Armour Penetration

Warship design and construction, terminology, navigation, hydrodynamics, stability, armor schemes, damage control, etc.
Serg
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Re: Armour Penetration

Post by Serg » Mon Apr 27, 2009 9:16 pm

Yeah. According to USNTM all VH plates thiner then 11" were produced only for experimental purposes. And IJN did not use standard VH armor thinner than about 11" for warships. I guess that the data for medium shells (which usually employed vs medium thickness VH) very incomplete and different from one experimental plate to another.

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Re: Armour Penetration

Post by marty1 » Mon Apr 27, 2009 9:24 pm

looked at it a couple years back and posted here.

viewtopic.php?f=13&t=80&start=30

just need to include same projectile test results against same thickness of USN class-A. the energy efficiency of a given projectile or given plate is simple. if someone has USN trials of class-A with any the projectiles used in trials against Japanese plates it is pretty straight forward to determine which was better.

Okun indicates in an old Warships article that USN Class-A of the sorts of thickness employed on cruisers was excellent. I don't recall him saying USN Class-A of the sorts of thickness used in battleships was particularly good. I thought what he actually said was that thicker US CLass-A armor of this period had problems.

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Re: Armour Penetration

Post by Bgile » Mon Apr 27, 2009 9:46 pm

marty1 wrote:looked at it a couple years back and posted here.

viewtopic.php?f=13&t=80&start=30

just need to include same projectile test results against same thickness of USN class-A. the energy efficiency of a given projectile or given plate is simple. if someone has USN trials of class-A with any the projectiles used in trials against Japanese plates it is pretty straight forward to determine which was better.

Okun indicates in an old Warships article that USN Class-A of the sorts of thickness employed on cruisers was excellent. I don't recall him saying USN Class-A of the sorts of thickness used in battleships was particularly good. I thought what he actually said was that thicker US CLass-A armor of this period had problems.
That was my impression as well.

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Re: Armour Penetration

Post by Tiornu » Mon Apr 27, 2009 11:53 pm

The problem with Class A is the exaggerated scaling effect caused by its thick face. This reduces its value against large shells but can actually help against cruiser-caliber shells.

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Re: Armour Penetration

Post by marty1 » Tue Apr 28, 2009 4:29 am

sounds like you read the same article. those are about the precise words Okun used. while I am perfectly comfortable with scale effects in the traditional sense of how these are defined in terminal ballistics, Okuns point regarding scale effects and face hardened armor was a little unclear to me.

moreover, the term "scale effect(s)" is\are typically employed to explain contrasts in either energy absorbed by the plate or energy required by the projectiles of differing calibers but matching t/d (or e/d if you like). in other words at e/d = 1 a 37mm AP round perforates the plate less efficiently than say a 16" AP projectile perforating an e/d = 1 plate. If you were to plot limit velocity as a function of normalized perforation (e/d) large caliber projectiles will normally have lower limit velocities for the same e/d value.

anyway, it didn't really jump out at me what he was driving at in terms of USN class-A armor or if he is using "scale effects" in a non-traditional manner as he was jumping back and forth between depth of the face and scale effect. I guess I would have to see a plot\graph to understand what he was going on about.

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Re: Armour Penetration

Post by Bgile » Thu Oct 15, 2009 3:32 pm

Lately Karl has been criticizing Nathan Okun by claiming "very prestegious authors as Friedman, Raven and Roberts, Skulsky, Koop and Schmoltke and Garzke and Dullin" don't agree with his results. As far as I know, these excellent authors are not ballistics experts at all and don't criticize his results, either. Where have these people shown any expertise in ballistics? Hasn't their research on the whole been more oriented toward gathering together historical facts? Aren't they generalists as opposed to specialists? I love their books and they contain lots of valuable information, but I don't think they are experts in ballistics and I don't think any of them have studied the ballistics of shells and armor plate anywhere near the extent to which Nathan Okun and some other folks have.

Where is this coming from? To me, it's like comparing apples to oranges.

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Re: Armour Penetration

Post by Byron Angel » Thu Oct 15, 2009 5:11 pm

Bgile wrote:Lately Karl has been criticizing Nathan Okun by claiming "very prestegious authors as Friedman, Raven and Roberts, Skulsky, Koop and Schmoltke and Garzke and Dullin" don't agree with his results. As far as I know, these excellent authors are not ballistics experts at all and don't criticize his results, either. Where have these people shown any expertise in ballistics? Hasn't their research on the whole been more oriented toward gathering together historical facts? Aren't they generalists as opposed to specialists? I love their books and they contain lots of valuable information, but I don't think they are experts in ballistics and I don't think any of them have studied the ballistics of shells and armor plate anywhere near the extent to which Nathan Okun and some other folks have.

Where is this coming from? To me, it's like comparing apples to oranges.


..... I quite agree with your assessment, Bgile. I don't think anyone else has studied the subject in such depth, had access to the vast amount of original source archival material, or possesses the professional skillset (physics PhD, IIRC) to properly evaluate it. I would definitely consider Nathan to be the best and last word.

Another point in Nathan's favor is that he is objective and displays no nationalistic bias so far as I have been able to observe.


Byron

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Re: Armour Penetration

Post by Karl Heidenreich » Thu Oct 15, 2009 10:49 pm

Lately Karl has been criticizing Nathan Okun by claiming "very prestegious authors as Friedman, Raven and Roberts, Skulsky, Koop and Schmoltke and Garzke and Dullin" don't agree with his results. As far as I know, these excellent authors are not ballistics experts at all and don't criticize his results, either. Where have these people shown any expertise in ballistics? Hasn't their research on the whole been more oriented toward gathering together historical facts? Aren't they generalists as opposed to specialists? I love their books and they contain lots of valuable information, but I don't think they are experts in ballistics and I don't think any of them have studied the ballistics of shells and armor plate anywhere near the extent to which Nathan Okun and some other folks have.

Where is this coming from? To me, it's like comparing apples to oranges.
I´m so sorry! I didn´t realize I was going to be accused to my mother for critizing the priest´s Sunday preach... I promise I will abide the teachings the next time.
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Re: Armour Penetration

Post by Karl Heidenreich » Thu Oct 15, 2009 10:52 pm

Oh, by the way: I have the right to question and to trying to understand things. If anybody else have memory I come up with the idea of making a study group and I was ignored.

And I never said that Friedman and Company were contradicting Okun´s writtings. I say they point to another things that seemed to contradict some of the un quoted, un sourced statements from Okun. That´s what I said.

What baffles me is the anger (wrath really) from everybody when it comes to question things. Really: looks like we are back at the Inquisition and if you do not abide the TEACHINGS then you go to burn in hell.
An appeaser is one who feeds a crocodile, hoping it will eat him last.
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Re: Armour Penetration

Post by Bgile » Thu Oct 15, 2009 11:04 pm

Karl Heidenreich wrote:Oh, by the way: I have the right to question and to trying to understand things. If anybody else have memory I come up with the idea of making a study group and I was ignored.

And I never said that Friedman and Company were contradicting Okun´s writtings. I say they point to another things that seemed to contradict some of the un quoted, un sourced statements from Okun. That´s what I said.

What baffles me is the anger (wrath really) from everybody when it comes to question things. Really: looks like we are back at the Inquisition and if you do not abide the TEACHINGS then you go to burn in hell.
Karl, I don't have any problem when you question things. My problem is when you list all those authors and say they all disagree with Okun and then don't give specific disagreements so I can look at them.

Okun is often the original author of his writing. It's often entirely new work. What references do you think he should give?

Your study group idea wasn't ignored, at least not by me; I explained why I was unable to travel to Washington DC to look at archival information. This whole forum is a kind of study group.

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Re: Armour Penetration

Post by Karl Heidenreich » Thu Oct 15, 2009 11:48 pm

Bgile,

The problem is that I regard you as a friend and don´t like to fight you, really. But regretably any author on any subject has to use premises and information, which is where the sources come in and then you interpret that information to write your text. If you open a book of Physics or Astronomy or Geology that is innovative you will find it full of bibliography. It´s basic.

If you open Friedman or R&R the references took more than a couple of pages. For example the combinedfleet webmasters´book on Midway: innovative? Yes. But full of new bibliography and references.

And I disagree with Okun´s conclusions so far. The USN BBs were not that good and Bismarck wasn´t that bad. On the contrary...
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Re: Armour Penetration

Post by Brad Fischer » Fri Oct 16, 2009 1:20 am

Byron Angel wrote: ..... I quite agree with your assessment, Bgile. I don't think anyone else has studied the subject in such depth, had access to the vast amount of original source archival material, or possesses the professional skillset (physics PhD, IIRC) to properly evaluate it. I would definitely consider Nathan to be the best and last word.

Another point in Nathan's favor is that he is objective and displays no nationalistic bias so far as I have been able to observe.


Byron
It should be pointed out too that at least four of them that I know of would defer to Nathan on this particular area of expertise. I know this from my own personal correspondence. Another point that should be made that many authors do not have any formal background in the subjects in which they write. Even the ones that do don’t generally have expertise in every specialized disciplines such as terminal ballistics. In that regard, I do not believe there are any naval historians that do have such expertise in a formal sense.

Brad

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Re: Armour Penetration

Post by Brad Fischer » Fri Oct 16, 2009 1:44 am

Bgile wrote:Your study group idea wasn't ignored, at least not by me; I explained why I was unable to travel to Washington DC to look at archival information. This whole forum is a kind of study group.
You won't find much I'm afraid. While there are literally full stacks that are uncategorized much of what is in the BuOrd files has very little of what you'd expect to find. I've spent several months worth of time in NARA over the years for my projects and haven't found anything of value that hasn't be "found" before.

Brad Fischer

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Re: Armour Penetration

Post by Bgile » Fri Oct 16, 2009 3:24 am

Brad Fischer wrote:
Bgile wrote:Your study group idea wasn't ignored, at least not by me; I explained why I was unable to travel to Washington DC to look at archival information. This whole forum is a kind of study group.
You won't find much I'm afraid. While there are literally full stacks that are uncategorized much of what is in the BuOrd files has very little of what you'd expect to find. I've spent several months worth of time in NARA over the years for my projects and haven't found anything of value that hasn't be "found" before.

Brad Fischer
Rats, that's too bad. Well, maybe saving me some time then. I'd probably still find some fascinating stuff, but not what we are looking at here.

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Re: Armour Penetration

Post by dunmunro » Fri Oct 16, 2009 4:55 am

Bgile wrote:
Brad Fischer wrote:
Bgile wrote:Your study group idea wasn't ignored, at least not by me; I explained why I was unable to travel to Washington DC to look at archival information. This whole forum is a kind of study group.
You won't find much I'm afraid. While there are literally full stacks that are uncategorized much of what is in the BuOrd files has very little of what you'd expect to find. I've spent several months worth of time in NARA over the years for my projects and haven't found anything of value that hasn't be "found" before.

Brad Fischer
Rats, that's too bad. Well, maybe saving me some time then. I'd probably still find some fascinating stuff, but not what we are looking at here.
I just spent a week in DC and 3 1/2 days in the USN Library at the Washington Navy Yard. I found a lot of info regarding my WW2 Naval AA study, including most of the WW2 USN AA studies, and other interesting stuff...

Regarding armour penetration, Nathan Okun probably knows a lot more about it that anyone did in WW2, because he has analysed AP data from every major navy and then synthesized the results into his penetration calculators. Consequently they are probably better than what was available then, even by the experts in that field.

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