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Re: Vanguard and Bismarck

Posted: Wed Oct 18, 2017 9:15 am
by Maciej
Dave Saxton wrote:
Could You give data from live tests?
I have boxes and boxes of documents. Unfortunately, because of my present circumstances they are in storage and they are not handy. Nonetheless, if I recall correctly the British study that found that no British battleship gun could defeat more than about 5-inches effective deck protection at less than 32k was documented in the ADM281 set of documents. This was a post war (WW2) live ammunition study.
Test against plates taken from Tirpitz. Armorur homogeneous, 65 degree oblique – penetration at 1100 f/s.
It corresponds to ~25 000 yards.

Tests against 8” armour at 45 degree – again full penetrations in condition to bust. Now I'm agay from my sources, but will check it later today or tomorow. It was not such bad.
Several years ago, I graphed various battleship gun’s deck penetration attainments on the Y axis vs range on the x axis. Seeing this in graphic form instead of on a chart was very interesting, particularly when put into the context of IZ. About 5 ½ -inches effective was the point of diminishing returns in terms of how much IZ it bought. 130-140mm was good to around for 30,000- 32,000 yards with just about every gun 14” and larger-including super heavies. Adding a couple of more inches only bought a marginal increase in IZ.
That correlates quite well with my pgraphs. With differences in details.
Something between 5 and 6” was „good enough”. Anythig thicker pushes protection in such area when shells falls so stepp, that increase in thickness must be very large to gain anything important.
If You add 2 thickness of deck on Bismarck add 2 thickness (or more if existed) on other ships.
Vanguard had weather deck ~30 mm thick, so sum was ~180 (magazines) and ~155 (machinery)
It is difference.
The problem is that the 30mm in not armour grade steel.
Armour/not armour is not so simple.
American STS used for deck protection sometimes, but was „construction steel” were tested with Tirpitz plates. Were slight better than German
Britiss Ducol steel were slight inferior. Say was 90% that of Tirpitz. So instead of 32 You have 29 mm.
Dismiss? British throw it away, and take into calculation only armour alone. But that plate was there.
I would agree wthat with very low obliques any impact of that plate on incoming shell is marginal. Byt with high oblique impacts ( as standard for deck penetration ) I'm not so sure.
It is not likely to induce much yaw because it is incapable of consuming much energy (and the distance between the weather deck and MAD is too small for much yaw to become manifest anyway),
Any yaw taking into caclulation is dangerous anyway.
and it is unlikely to de-cap incoming large caliber ordnance. In that case the Krupp rule for calculating effective thickness comes into play using the square root of plate 1^ + plate 2^+ plate 3^… method. This means its addition to the effective thickness is not significant. The British understood this, because they made sure that KGV’s deck protection was 5-inches over the machinery and 6-inches over the magazines, counting the homogenous armour plates only. This was deemed adequate against 16-inch fire out to ~30k in their IZ calculations.
Depends which 16” guns,
But I don't fully inderstand all British metodology
For example. They had tests of actual 14” shells fired from KGV. It clearly shows that at ~30 000 yards for new gun that could penetrate (more – perforate so in condition to burst) ~12” of british face hardened armour.
And still apply to any data that such a gun could penetrate 12” of vertical armour at ~16 000 yards or so (from memory have to check) with „0” inclination.
Splinter decks, as well as structural decks, in my opinion, are very inefficient allocations of armour weight. Why not just include that weight into the primary plate (or decapping plate if applicable) where it can do some good? Or exclude that weight from the design if it only provides a marginal or insignificant improvement of protection?
Yes/no
Depends on total distribution of compartments below.
Bisrmack just under the main deck had magaiznes. Any fragmets from plate could start troubles. Splinter protection could be very effective if there is room.
But if shell fully perforated deck, any splinter protection is waste of weight. See Jean Bart hit on Cassablanca.
Bismarck seem to be exact that design only with more modern materials and 30 knots. Everything else is virtually the same
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.
[/quote]
There is nothign in being agree/disagree there is description of design and logic behind.
Description of that 1919 design is simple
Modern AP shells become so powerful that it is virtually impossible to put single plate to protect ship from such shells at short range.
Deck had to be so thick that it is impossible to put it on top of belt to give adequate protection against such shells. So something different is needed.
So belt of moderate thickenss (12+ inch), heavy slope behind and main armour deck more or less on waterline level.
Higher plate to activate fuses, start yaw of shell and forece detoations above main armour deck.
Only this could quarantee protection of vitals from point blank range to long range.
Sounds familiar?

More – ship had to have 3 shafts, 8x15” C50 guns (4x2). Lenght in British therms, so in German metodology it will be C52 guns, 16x 6” guns in twin turrets preferable, but 12x6” acceptable. AA outfit to be decided later.
Distributon of artillery, internal arragement, armour scheme – it is simply description of Bismarck. With exact the same logic behind. With only difference – 25 knots max speed, and smaller fuel tanks. Bitish had larger bases netwoerk, so don't need very long range.

Re: Vanguard and Bismarck

Posted: Wed Oct 18, 2017 9:18 am
by Maciej
Dave Saxton wrote:I have always liked the Vanguard. The old 15" twins were good weapons and the Vanguard included many improvements based on war experience with the KGVs. Vanguard was also the first British warship built using extensive electric arc welding.
And I alway hate Vanguard.
I could see some of its advantages, improvemet os fire control, see weapons being much better than look like, but hate her.
I really don't know why :?:
But who says that "to like" or "to hate" need to be logical?

Re: Vanguard and Bismarck

Posted: Wed Oct 18, 2017 10:45 am
by Alberto Virtuani
Maciej wrote: "As mentioned more early combined protection of belt + slope was very unlikely.
But detonations inside hull even above main armour deck could not be ignored. Bismarck was destroyed by exactly this form of detonations (+ hits on turrets, superstructures and so on). Who cares if remains afloat if could not fight nor go anywere? So graph "total invulnerability" is exactly misleading......"
Hi Maciej,
thanks for the answers. It's clear to me that hits penetrating and exploding above the armored deck cannot be ignored.
However, this is true also for the British ships, just they have one more deck protected by the MAD, but still there are "vulnerable" equipment/uptakes etc. above this deck that can be devastated by enemy. Which additional critical equipment was exposed above the MAD of Bismarck compared to the British designs ?

My point is that if we speak of IZ diagrams, we should compare apples with apples, thus we should speak about vitals vulnerability and not about all other ship areas, because this is the IZ common understanding. In this sense, the diagrams you posted are a bit misleading (despite the descriptions you have put into them ) as they seem to show a worse IZ for Bismarck, while it was the other way round in terms of pure IZ.

In addition, I don't think your last statement above is entirely correct: Bismarck could not fight anymore after the final battle but she could still move. There was no proved impact on her power plant, coming from the British action on May 27. The impossibility to steer was due solely to the May 26 torpedo, not to the gunfire, at least according to most witnesses who said that the engines were still active and the shafts were still turning while the ship capsized and sank.


Bye, Alberto

Re: Vanguard and Bismarck

Posted: Wed Oct 18, 2017 11:29 am
by Maciej
Alberto Virtuani wrote:
Maciej wrote: "As mentioned more early combined protection of belt + slope was very unlikely.
But detonations inside hull even above main armour deck could not be ignored. Bismarck was destroyed by exactly this form of detonations (+ hits on turrets, superstructures and so on). Who cares if remains afloat if could not fight nor go anywere? So graph "total invulnerability" is exactly misleading......"
Hi Maciej,
thanks for the answers. It's clear to me that hits penetrating and exploding above the armored deck cannot be ignored.
However, this is true also for the British ships, just they have one more deck protected by the MAD, but still there are "vulnerable" equipment/uptakes etc. above this deck that can be devastated by enemy. Which additional critical equipment was exposed above the MAD of Bismarck compared to the British designs ?
Vanguard had there living quarters. Mess decks, and thats all
Of course various passages, line cables to fire controls and other such things.
My point is that if we speak of IZ diagrams, we should compare apples with apples, thus we should speak about vitals vulnerability and not about all other ship areas, because this is the IZ common understanding. In this sense, the diagrams you posted are a bit misleading (despite the descriptions you have put into them ) as they seem to show a worse IZ for Bismarck, while it was the other way round in terms of pure IZ.
It ius very hard to put such things in such simplified graph as IZ graph
In my opinion such graph with ship of „Bismarck” armour scheme is nearly pointless. Such graph had only sense with ships with AoN armour scheme. But if we want to show something.
That's why You can not ignore description. And if want to compare aples with aples, have to add placement of magazines.
Magazines of Bismarck were quite high. Any splinter from deck could damage them. Any penetration through belt + slope (what ever unlikely) will dagame them, and shallow path of hell could (theoretcally) reach them.
But on Vanguard/KGV and many others such hit was impossible, as magazines were deep inside hull. So shell had to some from very long distance, and with ship put forward/back nearly directly to enemy, or diving shell (or some sorf ot very heavy roll). So IZ of magazines (again magazines, not area above magazine) had IZ from 0 to something.
Will such graph be any useful?
So many varius variables had to be included that result will be unreadable at all. Try to search topic on navweaps forum and download one of pdfs, and put „on” all layers. See what happen. And those graph not include everything needed, so should have more on it. Good luck to analyze it.
But to show anything – possibly it is not so obvious – see that penetrating into citadel of shell in condition to burst is in red color, in „broken” condition in black, but in Bismarck penetration is on „orange” to show some difference, Possibly I should ude different color to show at once that those expected damages are not potentially the same.
In addition, I don't think your last statement above is entirely correct: Bismarck could not fight anymore after the final battle but she could still move. There was no proved impact on her power plant, coming from the British action on May 27. The impossibility to steer was due solely to the May 26 torpedo, not to the gunfire, at least according to most witnesses who said that the engines were still active and the shafts were still turning while the ship capsized and sank.


Bye, Alberto
I want to see Bismarck returning to port with that damage/
I know what blocked rudders. But You really think that after all those hits with some sort of miracle and making rudders operable, Birmarck would be able to return to port?
Seydlitz was undamaged compared to Bismarck, and was virtually sunk. Only very short distance from harmour saved her (and good work of damage control teams too)

Added
And turning of shafts says someth8ng but does not mean that ship is not doomed.
PoW had rotating shafts. Barham and queen Mary too....

Re: Vanguard and Bismarck

Posted: Wed Oct 18, 2017 12:52 pm
by Alberto Virtuani
Hi Maciej,
I see your point re. difficulty to compare AoN with "dual layer" ships in a IZ diagram, possibly colors (as you suggested, but possibly using yellow instead of orange to distinguish from British ships) would help.
you wrote: "Vanguard had there living quarters. Mess decks, and thats all"
Bismarck too had mainly mess decks, cabins, store rooms as well over her MAD. Which critical equipment was located over the Bismarck MAD and not over the Vanguard MAD ?
I would say that the really critical equipment located above the MAD are just the intakes /uptakes for power plant and the barbettes..... These are present in Bismarck and in the British ships as well (in Bismarck their "extension" is just higher due to one more "unprotected" level. PoW last received hit (a bomb in this case) in December 1941 damaged intakes and as a consequence a boiler room was disabled.....This can happen on any ship and Bismarck is not more vulnerable than the British ones in this sense.

you wrote: "Magazines of Bismarck were quite high"
Correct, but this can affect vulnerability only at long range (plunging fire) when hit rate is very low anyway. This proved not to be a problem during May 27 extensive shelling as no hit ignited a magazine, despite a lot of hits were exploding above the MAD, activated by the upper belt.

you wrote: "I want to see Bismarck returning to port with that damage"
I did not say that, even if without the rudders problem, who knows ? However she was still in motion when she sank, thus the power plant was not apparently affected by gunfire (we have witnesses stating that), while any other ship would have been sunk due to direct penetrations at waterline (and consequent loss of buoyancy). For Bismarck gunfire was simply not enough. Torpedoes (and possibly scuttling charges :think:) were needed to finish the job.


Bye, Alberto

Re: Vanguard and Bismarck

Posted: Wed Oct 18, 2017 1:03 pm
by Maciej
In case of sinking battleships by gunfire alone I hardly find anyone (modern when sunk) if magazines not detonated.
Some Russians ships were sunk this way on tsuschima battle but other examples?

Re: Vanguard and Bismarck

Posted: Wed Oct 18, 2017 1:35 pm
by Alberto Virtuani
Hi Macej,
what about Lutzow (WWI) and Kirishima (WWII, modernized) ?

Even without these cases, do you have any example of a prolonged heavy gunfire against any modern battleship, comparable to the May 27 against Bismarck ? :negative:


Bye; Alberto

Re: Vanguard and Bismarck

Posted: Wed Oct 18, 2017 2:07 pm
by Maciej
Modernized Kirishima was not "modern". Sorry
Lutzow - possibly. But was there any torpedo hit?
And it is not best exaple, as Derrfilinger had that slope, if I'm not mistaken.

But all those are not so revelant.
I'm repeating in various places (possibly not here yet) that there is not "overal" superiority of one design filosophy over another (except very few examples possibly)

See Bismarck/KGV-Vanguard configuration as example.
For British such armour scheme in WWII era was far from perfect. For distance from extreme long to say 12 000 yards KGV vitals were safe (who cares if were - they thoght that were).
If distance of fight is closer that means escort screw up or ship is so damaged before action that is doomed anyway.
Even with very surprise meeting nothing very dangerous should happen. Primary enemy was Germany, possibly Japan. Magazines were safe, no deflagration expected. Even with detonation well inside machinery, nothing very catastrophic. Ship will slow down, so what? Britih had numerical superiority so enemy will probably try to disengage, not kill enemy. Worst case scenario - enemy will run away like in Dogger Bank.
So better to gain protection in expected battle range (clearly 35-38 cm armour was more resistive than 15-32 cm, and scrap takes some mass), and loose some protection at so close distance, that who cares about that?

From German perspective things were different. Even if enemy was only France (Begin of Bismarck design), Germans will be outnumbered. Specially in light forces. If Enemy could be Britain (late Bismarck design stage when 38 cm guns were finally adopted) that numerical superiority of enemy would be even higher.
So meeting at very short distance, specially in North Sea mists, was quite possibtle in pre radar days. So ability to surviwe most (better all) machinery power even in point blank rage was quite important. Who cares about better protection at medium to long range, when by surprise there is possibility of hit at short range, which will disable or seriously slow down ship with fight against superior in numbers enemy. Such slow down - means sunk. Nearly automathically (see Blucher at Dogger Bank)
So loose some protection at "optimum range" (what ever it is) and gain in other areas, as it is critical (+ of course protection against cruiser fire, medium HE bombs and so on, not so important for British or Americans)
So for Germans any AoN scheme was not logical, and Majestic configuration much more preferable.
Different needs - different results.

Judging Bismarck configuration from British perspective is as useful as American sentence that Littorio was virtually worthless, as had too short range for Pacific operations.
Those Pacific operations were of course "very important" for Regia Marina :cool: :lol:

But I alerically response to any "proofs" about overal Bismarck's superiority or waht.
She was in superiority only against ships much smaller or much older. And any overal "superiority" if exist, need a lot of manipulation of data, or pure "creative accounting".
Compared to battleships build more or less on the same time, with more or less the same displacement was simply different. Gain something for loose something. Compromise as usual. and "compromise is solution that everyone is unhappy"

Re: Vanguard and Bismarck

Posted: Wed Oct 18, 2017 2:22 pm
by Dave Saxton
Armour/not armour is not so simple.
American STS used for deck protection sometimes, but was „construction steel” were tested with Tirpitz plates. Were slight better than German
Britiss Ducol steel were slight inferior. Say was 90% that of Tirpitz. So instead of 32 You have 29 mm.
Dismiss? British throw it away, and take into calculation only armour alone. But that plate was there.
I would agree wthat with very low obliques any impact of that plate on incoming shell is marginal. Byt with high oblique impacts ( as standard for deck penetration ) I'm not so sure.
Ducol was not even close to being an armour grade steel. The tensile strength was 80,000 psi and the elongation at that strength level and hardness (tensile strength and ductility vary with hardness) was 17%. German WHnA homogeneous armour was radically superior.

One of Thorsten's important findings was that, using the same testing methodology, the German armour was more ductile than the American homogeneous armour per hardness/strength. The elongation of the German armour using the same method was 25% at a tensile strength of 130,000 psi and even greater ductility at a lesser tensile strength. Krupp found that homogeneous armour performance was significantly improved against de-capped projectiles if the tensile strength of the armour was 80kg/mm2 or higher. For this reason we find that Tirpitz's panzer deck was treated to a higher level of hardness than the armoured oberdeck, or in cases where a spaced array system was not used.

The German homogeneous armour was not only superior to marine construction steels but also to other contemporary homogeneous armours. For example, American STS/Class B had a elongation of 25% at a tensile strength of ~120,000 psi. Of course once the material has been put to the torch, all bets are off.

I have a copy of the coupon provided to the Americans by the British of tests of Tirpitz homogeneous plates vs British homogeneous plates. The Tirpitz plates out performed the British plates by about 15%. Perhaps this is the reason why the British homogeneous armour adopted post war was essentially German WHnA under a different name. (The Americans adopted new materials post war that were roughly equivalent to Italian steels.)

Re: Vanguard and Bismarck

Posted: Wed Oct 18, 2017 2:27 pm
by Alberto Virtuani
Hi Macej,
I see your points, and I agree on the purpose of ship and possible war scenario that affect the choice of a design.
No modern battleship sustained a heavy gunnery punishment as Bismarck did, so it's difficult to judge who is best.

I still disagree about the overall design evaluation..... The choice to have a (theoretical) slight superiority in extremely long range immunity (when hits are less likely anyway) instead of a (solid) invulnerability at any practical (average to short) battle range, is IMO a severe error done by British and Americans with modern pre-war battleships. The only "excuse" being possibly that they tried to comply (more or less....) with the Treaty limitations, while for Iowa's and Vanguard the choice of the AoN design for armor was IMO just inferior to the German dual layer design.
you wrote: "Even with detonation well inside machinery, nothing very catastrophic"
Detonation in vitals not only slow down the ship (exposing her to other gunfire due to impossibility to disengage) but if penetration happens at waterline, it allow water to fill the huge machinery spaces, loosing buoyancy. This is why Bismarck could still be afloat after having received so many heavy shells on May 27.


Bye, Alberto

Re: Vanguard and Bismarck

Posted: Wed Oct 18, 2017 2:51 pm
by Maciej
Dave Saxton wrote:
Armour/not armour is not so simple.
American STS used for deck protection sometimes, but was „construction steel” were tested with Tirpitz plates. Were slight better than German
Britiss Ducol steel were slight inferior. Say was 90% that of Tirpitz. So instead of 32 You have 29 mm.
Dismiss? British throw it away, and take into calculation only armour alone. But that plate was there.
I would agree wthat with very low obliques any impact of that plate on incoming shell is marginal. Byt with high oblique impacts ( as standard for deck penetration ) I'm not so sure.
Ducol was not even close to being an armour grade steel. The tensile strength was 80,000 psi and the elongation at that strength level and hardness (tensile strength and ductility vary with hardness) was 17%. German WHnA homogeneous armour was radically superior.

One of Thorsten's important findings was that, using the same testing methodology, the German armour was more ductile than the American homogeneous armour per hardness/strength. The elongation of the German armour using the same method was 25% at a tensile strength of 130,000 psi and even greater ductility at a lesser tensile strength. Krupp found that homogeneous armour performance was significantly improved against de-capped projectiles if the tensile strength of the armour was 80kg/mm2 or higher. For this reason we find that Tirpitz's panzer deck was treated to a higher level of hardness than the armoured oberdeck, or in cases where a spaced array system was not used.

The German homogeneous armour was not only superior to marine construction steels but also to other contemporary homogeneous armours. For example, American STS/Class B had a elongation of 25% at a tensile strength of ~120,000 psi. Of course once the material has been put to the torch, all bets are off.

I have a copy of the coupon provided to the Americans by the British of tests of Tirpitz homogeneous plates vs British homogeneous plates. The Tirpitz plates out performed the British plates by about 15%. Perhaps this is the reason why the British homogeneous armour adopted post war was essentially German WHnA under a different name. (The Americans adopted new materials post war that were roughly equivalent to Italian steels.)
I don't care about PSI and other parameters.
I care about "take plate, fire shell, see what happen"
There were not many such tests, but results from those few done are known

Re: Vanguard and Bismarck

Posted: Wed Oct 18, 2017 2:53 pm
by Maciej
Alberto Virtuani wrote:Hi Macej,
I see your points, and I agree on the purpose of ship and possible war scenario that affect the choice of a design.
No modern battleship sustained a heavy gunnery punishment as Bismarck did, so it's difficult to judge who is best.
Question is not how much was needed to sink her, but how much was needed to distable her.
I still disagree about the overall design evaluation..... The choice to have a (theoretical) slight
Slight?
Armour the same thickness had 100 fs advatage on perforation limit, and was ~50 mm thicker, and covered much higher area, and covered much larger area agains diving shell.
Slight advatage. ???
OK, I have to redefine „slight”
superiority in extremely long range immunity (when hits are less likely anyway) instead of a (solid) invulnerability at any practical (average to short) battle range,
Well see – after two hits at that range Bisamrck was over. Lost so much ability that had to return to base.
PoW with inferior scheme after 7 hits stayed. Returned to base after short of fuel.
Hym.
is IMO a severe error done by British and Americans with modern pre-war battleships. The only "excuse" being possibly that they tried to comply (more or less....) with the Treaty limitations, while for Iowa's and Vanguard the choice of the AoN design for armor was IMO just inferior to the German dual layer design.
OK, so British were clever in 1891 when invented Renown/Majectic armour scheme – Bismarck was nothing more than repeat of that sheme – OK could be Canopus still 189something
and than become stu.... less clever....
happens.
you wrote: "Even with detonation well inside machinery, nothing very catastrophic"
Detonation in vitals not only slow down the ship (exposing her to other gunfire due to impossibility to disengage) but if penetration happens at waterline, it allow water to fill the huge machinery spaces, loosing buoyancy. This is why Bismarck could still be afloat after having received so many heavy shells on May 27.


Bye, Alberto[/quote]

What huge machinery spaces? See compartmensation of KGV/Vanguard.
Hudge machinery spaces were on US and French battleships.
For a while, at last on US battleships, as Iowa and later Montana, machinery compartments became smaller and smaller.

Re: Vanguard and Bismarck

Posted: Wed Oct 18, 2017 3:06 pm
by Maciej
Oh and I forget. Lion at dog her bank was disabled. And returned to base.
That is when you control the sea

Re: Vanguard and Bismarck

Posted: Wed Oct 18, 2017 3:45 pm
by Dave Saxton
I don't care about PSI and other parameters.
I care about "take plate, fire shell, see what happen"
There were not many such tests, but results from those few done are known
And I listed such a test where the German armour performed spectacularly. Krupp's findings were not theoretical. They verified it with extensive live fire testing. See ADM 213/951.

Of course, the British did not perform ballistic tests on Ducol, because it would be irrelevant.

Re: Vanguard and Bismarck

Posted: Wed Oct 18, 2017 5:08 pm
by Alberto Virtuani
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)......

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. :negative:
Effect of the bow hit was very bad for Bismarck but NO modern battleship was armored in the bow....The only weakness demonstrated was the shallow belt allowing an underwater hit. PoW hits were ONLY 3 from 15" and 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, see PoW official damage report), 4 hits were 8" from PG, only one hit the MAD (that obviously defeated the 8").....

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.
In a one to one duel, I would prefer to fight on a ship that cannot be penetrated in her vitals than on one that has no immunity below 24 km......I just agree with you that, considering the superiority in ship numbers, air support and intelligence, I would prefer to fight the war on a British warship than on a German one......

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.


Bye, Alberto