Bismarck's TDS so abysmal?

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Moderator: Bill Jurens

HMSVF
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Re: Bismarck's TDS so abysmal?

Post by HMSVF »

Bill Jurens wrote: Mon Jan 03, 2022 8:11 pm My thanks to Herr Nilsson for re-posting the previous correspondence on this.

I must admit that I remain somewhat baffled as to exactly how this sort of apparent flaw actually made it through the construction process.

There are three primary possiblilities:

1) That the designers of the ship just didn't think this out properly -- which I feel is unlikely, because most or all of them must have been, in reality, pretty smart guys.

2) What appears to be a flaw, actually isn't a flaw, and our negative interpretation of this feature resides in our incomplete or incorrect understanding of the full situation.

3) That the design was actually somewhat different originally, some changes occurred elsewhere, and that for some reason the flaw was recognized, but retained because no alternatives presented themselves.

Certainly this sort of arrangement would be very vulnerable to a deep-running torpedo, and problems would be exacerbated because a) without an intermediate void, which would at least slow down immediate flooding of the engineering spaces whilst it was filling up itself, any leakage into important interior spaces would have taken place immediately, and b) the source of this flooding would likely have originated low down close to the floor plates, which would mean the source might be quite quickly submerged and difficult to locate or access. There are other problems, too, insofar as this area is quite far from the ship's neutral axis in bending, which means it would typically be expected to be carrying high loads as the ship flexed in a seaway, etc.

The idea that some of the interior structures inside the protective system would have been capable of 'punching through' the holding bulkhead, might not represent a serious threat, as it's typically of fairly light construction anyway, but is still something you really do want to avoid. Structural items attached to the holding bulkhead should be, as much as possible, located on the inboard side, or arranged in such a way that they fail in tension as the holding bulkhead deflects inboard.

Comments very welcome indeed...



Bill Jurens

Bill,


Just say the magnetic exploders on the torpedoes carried by Ark Royals Swordfish had worked as planned....

What would have been the likely result in the event of a successful strike ?


Best wishes HMSVF
Bill Jurens
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Re: Bismarck's TDS so abysmal?

Post by Bill Jurens »

Depending, of course, on exactly where the hit(s) might have occurred,properly-operating magnetic exploders would have probably inflicted major damage to the the ship; the torpedo or mine then in effect 'goes around' the side protection system instead of attempting to defeat it directly. I would anticipate that two under-bottom hits, regardless of location, would have essentially relegated Bismarck, at best, to little more than a target for future attacks.

Bismarck appears to have essentially 'shrugged-off' a couple of aircraft torpedo hits which probably struck the main belt, i.e. were probably running a bit 'shallow' for the target. Bigger -- and deeper-running -- surface torpedo hits, e.g. those inflicted by Dorsetshire clearly did a lot more damage. It's unfortunate that although we can physically view much of the internal side protection system of Bismarck on the bottom, it's very difficult to determine how much of the distortions in the holding bulkhead was related to explosive damage, and how much stemmed from the impact on the bottom and the long subsequent slide. Sometimes one sees clues, e.g. small 'peppered' areas of corrosion which suggest the presence of fragment damage from explosions, but it's quite possible these are really just due to fairly localized failures of the protective coatings on the bulkheads themselves. If you see a small dent AND a corrosion circle, that suggests an explosion of course, but these subtle details are not easily seen in heavily corroded subject matter where the lighting is often somewhat less than optimal. So picking up small dents can be difficult.

Bill Jurens
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