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Stauffenberg44

A Real Pen on a Real Yamato (Shinano)

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Yes it was click bait, but here you go.

26-inch thick armor from Japanese Yamato class battleship, pierced by a US Navy 16-inch gun:

Spoiler

5a08cdeb72d81_Yamatopen.thumb.jpg.cbf34ecfb69d7c1a66fb41b3ba863d40.jpg

[Any guesses where that is? It looks like a main gun turret to me]

Edited by Stauffenberg44

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You know that was just a test, under ideal test conditions, at ideal angle and ideal range and not actual combat conditions, right?

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7 minutes ago, Lert said:

You know that was just a test, under ideal test conditions, at ideal angle and ideal range and not actual combat conditions, right?

Yes thanks, I think just everybody knows she was sunk under air attack, right?

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As Lert said, ideal conditions. Though I do think USN 16" AP could have made a real mess of the Yamato.

 

What is the armor from? It can't be the Yamato, as she was sunk in deep water (and exploded as she sank). Musashi was also sunk, but in shallow enough water to salvage something maybe? Or is it a piece from uncompleted work?

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3 minutes ago, AJTP89 said:

As Lert said, ideal conditions. Though I do think USN 16" AP could have made a real mess of the Yamato.

Speaking purely of armor slabs of this thickness, at some ranges, yes. Problem would be getting to those ranges in a good enough shape to put warheads on foreheads.

3 minutes ago, AJTP89 said:

What is the armor from?

Probably a spare piece. Three Yamato hulls were laid down, two were finished as battleships, one as carrier.

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I think it was from the Shinano:

Spoiler
Ballistic Tests on the IJN Shinano's Turret Face Armor

By Nathan Okun
Updated 31 August 1999


SOURCE:

U.S. NAVAL PROVING GROUND, DAHLGREN, VIRGINIA, REPORT #5-47, "BALLISTIC TESTS AND METALLUGICAL EXAMINATION OF JAPANESE HEAVY ARMOR PLATE" (November 1947)

SUBJECT:

Test of 26" (66cm) Class "A" Main Armament Turret Face (Port) Plate, originally for IJN SHINANO, the third Japanese YAMATO-Class super-battleship (converted into an aircraft carrier, instead, and sunk on its way to final fitting out yard by a U.S. submarine), which made up far left side of turret face looking from inside turret out of gun port, with "D"-shaped cutout making up about half of left curved gun port forming center of long right side of plate.

PLATE MATERIAL:

Japanese Vickers Hardened (VH) face-hardened, non-cemented armor (used only on YAMATO-Class battleships)

COMPOSITION OF STEEL:

ELEMENT.....PERCENT (By Weight)

CARBON-------0.48
MANGANESE----0.39
PHOSPHORUS---0.016
SULPHUR------0.026
SILICON------0.18
NICKEL-------3.67
CHROMIUM-----2.13
MOLYBDENUM---0.06
COPPER-------0.12

*****************

TENSILE TEST (SLOWLY INCREASING PULL) DATA:

COUPON_ Y.S._ T.S.__ %EL._ %R.A

LONG.__ 68.5_ 99.4__ 22.3_ 45.6
TRAN.__ 70.1_ 98.2__ 25.5_ 62.2
NORM.__ N/A__ 93.16__ 7.0_ 20.3
(Average of 6 coupons)

CHARPY V-NOTCH IMPACT DATA VS TEMPERATURE (°F):

COUPON# -105 -78 -50_ 0__ 50_ 100 <-TEMP.

LONG.#1_ 10G 23G 35G 73FG 75F 95F
LONG.#2_ 14G 20G 31G 77FG 94F 80F
TRAN.#1__ 8G 20G 30G 56FG 73F 70F
TRAN.#2__ 9G 20G 26G 48FG 71F 69F

DEFINITIONS:

LONG.=Longitudinal (parallel to plate face; long plate axis direction)
TRAN.=Transverse (parallel to plate face; short plate axis direction)
NORM.=Normal (in thickness direction)
Y.S.=Yield Strength (x1000 lb./sq.in.)(0.2% elongation point) (sq.in.=original cross-section)
T.S.=Tensile/Ultimate Strength (x1000 lb./sq.in.)
%EL.=PERCENT ELONGATION (% coupon had stretched when it broke)
%R.A=PERCENT REDUCTION IN AREA (% coupon cross-sectional area had shrank by at narrowest when it broke)

(Above data averaged from two coupons in each direction)

CHARPY V-NOTCH TEST=Hammer snaps off one end of coupon while other end is held in a vise with a notch-shaped groove put into coupon just above vise grip where coupon will fold and split apart (the higher the number, the greater the toughness)
"G"=All GRAIN (brittle fracture) at break point
"F"=All FIBER (ductile tearing) at break point
"FG"=Both GRAIN & FIBER MIXED at break point, more FIBER than GRAIN

********************

HARDNESS (ROCKWELL "C"):
(Ave. of two tests; measured from plate face surface directly into plate)

SURFACE:_46.5 (Tempered surface lost some carbon)
0.75":___50.0 (Maximum hardness of plate)
5.00":___36.0 ("Undrillable" face ends and transition layer begins)
9.25":___15.0 (Inner edge of back layer reached)

Hardness varied in smooth "ski-slope" curves between these points--at 0.75" hardness increase reversed direction abruptly. Back hardness varied from ROCKWELL "C" 11.0 to 15.5 in long undulations to back surface.

**********************

STEEL QUALITY:

Steel had many tiny pieces of dirt and so forth, being about the same as pre-WWI British Vickers Cemented (VC) KC-type armor steel in quality (VC was used for the first time in the Japanese battleship IJN KONGO, built in Britain, and manufactured in Japan under license thereafter), from which the unique Japanese armors New Vickers Non-Cemented (NVNC), the homogeneous, ductile form of VH used in a number of Japanese post-WWI warships, and VH itself was derived (this steel was not up to U.S., British, or German post-1930 steel quality). Carbon content was raised above VC steel level to increase ease of hardening, some copper added to allow some nickel (in short supply in Japan) to be removed (but not much), slight amount of molybdenum added to increase hardenability still more, and the cemented (carburized) thin surface layer used in VC (and in most other, foreign face-hardened armors) was eliminated with no loss of resistance from VC quality (a good design point). Surface of plate face was very smooth, unlike rough, pebbly surface of cemented plates, such as U.S. Navy Class "A" armor.

http://www.navweaps.com/index_tech/tech-040.htm

"Test of 26" (66cm) Class "A" Main Armament Turret Face"

Wrong ship (same Yamato-class) but I got the location right it seems.

Edited by Stauffenberg44
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30 minutes ago, Stauffenberg44 said:

Yes thanks, I think just everybody knows she was sunk under air attack, right?

I have the CD Movie YAMATO with English subtitle when you watch the film it's kind of sad these young men new that they were going to their death with just enough fuel to make it to Okinawa 3000 souls went down with that ship

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15 minutes ago, Eric_Von_Hess said:

I have the CD Movie YAMATO with English subtitle when you watch the film it's kind of sad these young men new that they were going to their death with just enough fuel to make it to Okinawa 3000 souls went down with that ship

Yes very.

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56 minutes ago, Stauffenberg44 said:

Yes thanks, I think just everybody knows she was sunk under air attack, right?

Wasn't Shinano torped by a sub? 

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53 minutes ago, AJTP89 said:

As Lert said, ideal conditions. Though I do think USN 16" AP could have made a real mess of the Yamato.

 

What is the armor from? It can't be the Yamato, as she was sunk in deep water (and exploded as she sank). Musashi was also sunk, but in shallow enough water to salvage something maybe? Or is it a piece from uncompleted work?

It was a plate that was either removed or never mounted to Shinano from a shipyard in Japan that the US DOD took and basically put right in front of a 16"/50 gun at a test range. 

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7 hours ago, Stauffenberg44 said:

Yes it was click bait, but here you go.

26-inch thick armor from Japanese Yamato class battleship, pierced by a US Navy 16-inch gun:

  Reveal hidden contents

5a08cdeb72d81_Yamatopen.thumb.jpg.cbf34ecfb69d7c1a66fb41b3ba863d40.jpg

[Any guesses where that is? It looks like a main gun turret to me]

It is displayed at the US Navy Proving Ground Dahlgren Virginia and was a test of Japanese armor intended for the turret faces of Shinano found at Kure versus the 16"/50 gun and 2700 lbs. AP round.  The piece is said to be 26" (probably 25.6") thick.  

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16 hours ago, Show_Me_Your_Cits said:

It was a plate that was either removed or never mounted to Shinano from a shipyard in Japan that the US DOD took and basically put right in front of a 16"/50 gun at a test range. 

Ok, thanks. I was wondering how long it took them to hit something that small at a reasonable range. But muzzle velocity isn't exactly field conditions, heck, a 5" AP would probably go through that close.

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45 minutes ago, AJTP89 said:

Ok, thanks. I was wondering how long it took them to hit something that small at a reasonable range. But muzzle velocity isn't exactly field conditions, heck, a 5" AP would probably go through that close.

 

I don't think it would. I don't have the penetration values in front of me but that's a 660mm plate of armor. Some battleship guns don't even have that at the muzzle. 

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Just now, Show_Me_Your_Cits said:

 

I don't think it would. I don't have the penetration values in front of me but that's a 660mm plate of armor. Some battleship guns don't even have that at the muzzle. 

I was exaggerating. The point was the test was highly unrealistic.

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2 hours ago, AJTP89 said:

I was exaggerating. The point was the test was highly unrealistic.

Actually, the test wasn't about penetration but to test the quality of the armor itself.  It wasn't about some self flagellating pat on the back "Oh, look how much armor our sixteen inch gun will penetrate!" but rather about seeing what the quality of armor the Japanese were using and making.  That's what the report cited in Stauffenburg44's post shows.

If you look carefully at the OP photo, you can see a number of small holes in the plate below where the shell penetrated.  Those are almost certainly drill holes to extract metal samples for testing of the plate.

Oh, and it wouldn't matter what the range between the gun and plate was.  The Dahlgren plate testing battery would have simply reduced the charge on the gun to get the desired striking velocity on the shell for the test.  I don't know off hand what velocity they used on that plate.

Edited by Murotsu

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1 hour ago, Murotsu said:

Actually, the test wasn't about penetration but to test the quality of the armor itself.  It wasn't about some self flagellating pat on the back "Oh, look how much armor our sixteen inch gun will penetrate!" but rather about seeing what the quality of armor the Japanese were using and making.  That's what the report cited in Stauffenburg44's post shows.

If you look carefully at the OP photo, you can see a number of small holes in the plate below where the shell penetrated.  Those are almost certainly drill holes to extract metal samples for testing of the plate.

Oh, and it wouldn't matter what the range between the gun and plate was.  The Dahlgren plate testing battery would have simply reduced the charge on the gun to get the desired striking velocity on the shell for the test.  I don't know off hand what velocity they used on that plate.

Per Ballistic Report 5-47, the plate was secured 400 feet from the gun for testing. Due to the fact no plate of such thickness had been produced by the US at the time, they ran the test at full charge to attempt to check the VL= limit of the plate. 2 Shots were fired. One partially penetrated, and one fully penetrated.

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1 hour ago, Azumazi said:

Per Ballistic Report 5-47, the plate was secured 400 feet from the gun for testing. Due to the fact no plate of such thickness had been produced by the US at the time, they ran the test at full charge to attempt to check the VL= limit of the plate. 2 Shots were fired. One partially penetrated, and one fully penetrated.

But, it still doesn't matter what the range was per se.  They could have reduced the charge and velocity if they wanted to test, say penetration at a particular range instead.  However, it looks like they wanted to test the limits of the armor here and full and partial penetration would have done that.  So, the test really wasn't about whether US Naval guns could smash a Yamato so much as it was about testing the quality of the armor and a plate that thick.

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8 hours ago, AJTP89 said:

I was exaggerating. The point was the test was highly unrealistic.

The only thing unrealistic about it was the angle at which the shell hit, almost 0* obliquity.   They reduced the charge to make the shell velocity roughly 1900 fps, which is  between 10-15,000 yards, or 7-8-ish miles.  

The range at which the test took place doesn't matter, as they can simply adjust muzzle velocity to duplicate the penetrating power of whatever range they are trying to test for.  They don't have to physically place the armor 10 miles (or whatever is needed) away and shoot until they hit it at full power.   So while it was conducted physically at point-blank range, the striking velocity was the same as 8 miles away.  

It's still very impressive.  

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1 hour ago, JuiceEFruit said:

The only thing unrealistic about it was the angle at which the shell hit, almost 0* obliquity.   They reduced the charge to make the shell velocity roughly 1900 fps, which is  between 10-15,000 yards, or 7-8-ish miles.  

The range at which the test took place doesn't matter, as they can simply adjust muzzle velocity to duplicate the penetrating power of whatever range they are trying to test for.  They don't have to physically place the armor 10 miles (or whatever is needed) away and shoot until they hit it at full power.   So while it was conducted physically at point-blank range, the striking velocity was the same as 8 miles away.  

It's still very impressive.  

The charge was only reduced on the 2nd and 3rd impacts, and yes it got hit by 3 shells since the first impact broke the plate the first time so they conducted the next test on just the second larger half and used the first section for the v-sharpy and impact tests for further cutting. Ironically they didn't reduce the velocity for realistic effect, but because they found that the shell literally went some 22 feet into the sand bar behind the plate due to the kinetic energy retention of the Mark 8 projectile at full velocity. Why it's Ironic? They still opted to not dig out the projectile on the 1992fps test to check body damage on a complete penetration.

1. First impact test had it at 2371fps off the oscillograph measuring the magnetized shell impact. 0 degree impact for complete penetration. Shell was not recovered

2. First impact on larger broken section of plate at 1992 fps also broke the plate in half with a complete penetration. Shell was not recovered.

3. Second impact on second section at 1707 fps for incomplete penetration with 20 inches of depth on penetration. Plate split and formed a full section crack running lengthwise up the entire plate; however, it did not entirely separate until they went to remove the projectile. Projectile was recovered and deemed to be effective and intact with a body bent at mid section point near the filler. Body did not form a complete rupture which would have allowed the fuse to properly set off the charge.

 

Edit: I actually forgot about this. It's also actually one of the few times in testing you get to see the Naval Penetration curves matching up with an actual test, as the listed penetration at 0 degrees for the 16"/50 Mark 7 gun with the Mark 8 AP shell was 20.03" at 1700-1740fps and the test literally landed a 20" pen at 1707fps.

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There were only 2 tests of the 26" armor.   One at 1992 fps, and one at 1707 fps.  The 1992 velocity test (the first one) is the one that broke the plate in two.  Muzzle velocity of a 16" 50 caliber with AP shells is 2500 fps. 

Nowhere in the report do they state they used a full or reduced charge, (not that I saw, anyway) but given the test was conducted at near-point blank range both tests had striking velocities of 1992 and 1707, they clearly did not use a full charge.  

1992 fps is roughly what striking velocity at a bit over 5 miles would have been.  That's the one that broke the plate.  It was never recovered.  In the report, they had 2 pictures of this one, which might be why you think there were 3 tests. 

1707 fps is what the velocity is at almost 12 miles, which is the one that holed the plate, while also breaking the plate into 2 pieces.  

So the plate broke both times, that's why the hole isn't a hole and more of a crescent moon shape. 

Edited by JuiceEFruit

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The first test isn't in the initial report, but since I've worked at Aberdeen and seen the microfilm reports on the sectional plates I've also seen the Oscillograph's microfilm reports on the readings. The first firing wasn't reported in the 5-47 report.

As for why it wasn't reported, they don't leave any mention in the Oscillograph reports nor in the metallurgy reports. Only reason I know about the first shot is that I was looking for reports on the Experimental 15'' plate that Nathan Okun hasn't been able to find much about as the US did their own sectional cut from it for testing before shipping it off to the UK for their own impact testing of that plate.

 

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