Battleship Vittorio Veneto

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paul.mercer
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Battleship Vittorio Veneto

Post by paul.mercer »

Gentlemen,
Much has been said about Bismarck, Rodney, KGV, Iowa and Yamato, but what about the new Italian Battleship Vittorio Veneto? I know very little about her except that she was new and had 9x15" guns, so, given a captain and crew who were willing to fight , how would she have performed against Bismarck or Tirpitz, a KGV, Nelson/Rodney and an Iowa, one on one - assuming that all ships had everything working and were fully worked up with competant crews?
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RF
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Re: Vittorio Veneto

Post by RF »

More realistically you are talking about a British battleship in the Med, such as Barham or POW. On paper the VV should have been a formidable ship......
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Re: Vittorio Veneto

Post by alecsandros »

I'll try to add some info about Vittorio Venetto...

The design was very interesting, featuring:
- spaced-array vertical protection - 70+10mm homogenous armor + 600mm cement layer + 280mm FHA + several more armored bulkeheads.
- spaced-array horizontal protection, totaling up to 212mm above the magazines.
- very good hull design, with a prismatic coefficient of 0.58@40.000tons (the lower the coefficient, the less drag the ship encounters on water)
- the most powerfull 15" guns ever mounted on a battleship, with penetrative power of over 450mm FHA at 20km and 320mm at 30km.
- innovative anti-torpedo system, named after his inventor "Pugliese".
- modern fire-control system, capable of automaticaly lifting and depressing the guns according to the radar feed.

The execution of the ships however, suffered greatly from shortage of good materials, lack of experience of the designers and builders, and economic interests of several supplyers...

Thus, in reality, Vittorio Venetto was not on par with contemporary designs. It's shortcomings were numerous:
- low silhouette and very low GM, causing instability in high seas and a very "wet" ship
- poor quality horizontal armor and poor distribution of the armor, causing severe reduction in protection.
- poorly incorporated fire-control, causing repeted breakdowns of the RPC and of the radars
- poor quality shells, causing great salvo dispersion
- extremely poor AA defense and secondary battery
- the Pugliese system was poorly incorporated into the ship's sides.
- because of the very deep side protection (both vertical armor and Pugliese) there was to little room for fuel, thus the ship's range was small (7000km IIRC)

=============

So, as to answer Paul's question, if VV would meet any post-1927 battleship, he would, most likely, be badly beaten and probably sunk.

Best Regards,
Alex
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Re: Vittorio Veneto

Post by RF »

With these drawbacks the VV would be particulary unsuitable for Atlantic operation.
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Re: Vittorio Veneto

Post by Dave Saxton »

Regarding the Italian radar:

The radar was developed by Marconi under Gov supervision and by Gov funding. More money was invested in the radar's devlopment than it cost to build and fit out a new Littorio class battleship. The cover name was Gufo which means Owl. The production version was known as the EC3. A model was first installed for trials aboard Littorio during March 1941. The test radar failed miserably; being not able to reliably detect targets except at ranges of a few thousand meters. An improved version was developed through the use of imported Dutch made vacuum tubes. This increased the power output from 1kw to 10kw. The production version with the Dutch tubes was reclassified as EC3B. The perfomance specifications were as follows:

Wavelength: 75cm
Output: 10kw
PRF: 500
IF receiver bandwidth: 600mhz (this doesn't seem correct-600khz is more likely)
Bearing Resolution: 6*
Range Resolution: 600 meters
Bearing Accuracy: 1-2* (It did not feature lobe switching)
Range Accuracy: 100-200 meters
Range: up to 30km (33,00 yards) depending on mounting height and target ship size.
Indication: J-scope

Tests were conducted on the destroyer Legionaire, and it was confirmed that it could attain the same Approx. detection ranges as a 1st generation Seetakt for destroyers (FuMO21).

One set was installed on Littorio in March 1942, Vittorio and Roma did not receive a set each until the summer of 1943. There were only 12 sets built during the war. As far as I know it was not intergrated into the firecontrol systems. However, since its resolution and accuracy did not compare well to contempory Allied and German firecontrol sets, it was not particularly conducive to firecontrol work. It could have been a very handy tool for general tactical and search purposes though.
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Re: Vittorio Veneto

Post by Dave Saxton »

alecsandros wrote:- the most powerfull 15" guns ever mounted on a battleship, with penetrative power of over 450mm FHA at 20km and 320mm at 30km.
- poor quality horizontal armor and poor distribution of the armor, causing severe reduction in protection.
- poor quality shells, causing great salvo dispersion
- extremely poor AA defense and secondary battery
- the Pugliese system was poorly incorporated into the ship's sides.
=============
The guns had a range exceeding 42km, but since the shells had a relatively sharp head shape, they had a tendency to scoop rather than penetrate decks even at extreme range. This sharp head shape combined with the high striking velocity is the reason for the exceptional vertical armour penetration, but this would drop off rapidly with range due to the head shape vs the increasing obliqity. In British tests the Italian shells always detonated properly though. No duds were encountered as they survived base slap in a fit state to burst.

AOD may have been a rather high quality material. Basing the quality on the elongation rating is not necessarly very useful, especially when dealing with a spaced array. The elongation rating obtained also depended on the testing methods. For example, the German testing methods for Wh resulting in a elongation of 20% would give a 25% elongation measurement using US methods. So Wh has the same or better elongation per hardness as STS. We would need to know the Italian methods to make any comparisons.

The Italians committed the sin of using laminated armour decks, and the sin of using a fairly robust inbetween deck. (however, if the upper deck yawed the shell up before the shell reached the inbetween deck it would cause the shell to strike the main armoured deck farther away from the normal and likely to scoop. Also if the two previous decks suceeded in breaking the shell up a bit before it reached the MAD, then the de-capped shell will likely not be able to defeat the mAD at even long range) I find that the effective thickness calculates to likely ~140mm or about the same as Iowa.

The Pugliese system may have not worked to its full potential in the smaller reconcructed battleships because it could not be utlized at the necessary scale. On the Littorios, the systems may have been compromized through faulty welding connections. The materials contained vanadium and this greatly complicates welding.

Overall they were formidable warships and I don't hink we can take for granted that they would be defeated by Allied warships. They might just turn the tables on an Allied battleship depending on circumstance.
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Re: Vittorio Veneto

Post by alecsandros »

Hi Dave,

a few clarifications to my above post:

About the AOD: I am not refering to it's specifications, but to the actual quality of the cast material. Indeed, on paper this type of armor should have been of great quality. However, in the real ship, and in the thicknesses actualy used, and in the spatial arrangement chosen by the Italian designers, I don't see it as a "good" horizontal armor at all. Mediocre, perhaps...
Most of the horizontal portion of the citadel is covered with 24-36 + 90-100mm of AOD. What is the function of a 24-36mm deck against BB shells... ? I see none. Probably no decap, very, very little or no yaw, no fuzing, and least of all loss of KE. So a BB shell would arive on the 100mm deck pretty much un-scathed. 100mm of AOD is not that nice... Most BB guns in service could land a shell through that armor at 20km... And closer to 20km, the vertical protection system becomes vulnerable to 15" and 16" shell fire...

Yes, the machinery and magazines are covered with additional armor totaling 169 and 212mm respectively. But the armor is, again, spread out ... Only the magazines have a good protection, with the MAD at 150mm thick above them.

The deck system of Roma and Littorio was perforated in 1943, by German glide-bombs. These were large projectiles, at 1.300kg, flying at maybe 300m/s and at an angle of descent which I estimate between 30 and 40*. The penetration of these weapons was rated at 130mm... At least one of them pierced the armor decks and went in the machinery spaces of Roma, and another in a main magazine... So... Not so nice things to say about this plate-system...

This is not at all to different from typical BB shells of the era: US super-heavy shell had 1.22 tons, Japanese 410mm shell had 1.01 tons... British 16" 0.93 tons... And they had considerably higher striking velocity... So I think they could perforate and hit VV magazines...

The guns:
Very powerfull weapons, that used variable shells. Variable in mass, and in distribution of the mass within the shell... Thus causing large salvo patterns.
This problem was not sorted out, for what I know, until Italy surrendered. And the best (or should I say "worst" ?) example of performance is presented by the ships themselves: throughout the Med campaing, fighting in several large naval battles, and firing hundreds of 381mm rounds, these ships couldn't hit anything right. I know of only one hit, on a British DD, which was perforated from side to side by a shell which did not explode (Probably it couldn't fuze because it hadn't experiecned any significant deceleration). And that's it... 1 hit in the entire war ?

The RPC and radar:
I came across them in "Regina Maria - Italian battleships of WW2", by Erminio Bagnasco.

Image

In another section, which I can't find now, he mentions radar breakdowns... I'm not sure about the integration of radar with main fire control; I have this impression though...
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Dave Saxton
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Re: Battleship Vittorio Veneto

Post by Dave Saxton »

If the ships coudn't hit anything but the sea this would indicate that radar probably wasn't intergrated or available, and they had to rely on much less accurate optical ranging finding. Historically most of their opprotunities for combat shooting occured earlier in the war before they had any radar. Littorio didn't have radar until 1942 and VV and Roma didn't have radar until 1943.

I ran across some historical writings based on Italian archives on the RM several years ago. They addressed the dispersion issues of their guns. What the archives revealed was that the dispersion problems stemmed from inconsistencies of the bagged charges and not mainly the shells. A small inconsistency of the charges is multiplied by the average velocity in the ranging. So inherent inconsitencies of bagged charges don't cause too much problem at lower average MV, but at higher average V it does cause problems. The Italians began to carefully re-bag their charges, just the USN would do 40 years later.

If the upper deck and the inbetween deck combined failed to de-cap incoming shells then this would indeed be less than optimal. Be aware however, that the upper deck was a laminate of two armour grade plates totalling 48mm and the middle deck was also a laminate totalling 36mm. The laminates consisted of AOD and ER. ER was not, as has been assumed in some circles simply an Italian version of Ducol, but an armour grade alloy. True the laminates instead of a single plate results in far less effective thickness and energy consumption, but it may have been capable of effecting de-capping?

150mm single plate over the magazines is rather impressive. This is the same as KGV's protection over the magazines and it is superior to South Dakota/Iowa's total magazine protective effective thickness. Of course if the two fairly thick laminated above decks failed to de-cap and they together caused the striking angle at the MAD to be significantly closer to the normal; the shell would be much more effective against the 150mm or 100mm main plates than it would normally be.

The question of the impact angle of the guided bombs would make a significant difference of these very heavy and fast bombs' penetration abilities.

In this scenario, if the battle occurs at less than ~27,000 yards (as is likely in 1943), and in good visibilty, some advantages will lay with the Italian battleships. The Italian vertical protection is superior to any Allied battleship and the Italian 15" gun is very dangerous vs vertical armour. What it may boil down to is whom can hit more often and can hit first. The Allied battleships probably hold the advantages in that context, but will their hits be as effective against the Italian battleships as the Italian battleships (likely fewer) hits will be against the Allied battleships?
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.
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Re: Battleship Vittorio Veneto

Post by tommy303 »

They addressed the dispersion issues of their guns. What the archives revealed was that the dispersion problems stemmed from inconsistencies of the bagged charges and not mainly the shells. A small inconsistency of the charges is multiplied by the average velocity in the ranging. So inherent inconsitencies of bagged charges don't cause too much problem at lower average MV, but at higher average V it does cause problems. The Italians began to carefully re-bag their charges, just the USN would do 40 years later.
It was probably a combination of the two--inconsistencies in both bagged charges and shell manufacture. Taken together they can make precise shooting extremely difficult, particularly at long ranges where dispersion effects are more noticeable than they are at closer ranges. The problem was in the manufacture of both shells and charges, and the rather loose tolerances accepted between suppliers. The 38,1cm was actually devastatingly accurate when using specially prepared ammunition for regulating the fire control systems and developing range tables, but in actual service such atypically high quality shells and charges were the exception rather than the norm. Differences in charge weight will cause wide variations in muzzle velocity, as will variations in shell weight if not kept to within acceptable ballistic tolerances, but it went further than just that in the Italian service. Wide variations in the final machining of the shells often led to over or undersized projectiles--the former leading to spikes in pressure, which in turn led to higher MV, while in the latter case, undersized shells would not tend to align well in the bore and gas blow by past the driving bands would lead to less than anticipated pressure. This resulted in both lesser muzzle velocities and ranges than predicted by the range tables and fire control, but also led to higher bore erosion.

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Re: Battleship Vittorio Veneto

Post by Thorsten Wahl »

There were british tests in 1937 on a spaced target showing a somewhat lesser ballistic limit velocity for the spaced Vittorio Veneto-arrangment then a single plate against 15" shell
spacing of the target was a 6-7 inch "eggbox"

Image

(remember the german findings at the same time on a sufficient spacing between fore- and mainplate was ~70 cm ) so 6-7 inch didnt do the job

The tests were repeatet in 1945 and 1949 for a more systematic approach, but because of low funds the tests were only partly performed - especially research "on the most efficient spacing" between the plates was almost completely strikken

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Fritz was released from the aircraft at a target height angle of around -65 degrees and even it falls in a slightly flatter ballistic trajectory the impact angle at the end was around 10-20 degrees from the normal, impact speed around 330+ m/s depending on height of release and could pierce then around 170 mm armor
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Re: Battleship Vittorio Veneto

Post by dunmunro »

Very interesting report. Can you tell us the source?

thanks
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Re: Battleship Vittorio Veneto

Post by Dave Saxton »

Thorsten Wahl wrote:remember the german findings at the same time on a sufficient spacing between fore- and mainplate was ~70 cm ) so 6-7 inch didnt do the job
The actual spacing of the Italian belt system was greater than 6-7 inches. About 10" IIRC. George Elder found that many early British spaced armour experiments simply used insufficient spacing and so gave non-useful results. Proper spacing is very important for at least two reasons. One is that enough distance is needed for the cap to become seperated from the shell. Another is that there must be sufficient disatance for yaw from the relatively slow proccess of precession to become manifest. The proper spacing issue is one reason that the British eventually discovered that two plates in direct contact with each other, as in a laminated deck, perform worse than if the two plates had some space between them.
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Re: Battleship Vittorio Veneto

Post by Thorsten Wahl »

but 10 inch = 25 cm I suspect this spacing is not enough to complete decapping for optimal performance

some effect of decapping can be found if you compare
ballistic performance of 80/240 plate in contact ,320 single plate and 80/240 spaced (plates in lbs)
Image
performance
summary ADM 281-31.jpg
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Re: Battleship Vittorio Veneto

Post by Dave Saxton »

(the image doesn't work for me, but I'm some what familar with most of ADM281)

If I recall from Pugliese's notes in Designing a Battleship(Elder, unpublished), the original de-capping array design was rejected by the RM, because of concerns of a large interspace becoming flooded (and additionally the outer plating becoming stripped away by HE, which was also a big German concern with such design). So they went to the absolute minimum that testing indicated could be effective (in concert with other factors), and filled the interspace in with concrete. The belt was also made up of several segments so that there could not be longitudinal progressive flooding of the insterspace and surrounding areas. As I recall they expected other factors besides de-capping (yaw effects mainly) to contribute to destruction of the shell. I agree that the truncated interspace of the Littorio class is a probable problem in light of the German findings in context of the primary de-capping concept.
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Re: Battleship Vittorio Veneto

Post by 19kilo »

Good(ish) armor I guess. Too bad it couldnt stop the Fritz X.
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