In previous articles (About the durability of Russian armor during the First World War и On the durability of Russian naval armor in the context of the tests of 1920) I, on the basis of an analysis of experimental firing in 1913 and 1920, came to the conclusion that the durability of cemented Russian armor installed on battleships of the "Sevastopol" type was characterized by a "K" coefficient equal to 2005.
Let me remind you briefly that this coefficient is one of the variables of de Marr's armor penetration formula. And in more detail about him described in previous articles.
But before starting a conversation about German armor, it is necessary to say a few words about this.
On criticism of the method for determining the resistance of Russian armor
As mentioned earlier, I am building this series of articles in the format of a dialogue with dear readers. And I always carefully study the comments to my articles. I should note that so far I have seen only one objection to my assessment of the resistance of Russian armor. And it consists in the following.
Often, the impact of a shell on the armor caused serious damage to the latter in a certain radius from the point of impact.
So, for example, as a result of one of the hits of a 356-mm projectile in 270 mm armor on tests in 1920
"The cemented layer bounced at a diameter of 74 * 86 cm."
Therefore, personally, I do not see anything surprising in the fact that two of our "suitcases" with a caliber of 305 mm, hitting 69 cm and a meter from the nearest hit points of previous shells, showed reduced armor resistance ("K" is less than or equal to 1862) ...
However, one of my readers said that "on diameters" is still not "in radius". Consequently, both 305-mm shells did not hit the damaged layer of armor. And, since the shells hit the armor plate in places where the observers did not notice the presence of damage, then in such places the armor had to show its inherent resistance, that is, "K" = 2005.
And since this did not happen, it means that the real strength of Russian armor - "K" is no more than 1862.
I cannot agree with this approach. And that's why.
When each projectile hit, the armor plate experienced a very strong physical impact. So, for example, when a 356-mm high-explosive projectile with explosives hit (exploded on the armor, knocking out the plug), the plate received changes in geometric dimensions: it bent, and the deflection arrow in the area of the hole reached 4,5 inches, and the lower and upper edges of the armor plate rose by 5 and 12 mm, respectively. At the same time, the observers did not notice any damage around the impact site, but, despite this, the plate still bent.
Could such effects not affect the overall strength of the armor?
Can we say that outside of the visible damage by type
"A series of concentric cracks and gouges at diameters of about 50-60 cm"
did the armor fully retain its protective properties?
As for me - in no case is it possible.
Let's not forget that Krupp's armor, thanks to a special hardening (cementation) procedure, was, in fact, two-layer. The upper layer was made of more durable, but at the same time more fragile armor. And behind it was already a less durable, but more viscous layer of armor steel.
When hit, the armor could well delaminate ("the cemented layer bounced off at a diameter of 74 * 86 cm"). And it would be completely logical to assume that this layer received damage, microcracks. Also outside the radius of visible damage.
In other words, if damage to the armor is noticed within a radius of 30 cm from the hole made by the projectile, this does not mean that beyond these 30 cm the armor has remained unchanged. The physical impact of a projectile, even not loaded with explosives, could lead to partial delamination of the cemented layer, microcracks (etc.) inside the armor. And they, of course, reduced the strength of the slab by weakening it.
Of course, this attenuation certainly decreased with distance from the point of impact. But the fact that the armor to some extent (by about 7,1%) lost its protective properties at a distance of 70-100 cm from the place of the projectile hit - in my opinion, there is nothing surprising.
Under fire - traditional German quality
To my deep regret, there is relatively little data on the actual shelling of German armor plates.
And those that exist are extremely uninformative. Due to the fact that during these attacks, no one tried to determine the ultimate armor resistance of German armor.
As a matter of fact, there is information about two such attacks.
Information about one of them is given in the book by T. Evers "Military Shipbuilding".
In addition, there is also information about the shelling of the captured German battleship Baden by British 381-mm Greenboy shells.
A complete list of shots is given in the book of the respected S. Vinogradov "Superdreadnoughts of the Second Reich" Bayern "and" Baden ". But, unfortunately, it contains a number of inaccuracies.
Of course, you can remember the famous Battle of Jutland, in which German ships received many hits from 305-mm, 343-mm and 381-mm shells of the British. But, sadly enough, it is absolutely impossible to draw any conclusions on the basis of the combat damage of the German ships.
First, the British themselves admitted that the quality of their armor-piercing shells used at Dogger Bank and in the Battle of Jutland was very, very low. That is why they subsequently hastily created a new type of armor-piercing shells (the "Greenboy" program).
Thus, if in some situation the British shell did not penetrate the armor, this can be attributed to the quality of the shell itself. However, for the most part, British shells did not penetrate German armor due to premature rupture. Since their tubes were set for minimum deceleration. As a result, the description of German damage is replete with situations when, for example, 343-mm shells exploded when overcoming 230 mm of armor, which a normal armor-piercing shell of this caliber should have easily penetrated at that distance.
In addition, there is another aspect that makes it extremely difficult to assess the durability of armor by its damage in battle.
Usually the maximum that can be reliably known is the caliber of the projectile and the thickness of the armor it hit. Although errors are already possible here. Since historians can sometimes confuse the calibers of the shells.
More or less accurately, you can find out the distance from which the projectile was fired. But the angle at which the projectile hits the armor, as a rule, cannot be accurately determined. But this is an extremely significant amendment.
So, for example, the German 305-mm / 50 gun "Derflinger" at a distance of 80 cables could well penetrate 254 mm armor plate with "K" = 2 - but only if this armor plate was in an ideal position. So, the angle of deviation from the normal is determined only by the angle of incidence of the projectile (000 degrees).
However, if the fired ship is at an angle to the Derflinger so that the deviation from the normal when hitting the armor is 30 degrees, then the projectile will be able to overcome only 216 mm.
At the same time, the difference in the position of the ships is sometimes extremely significant - for example, in the battle at Dogger Bank, when the British battle cruisers were catching up with the German ones, being in a parallel wake column, far behind the German formation. Here German shells hit the British armor belts at a very acute angle.
So it should come as no surprise that even a relatively weak 229 mm armor
"Admiral Fischer's cats"
such hits could well withstand.
The shelling of "Baden"
The British monitor "Terror" fired at the German battleship.
The purpose of the tests was to check the quality of the British shells. And the parameters of the shelling were selected in such a way as to correspond to the distance of effective fire combat, by which the British after the First World War understood 75-80 cables.
Accordingly, the charge of the "Terror" guns was selected in such a way that the speed of the projectile on the armor was 472 m / s. The British believed that this corresponds to a distance of 77,5 cables.
This was the correct methodology for testing the effectiveness of British shells. Because according to the results of these tests, the British saw in practice the results of shelling with armor-piercing, semi-armor-piercing and high-explosive 381-mm shells of various parts of the German heavy ship at a typical battle distance for that time.
But for determining the quality of German armor, these tests, alas, are of little use. The thing is that the British armor-piercing projectile with a deviation from the normal 18 deg. had to overcome as much as 364 mm of armor plate, the armor of which, with a thickness of less than 300 mm, would have "K" = 2000.
Accordingly, only 350 mm German vertical armor had any chance of holding the British shells. And everything that had a smaller thickness made its way a priori.
In total, during the shelling on February 2, 1921, 350 shots were fired at the vertical 4 mm armor of the battleship "Baden", mixed with firing at other parts of the ship.
Below I will indicate the serial number of the shot.
I will note that the calculations of "K" were made by me with an adjustment for an unequal increase in the durability of the armor with an increase in the thickness of the armor plate over 300 mm.
Shot number 9. Armor-piercing projectile, hitting the barbet of the 3rd tower at an angle of 11 degrees. The fuse went off when the projectile passed about 2/3 of the armor plate. If we assume that the British projectile was unable in this case to overcome the 350 mm obstacle, this would indicate that the "K" of German armor is 2107 or higher. But the problem is that the fuse could be triggered prematurely, which is why, in fact, the armor plate was able to reflect the blow.
Shot number 10. A high-explosive projectile, hit the barbet of the second tower at an angle of 12 degrees, exploded on impact. There is nothing surprising in this. It is impossible to expect such powerful protection from a high-explosive projectile. So this shot cannot help in any way in determining the quality of German armor.
Shot number 14. An armor-piercing projectile hit the 350 mm frontal armor plate of the 2nd tower at an angle of 18 degrees, pierced it and exploded inside. As you can see, the conditions were worse than shot No. 9. But the armor was still broken. According to this shot, the "K" of German armor was 2041 or lower.
Shot number 15. An armor-piercing projectile, hit the 350 mm armor of the conning tower at an angle of 30 degrees. The armor was not pierced, there was only a pothole. There is nothing surprising in this - with such a deviation from the normal, the projectile had no chance to overcome such protection. The shot indicates only that "K" in this case turned out to be equal to 1860 or higher.
In general, it can be stated that the shelling of "Baden" gave too little statistical data.
We have two cases where the British shells met the German armor in conditions close to the maximum armor penetration: we are talking, of course, about shots No. 9 and No. 14. In the first case, "K" turned out to be equal to or higher than 2107, in the second - equal or lower 2041. The data obviously contradict each other. So I can only state the existence of two versions.
If at shot No. 9 the projectile fuse worked normally, then the durability of German armor should be determined somewhere in the range from 2041 to 2107;
If at shot No. 9 the projectile fuse was triggered prematurely, then the "K" of the armor of the battleship "Baden" is 2041 or lower.
Let us now analyze the data given by T. Evers.
Trial firing of the German fleet
There is almost nothing at all for analysis.
Honestly, I do not understand at all why the Germans were shooting at 200-300 mm armor at a speed of 580 to 700 m / s at the time of impact.
It is possible, of course, that the German sailors were interested in the angles of the ricochet - at the same 200 mm, the shot was fired with a deviation from the normal 30 degrees. But even in this case, one could safely count on the breakdown of the 388 mm thick armor plate ...
In fact, from the entire table given by T. Evers, only firing at 450 mm armor plate is of interest, into which a projectile weighing 734 kg hit with zero deviation from the normal. That is, exactly under 90 degrees. to the surface of the plate at a speed of 551 m / s. At the same time, the shell not only pierced the armor, but also flew 2530 m into the field.
Taking into account the decrease in the resistance of the armor with an increase in its thickness, the armor plate actually exposed to 450 mm shelling will correspond to the calculated one, 401 mm thick.
Thus, if the German armor had been penetrated by 734 kg by a projectile at the limit of its capabilities, it would have shown "K" = 2075. But in fact, the projectile "flew" as much as 2,5 km behind the armor, we see that the projectile is still far has not exhausted his capabilities. And that the real K was well below 2075.
I can only conclude that under the most positive assumptions for German armor, its "K" was 2041 or lower.
In other words, the German Krupp cemented ship armor was as much as 1,8% stronger than its Russian counterpart, which had a "K" coefficient (according to our earlier calculations) equal to 2005. But taking into account not too extensive statistics, one should rather talk about the fact that Russian and German armor had approximately equal resistance to shells.
There is one more important aspect.
Comparing the protective properties of the armor, we compare the Russian pre-war armor with the armor of the last German superdreadnoughts Bayern and Baden. And she, according to some reports, was improved relative to the one that was used in the construction of the German battleships of the previous series and, of course, battle cruisers.
Consequently, it cannot even be ruled out that the German armor plates, which defended the "Konigi", "Moltke" and "Derflingers", had slightly less durability than those that were installed on battleships of the "Sevastopol" class.
What could refute these considerations?
It can be assumed that the British and German shells were better and stronger than the Russian 305-mm 470,9 kg "suitcases".
But, generally speaking, almost all sources claim that the Russian shells were of very high quality.
Moreover, studying the data of T. Evers, one can even doubt the quality of the German shells. So, a 380-mm German high-explosive projectile with a cap hit 170 mm armor at an ideal angle (90 degrees, that is, without deviating from the normal) at a speed of 590 m / s. Note that in terms of the specific content of explosives (8,95%), this projectile occupied an intermediate position between the Russian armor-piercing (2,75%) and high-explosive (12,49%).
It is clear that the smaller the explosive charge, the stronger the walls of the projectile. And the German land mine cannot be called thin-walled. However, he was unable to overpower armor with a thickness of only 45% of its own caliber.
In our country, smaller-caliber high-explosive shells hit 225 mm armor, exploding in the process of overcoming it. Of course, a single example cannot claim to be a rule in any way. But (from the available statistical material) we have no reason to consider the German shells superior in quality to the Russian - adjusted for calibers, of course.
Of course, all of the above is not solid proof.
We can be more or less confident in the strength of Russian armor. But to assess the German statistical material is still not enough.
However, there is one more, indirect confirmation that the German cemented armor of the First World War, if it had a coefficient of "K" over 2000, then very little.
The fact is that T. Evers in his "Military Shipbuilding" already mentions a new generation of Krupp's cemented armor, which, among other things, was used in the creation of the battleship "Bismarck".
Below is a copy from The Battleship Bismarck: Anatomy of the Ship (Jack Brower).
As you can see, the compositions of the armor are identical.
What follows from this?
The fact is that T. Evers in his book proposes to use de Marr's formula (which I also use) with the coefficient "K" (in his book, this is the coefficient "C") equal to 1900 for non-cemented and 2337 - for cemented slabs.
It is quite obvious that this factor should be used specifically for the latest types of armor.
Thus, we see that the increase in durability of the famous German armor in comparison with the Russian and German armor of the First World War (if we consider them equivalent) is only 16,6%.
If we assume that the German armor of "König" and "Derflinger" was still superior to the Russian one by at least 10 percent, it turns out that the next generation of German armor, created 20 years later, turned out to be only 5-6% better than the previous one.
Of course, such an assumption looks extremely dubious.
Based on the foregoing, I think it would be correct to assume the approximate equality of the quality of Russian and German armor of the era of the First World War.
In all subsequent calculations, I will calculate the armor penetration for both the Russians and the German guns with a "K" factor of 2005.
To be continued ...