POTD: Big Guns Make Very Big Holes

Nicholas C
by Nicholas C

War History Online posted this photo on their Facebook page.

26-inch thick armor from Japanese Yamato class battleship, pierced by a US Navy 16-inch gun. The armor is on display at the US Navy Museum.

I found this Ballistic Test Report which I believe to be about this specific piece of armor.

Ballistic Tests on the IJN Shinano’s Turret Face ArmorBy 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

Nicholas C
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  • Ed Canupp Ed Canupp on Oct 31, 2016

    That left a mark!

  • Mazryonh Mazryonh on Nov 03, 2016

    Since the photo shows the damage from a 16-inch gun, something which Iowa-class battleships carried 9 of, on a piece of armour intended for a battleship, I think this is a good opportunity to remind readers here of something Admiral Sergei Gorshkov of the Soviet Union once said after seeing the refitted Iowa-class battleships in an exercise in the 1980s:

    "You Americans do not realize what formidable warships you have in these four battleships. We have concluded after careful analysis that these magnificent ships are in fact the most to be feared in your entire naval arsenal. When engaged in combat we could throw everything we have at those ships and all our firepower would bounce off or be of little effect. Then when we are exhausted, we will detect you coming over the horizon and then you will sink us."

    Given what this blog entry shows and Gorshkov's quote, it seems big guns and thick armour on warships are overdue for a major comeback.

    • See 1 previous
    • Mazryonh Mazryonh on Nov 05, 2016

      @Charlie_C The Iowa-class ships are big enough that they can mount more CIWS systems without too much trouble, and they certainly have enough storage space to keep many reloads for them. The only problem is whether the crew can actually reload them in time before the next wave of missiles come in.

      Of course, saturation missile attacks are likely going to become the norm if a full-scale war breaks out. And if that doesn't work, there's always torpedo swarms . . .

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