Bismarck class turret protection

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Dave Saxton
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Postby Dave Saxton » Fri Oct 20, 2006 8:21 pm

Tiornu,

What was the range of the Hood hit on Dunkerque?

BTW, I know your feeling bad about the Met's, and my condolenses, but at least they made it that far, and had a great year. It was a great game and it came down to one or two pitches. What a great play by Endy Chavez.

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Postby Tiornu » Fri Oct 20, 2006 9:00 pm

The range on Dunkerque was in the neighborhood of 18,000 yards. I believe that was near the limit of visibility that day.
I was shocked that the Mets got as far as they did. I think they can be proud of their peformance this year.

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Postby Tiornu » Fri Oct 20, 2006 9:02 pm

So the Krupp curves are skewed toward protection?

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Postby Dave Saxton » Fri Oct 20, 2006 10:13 pm

If I understand Hoyer, then a curve based on the Vnot (most common), would predict more penetration than would actually occur as defined by the Vg limit.

In some cases, we have different German penetration data for the same range. It may be for the Vnot, Vg, or Vh velocity limits? Some penetration data (and different from say the Gkdos curves) is classified as "durchschlagsleistungen" which may translate to through penetration, (I think). What would "through penetration" actually mean? Is this intact penetration of the projectile, penetration of a broken projectile, or a hole through the plate? Durchschlag implies to just barely beat through or to just struggle through in some contexts, I'm told.

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Postby tommy303 » Fri Oct 20, 2006 11:29 pm

Durchschlagsleistungen = strengths of penetration; in the same vein, durchschlagen is to pierce, strike, or punch through something with force. This would usually imply complete penetration unless a qualifier was added to the phrase in which the verb was used to indicate otherwise.

As to durchschlagen meaning to just barely get through something, the meaning is most usually what one in English would say, 'to muddle through a task.'

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Postby Lutscha » Sat Oct 21, 2006 2:01 am

Durchschlagen means get through, pierce, penetrate.

If it means complete penetration I don`t know, I´m more familiar with the English special vocabulary although German is my native language...

But it does not mean to get barely through something, it just means to get through, intact or not. (but I don`t know how it was exactly meant as far as shells are concerned)

Muddle through a task is not a good translation... O_o

Durchschlagsleistungen means penetration abilities.

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Hoyer Document

Postby Bill Jurens » Sat Oct 21, 2006 3:42 am

I've seen a number of references to "Hoyer", etc. on this thread. Can I get more information on the name and availability of the original document?

Bill Jurens

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Postby José M. Rico » Sat Oct 21, 2006 10:52 am

On Gkdos 100 there are actually 2 curves:

Roten Kurven = Heilbleibenkurven (Geschoß bleibl Heill)
Red curves = intact curves (shell remains intact [during penetration])

Schwarze Kurven = Grenzschußkurven (Geschoß zerbrichtl)
Black curves = limiting shot curve (shell disintegrates)

From the Red Curves one gets the following data for the 38 cm Psgr. L/4,4 AP shell against belt armor:

Range Penetration
18km 442mm
20km 412mm
21km 392mm
22km 378mm
24km 350mm
25km 335mm
26km 320mm
28km 294mm
30km 275mm

As you can see Gkdos 100 offers no intermediate definitions. It is either "intact shell penetration" or "shell disintegration". This is interesting because for example from 19,000 meters the figure for "intact shell penetration" is 430 mm, but if the thickness of the plate is increased by only 10 mm, to 440 mm, then the shell "disintegrates" according to the "black curve"!!

From 24,000 meters we get 350 mm for "intact shell penetration" and the shell "disintegrates" against 370 mm.

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Postby Dave Saxton » Sun Oct 22, 2006 7:19 pm

There's quite a disparity between penetration predicted by the curves and the data listed by the Strengths of Penetration table:

10km 510mm
14km 448mm
18km 390mm
20km 364mm
21.2km- 350mm
22km 340mm
24km 320km
25km 308mm

These figures are used quite a bit in the literature, so it's a mystery to me as to how they relate to the radically different numbers generated by the curves.

The differences in what amour amount is penetrated by an intact projectile, and the amount of a broken shell, in the red and black curves, probably has much to do with the velocity needed for intact penetration (Vh) more closing matching the Vg velocity limits. Indeed manipulation of critical velocities is a common tool. Critical velocities are very dynamic as to striking angle, hence we find the use of back-sloped face plates, angled facets ect.. this could provide a way to limit the effects of shells striking at shorter range than the designed IZ. It's obvious that the Germans were mainly concerned with intact penetration in their IZ calculations, rather than make turrets ect... proof to any type of penetration. Proof against various types of partial penetration and so forth were probably not deemed as realistic goals.

It's interesting that The English and the Italians actually use less thick faceplates on 15-inch gun Battleships. What was their thinking here? I suspect that they were factoring in compound obliquity effects, not only the relationship between the angle of fall and the slope of a face plate, but also the curvature of the face plate. We have a similar situation regarding the Bismarck class turret fronts.

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Postby tommy303 » Sun Oct 22, 2006 10:32 pm

Dave,

It's obvious that the Germans were mainly concerned with intact penetration in their IZ calculations, rather than make turrets ect... proof to any type of penetration. Proof against various types of partial penetration and so forth were probably not deemed as realistic goals.


I would say there is probably a fair amount of truth in that statement. The history of gun vs armour swung like a pendulum back and forth since the first ironclads--amour at first defeating the gun, until the introduction of bigger guns and specialized shot; this then followed by thicker or better armours etc. I believe, by the 1930s the power of the big naval gun had achieved a measure of ascendency over the armours of the day to such a degree that made it difficult to provide complete protection against all hits without having to overcome the difficulty of manufacturing truly massively thick plates and accepting the weight penalties of installing them.

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Postby RF » Mon Oct 30, 2006 2:25 pm

tommy303 wrote:Dave,

It's obvious that the Germans were mainly concerned with intact penetration in their IZ calculations, rather than make turrets ect... proof to any type of penetration. Proof against various types of partial penetration and so forth were probably not deemed as realistic goals.


I would say there is probably a fair amount of truth in that statement. The history of gun vs armour swung like a pendulum back and forth since the first ironclads--amour at first defeating the gun, until the introduction of bigger guns and specialized shot; this then followed by thicker or better armours etc. I believe, by the 1930s the power of the big naval gun had achieved a measure of ascendency over the armours of the day to such a degree that made it difficult to provide complete protection against all hits without having to overcome the difficulty of manufacturing truly massively thick plates and accepting the weight penalties of installing them.


There is also the point that technology itself provides some of the answers to problems like that, particulary as this sort of issue affected tanks.
The British came up with one solution for the Challenger tank, the use of Chobham armour, which proved itself in the Iraq campaigns, though this of course is light years ahead of the WW2 technology.
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Postby paul mercer » Tue Dec 19, 2006 4:36 pm

I think I read somewhere that hitting a modern tank turret by a shell was designed not to penetrate but to knock bits off the inside so killing the crew. Would'nt the internal concussion from a direct hit on a turret by a heavy shell be it 14"/15" or 16" be enough to kill the occupants or at least knock the internal equipment about (which in turn could also kill or injure the crew)?

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Postby Tiornu » Tue Dec 19, 2006 9:53 pm

The HESH round is designed to send a "scab" of armor shooting off into the tank interior. Naval rounds do not act the same, but they will often create splinters even if they don't penetrate. I believe it was Seydlitz at Jutland--a 15in shell struck the faceplate and failed to penetrate but did make a nice 15in plug of armor that went clanging around the gun mechanisms. No men were killed, but the elevating gear for one gun was disabled. The crew was able to couple the two guns together so both returned to action.
The USN was a big fan of turret armor, and they certainly felt that turrets and their crews could survive direct hits. Trials held shortly after WWI, intended to simulate high-velocity, non-penetrating hits, convinced the Americans that such damage posed minimal problems. I believe the only alteration inspired by the trails was the removal of some anti-splinter plating which showed it could deform and interfere with gun elevation.

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Postby Bgile » Wed Dec 20, 2006 12:39 am

paul mercer wrote:I think I read somewhere that hitting a modern tank turret by a shell was designed not to penetrate but to knock bits off the inside so killing the crew. Would'nt the internal concussion from a direct hit on a turret by a heavy shell be it 14"/15" or 16" be enough to kill the occupants or at least knock the internal equipment about (which in turn could also kill or injure the crew)?


The HESH round has been discarded because it doesn't perform as well as modern sabots. IIRC it also had to be stored vertically in the turret, which limited the number of rounds carried and caused other ammo storage and survivability problems.

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Re: Bismarck class turret protection

Postby dahlhorse » Wed Jun 25, 2008 2:34 pm

One thing people fail to recognize and come to terms with is that no other battleship when surrounded by enemy forces and unable to steer with speed reduced to 5 to 7 knots in strong headwind with crew exhausted would have been able to take the pounding the great Bismarck took at close ranges for naval warfare; everyone seems to think that the rodney or the POW or KGV or iowa or any other class battleship have better armour or better guns or better this and better that. It is all nonsense; come to one conclusion in your heads and do not forget it; The Bismarck took one hell of a ganging up on and pounding and still had to be scuttled by "His" crew to send it below the surface; NO other battleship would have been able to take that pounding from all angles and then have to be scuttled to end it.The Bismarck would still pummel any battleship then or now one on one; If it was matched up with the same radar technology and sensors of modern day. END OF STORY


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