As you know, a human hobby is a very diverse thing: what people are not fond of. They collect beetles, grow flowers, create huge houses of cards, draw, solve crosswords, play computer games, etc.
We can only state that for a pleasant pastime, humanity has come up with a lot of different activities. But even the same hobby can be practiced with different intensities. It will be enough for one lover of computer games to drive some shooter for half an hour after work in order to relieve stress without particularly straining. Another - will spend hours looking for the best way to level up the character, keeping in mind dozens of parameters of the role-playing system.
All this is neither good nor bad, it does not indicate the depth of the mind, or, conversely, about its absence. It's just that each of us chooses not only the type of activity to our liking, but also the depth of immersion in it.
So, not all of those who would like to read about the comparison of German battlecruisers and Russian dreadnoughts are interested in understanding certain nuances of armor penetration formulas, to study individual hits on tests, etc. This, I repeat, is neither good nor bad, everyone has the right to determine the level of history study that is comfortable for him.
Therefore, for those of you, dear readers, who are not interested in wading through the jungle of formulas and coefficients, I will immediately report the conclusions I came to during the preparation of the article.
conclusions
In a previous article, I made the assumption that the "K" of Russian cemented armor had a value of 2005. However, when firing a compartment protected by 270 mm armor, individual hits showed significantly lower armor resistance, since "K" fell to 1862 or lower. In another case, on the contrary, the "super strength" of the armor plate was demonstrated, since the value of "K" when hit reached 2600.
The analysis of hits showed the following: the cases when this coefficient turned out to be lower are fully explained by the damage received by the armor plate as a result of previous impacts. In other words, this happened when the projectile hit the armor plate at a relatively small distance from the previous hits. At the same time, the case when "K" turned out to be significantly higher than the 2005 value can be explained by the fact that not an armor-piercing, but only a semi-armor-piercing projectile was used, which had a smaller wall thickness, and, consequently, strength.
But the 370-mm armor did not live up to expectations. The "K" coefficient for a 370-mm plate is very unambiguously determined not more than 1800-1820, or even worse, which is obviously inferior to the durability demonstrated by a thinner 270-mm armor plate.
Why could this happen? As you know, the Russian industry before the First World War could not mass-produce cemented armor plates with a thickness of more than 270-275 mm. Accordingly, the 370-mm armor plates created for testing were piece products and technologically not worked out. Therefore, despite assurances that the 370-mm armor plate fully meets all the requirements for it, most likely it failed. And even adjusted for the drop in durability with an increase in the thickness of the armor over 300 mm, it still had a coefficient "K" lower than the 225-270-mm slabs created for Russian dreadnoughts.
In general, based on an analysis of the results of tests of Russian armor in 1914 and 1920.it will be legitimate to use the coefficient "K" equal to 2005 in further calculations for it.
Well, that's all.
And those readers who do not want to understand the peculiarities of each hit can safely postpone this material, because they will not find anything important for themselves in it anymore.
Well, for those who are interested in the nuances …
Test compartments
In total, 2 compartments were prepared for testing, simulating the compartments of the battleship behind the main armor belt. The first compartment was protected by frontally located 4 armor plates, each of which had a thickness of 270 mm. The manufacturer was either an Arab or a big joker, so the numbering of the armor plates went from right to left. If you look from left to right, then the numbering of 270-mm armor plates was as follows: 1b; 2a; 2; 1.
Of course, the protection was not limited to "frontal" armor. For armor plates No. 1 and No. 2 there was an armored bulkhead and bevel made of 75-mm cemented armor. Behind armor plate No. 2a, the bevel had a variable thickness - 75 and 100 mm, while the armor bulkhead was 75 mm. Behind the armor plate 1b, the bevel was 100 mm, the armor bulkhead was 75 mm.
Compartment No. 2 also consisted of 4 armor plates, two of which were 320 mm thick, and two more - 370 mm. For some reason they were arranged in a checkerboard pattern. In order not to confuse the dear reader, I give their numbering and thickness according to the arrangement from left to right: № 6 (320 mm); No. 4 (370 mm); No. 5 (320 mm) and No. 3 (370 mm).
The second protection circuit was simple: behind the 370-mm armor plates there was a 12-mm bulkhead and a 50-mm bevel of uncemented armor, while behind 320-mm armor plates there was a 25-mm bulkhead and a 75-mm bevel, the latter being made of cemented armor plates …
All 270-mm, 320-mm and 370-mm armor plates had a standard size of 5, 26x2, 44 m.
In total, according to the test logs, 29 shots from 356-mm and 305-mm guns were fired at these compartments. In addition, four more 356-mm projectiles were suspended inside the compartments and detonated (one detonation, however, was not very successful) to study the damage from the explosion of a large-caliber projectile in the armor-plated space. Moreover, all the explosions and 26 shots were fired during 1920, and the last 3 shots were fired only in 1922.
The data of the Journal No. 7 dated July 9, 1920 are of the greatest interest for our analysis. The fact is that the purpose of this type of test was precisely
"Determination of the maximum speed with which an armor-piercing 12-inch projectile is penetrated by 270-mm side armor with a set behind it", as well as the maximum penetration of the projectile for 370-mm armor plate. During this part of the tests, 270-mm armor plate No. 1 and 370-mm armor plate No. 3 were fired upon.
Below we will consider a complete list of the impacts that these 270 and 370 mm armor plates were subjected to.
Results of shelling 270-mm armor plate No. 1 with 356-mm shells
A feature of the tests of this plate is that before the start of testing 305-mm projectiles, it was fired at with fourteen-inch shells and received 5 hits. The shells were of different types, with and without explosives, their speed also varied, but there was something in common - they all hit the armor plate at an angle of about 60º to the surface, that is, the deviation from the normal was 30º in all cases.
The first hit was a high-explosive 356-mm projectile containing a full explosive charge. The energy from the impact and detonation was enough to pierce the 270-mm armor through and through, although the plug did not go through the skin behind the armor. The plate bent: 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. Place of impact (as indicated in the report): 157 mm from the bottom and 157 mm from the right edge of the slab.
The second hit was a semi-armor-piercing 356-mm projectile without explosives at a speed of 446.5 m / s. The armor was not pierced, only a pothole with a diameter of up to 30 cm and a depth of 23 cm turned out. However, the cemented layer of armor received
"A series of concentric cracks and gouges at diameters of about 50-60 cm."
The point of impact is 237 cm from the bottom edge and 173 cm from the right edge of the slab.
The third hit was a semi-armor-piercing 356-mm projectile without explosives at the same speed of 446.5 m / s. Obviously, all other things being equal (the same speed and angle of incidence of the projectile, the thickness of the armor plate), one would expect a commensurate effect with the second hit. However, it turned out differently - the semi-armor-piercing projectile not only passed the 270-mm armor plate, but also broke an oval piece of the bulkhead made of 75-mm cemented armor measuring about 60 by 40 cm, and was found only 100 fathoms (about 230 m) behind the compartment. Place of impact - 239 mm from the bottom and 140 cm from the right edge of the armor.
If we calculate de Marr's armor-piercing ability for an armor-piercing 356-mm projectile with the corresponding tip for the above parameters and the coefficient "K" = 2005, then it should have penetrated a 270-mm armor plate at the limit of its capabilities. After that, maintaining a speed of about 73 m / s, he could barely overpower 28 mm of uncemented armor. It is easy to see that the results of both hits do not match the calculated data. But why?
Perhaps, of course, the whole point is in the inaccuracy of the Jacob de Marr formula: we see that the calculation gave some intermediate value, and one shell "did not reach" the calculated result, and the second exceeded it. But still, the scatter of results is too large to be attributed to the probabilistic nature of the formula.
As a matter of fact, it turns out that in the first case, when the armor was not pierced, the ratio of the quality of the armor and the projectile gave the coefficient "K" about 2600. While the second shot gave the coefficient "K" equal to or lower than 1890. It can be assumed that the first the shell was substandard or, on the contrary, the second one turned out to be unusually good workmanship. And this (in combination with the probabilistic nature of the formula) gave such an effect. But, in my opinion, such an explanation looks overly stretched.
The following is much more likely. The first semi-armor-piercing projectile did not penetrate the "de Marr's" armor, because it was not armor-piercing, but only semi-armor-piercing. That is, it had a smaller wall thickness, which means it had a lower body strength. Hence the extremely high coefficient of durability (over 2600).
The second semi-armor-piercing
"Fulfilled increased socialist obligations"
with "K" less than 1890 simply due to the fact that he got into the area of armor weakened by the previous hit.
Both hits were approximately at the same level from the lower edge of the slab - 237 and 239 cm, while 173 and 140 cm, respectively, separated them from the right edge. In other words, the distance between hits was much less than 40 cm. Let us now recall the violations (cracks) of the cemented layer, observed within a radius of up to 60 cm from the first "semi-armor-piercing" hit. It is not surprising that the cracked armor did not show "passport" strength.
The fourth hit was an unloaded 356-mm high-explosive projectile (without explosives) at a speed of 478 m / s. Nothing unexpected happened - the projectile split into pieces, making a pothole in the armor with a depth of only 11 cm. But at the same time
"The cemented layer bounced at a diameter of 74 * 86 cm."
The place of impact is 89 cm from the bottom and 65 cm from the right edge of the armor plate.
Fifth hit - unloaded semi-armor-piercing ammunition was not brought to the nominal weight (748 kg) and had only about 697 kg, the speed at the time of hitting the armor plate was 471 m / s. The armor was pierced, the projectile collapsed when overcoming the armor, while its cylindrical part remained lying here. But a piece of the head of the projectile still retained enough energy to break through the 75-mm bulkhead of case-hardened steel. Place of impact - 168 cm from the top and 68 cm - from the right edge of the armor.
According to Jacob de Marr's formula, if the projectile as a whole had overcome the 270-mm plate and the 75-mm armor plate behind it with the given parameters, this would indicate that the "K" of such armor would be less than or equal to 1990, which is very close to the value I calculated in 2005. Some reduction can be attributed to the probabilistic nature of the armor penetration and the fact that the 75-mm armor plate already had damage.
In addition, the coefficient "K" equal to 2005 corresponds to the penetration of the projectile behind the armor as a whole, while in this case the main part of the projectile did not even reach the 75-mm armor plate. And this is also understandable - after all, the ammunition was not armor-piercing, so the destruction of the projectile when overcoming 270-mm armor is not surprising.
Thus, we come to the conclusion that the shelling of armored plate No. 1 with 356-mm projectiles in no way refutes the conclusion that the "K" of Russian armor had the value of 2005. Cases of lowering "K" are quite explainable by the damage caused to the armor by previous hits … Though…
Alas, there were some mysteries again. Dear S. E. Vinogradov in "Giants …" gives photographs of the said armor plate after the shelling of 356-mm.
In the photo we see the hits of five shells. There are no problems here, but … their places clearly do not correspond to those indicated in the reports. Nevertheless, damage from the second and third hits is quite clearly visible - the distance between them is minimal. And the end-to-end is just one of them.
Shelling 270-mm armor plate No. 1 with 305-mm shells
A total of 3 such shots were fired, and in all cases they were fired with unloaded 305-mm armor-piercing shells, reduced to the nominal weight of 1150 pounds or 470.9 kg. Thus, the influence of low-quality (not triggered on time) fuses was completely excluded. The shells hit at an angle of approximately 67º, or 23º from the normal.
The first shot with a 12-inch projectile was fired at an initial velocity of just over 520 m / s (1708 f / s). Taking into account the deviation from the normal, such a projectile with "K" = 2005 would have to penetrate almost 322 mm of monolithic armor. The combination of spaced 270 mm and 75 mm armor gave less armor resistance. In order for a projectile with the above parameters to penetrate such protection at the limit of its capabilities, the coefficient "K" of the spaced armor had to be 2181. Accordingly, there is nothing strange in the fact that the projectile not only pierced 270- and 75-mm armor plates, but also flew into the field for more than 300 m.
There is one more nuance. The fact is that the place where the shell hit the slab was only 55 cm from the bottom and 72 cm from the left edge of the slab. At the same time, the 270-mm armor plate, starting from 1, 2 m from the bottom, had a thinning towards the lower edge. That is, a 305-mm projectile, most likely, pierced not 270 mm plates, but less.
The second shot was fired at an initial velocity of 1564 feet per second (476.7 m / s). The projectile, having overcome the 270-mm armor plate, for some reason turned around and hit it sideways in a 75-mm bevel, as if "driving" over it. As a result, a through hole with a length of about one and a half meters and a width of 102 to 406 mm was formed in the bevel. However, the projectile did not pass inside, but ricocheted upward, striking the vertical armored bulkhead and armored deck butt-to-toe. There, however, he did not achieve anything and fell down, where he was found as a whole. The point of impact is approximately 167 cm from the bottom edge of the slab and 55 cm from its right edge.
As you can see from the description, the projectile retained a lot of kinetic energy, but it is very difficult to calculate the ultimate armor penetration for this shot. I will only note that at a speed of 476.7 m / s and a deviation from the normal of 23º, this projectile should have been calculated to penetrate a 280.6 mm armor plate having a coefficient "K" = 2005. In other words, there is nothing in the breakdown of a 270-mm plate. surprising, but how did the projectile then manage to push through 75 mm of cemented armor?
The answer is extremely simple. The fact is that this hit fell on a damaged cemented layer, deformed as a result of the 4th hit by a 356-mm projectile. The places of these hits were separated by only a little less than 69 cm. But at the same time, as a result of hitting a fourteen-inch ammunition (as already mentioned above)
"The cemented layer bounced at a diameter of 74 * 86 cm."
That is, the slightly better armor penetration of the Russian projectile is again fully explained by the damage and drop in the armor resistance of the 270-mm plate in the place of its hit.
The third shot was fired at the same armor plate, all with the same angle of deviation from the normal, but at a lower speed - 1415 f / sec or 431.3 m / sec. And, judging by the description of the hit results, this time the armor penetration of 470.9 kg of the projectile turned out to be close to the limit. Our shell overpowered the armored plate, but then touched the B-pillar sideways and hit the 75-mm bulkhead flat. There was no energy left for the breakdown of the armor, the projectile only pushed it to a depth of 15 cm, and fell immediately without collapsing. The place of impact is approximately 112 cm from the top and 93 cm from the left edges of the armor plate.
According to calculations, a 470.9 kg projectile with the above parameters (431.3 m / s with a deviation from the normal by 23º) could penetrate no more than 243-mm armor with a coefficient "K" equal to 2005. It also overcame 270 mm of armor, and this indicates that its "K" was equal to or lower than 1862. However, if lower, then very slightly, since the projectile has practically exhausted its energy during the "penetration" of the plate.
The place of hit of this 305-mm projectile was a meter from the point of contact with the armor of the 5th 356-mm ammunition, which (being unloaded) made a hole 36x51 cm in the slab. an inch projectile is not contained. But, judging by the previous descriptions, the armor at the point of impact of the third 305-mm could very well (and even should) have been weakened. In addition, it should be borne in mind that before this hit, the 270-mm armor plate had already been hit by 5 * 356-mm and 2 * 305-mm shells. That could not but affect its overall strength.
However, I cannot but note that these hits somehow correlate very poorly with the photo of the compartment after the tests, given by the same Vinogradov.
According to the photograph, the 2nd 305mm round did not penetrate the slabs at all.
Shelling of 370-mm armor plates
The first shot at it was also the first test shot. A high-explosive 356-mm projectile, loaded with explosives, hit the plate and gave a full gap. As a result, a dent with a deflection arrow was formed at the edges of the 38 cm pothole. The cemented layer of armor was knocked down in a circle with a diameter of 48–50 cm to a depth of 15 cm. The impact site was 135 cm from the bottom and 157 cm from the right edge of the slab.
This was the only hit from a 356 mm projectile. Subsequently, the 370-mm plate was fired at with 305-mm armor-piercing shells without explosives, the angle of incidence was approximately 68º or 22º from the normal.
The second shot - a 305-mm projectile hit the armor plate at a speed of 565.7 m / s. The defense did not withstand the blow at all. The 370-mm armor belt was pierced, and the 50-mm bevel behind it, and the 6-mm hold bulkhead, and even the 25-mm sheet of the steel base of the compartment. Place of impact - 137 cm from the bottom edge and 43 cm from the right.
Taking into account the fact that the projectile resistance of armor, starting from 300 mm, does not grow in direct proportion to its thickness (the "K" coefficient gradually decreases), the 370-mm armor plate is approximately equivalent to 359 mm of the "original K" protection. But even if we assume that in this case the energy of the projectile was only enough to overcome the plate of the armor belt with a deviation from the normal of 22º and a 50-mm bevel of uncemented steel with a deviation from the normal of about 30º, then the coefficient "K" of the armor would be equal 1955 or less. But the projectile still retained enough energy to penetrate 6 mm and 25 mm steel and go deep into the ground.
Why is the angle of 30º taken for the bevel? Theoretically, the projectile should fly almost parallel to the ground after overcoming the 370-mm plate. In this case, the angle of hitting the bevel should be 45º. But the projectile went down the compartment, so, obviously, the deviation from the normal turned out to be less. Although it is unclear how much.
In general, we see that the protection absolutely did not show the calculated "K" = 2005. Could this be a consequence of the fact that the plate received some damage from the previous high-explosive projectile?
In principle, this is possible. The 305-mm projectile hit a place about 114 cm away from the previous hit, which is not that far. Still, the previous hit was high-explosive, the 356-mm shell did not penetrate the armor and did not cause visible damage outside the chipped cement layer. Therefore, the question remains controversial.
The next hit was a 305-mm projectile at a speed of 513.9 m / s. The shell pierced 370mm armor, bounced off the 50mm bevel, pierced the 12mm bulkhead, and fell about 43 meters behind the compartment. The point of impact is 327 cm from the lower edge of the slab and 50 cm from the left.
In terms of armor durability, the results are extremely disappointing. In this case, the breakdown of armor was indeed observed, close to the limiting one, but the coefficient "K" in this case was less than 1825. And it is hardly possible to write off this for damage to armor from previous shots - the nearest hit (all the same high-explosive 356-mm projectile) was located at a distance of 195 cm. Hardly at such a distance, the damage to the armor from the rupture of a fourteen-inch land mine could be significant, if at all.
The last two 305-mm projectiles had an impact speed of 485, 2 m / sec. The first of them hit the slab 273 cm from the bottom and 103 cm from the right edge of the slab, but did not pierce the armor.
The second hit a place 231 cm from the bottom of the slab and 39 cm from the left edge, and the effect of his hit was very interesting. The shell knocked out the plug of the 370-mm armor, but not only did not go inside, but in general bounced back and was found about 65 meters in front of the test compartment. Oddly enough - as a whole.
Thus, 305-mm armor-piercing shells at a speed of 485.2 m / s could not overcome the 370-mm armor plate either as a whole, or even in the form of fragments. Accordingly, we can say that in this case the coefficient "K" was slightly higher than 1716.
The conclusion is obvious - the durability of the 370 mm armor plate turned out to be about 10% lower than expected. The reasons for this, apparently, should be sought in the inability of the domestic manufacturer to create armor of a similar thickness in those years - without losing its quality.
Now let's move on to the German armor.
