Was the battleship Bismarck really the best of its time?

[spicmart]

Thank you, Thorsten!

[hans zurbriggen]

Hello Mr. Wahl,
thanks indeed for this new precious document.

Just to be 100% sure that I understand correctly its data, is there in the same document a specification of source and type of armor tested during various experiences ? I guess first two tests (a) and c) vs Class A US plates) were done against German KC plates.
Could you please confirm that other two (j) and l) vs Class B US plates) were done against German Wh plates ?
Thanks in advance

hans

[Thorsten Wahl]

US-Classifications of armour grade steels

1)Class A -face hardened armor = KC; KC(na), KVC (ger)= cemented armour (brit) (us classifcation did not clearly distinguish between cementation and other proceedings
2)Class B -thick homogenous armor usually >6" (~150 mm)= KNC(ger) = homogenous armour(brit)
3)STS Special Treated Steel -Rolled homogenous armor usually thinner then 6" (~150 mm) = Wotan hart(ger)= (rolled)homogenous armour (brit)

other
HTS high tensile steels such as St 52(ger); maybe Ducol(brit) and Wotan weich may be categorized here

in summarized reports you often find german plates with surprisingly low ballistic capabilities. I suspect older plates /experimental plates and further information (composition, heat treatment, naval plate vs army plate) would be required for classification of a problem,
as the german proceedings did not show large variations for their armour used for certain purposes. One has to consider the massive alloy shortages as the war went on. They may used inferior steels if no other were available and a lot of the work were done by slave work.

[hans zurbriggen]

Hello Mr. Thorsten,
thanks for your explanations.

hans

[SteveSmith]

Just some clarifications to the above.

For the U.S. Navy, Class A referred to any face hardened armor whether cemented or non-cemented. Class B referred to any homogenous armor.

Special Treatment Steel (STS) was a form of Class B armor (unless it was face hardened). While STS was technically Class B, the Navy frequently distinguished between the two. The lower belt plates for USS Iowa and USS New Jersey were specified as "STS" machined at the years while those for the other four ships were specified as "Class B" supplied by the BuOrd. The new book on USS New Jersey shows the machining used to produce the taper in the belt.

The U.S. Navy did not consider plates 4" or thinner to be "armor." That was the general dividing line between what could be rolled and what had to be forged at the time. Now much thicker steel can be rolled.

U.S. Steel mills generally followed the Krupp formula for cemented armor but they did not follow the Krupp process. They found the Krupp process to be impracticable for the scale of armor the U.S. Navy tended to request and so they essentially use the Harvey process for the actual cementing.

[BuckBradley]

This is very interesting. Is the "Harveyesque" method employed by US mills a possible source of the apparent inferiority of US plate (one reads everything from 10 to 25 per cent inferior to UK & German plates)??

[Bill Jurens]

Harveyized armor was not around for very long, and was quickly replaced by more resistant armor types.

One has to be very careful about this "20% inferiority" stuff. It seems to have originated some years ago as a relatively offhand comment, and has since become a meme.

The differences, in my opinion, largely lie in variations in acceptance testing criteria. Within the limits of physics and budgets, plates were manufactured in order to meet a given set of specifications determined by the purchaser. How the plate may have behaved outside of those acceptance parameters was, of course, of some interest, but was really of secondary importance.

So, it's not surprising that plates from Nation "A", designed for maximum resistance under conditions "X", "Y", and "Z" might perform differently than plates designed by Nation 'B" for maximum resistance under conditions, "P", "Q", and "R" when tested under "X", "Y", and "Z" conditions. Relative performance in most situations would only really apply under a set of very carefully controlled -- and largely quite arbitrary -- testing conditions. In any other set of (again quite arbitrary) testing conditions, the relative performance might be considerably different.

Which set of arbitrary testing conditions led to the best choice of plate construction overall, against all reasonable obliquities, calibers, and striking velocities? There was -- and because extensive testing was not really feasible either then or now -- no real way to answer that question in a meaningful manner...

So, testing -- let's say -- German plates under British conditions, and British plates under German conditions might not be revealing of any general overall superiority or inferiority at all. And what tradeoffs were made? Was a 5% improvement in penetration at 30 degrees obliquity worth a 12% decrease in penetration at 10 degrees obliquity? Good question...

Cost was also an issue. Was a 50% increase in cost worth a 15% decrease in weight, or might one be better a larger number of less-efficient plates at the same budget and covering a larger area? Another good question...

Insofar as most of the larger nations had the industrial capability to produce more or less any metallurgical condition that they wanted to, because many of the manufacturing processes were covered by patent (and thus the details were subject to examination by potential infringers if suit were undertaken) and because metallurgical skills were fairly internationally shared, the choices between 'inferior' and 'superior' armor in most cases did not involve the quality of armor production as much as it reflected the choices of the designers, and the details of the acceptance testing protocols.

The idea that armor was produced using secret cabalistic recipes, and produced in mysterious cauldrons like the witches' brew in Macbeth, though it may be melodramatic and exciting, is basically false. The production of armor represented a somewhat mundane, though metallurgically interesting, sideline of steel production, which required, to be sure, a certain degree of specialized knowledge and experience, but in the end to most steel companies it was just another -- albeit fairly profitable -- byproduct.

Because the customer decided how 'good' or 'bad' it was based upon a rather specific set of testing conditions, one had to work carefully to meet that specification, but usually no others. Whether the specification was optimal or not represented a fairly arbitrary decision, and one relatively unrelated to what might best be called 'overall quality'.

Bill Jurens

(edited to clean up syntax a bit without significant change regarding editorial content. WJJ 22 May, 2022)

[Patrick McWilliams]

Hi Hans,
Thanks for your reply, I agree - up to a point with your statement re Bismarck's protection, it has been said before in this Forum that even in her last battle that her armoured belts and decks were not penetrated, (although I have my doubts) possibly due to the most of the action being at close quarters where plunging fire was not such an issue and it proved very difficult to get her to sink her. However, the action did prove one thing and that is that fire from heavy shells can degrade the fighting capabilities of even the best built ships, even if they do not penetrate a vital area. We have been through a number of scenarios of Bismarck v practically every other WW2 battleship (including Iowas) in other threads and in my humble opinion if she was matched against an Iowa, which of course was an even more modern ship, in the end she would have suffered the same fate.
Bismarck was in the end basically shot to pieces at close range by two battleships and finished off by the heavier and more powerful torpedoes from the cruisers, whether or not the scuttling charges contributed much to her sinking is a debatable point, obviously it did not help to have the intakes blown open, but even before the final torpedoes hit her she was always going down. out of interest, I have just re-read the Barons book and he states that even before the final battle Bismarck had a list, presumably due to the hole in her stern.
Like the Titanic, it proves that no ship is unsinkable.

Hello Paul, your reply is spit on other, IMHO, you casting doubt on the ship being primarily scuttled – even if as you say, she'd have been sunk by torpedoes from Dorsetshire. Surely that point has been done to death elsewhere, especially with the evidence from the wreck enhancing the scuttling
theory.

[Patrick McWilliams]

Hi Hans,
Thanks for your reply, I agree - up to a point with your statement re Bismarck's protection, it has been said before in this Forum that even in her last battle that her armoured belts and decks were not penetrated, (although I have my doubts) possibly due to the most of the action being at close quarters where plunging fire was not such an issue and it proved very difficult to get her to sink her. However, the action did prove one thing and that is that fire from heavy shells can degrade the fighting capabilities of even the best built ships, even if they do not penetrate a vital area. We have been through a number of scenarios of Bismarck v practically every other WW2 battleship (including Iowas) in other threads and in my humble opinion if she was matched against an Iowa, which of course was an even more modern ship, in the end she would have suffered the same fate.
Bismarck was in the end basically shot to pieces at close range by two battleships and finished off by the heavier and more powerful torpedoes from the cruisers, whether or not the scuttling charges contributed much to her sinking is a debatable point, obviously it did not help to have the intakes blown open, but even before the final torpedoes hit her she was always going down. out of interest, I have just re-read the Barons book and he states that even before the final battle Bismarck had a list, presumably due to the hole in her stern.
Like the Titanic, it proves that no ship is unsinkable.

Hello Paul, your reply is spit on other, IMHO, you casting doubt on the ship being primarily scuttled – even if as you say, she'd have been sunk by torpedoes from Dorsetshire. Surely that point has been done to death elsewhere, especially with the evidence from the wreck enhancing the scuttling
theory.

[Byron Angel]

Assuming that the scuttling charges were designed and installed for the express purpose of sinking the ship, I'm not sure how their effect can reliably be dismissed or subordinated to the torpedo hits. The question as to which agent was predominantly responsible for her sinking is ultimately unanswerable IMO.

The only certainty (to my mind) is that the RN was not leaving until Bismarck had conclusively slipped beneath the waves.

Byron

[pgollin]

.

Yet again.

As everyone know, but for some reason seems to forget, there were NO, repeat NO, absolute measures of either shell "strength"/"penetration", or armour "strength"/"resistance".

These were only really measured on a nation, by nation, basis of firing their own projectiles (service or experimental) against their own service, or experimental armour. These were done both on a continuous quality control basis and on a trial/experimental basis. On the basis of British testing, thousands of tests were made, both as a check on batches and as experiments/trials. ALL tests were examined, and ANY oddities (excessively weak, or excessively strong) were checked further, including such things as sawing the projectile/plate such that hardness tests could be carried out on the "internals".

SOME of these thousands of tests are available, both as summaries, and fewer full reports in the archives.

BUT NONE OF THESE ARE ABSOLUTE MEASURES - THEY ARE MERELY RELATIVE.

There are in the records partial reports on the calibration of a new batch of 12-inch armour to be used as standardisation plates for projectile testing. These were first produced as a very, very controlled sets of plates and then these were tested against previously checked sets of projectiles. Each test was checked for any oddities and the ESTIMATED (i.e. calculated) penetration velocities recorded these were statistically checked and the final accepted figures were sent to the ordnance board who, after consultation, set the penetration velocity for the new batch of plates (NOT at 50%, but nearer 93% - such that almost all plates will resist penetration at a (slightly) higher muzzle velocity.

( N.B. even so, the Admiralty paid a supplement for plates produced that were found upon testing to be significantly stronger than the required testing spec. some of these additional payment slips are to be found in the KGV's Ships Cover. )

So the main RELATIVE checks on armour/projectile qualities are thousands of tests on one nation's armour and shell.

----------------

Against that are the tests of other nations' armour/shell. These usually numbered in the single, or less than 6 - and can only give an indication of what the penetration limits were (remember shells were not fired at the exact velocity to just achieve penetration, the limit had to be estimated).

Everything is statistical and relative.

.

[Byron Angel]

Well said, Phil.

Byron

[paul.mercer]

Hi Hans,
Thanks for your reply, I agree - up to a point with your statement re Bismarck's protection, it has been said before in this Forum that even in her last battle that her armoured belts and decks were not penetrated, (although I have my doubts) possibly due to the most of the action being at close quarters where plunging fire was not such an issue and it proved very difficult to get her to sink her. However, the action did prove one thing and that is that fire from heavy shells can degrade the fighting capabilities of even the best built ships, even if they do not penetrate a vital area. We have been through a number of scenarios of Bismarck v practically every other WW2 battleship (including Iowas) in other threads and in my humble opinion if she was matched against an Iowa, which of course was an even more modern ship, in the end she would have suffered the same fate.
Bismarck was in the end basically shot to pieces at close range by two battleships and finished off by the heavier and more powerful torpedoes from the cruisers, whether or not the scuttling charges contributed much to her sinking is a debatable point, obviously it did not help to have the intakes blown open, but even before the final torpedoes hit her she was always going down. out of interest, I have just re-read the Barons book and he states that even before the final battle Bismarck had a list, presumably due to the hole in her stern.
Like the Titanic, it proves that no ship is unsinkable.

Hello Paul, your reply is spit on other, IMHO, you casting doubt on the ship being primarily scuttled – even if as you say, she'd have been sunk by torpedoes from Dorsetshire. Surely that point has been done to death elsewhere, especially with the evidence from the wreck enhancing the scuttling
theory.

Hi Patrick,
You are quite right of course, the subject on scuttling has been 'done to death' over and over again, what I have always wondered is how many torpedoes were fired by Dorsetshire and how many actually hit, a point that would definitely had a bearing on how fast Bismarck went down.
I have looked back on most of the posts on the subject of her sinking but could not find any information - although of course I may have missed it.

[Patrick McWilliams]

Hello Paul,

It appears that Dorsetshire fired three torpedoes at Bismarck, two at her battered starboard side at 10.20 (one hit) and a third at her port side at 10.36, a hit. Bismarck sank 2-3 minutes afterwards. My source is the Baron's book, final battle map. on p. 249. The Imperial War Museum has a report from Dorsetshire about firing the torpedoes, but it is not accessible online: https://www.iwm.org.uk/collections/item ... 1030005299

All the best, Patrick

[Patrick McWilliams]

Paul, I found this on the kbismarck.com* site, to show my error above. Dorsetshire's three torpedoes all hit, two against Bismarck's starboard side and one against her more battered port side.