Perforation of armor plate, 15" and 16" guns

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Perforation of armor plate, 15" and 16" guns

Postby alecsandros » Wed Jan 15, 2014 11:51 am

While trying to do some comparisons between effective perforations of US, German and British 1930s 15" and 16" guns, I came across a disturbing aspect: IF US 16"/L50 was proofed against US Class A armor, THAN it's performance against German and BRitish plate would be at least 10% less able to perforate.

That goes also for the Japanese 18" gun, which was tested against Japanese armor... which in turn was a slight improvement over British WW1-era armor...

If this holds any truth, than on a side by side comparison, against the SAME plate, the German 16"/L50 naval gun would outperform any other gun, in terms of perforation of vertical face-hardened armor.

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Re: Perforation of armor plate, 15" and 16" guns

Postby northcape » Wed Jan 15, 2014 10:17 pm

But there never was a german ship with the german 16" gun, so this thought is a bit academic...

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Re: Perforation of armor plate, 15" and 16" guns

Postby alecsandros » Thu Jan 16, 2014 6:20 am

Perhaps; but they were used as coastal guns.

The odd implication is that the 15"/L52 had probably more perforation than all other contemporaries IF tested against KC n/A, at ranges up to 24km.

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Re: Perforation of armor plate, 15" and 16" guns

Postby northcape » Thu Jan 16, 2014 7:45 am

Where they 16" guns deployed in Norway or in France? If the latter, did they actually fire, e.g. during D-Day? Ah - I think I remember now, - "Batterie Lindemann", right ?

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Re: Perforation of armor plate, 15" and 16" guns

Postby alecsandros » Thu Jan 16, 2014 7:55 am

Yeap :)

They fired against British ships passing through the Channell

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Re: Perforation of armor plate, 15" and 16" guns

Postby Dave Saxton » Thu Jan 16, 2014 2:54 pm

alecsandros wrote: IF US 16"/L50 was proofed against US Class A armor, THAN it's performance against German and BRitish plate would be at least 10% less able to perforate.

the German 16"/L50 naval gun would outperform any other gun, in terms of perforation of vertical face-hardened armor.

That is in keeping with Hoyer and other experts that the most important factor for penetration of face hardened armour is striking velocity, rather than weight. Hoyer also said that the most important factor in the penetration of horizontal homogenous armour is head shape (under the cap) rather than weight. The latter is also confirmed by both British and German firing range data.
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Re: Perforation of armor plate, 15" and 16" guns

Postby Dave Saxton » Thu Jan 16, 2014 3:19 pm

northcape wrote:Where they 16" guns deployed in Norway or in France? If the latter, did they actually fire, e.g. during D-Day? Ah - I think I remember now, - "Batterie Lindemann", right ?

Cheers

Batterie Lindemann was installed between Calias and Cape Griz Nez. It consisted of 4 guns. Other batteries installed in the area were Batterie Siegfried later renamed Batterie Todt consisting of 38cm/52 guns, and Batterie Grosser Kurfuerst consisting of 28cm guns.

These guns were directed by aircraft spotting during the day and by radar at night. Calias B Seetakt sets began directing blind fire to ranges as great as 45km in Aug 1940. The British counter was radar jamming, first exercised in Feb 1941. This first use of radar jamming is told by Howse. A coastal convoy was just getting hammered by the German guns on dark night. As soon as the jammer was switched on the shooting ceased. The German counter counter response was to make Seetakt capable of changing frequency.
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Re: Perforation of armor plate, 15" and 16" guns

Postby alecsandros » Thu Jan 16, 2014 5:09 pm

Dave Saxton wrote: That is in keeping with Hoyer and other experts that the most important factor for penetration of face hardened armour is striking velocity, rather than weight. Hoyer also said that the most important factor in the penetration of horizontal homogenous armour is head shape (under the cap) rather than weight. The latter is also confirmed by both British and German firing range data.

Well, in that case ,
THe Italian 15"/L50 should also be considered.
The problem is I do not know how effective the shell would be against German KC n/A.
In theory, this shell should retain some 560m/s at 20km, 10% more than the German 15"/L52, owing to it's 850m/s initial velocity.

Should this be the case ?

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Re: Perforation of armor plate, 15" and 16" guns

Postby Dave Saxton » Thu Jan 16, 2014 9:14 pm

Yes, the Italian 15" should still have ~560 m/s at 20km. At 20km the Italian gun has virtually the same vertical armour penetration as the German 16"/52 despite less weight and a smaller caliber. Its not to say that such factors as weight and caliber are not important, they are just less important than striking velocity and head shape.

There is discussion included in R&R that is related to your other thread about British thoughts about fighting range. They concluded that for longer fighting ranges a heavy shell of the same caliber held the advantage against vertical armour, but at short and medium fighting ranges a higher velocity gun was better. To illustrate the concept the British were discussing we could compare the USN 16"/45 with the 2700lb shell to the USN 16"/45 with the 2240 lb shell. At 18k yards the older 16"/45 gun with higher MV had superior vertical armour penetration performance by about 5%, but at 28k yards there was no difference, and beyond that range the heavier shell will be superior. This is due to the greater velocity retention of the heavier shell.

Head shape also plays a role as the range increases against vertical armour. As the striking angle increases a blunter head shape will perform bettter and better relative to a sharper head shape. The KGV 14" with a sharp head shape could get equal or better performance compared to 15" and 16" at 12,000 to 16,000 yards battle range, but at 25km it would be inferior. However, due to the lighter overall shell weight, at 25km the 14" gun is getting a steeper angle of fall than a 16" gun of comparable MV. This is due to the lesser velocity retention of the smaller and lighter shell.

That same concept applies to the German 38cm vs the German 16"/52. At 18km the 38cm has within 3.7% the vertical penetration of the 16"/52, but from 25km to 35km it actually has superior deck penetration.
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Re: Perforation of armor plate, 15" and 16" guns

Postby alecsandros » Fri Jan 17, 2014 6:33 am

... I know most of the Italian work concerning battleship proteciton in the 1930s was about designing a proper space array. According to the materials I've read so far, it would appear that the "Littorio" vertical array was satisfactory against shells up to 15" fired at ranges as low as 15km.
However, I do not know how well the individual plates would compare to contemporary foreign plates of the same thickness.

How would the Italian Terni armor compare to the German KC n/A for example , in terms of stoping a BB caliber shell ?

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Re: Perforation of armor plate, 15" and 16" guns

Postby Dave Saxton » Fri Jan 17, 2014 2:30 pm

George Elder did much research on the Littorio design including study of papers by the designer. Elder reported that Italian Terni plates were probably very close to British WWII CA plates. Terni was associated with Vickers and the cemented plates used similar composition to the British plates as well as % of the plate that was face hardened, only to a greater level of hardness right at the face.
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Re: Perforation of armor plate, 15" and 16" guns

Postby alecsandros » Sat Jan 18, 2014 8:49 am

Ah, that would make the 15"/L50 the most powerfull gun for the 0-20km range, with the German 16"/L52 superceding it at all ranges above 20km.

It's interesting to observe that only a few guns with m-v above 800m/s were employed (or prepared) on capital ships during WW2.

Those were:

Italian 15"/L50, 850m/s
French 15"/L45, up to 830m/s
German 15"/L52, official 820m/s
German 16"/L52, official 810m/s

This says alot about the tactics favored by the respective navies, as all guns with high m-v tend to have low deck penetration values in the range interval battles are likely to occur (0-25km), but good and very good belt penetration values in the same intervals.

It's also remarkable that Italy and France could not produce a gun and shell combination that would make their weapons truly effective. Littorio and Richelieu classes suffered from excessive dispersion, rapid gun wear, and a low rate of fire.


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