Vanguard and Bismarck

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Maciej
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Re: Vanguard and Bismarck

Postby Maciej » Wed Oct 18, 2017 5:41 pm

Macej wrote: "Slight advatage. ???"

Hi Macej,
yes I confirm: VERY slight (28 vs 32 km accepting your figures ? How many hits do you expect from 30 km ?) if compared to Bismarck belt+slope IZ that was (as per your note) immune at any distance over 2 km distance (vs.24 km for Vanguard)......

To be fair designs had to be comparable to others of similar size and date.
Problem of Vanguard was that she grow up seriously during wartime modifications. As all allied battleships. So comparing her in 1946 configuration is not co fair (both ways) to Bismarck 1941*.
But there is another British design similar in size to Bismarck, newer than Bismarck, but still pre war. Lion 1939.
See graph and make conclusion
https://www.dropbox.com/s/5vybj53sqrnx5 ... 9.jpg?dl=0
For me it is much difference, not “slight”
Problem with “Bismarck” armour scheme was heavier than AoN. If expected enemy is so armed that it is impossible to build working AoN scheme, there is no other choice but go to something like Bismarck.
But if it is possible to make AoN working – You have graph.

you wrote: "after two hits at that range Bismarck was over.....PoW with inferior scheme after 7 hits stayed"

Are we speaking of the same battle ? All hits (on both sides) were totally irrelevant to judge of the armor scheme, as they happened outside the citadel or were under the belt..... No hit "tested" the armor scheme as designed at DS battle.

Deck of PoW was hit by shell. 8” only, but still


Effect of the bow hit was very bad for Bismarck but NO modern battleship was armored in the bow.…

But other battleships had nothing such important in bow. Possibly for reason of more space in citadel?
The only weakness demonstrated was the shallow belt allowing an underwater hit.

Yes, and it was test of armour scheme. If scheme is such that such hit is possible (and detonation after hit) it is test of armour scheme. Scheme is such that not covers important areas.
PoW hits were ONLY 3 from 15" and

Or 4, one hit is not so obvious, but
NO ONE tested her armor scheme as well (in addition only 1 exploded well before touching the deck, the other two did not explode at all,

Yes, agree

you wrote: "What huge machinery spaces? See compartmentation of KGV/Vanguard. "

What is the volume of an engine room or boiler room in Vanguard ? A shell exploding in a power plant compartment can easily affect other similar compartments as no protection (even against splinters) is provided between them and the flat trajectory can traverse the ship.

You have to be exact on traverse to make it work.
And it is not so clear. Graph shows only armour penetration (perforation to be exact).
After armour there were some plates, and closer to critical velocity exit speed would be not so much.
And after all – try some very late pdfs. Those graphs show border line as short cut about perforation/non perforation.
Later I added some “unknown area” based on kinetic energy, with US finding that shell with 80% KE compared to limit will with 90% probability not penetrate, and shell with 120% KE compared to limit with 90% will penetrated. Border become very large….
you wrote: " British were clever in 1891 when invented Renown/Majectic armour scheme – Bismarck was nothing more than repeat of that scheme"

You seem to ignore Dave's explanation about Bismarck scheme that is NOT the same even if it looks similar to old schemes. The slope of Majestic (as well as the slope of Hood) had not much influence on their IZ, it was there mainly to stop splinters, while Bismarck scheme has a completely different function, acting as a dual layer scheme that increases enormously the IZ.

If something is the same – than is the same.
And British description of 1919 scheme is clear.

*Both ways as comparing radars of Vanguard with radars of Bismarck will make British ship much better – but all is result of time, not British superiority. Same about fire control or AA guns.
But those improvements make mass of Vanguard larger, so if compare very selected part of design, not all overall, she will look worse, as become larger and larger (compared to 1939 design for example) and less armoured.

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Alberto Virtuani
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Re: Vanguard and Bismarck

Postby Alberto Virtuani » Wed Oct 18, 2017 6:04 pm

Macej wrote: "But there is another British design similar in size to Bismarck, newer than Bismarck, but still pre war. Lion 1939.
See graph and make conclusion"

Hi Macej,
the graph is clearly based on wrong assumptions: it's simply impossible that the heavier but slower 16" of Lion could do so better than the lighter but faster Rodney's 16" (that was actually unable to defeat the belt+slope during a prolonged action at very short ranges)..... Anyway we are speaking of existing ships, not of planned ones nor of never even built guns.

However, I like the red area, you can add it to the previous (IMO misleading) graph (re. Vanguard and rebuilt Hood) to have an idea how big is the IZ for Bismarck against the British 15" (from 2km to 28 km, basically any practical range) ......


you wrote: "If something is the same – than is the same."

No, it just look the same at first glance but has completely different purposes.


Bye, Alberto
Last edited by Alberto Virtuani on Wed Oct 18, 2017 6:17 pm, edited 6 times in total.
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Re: Vanguard and Bismarck

Postby Maciej » Wed Oct 18, 2017 6:06 pm

In case of "unreadable graph" see this one
https://www.dropbox.com/s/sc0b0fm3196xv ... D.pdf?dl=0
I made only one with such principle to show "unknown area" and other important things. Still not all - turrets/barbettes for example nor forward/back bulkheads not included on graph and many others.

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Re: Vanguard and Bismarck

Postby Maciej » Wed Oct 18, 2017 6:22 pm

Alberto Virtuani wrote:
MAcej wrote: "But there is another British design similar in size to Bismarck, newer than Bismarck, but still pre war. Lion 1939.
See graph and make conclusion"

Hi Macej,
the graph is clearly based on wrong assumptions: it's simply impossible that the heavier but slower 16" of Lion could do so better than the lighter but faster Rodney's 16"

You forget abut shell constructon difference
British build Lion’s gun.
Expected penetration of 12” plate by Nelson’s guns at 20500 yards, Lion’s guns at 28 000 yards.
14” by 16 000 and 22 250.
and so on
Problem with that Bismarck slope is that penetration limit is just under expected striking velocity. With those calculations.
So say striking velocity is 200 m/s and limit is 202 m/s. It is common in range from 0 to say 20 km.
So it seems taht Bismarck is so well protected, but was at limit. At last with those calculations.

(that was actually unable to defeat the belt+slope during a prolonged action at very short ranges)..…

By 14” guns, and 20 years old shells.
Anyway we are speaking of existing ships, not of planned ones.

OK, but existing ships were smaller than Bismarck. Or with large time between constructiuon of Bismarck and others. It is important too.
If You compare larger ships with smaller – is it fair? Or with large differences

you wrote: "If something is the same – than is the same."

No, it just look the same at first glance but has completely different purposes.
[/quote]
Yes. Heavy deck was for example for purposes of bomb protection. Pluggig fire protection was „accidental”
And many others.
Don’t explain it to engeener

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Re: Vanguard and Bismarck

Postby Maciej » Wed Oct 18, 2017 6:49 pm

I forget.
those ranges at which olates were expected to be penetrated are from official documets. Not calculated by me.

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Alberto Virtuani
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Re: Vanguard and Bismarck

Postby Alberto Virtuani » Wed Oct 18, 2017 6:50 pm

Macej wrote: "British build Lion’s gun."

Hi Macej,
No, AFAIK just a prototype that could never been used at the intended pressure..... Your source, please?

you wrote: "By 14” guns, and 20 years old shells."

The best available ones anyway, together with the 15" , and they all could not defeat the Bismarck protection at any reasonable range.

you wrote: "Don’t explain it to engeener"

Please avoid comments like this (I got a 5 years master degree in engineering at Politecnico of Milano, even if I'm not an expert of shell penetration) and try to answer Dave's statement (if you are able) with some more substance than "it is the same" just because on drawings it looks the same: :negative:

Dave Saxton wrote: "I disagree that it the same thing even if it looks similar on a cross sectional drawing. It is fundamentally different in concept. The earlier designs were based on arresting splinters after ordnance was fused by the outer layer. Hoyer’s lecture and other documents make it clear that the two armoured decks, and the scarps of the more modern design were part of the effective thickness calculations in the context of modern IZ requirements."



Bye, Alberto
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Re: Vanguard and Bismarck

Postby Maciej » Wed Oct 18, 2017 7:55 pm

No, AFAIK just a prototype that could never been used at the intended pressure..... Your source, please?

4 guns. According to Campbell.
No mountings.
Add:
to be sure about which gun we are talking about.
Lion 1939 was to be equipped with Mk II or Mk III guns. Slighty different in construction, but with the same ballistics.
2 guns of each type were produced and tested on proving grounds. Some of them used post war for new shell designs.

Lion 1945 were to be equiped with Mk IV guns. Those never materialized. Possibly one was produced (I'm not sure about this, and even if true it was modification/reworking of one of Mk II or Mk III, not new production). Exact parameters of that guns was never set.
end add
Please avoid comments like this

I will. Sorry

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Re: Vanguard and Bismarck

Postby Dave Saxton » Wed Oct 18, 2017 10:12 pm

Slight?
Armour the same thickness had 100 fs advatage on perforation limit, and was ~50 mm thicker,...


There were no 5" plates to recover from Tirpitz. The closest to 5" from Tirpitz available at that time would have been from the 120mm scarps. There's the claimed difference: 120mm vs 127mm.

Nonetheless my records indicate a test of 8" vs 80mm (German) 83mm (British) and the German armour was about 15% better. However, this is to be expected since the 80 mm homogeneous would have been from the panzer deck at ~250 brinnel hardness, and so designed to defeat de-capped projectiles.

Vanguard did not have 50mm greater deck protection ( I have already explained why).

Tirpitz: 80mm + 50mm = 130mm
100mm + 50mm = 150mm

Vanguard:127mm
152mm

Additionally,

North Carolina: 120mm
Iowa: 140mm
South Dakota: 145mm
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: Vanguard and Bismarck

Postby Maciej » Thu Oct 19, 2017 4:46 am

on edit

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Re: Vanguard and Bismarck

Postby alecsandros » Thu Oct 19, 2017 6:00 am

Maciej,
Tirpitz's belt was 33mm thinner then Vanguard's, but behind it was the armored scarp , 110 to 120mm thick (which Vanguard didn't have), and the 45mm Whotan torp bulkhead (which was comparable with Vanguard's internal armored bulkheads in way of the main magazines).

So you have that 110 to 120mm scarp to account for in Vanguard.

In terms of deck armor, Tirpitz's maximum armor thickness was found amidships and at the stern, around the secondary 150mm turrets. The weather deck armor was 80mm thick, and the main armor deck armor was 100mm thick. There were also several St52 steel decks between them, but I wouldn't consider them as armor, even if one of them was 20mm thick.

Most of Tirpitz's citadel though had 50mm weather deck + 80mm main armored deck for protection.

TO defeat that armor and to produce detonation beneath the MAD, one has to use long-range ballistics. SO long was the range required to obtain perforation of such an armor that it is almost beyond practical .

---

Other thicknesses: Tirpitz front turrets = 360mm, Vanguard 340mm
Tirpitz main barbettes: 340mm; Vanguard 324mm
Tirpitz main con tower: 350mm Vanguard 175mm
Tirpitz secondary con tower: 150mm Vanguard 50mm

All in all, the impression is that the 2 BB classes had overall comparable levels of protection to contemporary BB guns.
Tirpitz had thicker armor in the way of essential places ( main magazines , con tower ) , and Vanguard had more vertical armor - because her belt extended further down.

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Re: Vanguard and Bismarck

Postby Maciej » Thu Oct 19, 2017 8:05 am

Dave Saxton wrote:
Slight?
Armour the same thickness had 100 fs advatage on perforation limit, and was ~50 mm thicker,...


There were no 5" plates to recover from Tirpitz. The closest to 5" from Tirpitz available at that time would have been from the 120mm scarps. There's the claimed difference: 120mm vs 127mm.

No.
Difference in capability between plates were different and for different reasons.
Advatage 100 f/s was on face hardened armour. In that area British armour proved to be better. And thanks to avoid medium thickenss armour, belt could be as high as Bismarck, but with full thickness all way, when ob Bismarck ~1/3 of it ( or more ) was only 145 mm thick.
In case of homogeneous armour – German plates proved to be superior to British of the same thickness.


Vanguard did not have 50mm greater deck protection ( I have already explained why).

Tirpitz: 80mm + 50mm = 130mm
100mm + 50mm = 150mm

Vanguard:127mm
152mm


Additionally,

North Carolina: 120mm
Iowa: 140mm
South Dakota: 145mm


That is sort of calculation I name „creative counting”
Iowa had ~120 mm armour deck backed by ~20 mm backing.
North Carolina had ~95 mm deck baced by ~25 mm backing
South Dakota had variable thickness of deck – depends on area, but again backing was important part of it.
If for whatever reason we dismiss backing than Iowa had only 120 mm deck, and North Carolina less than 100 (again depends on are)
If for what ever reason we add backing on US ships than Vaguard add 12 mm, all way long

In case of weather deck.
Yes I know. Decapping/yawing others.
Were tests – results would be appreciated. Full scale or at last „cruiser scale” trials, not tank size guns and plates scaled up.
I’m ready to change my mind, and even to agree that combination of Bismarck’s decks 130 mm total was equal to 150 mm total. If results from live tests show that. Not some sort of theory.

No – all theories (except some German ) show that combination of many thin decks are less in protection value than single plate of combined thickness. So I can choose what ever theory I want – there are many of them, and all (except one) were the same – only differes in details.
What surpise that Germans used theroy that support they conception of designs?

We want to add weather deck – for what ever reason? OK
Vanguard add ~32 all way on citadel
US ships 32 to 38 (depends on class) all way on citadel

Simple counting of single deck armour alone should work on French designs, with very thin decks above armour deck and no backing behind.

And don’t forget about splinter protection.

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Re: Vanguard and Bismarck

Postby Thorsten Wahl » Thu Oct 19, 2017 3:44 pm

... face hardened armour... In that area British armour proved to be better

as far as I remember it was one plate produced in 1947 ;)that proved better then the flamecutted tiny sized armor pieces of Tirpitz made in 1940.
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Re: Vanguard and Bismarck

Postby Maciej » Thu Oct 19, 2017 8:05 pm

http://www.admirals.org.uk/records/adm/ ... 13-378.php

3x3.3 m is tiny?
Then there were not any "not tiny" plates on battleship.
And there were more than one better plate.
See link

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Re: Vanguard and Bismarck

Postby Paul L » Thu Oct 19, 2017 11:47 pm

Multiple Armor plates only offer less resistance than single plate - if the gap between these plates is shorter than the length of the attacking projectile. Otherwise the projectile is free to yaw as a result of previous plate perforation.

In examples were the gap between plates is less than the length of the penetrator, that penetrator is supported by these plates and unable to rotate or yaw.
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Re: Vanguard and Bismarck

Postby Dave Saxton » Fri Oct 20, 2017 5:17 am

That is sort of calculation I name „creative counting”


Call whatever you want, but you are not arguing with me. You are arguing with scientists and engineers from Krupp and the Kriegsmarine, who understood this far better than any of us. Moreover, their armour protection ideas have since been corroborated by numerous studies populating the post war research literature.

No – all theories (except some German ) show that combination of many thin decks are less in protection value than single plate of combined thickness.


The scientists and engineers from Krupp and the Kriegsmarine agree with you. What they said was that; the effective thickness of multiple armoured decks in most cases can be calculated accurately enough using the method:

Square root of: Plate 1,^2 + plate2, ^2 + plate3, ^2….ect

However, they also reported that a spaced array could match or exceed the sum total of the armoured plates if certain design conditions are featured. Among those conditions are that it should be in most cases only two plates of armour grade material (not construction steel), with one plate being the primary plate and the other a thinner plate. The primary plate should be significantly thicker and slightly stronger than the thinner plate. The main plate requires greater necessary velocity of the projectile to attain penetration than it normally would if the projectile was unaffected by the thinner plate. The thinner plate (the ober deck in a deck system) must still be heavy enough to affect the energy the projectile needs to penetrate the other plate.

This can be done in several ways. The 2nd plate in series can be set at an acute angle to the trajectory of the projectile (such as the scarp in the German designs) which causes a greater necessary velocity to attain penetration. Additionally, if the projectile is yawed then it will require a significantly greater velocity to attain penetration of the main plate than it would if it was not yawed. In order for yaw to become fully manifest requires great distance because the crucial precession aspect of yaw becomes manifest slowly. If the projectile is not capped then it will require a greater energy to attain penetration if the main armour has a tensile strength of 80kg/mm2 or greater. (Additionally, a capped projectile loses significant kinetic energy through the loss of the cap, but at the same time needs more energy to penetrate than it did before the cap was removed.) The German designs meets those conditions. Most other designs do not. This is why we can count 100% of the Tirpitz’s weather deck thickness in the effective thickness, but not the Vanguard’s weather deck thickness in its effective thickness. The Vanguard’s relatively thin, non armour grade, weather deck fails to provide for the above effects.

In the case of the American designs, the weather deck thickness is partly but not fully counted in the effective thickness calculations, because it was armour grade steel thick enough (38mm) to degrade the subsequent performance of the projectile some, but not thick enough to decap in most cases, and the distance between it and the main deck was too small for yaw to become fully manifested. The Americans considered it to add 50% of its thickness to the overall effective thickness. The Americans calculated that North Carolina’s effective deck protection was about 110mm-120mm. (88mm inboard + backing plate*, or 95mm outboard + backing plate = 92mm -99mm, plus 50% of the weather deck thickness) That is corroborated by the NC outer IZ limit of 28,000 yards against the new design 14”/50. The Krupp spaced array calculation methodology comes to about the same results attained by the USN.

The German spaced array deck system was verified by live fire tests according to Chief Engineer Tobicke. Tobicke referred to the 28cm and 38cm long range test shoots against the Hessen, which had such a spaced array built on it for testing, as having proved the system worked as designed. Furthermore, the dud 1600lb armoured piercing bomb hit suffered by the Tirpitz during August 24th 1944 proved that 50mm ober deck plus the 80mm panzer deck provided at least 130mm sum effective thickness. The bomb should have penetrated 130mm-140mm of deck armour and that is what it did. Its energy was completely consumed after it penetrated the 50mm ober deck and then the 80mm panzer deck.


* Two plates in direct contact to each other provide less effective thickness than if the plates are spaced.
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