Bismarck and her contemporaries

Discussions about the history of the ship, technical details, etc.

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sineatimorar
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Re: Bismarck and her contemporaries

Post by sineatimorar » Tue Nov 05, 2013 10:36 pm

The interesting thing is when using the facehard program on standard settings using the same ballistic figures, the German armour comes out with better results than the American armour by quite a margin and just a whisker shy of the british type. So his modification factor attempts did not yeald the expected results. I will pull my current results and try and post them on this blog. I believe the accepted thinking at this time is a close colleration between German armour and British depending on the manufacturing date of each?

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Re: Bismarck and her contemporaries

Post by Bill Jurens » Thu Nov 07, 2013 3:46 pm

In a previous post, someone asked if I might comment on ballistic computational issues. It is well-known that I remain skeptical regarding the reliability of figures obtained via various programs available on-line. This is largely because in most of these programs the precise computational procedures used, and the underlying assumptions by which these methods were chosen are often hidden in the software itself, and are practically inaccessible to the user. Only rarely will the computer program reveal these assumptions to the user, even less rarely will the user understand their full implications, and even less rarely will the participant in an on-line discussion reveal what most of these assumptions were. In practical terms, in order to be useful, each trajectory modeled should be set up by someone experienced in the methodology of ballistic computation. The authors of various and sundry on-line programs may or may not have such expertise at hand. Even if they did, so far as I know, none of the programs fully reveal the computational scheme that might be employed in the computation of any given trajectory, and none allow the user to make complete adjustments in order to ensure that comparative trajectories are in fact comparative.

In that regard, the situation is rather like that of 'out of the box' consumer income tax programs, which allow the user to compute an estimated tax bill by simply typing in numbers. These can work fine if the situation is simple, but if a truly optimum solution needs to be obtained, one really needs to have an accountant or tax advisor – who not only knows how to answer questions but also knows what questions to ask in the first place – look at the thing.

The creation of a meaningful comparative trajectory study – and most of the discussion in these sorts of fora revolve around attempts to compare one weapon with another --requires dealing with a number of often difficult-to-resolve ballistic questions. A representative, but by no means comprehensive list might include the following:

a) What common atmospheric conditions are assumed in the comparison? Different nations assumed different atmospheric conditions as 'standard', so in many cases even official range tables cannot be compared directly. This would include, to take only a few examples, differences in surface density and density lapse rate.

b) What computational method was used to model the trajectory.

c) Has the trajectory been calibrated against an official range table? If not, why not? If so, under what conditions was the official range table computed, i.e. was the range table designed to give accurate answers under normal conditions or was it designed to assist in computational convenience in order to make immediate corrections easier? If calibration occurred, was the base point at maximum range, or some other collection of intermediate values? What form factor and projectile drag function was used to compute the original range table in the first place?

d) What drag function was used to model the projectile? (This applies, incidentally, to the creation of the original range table, if available, as well…)

d) What form factor was used to model the projectile? Was the form factor varied with angle of departure in order to adjust for projectile stability issues, or was a constant form factor used?

As one other participant noted, there is no better way to begin to appreciate these sorts of difficulties than to attempt to write a fully functional ballistics program oneself. It's only then that you will realize how complicated things can be, and how many assumptions one cannot reliably quantify when employing an online ballistics program as a problem solver.

In that regard, it has been my perception that the wholesale employment of on-line and downloadable programs, which at least imply that accurate solutions to ballistic problems are easy to find (and perhaps even definitive) might in fact represent a counter-productive influence on naval historical studies. This is not to say that they cannot be useful for preliminary investigation, in much the same way as 'out of the box' income tax programs can often provide a reasonably reliable estimate of one's broader tax situation prior to audit, only that they should not be expected to provide definitive result when serious research is being attempted.

Bill Jurens

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Re: Bismarck and her contemporaries

Post by sineatimorar » Fri Nov 08, 2013 10:58 pm

Hi Bill,
Hope you are well, yes I am still been driven for answers. To digress for a moment, Your tax analogue I found amusing as I found that when I first went into business I ended up writing my own spread sheet to tax too take care off all of the ongoing tax obligations I faced, and pretty well for the reasons you list.

I decided to get a better understand of the issues I had previously I set to try my own hand at it for a ballistic flightpath simulator, guess what still working on it.

Can I pass some observations past you please if I may? I think I have the main answer why the out of the box programs give pretty reasonable flightpath results while completely missing the strike velocities. I find in my programme I have had to so far had to generate two seperate calculation sets to avoid a circular argument issue for the programme ( probably I think I will have to go into source code writing like c++ or the like to avoid programming limits set into the spreadsheet). Currently I think there is going to be some more calculation sets I will need to ' get it right'.
I have not as yet looked at your last suggestion to me as I felt as if it might contaminate my learn process of learning from self-discovery first ( I find it the best way of understanding the problem), but I will keep it in reserve if I end up throwing my hands up in total self disgust for not succeeding..

Regards Jason.

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Re: Bismarck and her contemporaries

Post by sineatimorar » Sun Nov 10, 2013 1:49 pm

I have yet another question too ask. I just gone over an interesting essay on the subject a battle damage forensic analysis. Other than for a first for me I finally seen the 356mm hit on the forward section of the BS from the p of w.
Once and for ALL it can definitively stated that it was NEVER patched up before the final battle. Patches were made but the order for welding them in place was never given.

Now to the question. Can any one direct me to information on how effective the 5.9 inch secondary battery was?
No where do I see any information on either use or accuracy other than some vague reference to their use in the final battle. Both engagements started at a range that is within their stated range envelope, yet it seems that only the main guns scored hits.

Going on the info from the battle of the river plate the Gs guns seemed to have been successfully used in that battle.

So what's the go here?

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Re: Bismarck and her contemporaries

Post by alecsandros » Sun Nov 10, 2013 3:41 pm

sineatimorar wrote:
Going on the info from the battle of the river plate the Gs guns seemed to have been successfully used in that battle.

So what's the go here?
... Because of the shape of the trajectory of guns , the effectiveness of a gun decreased with range.
Thus, even having 40km range for a gun did not guarantee hits at that range, as the shell fell at a very steep angle, thus offering a rather small danger space versus the target.

The rule of thumb was that the effective range of a gun was usualy 50% of it's maximum ballistic range.
(Interestingly enough, some friends on the forum suggested that Bismarck opened fire at Denmark Strait at exactly 50% of it's maximum gun range (as opposed to the British, who opened fire earlier))

Thus, Bismarck's (and Graf Spee's) secondary artillery had an effective range of , about 8-10km.
Also, my impression is that the secondary artillery in German capital ships was not triaxially stabilized, thus giving a comparatively smaller hitting chance than the main artillery (which was triaxilay stabilized)

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Re: Bismarck and her contemporaries

Post by Thorsten Wahl » Sun Nov 10, 2013 8:14 pm

alecsandros wrote:
sineatimorar wrote: Also, my impression is that the secondary artillery in German capital ships was not triaxially stabilized, thus giving a comparatively smaller hitting chance than the main artillery (which was triaxilay stabilized)
naval artillery - main and secondaries were biaxial stabilised for roll and pitch.

only german shipbased AA artillery was additionally stabilised (the trunnion was continously leveled)
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Re: Bismarck and her contemporaries

Post by sineatimorar » Sun Nov 10, 2013 9:36 pm

Ah thanks to you both, forgot that rule, think I have seen it before. So you would say that British 8 inch gun well and truly out ranged the 5.9 inch? By and by glad to see I am not the only one to have a slip of the finger now and again Wahl.

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Re: Bismarck and her contemporaries

Post by sineatimorar » Sun Nov 10, 2013 10:33 pm

I am unfortunately starting to wonder if there is a tactical error in the calibre selection of the 5.9 inch gun as the main secondary gun on German WW2 larger warships. The equation may have been improved if the 5.9/60 weapon was used, but only a little extra range. Clearly they were intended to take on/out the smaller more agile light cruisers and smaller classes of combatants. Where I am starting to have a bit of problem is the basic realisation that the BS would be highly unlikely to meet such opponents in full fighting trim. As it turned out at the ranges that combat started in the North Atlantic this calibre of cannon was out classed by the British 8 inch cruisers. This been the only escort mounted weapon mounted that met this 50% rule or at least came closer to it. So by using the traditional calibre weapon was a error over using something with greater range performance more reflective of the increased modern combat range?

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Re: Bismarck and her contemporaries

Post by Dave Saxton » Sun Nov 10, 2013 10:58 pm

German battleships traditionally had three artillery batteries.
SA = heavy artillery
MA = middle artillery
LA = light artillery

The SA was the main armament and the LA was the dual purpose secondary armament for use against surface and air targets. The MA was in addition. That's just the way the Germans did it. It does not correspond to the main armament /secondary armament approach most of us are used to. The max range to surface targets of the MA on Bismarck was 23 km. The max range to surface targets of the LA was 18 km.
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: Bismarck and her contemporaries

Post by sineatimorar » Sun Nov 10, 2013 11:31 pm

Hi Dave,
Yes I am aware of the usual arrangement. I was just wondering if there was an over sight as it seems that combat ranges started at 18,000 yrds approximately, and if this 50% rule applies the effective combat range for the 5.9 inch was about 13,000 yrds. Adequate for WW1 combat maybe but seemingly 5,000 yds short of the muster in WW2. So assuming the traditional setup ( by and by I think it was in some ways better to have dedicated AAA) was still used, was using the same calibre in both wars in error? Should have they developed something with a better combat range more reflective of the conditions of the day?

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Re: Bismarck and her contemporaries

Post by sineatimorar » Mon Nov 11, 2013 2:46 am

Further to the question. The upper belt was designed to stop anything at or below 203 mm in calibre from penetrating the armour array of the hull correct? Therefore the British treaty cruisers armed with 203 mm cannon were obviously considered part of the threat matrix when designing this ship. Therefore you would require a weapon system to at least be able to neutralize this threat.

Now lets consider the tactical situations in which you would consider meeting such a threat. Either one on one or as a fleet engagement would be the most obvious. Secondlly it is most likely that any 'fleet' engagement would be at a minimum of the like of the river plate battle that would require split fire targeting by the Germans.

Taking into account the salvo method used was by the battery, the main guns could cope with only two targets at once, leaving any other target to the secondary battery to whit one further target could be enaged if the enemy doesn't split forces. So the secondary battery has to be at a minimum, ballistically matched to the expected threat's ballistics performance.

When it comes to the British treaty cruisers I wonder if this was the case. Is three turrets cerficant number to be effective ?

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Re: Bismarck and her contemporaries

Post by alecsandros » Mon Nov 11, 2013 6:49 am

sineatimorar wrote: So you would say that British 8 inch gun well and truly out ranged the 5.9 inch? By and by glad to see I am not the only one to have a slip of the finger now and again Wahl.
Clearly so.
The disproportion of hits by the 5.9 and 8" calibers would come mainly because the 8" shell would fall at a far more acute angle than the 5.9". Thus, the danger space would be greater.

As for the use of 5.9" in the German battleships, it was the largest caliber that could be mounted while keeping the other elements intact.
As you can see, the Bismarck yielded a secondary artillery equal to the main armament of a heavily armed light cruiser (12 x 6" guns).

The only way to counter heavy cruisers (8" guns) with the secondary artillery of a battleship meant to have 8" secondaries mounted on the battleships. This was not feasible, as the 8" mounts were large, heavy, and required more armor, and more weight attributed to their powder and shell magazines.

As was seen, there were no battleships/battlecruisers built with larger than 6" secondaries.

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Re: Bismarck and her contemporaries

Post by Thorsten Wahl » Mon Nov 11, 2013 9:29 am

sineatimorar wrote:...Once and for ALL it can definitively stated that it was NEVER patched up before the final battle. Patches were made but the order for welding them in place was never given.
its questionable

according vorläufige Vernehmung Matrosengefreite Manthey, Herzog und Höntzsch
"24.5. Löcher in der Back von ObLt. (Ing.) Richter dichtgeschweißt"

"24.5 Holes in the forecastle welded shut by..."
Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!

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Re: Bismarck and her contemporaries

Post by alecsandros » Mon Nov 11, 2013 9:44 am

Thorsten Wahl wrote:
sineatimorar wrote:...Once and for ALL it can definitively stated that it was NEVER patched up before the final battle. Patches were made but the order for welding them in place was never given.
its questionable

according vorläufige Vernehmung Matrosengefreite Manthey, Herzog und Höntzsch
"24.5. Löcher in der Back von ObLt. (Ing.) Richter dichtgeschweißt"

"24.5 Holes in the forecastle welded shut by..."
However, we also know eye-witnesses reports were not very reliable...

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Re: Bismarck and her contemporaries

Post by sineatimorar » Mon Nov 11, 2013 1:50 pm

Ok. So as to deal with 8 inch cruisers you need 8 inch secondaries. As I am fully aware of the design limits set in designing battleships of this era, the conclusion is that the secondary battery of the BS was not designed to counter anything larger than a 6 inch light cruiser. Hence inclusion of PG into the mission ( as a result of the river plate battle maybe?). Terminal ballistics involve not only strike angle, but weight and velocity of shell at point of impact. Throw into this mix the AP cap design and that gives you the threat matrix.

As to the patch on the bow. You can easily find the forensic report (http://www.navalengineers.org\ Bismarck.pdf)
There is a picture of the hole itself. No sign of a patch, weld bead nada. Nor on any other location on the bow.
I tend not to bother arguing what is clearly physical evidence, just the assumptions that either just do not add up or seem to ignore the blinding obvious. God knows I made a few half informed assumptions in my time, we are all only human. I never believed the titanic split apart while sinking either, until the evidence was clearly showed otherwise.

Here is a guide line for any investigation. If more than two seperate sources suggesting the same evidence, you have what is called a strong lead. If you have three or more independent sources supporting physical evidence you made your case.

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