did the most damage to Bismarck, but on May 27, KGV had severe output problems (much worse than PoW on may 24) and therefore it was Rodney that at the end contributed most.

In a duel with a fully operational battleship however, the not exceptional 16" gun precision together with the severe lack of velocity and the "all forward" armament could play a (negative) role in the outcome. Nelsons were under many aspects very innovative ships in the 20's, but against a modern "35000" during WWII they were already quite outdated.

Bye, Alberto
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Re: Hood v Vittorio Veneto

Postby Maciej » Sun Jun 19, 2016 10:28 pm

In case of Bismarck damage - I'm curious why people are so sure that Rodney put most damage?
OK – forward director probably destroyed by Rodney and forward turrets possibly too.
That’s make most damage? If yes - than this is more about (un)lucky hits not capability of artillery.
In case of shells out
Rodney fired 390
KGV 339
So Rodney fired more, but not so extremely more.

In case of accuracy
Sentences “accurate” “inaccurate” “fast” “slow” and so one is good to put into context. For British with 15” guns with spread under 100 yards in 24 000 yards firing, any gun was “inaccurate”. Sometimes they made larger spread on purpose with those guns, as too tight salvos reduced effect of shotgun.
Compared to those guns 16” were really inaccurate. But compare them to US guns for example to see what does “inaccurate” mean.
DNO report 1935.
From 76 salvos full charge 8 were “abnormal large”
From 139 reduced charge 17 were “abnormal large”
So 11-12%
Usually spreads were 200-300 yards. Some larger. 2 were really large – over 1000 yards.
Mean spreads expected in battle in yards
guns firing…..full charge spreads……..reduced charge
…...6…………………..380…………………………..450
…...7…………………..400…………………………..480
…...8…………………..420…………………………..500
…...9…………………..440…………………………..530


From actual firing 30 rounds per gun in 1936.
Salvos spread 260 to 390 yards, 1.63 to 2.2 salvos per minute.

By comparisons Hood
2 salvos per minute, mean spread 172. From 132 shells ordered 123 fired.

In 1937,
16” guns ( not stated which ship )
distance 17 700 yards
Full gun salvos per minute 1.6, spread 276 yards

Distance 20 900 yards
1.59 salvos per minute, spread 355 yards


In case of error of making straddle, Nelsons usually were better than 15” ships. Hardly surprising, as in 30-thies Nelsons had more modern fire control. First 15” British ship with better fire control was reconstructed Warspite, but I have no data from exercises of that ship before the war.

So those guns were not so bad compared to other navies.
Compared to 15” are clearly less accurate. Guns and turrets – not artillery as a whole. Making tight salvos is a part of success. There is need to make straddle too.


From memory Littorio class had guns produced by 2 manufacturers.
One was better with ~350 meters spread ( ~380 yards )
Others were worse with ~550 meters spread ( ~600 yards )
I know distances were a bit larger – just over 20 km, so not directly comparable, but what we can see that Nelsons guns ( guns, not whole artillery as a system ) were not worse in accuracy than Littorio’s
Hard to say if better – as ranges for which I have data are not the same, so possibly a bit better, but who knows, but not worse.
(In)accuracy of guns we can throw away, or put some extra points for Nelsons ( not many but still )

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Alberto Virtuani
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Re: Hood v Vittorio Veneto

Postby Alberto Virtuani » Mon Jun 20, 2016 6:44 am

Hi Maciej,
when I said that the Nelson's gun was inacurate, I was comparing it to the British 15" (and in some way the 14" too), thus zeroing the only advantage that the British ship can have against a Littorio at long ranges (QE'e and KGV's had this advantage). At average / short ranges both Nelson and Littorio would have been accurate enough to consistently hit (and damage....), but Littorio was better protected, had a slightly better punch, was much faster and bigger and had no blind arcs aft.

Regarding Bismarck action, Rodney was the one that closed the range first, and adding to the fact that she did the damage to the fore part of the German ship, I would say that statistically she should have put more (and much heavier) hits on her. Rodney fired anyway almost 20% more with 1 gun less, 2" caliber more and being more than 15 years older ( :shock: ).


Bye; Alberto
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Re: Hood v Vittorio Veneto

Postby Maciej » Mon Jun 20, 2016 10:37 am

Rodney fired anyway almost 20% more with 1 gun less, 2" caliber more and being more than 15 years older ( :shock: ).

No need to be shocked ;)
Heavy guns can give problems. In case of Nelsons there were time to remedy them. Initially there were problems, and after ~10 years all of them ( except some accuracy ) were solwed.
KGV were quite new, and due to war there were no serious testing of guns in long time firing.
Actual real long time firing was Bismarck action...
Short time practice not always could show problems. After all first ~30 minutes of firing gives no trouble on KGV ( on PoW problems were from begin, but she was quite new, and had no real exercise before action ).
I don't have exact data, but I expect that those 300+ shells fired by KGV against Bismarck was more - much more than whole shellf fired by both ships of that class before action. So some troubles was expected.

I read somewhere that such "model reliability" of British 15" guns and turrets were thanks to it's "conservative" design ( basicelly enlarged 13.5", and 13.5" basically enlarged 12" )and long time duty, so it was a long time to remedy any problems, and make correct drill procedures.
Both Nelsons and KGV had quite new turrets, quite different from previous, so all had to be worked from begin.
It hurts sometimes.
Take new program - much better than "good old one", with much better options and so one, but with totally new user interface.
And work on it with heavy pressure of finishing some project in a few days...


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