Stern section of the Bismarck - question

[George Elder]

Hi Bill:

We were speaking of bows and sterns, and I think you will find that the bow of the Bismarck has a radically different structure than was the norm in most WWII BBs. For one thing, it was armored, nearly all the way to the stem. And to equate this construction's structural issues with the analogy that the Bismarck is to other BBs as the Brooklyn is to other CLs is a patently untenable argument. It is like comparing vegitables with types of fish. On the face of it, in the Bismarck we have a relatively short armored bow vs structures that are usually unarmored and longer in most WWII BBs. We have evidence of German bows being hit by unerwater blasts without suffering failures -- despite damage that would certainly invite a collapse in one of the twins. As for the forward framing section, I repeat -- you don't have the framing plans. So how can the claim be made that the Bismarck was lightly built, etc., etc.?
I'll let other judge the efficacy of your position, but at this stage -- I think a thorough examination of the detailed basis for your claims is the best way to go. I will await your formal papers, and then give them the type of detailed examination that is appropriate. As it stands, I am of the view that some remarkable and unsubstantiated claims have been made, and that terminology (sophmoric) has been used that would make most objective reviewers question the degree to which you can be deemed a dispassionate observer of the facts.
There is nothing wrong with being an advocate, but it seems best not to claim otherwise when the available evidence points in the direction of a definite "tilt." This thread has been revealing, but I am not sure anything new is being revealed.

George

[iankw]

I have read this thread with interest and, thus far, managed to keep out of it. However Patrick, how, exactly would a shell exploding on the bridge of PoW cause it to sink? Also, IIRC, Bismarck took a hit in the bow which failed to explode. Would that have caused her loss had it exploded, in the same way that the PoW one would, apparently?? PoW seems to have survived similar hits/damage to Bismarck (and from larger calibre shells), so I fail to see your point here.

[Randy Stone]

...claim Bill posted that Bismarck was "...lightly built..." he made no such claim.

He made the statement the Bismarck was "... rather 'lightly' constructed compared to her contemporaries...." That is quite a different statement.

I must confess I was struck by this statement as I too, at first glance, read that 'Bismarck was lightly built.' But paying closer attention to his words indicates the analogy he painted of Bismarck being related to her contemporaries as similar to the Brooklyns' relationship to her contemporaries, which is by no means comparing 'vegetables to fish.'

If a factual interpretation, it is very interesting and, frankly, I am quite interested in what Bill has to offer.

Randy

[Javier L.]

Patrick McWilliams:

I don't see how the Bismarck could have been "lightly" constructed either. However I disagree with your claim that that Prince of Wales would have been sunk if one of Bismarck's 15" shells that penetrated the bow or bridge had exploded. Damaged yes, but not sunk. Anyway I don't recall any 15" shell from Bismarck hit POW bow.

Bill Jurens:

Thank you for giving the impact speed. I agree, the mud must have softened the impact with the ocean floor but still I think it is remarkable the hull of the ship is in the condition it is today and not worst. The bow did not only collapse but wasn't smashed either, and an impact at 20 knots is something to worry about.

About your claim of Bismarck being "lightly" constructed I disagree or else I just don't understand what you are trying to say. In terms of displacement Bismarck was not "light" at all in fact she was the largest battleship at the time of commissioning when compared with her contemporaries. In terms of armor I don't think Bismarck was "lighty" constructed either since 40% of her weight was armor. On the contrary, I think that the battleships that used the "all or nothing" protection system, although had places with thicker armor plates, overall had less structural strength than Bismarck with a very long citadel, splinter belts, internal bulkheads, etc.

Javier

[George Elder]

I think a more formal paper of the subject will be in order because all we have now are a series of claims. As I consider the Bismarck design as a whole, I am quite sure that certain areas were very lightly built, which would only be natural in regions werein great structural strength and/or passive protection were not required. But we have consideral structural support inherent within the ship itself. For example, the members surrounding the internal splinter/torpedo bulhead certainly appear robust, which I take was a component in the longitunial strength system. Indeed, the lessening of crushing damage when the ship impacted might, in part, have been due to this robust and continuous bulkhead system -- which is quite unlike systems in many other designs. Yet I cannot examine what has not been presented, that being the data and details to back the claim. To the best of my knowledge, we don't even have the girder dimensions in many parts of the ships. So there is little to do here.

George

[iankw]

Bill has much more experience in these things than I do. He has seen a lot more wrecks/plans/ships than I have. He has spent a long time studying plans of the Bismarck, and hours of footage of the wreck. If he says that it is his "impression" (he is allowed to have those?), that the ship was rather lightly constructed overall, then that is good enough for me, until someone comes up with a "viable" alternative, other than inaccurate comparisons with PoW.

I'm a newbie here, and know little about the technical aspects, but I am learning all the time. What I DO know, however, is that shooting the messenger is rarely a way forward, even if you don't like the message.

Just my 4 penn'orth.

[iankw]

Hi George, we cross posted, it seems. Before anyone else points it out to you, and maybe not as gently as I. Bill actually said that the design was "sophmoric", not the techniques. I see a world of difference there, and not one addressed by Dave's wonderful piece on welding.

[Bill Jurens]

The sometimes somewhat negative replies to my assessment of Bismarck as being somewhat lightly constructed with comparison to her contemporaries suggested that I should check some figures to see if they matched my intuition.

Here, from a variety of sources and rounded to the nearest percent, are the percentages of displacement assigned to 'hull structure' for a collection of battleships contemporary to Bismarck.

Bismarck 27%
North Carolina 35%
South Dakota 38%
Iowa 34%
King George V 39%
Vittorio Veneto 28%

Now these figures can't be taken TOO seriously, as they admittedly do come from a variety of sources, may be measured against different displacments, and probably reflect subtle or significant differences in 'book-keeping' from nation to nation, etc., but their general trend does seem to indicate -- as I had intuitively felt -- that Bismarck's hull structure was indeed a bit on the 'light' side. (They are not, incidentally, 'cherry-picked" and honestly represent the first figures I came across for each particular ship.) A two or three percent difference in weight is probably not really noticeable, but 10% -- the difference between Bismarck and South Dakota for example -- probably is, although probably more at a subliminal level than anything else. That matches what I've been seeing.

This, of course, does not suggest that EVERY part of Bismarck's structure was therefore 10% lighter than South Dakota's structure, but it is probably indicative of general trends.

I'd have to emphasise again that saying a structure is lightly built is not the same as saying that it's badly built. A new Wal-Mart store is much more lightly built than, say, a department store built in the late '40s, but it does not necessarily follow that the structure of the Wal-Mart is in any way inadequate.

I hope this helps.

Bill Jurens

[George Elder]

Bill notes the following hull weight figures:

Bismarck 27%
North Carolina 35%
South Dakota 38%
Iowa 34%
King George V 39%
Vittorio Veneto 28%

He then notes that these figures cannot be taken too seriously, and I have to agree. I will give just one example, a very considerable amount of STS was worked into the hulls of US ships, but that is not included in armor weights but in hull weight. The torpedo protection of the Veneto class, which weighed well over 1,000 tons was counted as hull weight, so should we reduce her hull weight even further? And how do we calculate the armored strakes that are carried forward and aft in the Bismarck? Are they removed from the hull weight? What about the structural members that also performed a strength function, such as the Bismarck's internal longitudinal bulkheads, weather deck, and main armor deck? Are these hull or armor weights? And guessing is not a good enough answer by a long shot on any of these questions for 2% here and 3% there can make a big difference.
And while gross weights can give some insights, I believe more specific measures can be found. For example, my understanding is that structural strength calculations involve frame types, distances and sizes, although plate thickness and types, as well as joint construction, are also part of the mix. I suggest these calculation were done for the Bismarck class, as they were done for all warships. We have such data on British, Italian and some US ships. It seems that Bill must have this data to hand as it relates to the Bismarck, for that may indeed give some specific legs to his claim.
But I would truely welcome data on the framing issues as they relate to the fore and aft sections of the ship. These are where most claims and points of contention now reside, and it seems a good place to start. As for using general weight returns, unless we can seperate how these figures were determined, we cannot assume that a 5-10% difference has any meaning at all. And the more pressing problem is that some armor weights are integrel in hull strength calculations because the plates do play a strength role. Indeed, to sperate these weights form strength calculations would not be possible or desireable, as Bill well knows.
So let us go back to frame size and spacing. What is about the frame size and spacing in the Bismarck that has Bill concerned?

George

[George Elder]

Bill has come out to play now, and the subject can be engaged as it deserves to be.

Bill:

Thanks for engaging the subject as it ought to be. I've been doing some digging into the numbers you used, and Friedman is none to sure about them as they relate to US ships for the some of the reasons you mentioned. Specifically, he notes all the STS that was used in the hull (underwater protection bulkheads, splinter bulkheads, etc.). The thicknesses here are mostly 17-38 mm, but the areas are vast. For example, one can find parts of the 17 mm thick torpedo bulkheads that are 400' long by 30' tall. Each of these weighs about 135 tons (please check my math: 30' x 400' x .056' x 400 lbs per square ft). So port and starboard, one such bulkhead system equals about 270 tons. Four of these equal over 1,000 tons that can be deducted from hull weight. And we're not even talking about the many other splinter bulkheads inboard or the outboard splinter plating. So I am not sure we can use this raw weight tool very well untill we're all on the same page.
But of greater concern is that some of this material, and the armor used in the Bismarck, had a twin function. In the Bismarck's case, this is particularly important because here we have a citadel that stretched about 70% of the ship's length, which is far mor than the typical 52-55% citidel length in most WWII era battleships. So with regard to these areas, I cannot see how one can seperate the armor's structural roles from its protective capacities. In this sense, the armor is dual purpose.
This is why I having difficulty in understanding exactly what you mean by lightly built. Are you referring to the areas outside the citidel? If so, are you referring to the bow or stern? If you are referring to these regions, than by what criteria are you judging them lightly built? Once I can understand this, then we can get into more depth -- and you know how I like that.

George

[Bill Jurens]

Comments to the effect that I am 'coming out to play' and or am 'now engaged' are entirely false. Honestly, I see little to no point in further pursuing this hull strength 'discussion' -- if that is indeed the appropriate word -- particularly when my repeated attempts at explanation at are clearly falling (at least in some instances) on deaf, thankless, and argumentative ears. Having committed no crime, I certainly see no need to continue to respond in detail to apparently endless and agressive cross-examinations. I've said my bit, and I've explained the basis for my observations. If some find my experience inadequate, my judgement poor, or my evidence lacking, then so be it. I would be glad to read their counter-arguments and evidence.

Regarding another issue, I think I was misquoted regarding my description of pre-war USN antiaircraft firings. Contrary to a previous memo in this thread, I did not say the USN was 'very pessimistic' regarding these tests, I said "In general, it might be said that these [tests] reveal the existence of a rather efficient system, though certainly one which hardly anyone in the USN was happy with." One must put this in context; the USN was NEVER really happy with their anti-aircraft gunnery, regardless of fuze type. i.e. they always saw whatever performance that was achieved as something to be improved upon. Complacency and progress are somewhat incompatible, and the USN progressed rapidly throughout the war and before. They progressed rapidly largely BECAUSE they were always unhappy with their results, results which some other navies might well have been perfectly happy to accept as the best which could be accomplished.

I will state again that the relative utility of a single purpose vs a dual purpose anti-aircraft armament is more or less entirely independent of the type of fuze used in the shell. The VT fuze might have, for the sake of argument, doubled the efficiency of any given gun battery, but if the dual purpose gun battery were twice as effective as a single purpose battery to begin with it would remain twice as good as the single purpose battery after the VT fuze were introduced. In other words, the introduction of a VT fuze might improve efficiency, but would not change RELATIVE efficiency of a single purpose and a dual purpose battery.

Bill Jurens.

[Evangelos Pagotsis]

Hello all,

I’ve just been told that my monograph “Battleship BISMARCK, The Nine Days Epic” published in Greek in December 2004, has attracted some interest in your forum. The postings are now some 16 months old, but for anyone still interested I thought I should provide some comments.
The claim of “…a structural flaw in the stern design of German armored ships, heavy cruisers, battleships, and battlecruisers” is not mine, as I’m not qualified to make such statements. In my original draft, it was attributed by footnote to the article “Bismarck’s Final Battle” by William Garzke and Robert Dulin, published in three parts in Warship International, in 1994. Unfortunately, all footnotes were deleted to fit the 84-page, magazine-like format. The point of Garzke & Dulin was not that the collapse of the stern was the direct cause of BISMARCK’s loss, but that the stern collapsed onto the rudders thereby jamming them and making repairs impossible while under-way and with the means available, so causing the loss of the ship indirectly. The arti-cle is relevant to the debate here 16 months ago, but take a look at this paragraph:
“The need to provide clearance for the centerline propeller also resulted in a longer than usual over-hang in which the weights of the rudders, steering gear and the protective armor for the steering gear was located. Buoyancy aft was limited by the smaller immersed volumes that resulted from the cut-away. These characteristics led to problems in German cruisers and battleships when they were tor-pedoed in the stem. Because of the lighter structure and smaller buoyancy than that found in a quad-ruple stem form these ships were more prone to damage from the whipping phenomena which occurs when the extremities of a ship are subjected to explosion-induced forces. The spectacular stem fail-ures of the armored cruiser Lützow and heavy cruiser Prinz Eugen were examples of this.”
The authors seem to suggest that LÜTZOW had a centerline propeller, don’t they? I was initially certain they were wrong, so I checked Conway’s Fighting Ships 1922-1946. On page 227 of the 1997 reprint and under the DEUTSCHLAND-class headline, it reads: “Machinery: 3 shafts”! I also searched the web and came across some ref-erences to the correct, two-shaft arrangement, but being unfamiliar then with the Panzerschiffe, I accepted the version – or what seemed to be the version – of two respected authorities in the field and the data of a reputable reference work. During my subsequent research for a similar project on GRAF SPEE, I realized the error and learned my lesson.
I’m grateful to Mr. George Roumbos for bringing my work to your attention, but there were several errors in his translation of extracts, as some members already guessed. For instance, he wrote: “In order to avoid vibrations, they had to assure enough strength between the hull and the central screw blades…”, which of course makes no sense. “Strength” is an accurate translation of the Greek word “antohi”, but I used the word “anohi” (notice a “t” missing from the latter) which means “clearance”! Mr. George Elder correctly deduced the meaning of my sentence, in his posting of 4 January 2005, 5:40 pm.
Mr. Roumbos also wrote: “The ship sunk before the stern broke away, which was also caused due to additional hits on the area, combined with low quality welding and structural planning of not expanding the hull-long torpedo bulkheads aft of the rudder compartment…”. My original sentence pointed to the “…structural design mis-take of not extending the longitudinal bulkheads…” bounding the Steering Gear Room aft into the stern-end structure, based again on Garzke & Dulin.
I called some features of BISMARCK “backward”, not “retrogressive”. This must be placed in the context of some previous articles on BISMARCK in Hellenic military his-tory magazines, which praised the ship’s design as extremely intelligent, and its technology equally advanced. I used the word “backward” to emphasise that the ar-mour scheme and the use of single-purpose LA and HA guns detracted from this glo-rified image, along with several technical faults and problems described by Timothy Mulligan in his article “Bismarck – Not Ready For Action?” (Naval History, February 2001).
But technical issues were a minor concern in my monograph, which was written as a detailed operational history of “Exercise Rhine”. That is why I did not use the find-ings of the Cameron Expedition, plus I couldn’t interpret them anyway since I’m not a naval architect or marine engineer. Incidentally, the above article by Garzke & Dulin includes some of their findings from the Ballard expedition.
The goal of my monograph, explicitly described on the back-cover, was to use and correlate primary sources in order to reconstruct events as accurately as possible, and to examine decisions based on the situational awareness of the various com-manders, instead of judging them by their results. In the course of writing, it was possible to resolve some inconsistencies in the primary sources, to provide what I think was a somewhat original answer to the question “Why was the BISMARCK not refuelled at Grimstadfjord?” and to deal with some minor issues in secondary sources such as these:
• How come Vice-Admiral Holland in HOOD ordered steam for maximum speed at 19:39 of May 23rd and turned to heading 295° at 19:48 – according to Captain Leach of the PRINCE OF WALES – if he (Holland) received the enemy report by SUFFOLK at 20:04 according to Ludovic Kennedy in “Pursuit” and others?
• Why Russell Grenfell in “The Bismarck Episode” was mystified by how Holland could have expected so early a contact with the enemy, anytime after 01:40 of May 24th according to his signal of 00:15?
To avoid cluttering the text of the monograph, these minor issues were covered in my article “Inaccuracies, distortions and myths for the BISMARCK, The Bibliographi-cal Adventures of the German Battleship”, in WAR & HISTORY magazine, November 2004.
I hope this posting is not too long,
Evangelos A. Pagotsis