1919: Analysis of Hood's magazine protection

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alecsandros
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1919: Analysis of Hood's magazine protection

Post by alecsandros » Fri Jun 07, 2013 6:48 pm

Hello,
I just found a piece of work from 1919. It's an analysis of Hood's defensive scheme against 15" APC shell.

It is absolutely remarkable, especialy the drawing on the bottom of the article...
For me, it is a new paper, maybe some of you already know it...
anyhow,
here it is:

http://www.hmshood.org.uk/reference/off ... 1-9226.htm

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Re: 1919: Analysis of Hood's magazine protection

Post by Djoser » Tue Aug 13, 2013 3:35 am

Very interesting, thanks!

I was just looking for that old thread about the Hood's front magazine also possibly exploding from the blast channeled down the length of the ship. In spite of the bow apparently being blown off, it seems unlikely to me as eyewitness accounts don't seem to verify it.

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Re: 1919: Analysis of Hood's magazine protection

Post by paulcadogan » Tue Aug 13, 2013 9:40 pm

Hi Djoser,

The double explosion hypothesis has long been completely debunked by those in the know - chief among them Bill Jurens - in this and in the Hood forum (which sadly has now passed into internet history).

Even if you look at the wreck you can see that the forward break-up occurred forward of magazines' location (that part of the upturned hull is "intact" - i.e. not blown up). It was purely due to implosive forces as the ship went down.
http://www.hmshood.com/hoodtoday/2001ex ... /index.htm
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Re: 1919: Analysis of Hood's magazine protection

Post by dunmunro » Thu Aug 15, 2013 3:27 am

So a 15in shell could penetrate 7in + 1in HTS of side armour inclined at ~40 degs and still go through a 2in scarf at 10degs and still perforate a 2in deck inclined at 70 degs. This shows how very vulnerable Scharnhorst's deck was to plunging fire and it even implied that Bismarck was vulnerable through her upper 145mm ( 5.7in) belt.

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Dave Saxton
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Re: 1919: Analysis of Hood's magazine protection

Post by Dave Saxton » Thu Aug 15, 2013 2:13 pm

Your comparing apples to oranges. :negative:
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: 1919: Analysis of Hood's magazine protection

Post by dunmunro » Thu Aug 15, 2013 6:21 pm

Dave Saxton wrote:Your comparing apples to oranges. :negative:
Why so?

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Re: 1919: Analysis of Hood's magazine protection

Post by MikeBrough » Thu Aug 15, 2013 7:17 pm

I'm guessing it's down to the difference between 1918 armour and 1930s.

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Re: 1919: Analysis of Hood's magazine protection

Post by dunmunro » Thu Aug 15, 2013 8:31 pm

MikeBrough wrote:I'm guessing it's down to the difference between 1918 armour and 1930s.
We are comparing rather thicker side armour on Hood (~170mm on Hood versus 45mm for Scharnhorst and 145mm on Bismarck) than the KM ships, and the side armour on Hood is being struck at 40 degs inclination rather than ~20 as would be the case on Bismarck or Scharnhorst, and it is being penetrated by a ~1919 vintage AP shell, so all in all, I would say that it exaggerates the protection offered by the 145mm upper belt on Bismarck, even considering the differences in armour quality.

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Re: 1919: Analysis of Hood's magazine protection

Post by alecsandros » Fri Aug 16, 2013 5:16 am

dunmunro wrote:
MikeBrough wrote:I'm guessing it's down to the difference between 1918 armour and 1930s.
and the side armour on Hood is being struck at 40 degs inclination rather than ~20 as would be the case on Bismarck or Scharnhorst, and it is being penetrated by a ~1919 vintage AP shell, so all in all, I would say that it exaggerates the protection offered by the 145mm upper belt on Bismarck, even considering the differences in armour quality.
.. Hood's main belt was declined at 10*, so the impact obliquity was 30* in the drawing.
.. Bismarck's belt near the magazines was declined at angles between 7 - 17*.

I find it rather hard to see how a 15" shell could perforate 95mm of Whotan horizontal armor after passing through the upper belt...

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Re: 1919: Analysis of Hood's magazine protection

Post by dunmunro » Fri Aug 16, 2013 8:41 pm

alecsandros wrote:
dunmunro wrote:
MikeBrough wrote:I'm guessing it's down to the difference between 1918 armour and 1930s.
and the side armour on Hood is being struck at 40 degs inclination rather than ~20 as would be the case on Bismarck or Scharnhorst, and it is being penetrated by a ~1919 vintage AP shell, so all in all, I would say that it exaggerates the protection offered by the 145mm upper belt on Bismarck, even considering the differences in armour quality.
.. Hood's main belt was declined at 10*, so the impact obliquity was 30* in the drawing.
.. Bismarck's belt near the magazines was declined at angles between 7 - 17*.

I find it rather hard to see how a 15" shell could perforate 95mm of Whotan horizontal armor after passing through the upper belt...
The drawing clearly shows that the target's 7in+1in HTS armour was penetrated at 40 degs inclination, and the shell went on to penetrate another 2in scarf, .75in bulkhead and perforated a 2in HTS deck after striking it at 70 degrees inclination.

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Re: 1919: Analysis of Hood's magazine protection

Post by Pandora » Fri Aug 16, 2013 9:08 pm

dunmunro wrote:So a 15in shell could penetrate 7in + 1in HTS of side armour inclined at ~40 degs and still go through a 2in scarf at 10degs and still perforate a 2in deck inclined at 70 degs. This shows how very vulnerable Scharnhorst's deck was to plunging fire and it even implied that Bismarck was vulnerable through her upper 145mm ( 5.7in) belt.
I can't find where in that paper are Scharnhorst and Bismarck mentioned?

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Re: 1919: Analysis of Hood's magazine protection

Post by Pandora » Fri Aug 16, 2013 9:11 pm

dunmunro wrote:The drawing clearly shows that the target's 7in+1in HTS armour was penetrated at 40 degs inclination, and the shell went on to penetrate another 2in scarf, .75in bulkhead and perforated a 2in HTS deck after striking it at 70 degrees inclination.
could all those values be double checked using facehard?

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Re: 1919: Analysis of Hood's magazine protection

Post by dunmunro » Fri Aug 16, 2013 10:38 pm

Pandora wrote:
dunmunro wrote:The drawing clearly shows that the target's 7in+1in HTS armour was penetrated at 40 degs inclination, and the shell went on to penetrate another 2in scarf, .75in bulkhead and perforated a 2in HTS deck after striking it at 70 degrees inclination.
could all those values be double checked using facehard?
Why would we want to double check actual test results against a computer program?

But if you feel so inclined, please do so and give us the results.

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Re: 1919: Analysis of Hood's magazine protection

Post by dunmunro » Fri Aug 16, 2013 10:41 pm

Pandora wrote:
dunmunro wrote:So a 15in shell could penetrate 7in + 1in HTS of side armour inclined at ~40 degs and still go through a 2in scarf at 10degs and still perforate a 2in deck inclined at 70 degs. This shows how very vulnerable Scharnhorst's deck was to plunging fire and it even implied that Bismarck was vulnerable through her upper 145mm ( 5.7in) belt.
I can't find where in that paper are Scharnhorst and Bismarck mentioned?
I can't believe that you are unable to draw the obvious comparisons and conclusions.

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Re: 1919: Analysis of Hood's magazine protection

Post by Pandora » Sat Aug 17, 2013 12:26 am

dunmunro wrote: Why would we want to double check actual test results against a computer program?
to see how accurate that computer program is. You have mentioned facehard several times before to support many of your arguments, so why not?
dunmunro wrote:But if you feel so inclined, please do so and give us the results.
If I asked is because I don't know how to use that software. :(

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