Bismarck/Tirpitz = most powerfull European battleships

Discussions about the history of the ship, technical details, etc.
JtD
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Re: Bismarck/Tirpitz = most powerfull European battleships

Post by JtD » Tue Sep 21, 2010 6:00 pm

alecsandros wrote:US empirical formula gives 124mm STS, and that is probably exaggerated. It is more likely 110-115mm.
This depends on the formula, data published for the gun, based on the US formula, gives 140mm at a range of 22000m. 124mm is what the 16"/50 would do at that distance.
Bismarck's minimum compounded strength was ~ 110 mm (50+80mm), of completely different quality and arrangement than the French ships had. Throsten Whal has several very interesting posts taken from German archives, in which he explains very thoroughly the qualities of double-decked Whotan, with different tensile strengths.
Bismarck's maximum compounded strength was ~ 180-190mm (80+120mm), practicaly impenetrable by any shell at ranges < 30km.
I would like to know how you calculate the compound strength. a+b-15mm is hardly the way to go, and I would like to know your source for 80mm + 120mm deck armour on the Bismarck. Then please check upon the protection of the secondary magazines, and pay particular attention to the thickness of the upper armour deck below the superstructure. Secondary magazines is what we are talking about here.
Given the shell's trajectory, what relevance does it have an armored deck.. ?
Splinter protection, watertightness. Richelieu, quite likely, would not have lost bunker capacity. It certainly would not have suffered flooding to the same extend.
For this discussion's sake, I'm talking about what happens in a direct battle.
Richelieu as it was in 1945 vs Tirpitz as it was in 1944 (maybe with the late war radars added)...
Ok, I don't care about dicksize.
...think about the Bismarck-Hood engagement and remember the shooting was carried out before the 1943 modernization...
I prefer to think about long range gunnery against PoW, where Bismarck did not perform well. Medium range was quite good, though.
This was ~ 3 shells/minute/gun for Bismarck firing at ranges <20km, and about 1 shell/minute/gun for Richelieu.
3 shells per minute per gun is impressive, would be more so if it was true. Krupp designed the turrets with a 22 seconds cycle in optimum gun position, if my memory serves me right. Richelieu could manage 35 seconds, again afaik.

And, you know what, Richelieu could get through the Panama channel, something Bismarck couldn't. That's an interesting quality which is obviously irrelevant when just making idiotic slug it out comparisons. The thickest 7 belts built into modern WW2 battleships were never tested in combat. Just so you know. The single most deadly weapon battleships faced in WW2, were torpedoes. Thought you should know that, too.

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Re: Bismarck/Tirpitz = most powerfull European battleships

Post by alecsandros » Tue Sep 21, 2010 6:20 pm

phil gollin wrote:
Re. "B" - I do not know (and do not believe that) - the British yaw tests started during WW2.
That's a good option - for an ostriche... Just hide your head in the sand... And everything goes away...
Re "C" - Any idea what you are talking about ? (You are aware I hope that the main penetration formula used from the 50's until fluid dynamics became practicable was based on this post-war testing.
Any reason you raise such a question besides poor reading comprehension ?
-------------------------
As a general note, the US formula that keeps being quoted here was a USN Empirical formula which was revealed as a great secret to the British in WW2. They took one look at it and dismissed it as it is only applicable to particular "families" of armour/shell designs. Different "families would give different results. It is a crude approximation, suitable for general ideas, NOT some sort of wonder formula.
If you would pay more attention to what its' written around here, you would find that the USN empirical formula is as smashed up as a formula can get in a forum. It's just a quick reference and provides good averages for certain shells and ranges.
Oh, and remember, not all guns are "new" and have "new gun" velocities (in fact strictly speaking none will have except by great chance) and ships move in a seaway changing the angles a small amount. Don't get hooked on fighting war-games, remember "real life".
Yes I know. There are even formulas simulating the loss of mv/shot...

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Re: Bismarck/Tirpitz = most powerfull European battleships

Post by alecsandros » Tue Sep 21, 2010 6:32 pm

JtD wrote: This depends on the formula, data published for the gun, based on the US formula, gives 140mm at a range of 22000m. 124mm is what the 16"/50 would do at that distance.
http://www.navweaps.com/index_nathan/Pe ... States.htm
Deck perforation at 24000 yards for 2700pds shell fired from 16/L45 = 4.5" to 5.4", with an average of 5" = 124mm
I would like to know how you calculate the compound strength. a+b-15mm is hardly the way to go, and I would like to know your source for 80mm + 120mm deck armour on the Bismarck. Then please check upon the protection of the secondary magazines, and pay particular attention to the thickness of the upper armour deck below the superstructure. Secondary magazines is what we are talking about here.
It comes from Dr Gercke's study's, as they appear in ADM 213/915. It's available for download at http://www.bismarck-class.de
The formula takes into account the relative ballistic coefficient of the 2 decks, and it's very different from the usual sqrt (a^2+b^2) used by the British and Americans.
In fact, according to Gercke, some parts of Tirpitz's deck system was equivalent to 195mm single sheet.

Bismarck had 80+120mm max deck armor thickness. Moreover, the "120mm" part was inclined at 62* from the vertical, making perforation much more unlikely.
The sources abound. You may want to check here for a quick reference:http://www.kbismarck.com/proteccioni.html

Why do you concentrate on the secondary magazines.. ? They are important, of course, but when did you mention them previously so that you now say "secondary magazines is what we are talking about here" ?
Splinter protection, watertightness. Richelieu, quite likely, would not have lost bunker capacity. It certainly would not have suffered flooding to the same extend.
If you would read the "2000 tons of waters in the forecastle" thread, you would learn that the "extent" of the flooding in Bismarck's bow is higly questionable.

I prefer to think about long range gunnery against PoW, where Bismarck did not perform well. Medium range was quite good, though.
Bismarck's gunners were hindered by the setting sun. This is briefly but precisely recorded in the Baron's book
3 shells per minute per gun is impressive, would be more so if it was true. Krupp designed the turrets with a 22 seconds cycle in optimum gun position, if my memory serves me right. Richelieu could manage 35 seconds, again afaik.
There is a movie showing Bismarck firing 4 gun salvos at 18 second intervals. Jose and a few others around here may have a link. I don't....
The thickest 7 belts built into modern WW2 battleships were never tested in combat. Just so you know. The single most deadly weapon battleships faced in WW2, were torpedoes. Thought you should know that, too.
And what makes you think I dind't know that already... ? Maybe you should read a little bit more on the forum... And then post such comments.

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Re: Bismarck/Tirpitz = most powerfull European battleships

Post by alecsandros » Tue Sep 21, 2010 6:51 pm

Lutscha wrote: I don't want to see vague references to some test results I want to see them myself.
Hoyer is a good reference; you can find many interesting aspects in that file I linked you to.

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Dave Saxton
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Re: Bismarck/Tirpitz = most powerfull European battleships

Post by Dave Saxton » Tue Sep 21, 2010 7:05 pm

One notes that the body of mostly secondary and beyond secondary based sources that have established the conventional wisdom concerning the Bismarck's design, and particularly the armour scheme, are vaugely cited, if cited at all.
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: Bismarck/Tirpitz = most powerfull European battleships

Post by Lutscha » Tue Sep 21, 2010 7:12 pm

Dave Saxton wrote:One notes that the body of mostly secondary and beyond secondary based sources that have established the conventional wisdom concerning the Bismarck's design, and particularly the armour scheme, are vaugely cited, if cited at all.
Most people here know what is written by Okun on navweaps and this can be easily shown via linking (and has been done).

I ask again, why are all these documents not provided for anyone? They are NOT readily available. What would be easier than to proof ones (your) point with such primary sources?

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Re: Bismarck/Tirpitz = most powerfull European battleships

Post by Thorsten Wahl » Tue Sep 21, 2010 7:14 pm

some thougts on effectivenes of spaced armor according GB and US reports.
AD A954 865 Spaced Armor 1950.JPG
(229.53 KiB) Not downloaded yet
decapping gb.JPG
(156.01 KiB) Not downloaded yet
The theory behind you can find at
http://www.bismarck-class.dk/


http://www.bismarck-class.dk/miscellane ... n_1946.zip

page ~90

related material on dtic.mil

http://www.dtic.mil/srch/search?searchv ... zation=YES
Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!

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Re: Bismarck/Tirpitz = most powerfull European battleships

Post by JtD » Tue Sep 21, 2010 7:53 pm

alecsandros wrote:http://www.navweaps.com/index_nathan/Pe ... States.htm
Deck perforation at 24000 yards for 2700pds shell fired from 16/L45 = 4.5" to 5.4", with an average of 5" = 124mm
Ok, my number is against rolled homogeneous armour, qualities not stated. German decks from your source: 5.2" = 132mm.
It comes from Dr Gercke's study's, as they appear in ADM 213/915. It's available for download at http://www.bismarck-class.de
The formula takes into account the relative ballistic coefficient of the 2 decks, and it's very different from the usual sqrt (a^2+b^2) used by the British and Americans.
In fact, according to Gercke, some parts of Tirpitz's deck system was equivalent to 195mm single sheet.
Which ones?

What I found in Gercke is that 50mm of homogeneous armour backed up by 80mm of homogeneous armour are equivalent to 80mm of homogeneous armour (V2 = 0.82 V1 with V^2.5 ~ S). Great stuff, isn't it.
Bismarck had 80+120mm max deck armor thickness. Moreover, the "120mm" part was inclined at 62* from the vertical, making perforation much more unlikely.
Ok, so the torpedo protection system was well protected. Where exactly was it 80+120mm? According to the construction plan of Bismarck, you had
- 50mm upper deck, except for around the rear, secondary turrets, where you could find 80mm
- 80mm outside the main magazines on the main deck
- 95mm above the main magazines on the main deck
- 110mm for the inclined parts of the main deck, above the TDS
Why do you concentrate on the secondary magazines.. ? They are important, of course, but when did you mention them previously so that you now say "secondary magazines is what we are talking about here" ?
Because you claim the inadequacy of the Richelieu armour is proven by the fact that a 16" shell penetrated into the secondary magazines. Why not stick with that instead of looking into the protection of the TDS against plunging fire? Like, say, take the 50mm and the 80mm Bismarck had for the biggest part and compare that performance against a 16"/45 shell?
If you would read the "2000 tons of waters in the forecastle" thread, you would learn that the "extent" of the flooding in Bismarck's bow is higly questionable.
Yes, it is. Bill Jurens pointed that out years ago. But whatever it was, Richelieu would likely not have had the same amount of flooding. Leaving the fact aside that there is no main transverse bulkhead to rupture in the same position as on Bismarck, the exit hole of the shell would have been much smaller, and therefore far less water would have been taken in and the damage would have been far easier to repair.
There is a movie showing Bismarck firing 4 gun salvos at 18 second intervals. Jose and a few others around here may have a link. I don't....
36 seconds per round per gun - that's reasonable.
And what makes you think I dind't know that already... ? Maybe you should read a little bit more on the forum... And then post such comments.
Well, if you know, try to think about it.

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Dave Saxton
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Re: Bismarck/Tirpitz = most powerfull European battleships

Post by Dave Saxton » Tue Sep 21, 2010 8:05 pm

Lutscha wrote:
Dave Saxton wrote:One notes that the body of mostly secondary and beyond secondary based sources that have established the conventional wisdom concerning the Bismarck's design, and particularly the armour scheme, are vaugely cited, if cited at all.
Most people here know what is written by Okun on navweaps and this can be easily shown via linking (and has been done).

I ask again, why are all these documents not provided for anyone? They are NOT readily available. What would be easier than to proof ones (your) point with such primary sources?
And what of its citations?

There is a body of primary sources which may be used that are NOT available online, that exist in archives or among peoples private collections, or old computors,...... You can't seriously expect internet links provided for public forum debates?! Most of the time people link to wiki or navweaps and they mean little to me. I can't consider them authorative. So what?

One could add most of the ADM281 library, Others from the ADM213 library, Bericht 166, APP special Number 29 and 30, The pentration of Armour Plate Supplimental 6190...ect.. ect... and on and on- not availble online or proprietary.
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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Dave Saxton
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Re: Bismarck/Tirpitz = most powerfull European battleships

Post by Dave Saxton » Tue Sep 21, 2010 8:20 pm

JtD wrote:What I found in Gercke is that 50mm of homogeneous armour backed up by 80mm of homogeneous armour are equivalent to 80mm of homogeneous armour (V2 = 0.82 V1 with V^2.5 ~ S). Great stuff, isn't it.

.
What is the context of this snippet? Gercke does report that in most cases multiple thin plates result in Vnot= (square root) V1(squared) +V2(squared)+v3(squared)... but did you notice when he outlines how a two plates system can match or exceed the effective thickness of a single plate of equal sum thickness? If we apply this to the Tirpitz's two plates system, we end up with an effective thickness exceeding the sum thickness.
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: Bismarck/Tirpitz = most powerfull European battleships

Post by alecsandros » Tue Sep 21, 2010 8:33 pm

JtD wrote:
What I found in Gercke is that 50mm of homogeneous armour backed up by 80mm of homogeneous armour are equivalent to 80mm of homogeneous armour (V2 = 0.82 V1 with V^2.5 ~ S). Great stuff, isn't it.
For Bismack and Tirpitz, V2 = 1.07xV1, and not 0.82.

195mm is from my memory and I think it's wrong.

It's more like 210mm for Tirpitz 95+20+120mm.
Ok, so the torpedo protection system was well protected.
This is not about the torpedo protection system. You seem to have a vague representation of Bismarck's geometry.
http://www.kbismarck.com/proteccioni.html
The inclined portions of the second deck (turtle deck) also protect the ship's main magazines against some post-penetration trajectiories. And not only the main magazines, but also some parts of the machinery.

If you woudl take teh time to read Hoyer's opinions and see his drawings, we wouldn;t be having this discussion.

Where exactly was it 80+120mm?
"The upper armour deck was 50-80 mm (Wh) thick and covered most of the ship's length (from frame 10.5 to 224). The 80 mm (Wh) platting was located from forward to aft of each pair of main turrets, around the secondary turrets, and under the control tower. A lightly protected 20 mm (St 52) thick battery deck was located 2.4 meters beneath the upper deck. The third armour deck was 10.3 meters above the keel, and featured the classic "turtle deck" arrangement with sloped edges. The amidships flat portion of the main armour deck marked the top of the internal armoured raft, and it was normally situated about one meter above the designed waterline. It was 80 mm thick over the machinery and 95 mm over the magazines. The outboard sloped portion of this deck was 110-120 mm (Wh) thick, and inclined downward at about 22° from the horizontal to where it met the lower edge of the main armour belt under the waterline. The armour deck's slopes presented attacking shells that penetrated the side armour with impact obliquities of up to 68°, and were 110 mm thick around the machinery and 120 mm thick adjacent to the magazines. Subsequent analysis indicated that the combined external citadel and internal raft could provide the vitals with relative immunity from 406 mm/45 APC shells fired at point-blank range. "
Because you claim the inadequacy of the Richelieu armour is proven by the fact that a 16" shell penetrated into the secondary magazines.
That is what you understood, not what I meant. What I meant was that that 16" perforation showed the French homogenous armor to be of somewhat lesser quality than British, American and German homogenous. And that's all there is to my statement...
36 seconds per round per gun - that's reasonable.
No. 18 seconds - 4 gun salvos. That means at every 18 seconds, 4 guns are fired. Since the turrets were individualy fed, this means the firing cycle for one turret was 18 seconds.

Maybe you should give more thought to this.

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Re: Bismarck/Tirpitz = most powerfull European battleships

Post by Lutscha » Tue Sep 21, 2010 9:08 pm

Dave Saxton wrote:
Lutscha wrote:
Dave Saxton wrote:One notes that the body of mostly secondary and beyond secondary based sources that have established the conventional wisdom concerning the Bismarck's design, and particularly the armour scheme, are vaugely cited, if cited at all.
Most people here know what is written by Okun on navweaps and this can be easily shown via linking (and has been done).

I ask again, why are all these documents not provided for anyone? They are NOT readily available. What would be easier than to proof ones (your) point with such primary sources?
And what of its citations?

There is a body of primary sources which may be used that are NOT available online, that exist in archives or among peoples private collections, or old computors,...... You can't seriously expect internet links provided for public forum debates?! Most of the time people link to wiki or navweaps and they mean little to me. I can't consider them authorative. So what?

One could add most of the ADM281 library, Others from the ADM213 library, Bericht 166, APP special Number 29 and 30, The pentration of Armour Plate Supplimental 6190...ect.. ect... and on and on- not availble online or proprietary.
I think there is a difference in quality between wikipedia and all the material Okun published online. Okun is considered an expert in his field and has also helped authors like G&D with their work and he publlished his works online. Since his work stood for years and he also used input of others to refine it you can hardly blame people wanting to see the sources which contradict him.

I can only speculate why the British spaced array tests are kept exclusive by a few people.

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Re: Bismarck/Tirpitz = most powerfull European battleships

Post by Bgile » Tue Sep 21, 2010 9:34 pm

alecsandros wrote:
36 seconds per round per gun - that's reasonable.
No. 18 seconds - 4 gun salvos. That means at every 18 seconds, 4 guns are fired. Since the turrets were individualy fed, this means the firing cycle for one turret was 18 seconds.

Maybe you should give more thought to this.
Maybe I can clarify this a bit. I timed the salvoes from the video and the fastest salvo interval for one turret group was 18 seconds. In the same video there are salvo intervals of 22 and 25 seconds. So no, she didn't fire repeated salvoes at 18 second intervals, but she was capable of that rate of fire because there was one interval like that. Obviously this can vary a lot from one salvo to the next due to differences in drill. It's clear to me at least that she was capable of rapid shooting at least for short periods, but probably not repeatedly at 18 seconds.

To repeat, this interval is for the same guns, so multiplying it by two is not appropriate. It's the time it took (for example) turrets A and B to fire 4 shells again after firing 4 shells previously. It also included elevation and return to loading angle for both turrets, since the film was made during actual combat. Also, since four guns were fired simultaneously in both salvoes, the time interval represents the salvo interval of the slowest of the four guns.

I'm obviously not a Bismarck fan boy, but I do recognize that in "good rapid" conditions she was capable of rapid shooting. She averaged about one minute per salvo for the engagement so there were obviously pauses and slower intervals.

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Re: Bismarck/Tirpitz = most powerfull European battleships

Post by JtD » Tue Sep 21, 2010 9:47 pm

Dave Saxton wrote:What is the context of this snippet? Gercke does report that in most cases multiple thin plates result in Vnot= (square root) V1(squared) +V2(squared)+v3(squared)... but did you notice when he outlines how a two plates system can match or exceed the effective thickness of a single plate of equal sum thickness? If we apply this to the Tirpitz's two plates system, we end up with an effective thickness exceeding the sum thickness.
Page 97, two homogeneous plates behind each other, one 50mm, one 80mm make a C1/C2 of 1, the e = 0.6 and therefore V2/V1 = 0.82. Means that the shell needs 82% the speed of a shell that punches through 130mm. So, as far as the horizontal armour is concerned, we don't end up with an effective thickness exceeding the sum thickness.

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Re: Bismarck/Tirpitz = most powerfull European battleships

Post by JtD » Tue Sep 21, 2010 10:05 pm

alecsandros wrote:For Bismack and Tirpitz, V2 = 1.07xV1, and not 0.82.
Says who. And more importantly, why?
This is not about the torpedo protection system. You seem to have a vague representation of Bismarck's geometry.
http://www.kbismarck.com/proteccioni.html
The inclined portions of the second deck (turtle deck) also protect the ship's main magazines against some post-penetration trajectiories. And not only the main magazines, but also some parts of the machinery.
Okay, so 0.8% of the ships vitals were protected by the inclined part of the turtle deck against fire that also hit the upper deck at 25° angle.

The quote you brought for the upper deck armour contradicts the original building plan. 50mm is what is in the original document says, 80mm is what some website claims without giving a source. You decide.
That is what you understood, not what I meant. What I meant was that that 16" perforation showed the French homogenous armor to be of somewhat lesser quality than British, American and German homogenous. And that's all there is to my statement...
Okay, so when you say that Richelieu's deck was penetrated because of the poor quality of the armour which was not made up for by greater thickness, you don't mean that Bismarck's deck would not be penetrated when hit in the same way. Odd then how you place emphasis on how great the horizontal protection of Bismarck was and that there was no way for the shell to penetrate the ever increasing composite thickness of her decks.
No. 18 seconds - 4 gun salvos. That means at every 18 seconds, 4 guns are fired. Since the turrets were individualy fed, this means the firing cycle for one turret was 18 seconds.
4 guns out of 8 are fired. Means each gun fires every second salvo. So it fires every 36 seconds. Not what you meant? Please be as clear as Bgile was in the meantime.

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