Battleship Vittorio Veneto

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RF
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Re: Battleship Vittorio Veneto

Post by RF » Mon Jan 24, 2011 9:16 am

Thorsten Wahl wrote: The events at Narvik werent suitable to conclude for good shotings as the area for maneuvering was extremely limited.
Which also made Warspite more vulnerable to being torpedoed; the shooting in restricted waters achieved the desired results but at a risk.
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Re: Battleship Vittorio Veneto

Post by Bgile » Mon Jan 24, 2011 4:34 pm

RobertsonN wrote:Interesting figures. Does anyone know if it was possible to quantify the effect of rate of fire on accuracy? Friedman in US cruisers says that prewar practice results could not be reproduced in the War against fast maneouvring cruisers at long range because the rate of fire of their 8 in guns (3 rpm) was too slow. The result was the Des Moines class with automatic 8 in guns.
This implies that battleships were in an even worse position with their slower rate of fire (2 rpm was good). It is often said that Prinz Eugen hit the Hood before the Bismarck because of its higher rate of fire (despite a smaller danger space).
The VVs did not compare well, with only 1.3 rpm. Perhaps this is why they fired turret salvos to give 3 salvos per effective boadside, whereas British ships fired alternate 4 and 5 gun salvos for 2 salvos per effective broadside.
Is it possible you may have gotten the passage turned around? My recollection is that 8" rate of fire came into question because the engagements involving US cruisers were occurring at night at relatively CLOSE range and were fleeting, where there wasn't much time to score decisive results before the target disappeared. You needed a high rate of fire to get lots of hits quickly while you could see the target.

At long ranges time of flight tended to overshadow physical rate of fire, since it wasn't always useful to fire another salvo when you didn't know whether you had a good firing solution.

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Re: Battleship Vittorio Veneto

Post by RobertsonN » Mon Jan 24, 2011 5:05 pm

Bgile wrote "Is it possible you got the passage (about US heavy cruisers) turned wrong way round?

No. Friedman says in the individual chapters about ship classes and in the conclusions that the rate of fire of US heavy cruisers (3 rpm) was their main shortcoming and was the main reason they could not fire accurately enough at long range. He also says that 6 in cruisers were much preferred in the US navy from the rate of fire point of view. The problem with this gun was that it did not outrange the Japanese long lance torpedoes.
As to short range night actions, Friedman says US gunnery was well in advance of the Japanese. No problems with rate of fire or any other gunnery problem here, only again the effectiveness of the Japanese torpedoes.

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Re: Battleship Vittorio Veneto

Post by Bgile » Mon Jan 24, 2011 6:42 pm

RobertsonN wrote:Bgile wrote "Is it possible you got the passage (about US heavy cruisers) turned wrong way round?

No. Friedman says in the individual chapters about ship classes and in the conclusions that the rate of fire of US heavy cruisers (3 rpm) was their main shortcoming and was the main reason they could not fire accurately enough at long range. He also says that 6 in cruisers were much preferred in the US navy from the rate of fire point of view. The problem with this gun was that it did not outrange the Japanese long lance torpedoes.
As to short range night actions, Friedman says US gunnery was well in advance of the Japanese. No problems with rate of fire or any other gunnery problem here, only again the effectiveness of the Japanese torpedoes.
I'm not disputing the rate of fire issue; just the reason. Why would rate of fire be an issue at long range, where you normally wait until the fall of shot to fire the next salvo? It doesn't make any sense to me. I'm not at home, but I will have to look at Friedman's cruiser book. This seems very odd to me, especially since six inch splashes couldn't be observed much over 18,000 yds.

I'm also not disputing that US gunnery was better than Japanese gunnery. The 8" gun didn't outrange long lance torpedoes either, and firing range in typical night engagements was less than 10,000 yds, at which rate of fire did count.

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Re: Battleship Vittorio Veneto

Post by RobertsonN » Tue Jan 25, 2011 9:04 am

I've looked at US Cruisers in WWII again. What Friedman says is a bit less clear than I took it to be and you may be correct. First of all, he says the US discovered what the RN had already found against the Italians. That it was much harder to hit fast manoeuvring ships (which were retreating) than had been expected before the War. But these engagements in the Mediterranean were mostly long range.
He also says that after a battle (Rennell Island?) on 29 Jan. 1943 that all US 8 in gun cruisers were concentrated for action in the Aleutian Islands. The remaining series of night cruiser battles were conducted by the US using exclusively 6 in gun cruisers. This suggests that the 8 in gun cruisers were now viewed as rather unsuitable for the type of battles being fought in the Pacific War.
As to prewar doctrine, Friedman mentions two schools of thought: one, rapid fire from the start at longe range in the hope of scoring a damaging hit, and, two, the slower deliberate finding of the target first. After the War, the Kraker Commission on lessons in ordance found that US fire control computers were incapable of dealing with fast manoeuvring targets (range not stated) probably because it had been assumed before the War that the enemy would steer a fairly steady course and speed in order for their own fire control to work. The second finding was that the rate of fire of the 8 in gun was too slow. Incidentally, I have a German book that says the main shortcomings of the Admiral Hipper for ocean raiding were: unreliable machinery, inadequate range, guns with too low rate of fire (8 in/4 rpm) and too little ammunition.
The deliberate finding of range school does rather assume that both sides are happy to fight at long range. In the Denmark Straight battle, the Hood opened fire at 05.52 at an estimated 25000 yds. Lutjens held his fire initially and when the Bismarck's fifth salvo hit the Hood the range was down to 16500 yds, relatively close range. So they were closing at a good 1000 yds/a minute, which probably made hitting difficult.
Anyhow, thanks for clarifying this point in Friedman's book, which I've somewhat misinterpreted for twenty years.

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Re: Battleship Vittorio Veneto

Post by lwd » Tue Jan 25, 2011 3:25 pm

By 43 didn't most of the cruisers have fire control radar? Once you have the skill and confidence to in it's use shell time of flight may be less of a problem.

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Re: Battleship Vittorio Veneto

Post by Bgile » Tue Jan 25, 2011 4:21 pm

lwd wrote:By 43 didn't most of the cruisers have fire control radar? Once you have the skill and confidence to in it's use shell time of flight may be less of a problem.
I'd tend to agree that high rate of fire at long range became more practical once really good FC radar had been introduced.

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Re: Battleship Vittorio Veneto

Post by RobertsonN » Tue Feb 01, 2011 9:28 am

I thought members would be interested in a German forum I have found:

http://forum-marinearchiv.de

If you look up a piece entitled "Side armor Bismarck/Scharnhorst, why not sloped?" (it is all in German) you will find on pages 16 and 17, detailed comparisons of most Second War battleships using Nathan Okun's programs. There are good graphics showing where shells end up for various ranges.

It comes to different conclusions from our group. VV is best at short range and Richelieu at long range. KGV is weakest at most ranges. South Dakota has a vulnerability at the top of the lower belt at most ranges.

From what I've learnt on this and other sites I know that Okun's programs work best with AON systems and do not reproduce what happens with well designed layered armor systems.

Regarding KGV I don't know if the programmer took into account the fact its side armor was of better quality than most of its oppenents. The result does, however, show that a simple AON system could be vulnerable given the increase in gun performance that occurred in the 1930s. I am sceptical about the pointed Italian 15 in shells being able to penetrate the scarp of the Bismarck system at both 10000 and 15000 m. These shells were more likely to scoop or be deflected on oblique impact. The point of vulnerability at the top of the lower (class B) belt on the South Dakota is something I have wondered about before. The similar Iowa had a 10.5 ft main belt (class A armor): 1 ft wider than that of the Hood. However, on the US ship the belt was inboard and more steeply inclined, reducing its effective height and making it vulnerable to shells that were only borderline plunging.

Anyhow, it goes to show that interest in battleships is still alive and well in many countries. And it's a bit like comparisons in car magazines, the ranking of the cars/battleships tends to vary from country to country.

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Re: Battleship Vittorio Veneto

Post by RF » Tue Feb 01, 2011 1:43 pm

I suppose it is like as with cars, except of course that you can't go out and test drive your own battleship. The roads wouldn't just be big enough or wet enough.
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Re: Battleship Vittorio Veneto

Post by Thorsten Wahl » Tue Feb 01, 2011 7:46 pm

RobertsonN wrote:I thought members would be interested in a German forum I have found:

http://forum-marinearchiv.de

If you look up a piece entitled "Side armor Bismarck/Scharnhorst, why not sloped?" (it is all in German) you will find on pages 16 and 17, detailed comparisons of most Second War battleships using Nathan Okun's programs. There are good graphics showing where shells end up for various ranges.

It comes to different conclusions from our group. VV is best at short range and Richelieu at long range. KGV is weakest at most ranges. South Dakota has a vulnerability at the top of the lower belt at most ranges.

From what I've learnt on this and other sites I know that Okun's programs work best with AON systems and do not reproduce what happens with well designed layered armor systems.
it was 2008 some of the knowledg we have today was recovered in 2009 and 2010. If you read until page 22 there are some suggestions for corrections from my side.
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Re: Battleship Vittorio Veneto

Post by RobertsonN » Wed Feb 02, 2011 11:50 am

Thank you, Thorsten.
I've now read through that German site to the end (btw, does 'Aufrichtung' mean yaw?).

I agree that the Bismarck has the best protection in the 10000 and 15000 m situations considered in these calculations. VV is second best. This is also the view of experts as diverse as Dave Saxton and Nathan Okun. I agree that there is some doubt whether the VV 70 + 10 mm decapping belt is sufficient to decap all shells. Perhaps it was good enough against Italian APC shells.

I now also notice that these calculations assume that in the Sodak/Iowa that the 1.25 in hull plating will cause decapping at 30000 yds and perhaps at 10000 yds. That seems unlikely, although it might be the case for some very blunt nosed shells that are easily decapped. If there is no decapping then shells striking at the point of vulnerability will go further into the ship before exploding.

I have now checked in an old book about the Iowas by Malcom Muir that the upper class A belt was only 10.5 ft wide (Muir gives a weight of 1086 long tons per side, which is exactly the weight of a 12.2 in thick, 464 ft long, 10.5 ft deep belt). The remaining 28 ft deep lower belt was Class B armor (1551 long tons per side).

Neil

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Re: Battleship Vittorio Veneto

Post by RobertsonN » Wed Feb 22, 2012 5:46 pm

I have just otained a copy of 'The Littorio Class' (English translation) by Bagnasco and de Toro. It must surely be one of the most complete studies of a battleship class ever published, and together with 'Warships after Washington' by Jordan means an unexpectedly good start to the year for batteship enthusiasts.

I remember, in our discussion about the Vittorio Veneto, an unknown was whether the upper deck would decap an incoming shell. Failure to do so would likely have been a significant weakness. Bagnasco says on p. 58 that the Italians built a section of the ship and carried out 'simulated firings' (whatever that means) of 406 mm shells at the structure with an angle of fall of 18 deg corresponding to a range of about 26000 yds. In all cases, the shells were decapped and went on to dent or distort the MAD, with no penetrations or perforations. In a Table at the end, there are penetration data for the 15/50 that were issued to the Fleet in autumn 1942, indicating that it could penetrate a 105 mm deck at this range (it actually has 15 mm but that is an obvious misprint and a couple of other penetration figures also miss out a 0).

On the other hand, tests indicated that heavy AP bombs could easily penetrate the MAD if dropped from at least 2500 m. However, standard 1280 kg bombs often broke up on the upper deck and never managed to penetrate the MAD. More extensive bomb tests in 1943 indicated that even the turret roofs could be penetrated by 820 kg and 480 kg bombs if dropped from altitudes of at least 5200 m and 7200 m, respectively.

It's a great book for £28.80 here in the UK.

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Re: Battleship Vittorio Veneto

Post by alecsandros » Wed Feb 22, 2012 7:16 pm

RobertsonN wrote:sts.

I remember, in our discussion about the Vittorio Veneto, an unknown was whether the upper deck would decap an incoming shell. Failure to do so would likely have been a significant weakness. Bagnasco says on p. 58 that the Italians built a section of the ship and carried out 'simulated firings' (whatever that means) of 406 mm shells at the structure with an angle of fall of 18 deg corresponding to a range of about 26000 yds.
36mm upper deck decapping 406mm shells ?

Maybe Italian-built shells...

US 16"/45 1225kg shell had angle of fall of 18* allready at 18km, and 25* at 22km.
Also, British 16"/45 930kg shells had AoF of 24,5* at 22km.

Also, it remains the problem of the actual resistance of the armor mounted on the ships. I remember a lengthy discussion about Roma's horizontal and vertical armor impurities and hardness...

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Re: Battleship Vittorio Veneto

Post by Dave Saxton » Wed Feb 22, 2012 7:42 pm

Most interesting. This corresponds to British tests post war that indicated that de-capping of deck hits usually enhanced over all deck protection. The typical hardness and tensile strength of AOD here was probably a factor. In German tests it was found that a de-capped shell, compared to an capped shell of equal weight and velocity, had less penetrative power if the tensile strength ( and therefore greater brinel hardness as well) of homogenous armour was greater than 80kg/mm2.

This also corresponds to British tests of Italian shells that indicated they would most likely scoop vs decks at these ranges due to their rather sharply pointed main body nose shape. However, these same tests indicated that the Italian shells remained in fit state to burst with intact fuze after base slap, and most other shell designs usually did not.

It's also interesting that these sharper nose shapes were de-capped by the armoured upper deck at these battle ranges. Rounder shapes (hence greater oblique penetration potential) would be easier to de-cap yet, indicating that a de-capping array is better way to deal with the enhanced deck penetration of more blunt nosed AP.

105mm for the Italian 381/50 at 23,800 meters is about 20% greater than most other charts predict for it.
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Re: Battleship Vittorio Veneto

Post by Dave Saxton » Wed Feb 22, 2012 10:19 pm

alecsandros wrote:36mm upper deck decapping 406mm shells ?

Maybe Italian-built shells...

US 16"/45 1225kg shell had angle of fall of 18* allready at 18km, and 25* at 22km.
Also, British 16"/45 930kg shells had AoF of 24,5* at 22km.
...
Some factors to consider here:
1) The angle of fall at this range of the high velocity Italian 15" means that the shell is striking 72* from the normal. Striking at the normal it takes homogenous armour 20% the caliber to effect de-capping, but as the striking angle becomes more acute it requires less thickness.

2)The total thickness of the de-capping plate is more than 36mm. This will not give it much more than 36mm effective thickness vs penetration being a laminate, but it may improve de-capping as if its actually closer to 50mm.
Maybe Italian-built shells...
3) The Italian shells are probably going be more difficult to de-cap than an American or German shell, actually.
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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