Having described the artillery of the main caliber of the battle cruiser Izmail, let's say a few words about its other weapons. The anti-mine caliber of the battle cruiser was supposed to be 24 * 130-mm / 55 guns, placed in casemates. I must say that this artillery system (in contrast to the 356-mm / 52 guns) turned out to be very successful and well-balanced - a projectile weighing 35.96-36, 86 kg (according to various sources) had an initial speed of 823 m / s. As a result, it was possible to achieve significant firepower: a fairly heavy projectile, whose power was not much inferior to the six-inch and a very high rate of fire. Recall that the British, who had the opportunity to "test" 102-mm, 140-mm and 152-mm artillery systems in battle, eventually came to the conclusion that it was 140-mm that was optimal for a deck installation, and in its performance characteristics it was quite close to the domestic 130 mm / 55. Of course, our artillery system also had drawbacks, such as the cartridge loading and a relatively small resource (300 shots), which, of course, was a problem before the appearance of laners. Nevertheless, the weapon itself should be considered very, very successful.
But the number of these weapons … There are questions about this. No, without a doubt, a dozen rapid-fire cannons on one side were capable of putting a real curtain of fire, breaking through which enemy destroyers would have risen at exorbitant prices, but … isn't it too much? Still, the Germans quite got along with a dozen 152-mm guns on both sides. It is clear that a six-inch gun is more powerful, and that 130-mm guns required more, but not twice! The British on their battlecruisers also had 16-20 102-mm guns ("Lion" and "Rhinaun") or 12-152-mm ("Tiger"). In general, according to the author of this article, 16 barrels of 130-mm caliber would be quite enough for mine defense, but the additional 8 barrels could well be abandoned. Of course, the weight of 8 130-mm guns could not afford to radically increase the protection of the battle cruiser, but if we take into account the ammunition for them, feed mechanisms, additional artillery cellars, the mass of armor spent on protecting the casemates, the growth of the crew for gunners serving these guns … in general, the savings turned out to be not so small, and it is strange that the designers did not take advantage of this opportunity.
In addition to the aforementioned weapons, it was also planned to equip the battle cruisers with 4 * 63-mm / 35 anti-aircraft guns, which were already replaced with the same number of 100-mm / 37 guns for the same purpose during construction. The list of artillery weapons was completed by 4 * 47-mm salute cannons and the same number of Maxim machine guns.
As for the torpedoes, the Ishmaels, like almost all modern ships, were armed with torpedo tubes: I must say that this was almost the most unfortunate type of ship armament. In total, it was planned to install 6 * 450-mm traverse torpedo tubes, the ammunition load was supposed to be three torpedoes per vehicle. However, unfortunately, the Russian Empire missed the moment when it was necessary to switch to underwater ammunition of higher power, as a result, when the leading naval powers adopted 533-mm caliber and even more, Russian sailors still had to be content with relatively weak and short-range 450- mm torpedoes. And, of course, the installation of such ammunition on a battle cruiser could not make any sense - however, in fairness, we note that the same can be said about the more powerful torpedo tubes of our allies and enemies.
Reservation
Let's move on to his armor protection. As we said earlier, the Izmailov armor was among the "damaged" elements of the ship, due to the desire of the sailors to get a fourth main-caliber turret for it. There was no money for a corresponding increase in the cost of battle cruisers, because budgets for shipbuilding had just been approved, which included the creation of three-turret nine-gun battle cruisers, and some redistribution of funds from light cruisers in favor of linear cruisers did not fundamentally solve the matter. It was impossible to reduce the speed, it was considered the most important element of the battle cruiser, and compared with the ships of the same class in England and Germany, and so it was not outstanding (although it was still reduced for the forced mode - from 28, 5 to 27, 5 knots) - accordingly, it remained only armor. As a result, the thickness of the main armor belt was reduced from 254 to 237.5 mm, the upper - from 125 mm to 100 mm, the forehead of the turrets was reduced from 356 to 305 mm, the thickness of the barbet - from 275 mm to 247.5 mm, etc.
But, in addition to the desire to save money, the final version of the Izmailov armor was influenced by the test results of 305-mm shells mod. 1911 (shelling of the battleship "Chesma"). Let's describe the final result with instructions on what exactly changed and for what reasons.
The basis of the vertical protection was the main armor belt, within the citadel, composed of armor plates 5 250 mm high and 2,400 mm wide. The upper edge of the armor plates reached the middle deck, the lower one was submerged in water by 1,636 mm at a normal displacement. Over the course of 151.2 m, the thickness of the armor plates reached 237.5 mm, while at the last 830 mm there was a bevel towards the lower edge, but, unfortunately, it is unclear how much the thickness of the armor plate decreased at the lower edge. The slabs were attached to each other using the “dovetail” technology (adopted based on the results of the shelling of the Chema), and laid on a 75 mm wooden lining.
In the nose from 237.5 mm of the belt, the geometric dimensions of the plates remained the same (that is, each armor plate protected 2.4 m at the waterline), while the first armor plate had a thickness of 200 mm, the next - 163 mm, the next 18 m sides were protected by 125 mm armor, and the remaining 19, 2 m to the stem were covered by armor of 112, 5 mm thick. But in the stern at the level of the main one there were two armor belts: the lower one started from the lower edge of 237.5 mm armor plates, but did not reach the middle, but only to the lower deck. As for its thickness, that is, there is some ambiguity in the description - it is indicated that the first armor plate, adjacent to the 237.5 mm belt, had a thickness of 181 mm (according to other sources - 205.4 mm), however, it is indicated that the ship was such armor protected over 3 spans (3, 6 m), while the standard slab width was 2 spans (2, 4 m). Most likely, a plate of increased width was used, especially since its height was significantly less than 5, 25 m of the armor plates of the ship's citadel. Further, the armor belt was made up of 125 mm boneplite and continued almost to the very sternpost, or rather, to the inclined traverse that covered the stern of the ship. Therefore, the last armor plate of the lower belt was, as it were, cut from right to left - along the bottom, apart from the length of the lower belt, it was 20.4 m, and along the upper belt - 16.8 m. The second armor belt had a thickness of 100 mm, it began immediately from 237.5 armor plates (“there was no transitional armor plate) and had 20.4 m length, ending just where the upper edge of the lower 125 mm armor belt ended. The last 5 m of the ship's hull was protected by only 25 mm of armor.
Above the main one was the upper armored belt, which protected the side between the middle and upper decks. It started from the stem, and for 33.6 m had a thickness of 75 mm, then 156 m of the hull were protected by 100 mm of armor plates, and sources claim that it was 100 mm. and 75 mm sections consisted of cemented armor (the author of this article has some doubts about 75 mm). Noteworthy is the discrepancy between the armor belts - the upper 237.5 mm and the lower 100 mm - the latter (counting from the nose) began 3.6 m earlier than the transitional 163 mm armor plate, but ended before reaching 4.8 m before the completion of 237.5 mm plot. Further in the stern, the board was not booked at all.
The side from the upper deck to the forecastle for 40, 8 m from the stem did not have protection, but then for 20, 4 m (the area of mine artillery casemates) it was armored 100 mm, and then from the side to the conning tower there were oblique traverses of the same thickness.
One external armor belt did not exhaust the Izmailov's vertical armor - behind the 237.5 mm plates were the lower deck bevels, which had 75 mm thickness (50 mm of armor laid on 25 mm of steel). The lower edges of the bevels traditionally adjoined the lower edges of 237.5 mm armor plates, and from their upper edges from the lower to the middle deck there were vertical armor partitions 50 mm thick. These armored partitions, however, for an unclear reason, did not protect the entire citadel, not reaching 7, 2 m in the stern before its end. Thus, the vertical protection at the level of the main armor belt consisted of vertical plates 237.5 mm, inclined bevels 75 mm thick, smoothly flowing into the vertical 50 mm armor bulkhead, the upper edge of which (as in the 237.5 armor belt section) reached the middle deck … Above the middle deck, opposite the upper 75-100 mm of the armor belt, there was a second vertical armored bulkhead 25 mm thick - it protected the ship from the barbet of the 1st tower, to the barbet of the 4th, adjoining them closely. In addition, it continued from the barbette of the bow tower to the bow, serving as the rear wall of the casemates of 130-mm guns at the level between the middle and upper decks, as well as the upper deck and forecastle deck. Thus, where outside the citadel in the nose was located 100 mm armor of the upper armored belt, behind it was either a barbet or a 25 mm armor bulkhead, which reached the very forward traverse.
In general, I must say that the traverses have become that part of the armored structure, on which the designers have saved especially much. The bow traverse looked like this - it was located 42 m from the stem, that is, where the 237.5 mm armor belt began, thereby closing the citadel, and passed along the entire ship from top to bottom. At the same time, the space from the forecastle deck to the upper deck was protected by 100 mm armor, from the upper to the middle - only 25 mm. But here the traverse at least stretched from side to side, but below, between the middle and lower decks and from it down to the very bottom, its thickness again increased right up to 75 mm, but only the inner space was protected, fenced off by 50 mm armored partitions and 75 mm bevels. In general, the bow traverse looked at least strange, especially the 25 mm part of it between the upper and middle decks. True, opposite him, 8, 4 m further in the bow, there was another traverse between these decks, the same 25 mm thick, but, of course, neither separately nor together did such "protection" protect from anything.
The aft traverse was much stranger. Usually, on other ships, it looks like an armored partition located perpendicular to the centerline of the ship and connecting the edges of the armor belts that form the citadel. Sometimes the traverses were made angular, that is, the armor belt seemed to continue, going inside the hull, for example, to the barbets of the main caliber towers. But on "Izmail" the stern traverse was a set of armored partitions (its own on each of the decks!), Located very chaotically. The space between the upper and middle decks was protected by 100 mm of traverses, which closed the 100 mm upper armored belt, ending a little further than the barbette of the aft 356-mm turret. But below it did not continue, remaining the only defense between these decks. But on the next "floor", between the middle and lower decks, there were two such defenses: about 8, 4 meters from the lower edge of the 100 mm traverse towards the bow (and right under the edge of the barbette of the 356-mm stern tower), the first 75 mm began partition - again, not across the entire width of the hull, but only between 50 mm bulkheads. The second, on the contrary, was 18 m aft from the upper traverse, had a thickness of 75 mm and stretched from side to side and was also notable for the fact that it, the only one, protected two interdeck spaces - between the middle and lower decks, and also under the lower deck to the lower edge of the armor belt. But, besides this, there was also a second traverse 75 mm thick, covering the citadel from the lower deck to the lower edge of the armor belt, but not along the entire width of the side, but only in the space outlined by bevels - these two traverse were separated by 21.6 m.
In short, we can say that the citadel in the stern was closed with a 100 mm traverse at the level of 100 mm of the armor belt and 75 mm at the level of 237.5 mm of the armor belt, but in the stern there was another traverse of 75 mm. In the bow, the traverse thickness generally varied from 50 to 100 mm, and at some angles - even 25 mm. It remains only to state that the final version of the battle cruiser protection from longitudinal fire completely degraded and became simply insignificant in comparison with the initial requirements (for a nine-gun project) to provide protection equal to the thickness of the main armor belt, that is, at least 250 mm.
But the horizontal armor of the hull turned out to be quite at the height and much better than the original project. The battle cruiser had three main watertight decks - upper, middle and lower. In addition, there was also a forecastle deck, as well as two decks at the extremities that ran from the traverse to the bow and stern below the waterline (they were called "platforms".
So, putting aside the forecastle for now, we note that according to the initial project, the thickest armor - 36 mm - should have been received by the upper deck, while the protection was designed solid, that is, no unprotected places were supposed (except, of course, chimneys and other necessary openings). But the middle deck was supposed to have only 20 mm, and only outside the casemates. As for the lower deck, its horizontal part was not supposed to be armored at all - it was supposed to be a regular deck 12 mm thick (slightly more than usual) and only its bevels were supposed to have 75 mm. In addition, the stern platform was supposed to have 49 mm of armor, the bow - 20 mm.
However, during the shelling of the Chesma, it turned out that the domestic views on horizontal booking were completely wrong. It was assumed that the main obstacle would be the upper deck, while those below it would contain shell fragments, but in practice everything turned out differently. Yes, the 36-37.5 mm deck really forced both high-explosive and armor-piercing 470, 9 kg 305-mm shells to detonate, but the explosion energy was such that the thin lower deck was pierced not only by fragments of the shell itself, but also by fragments of the broken upper armored deck. As a result, the horizontal protection was significantly improved in the final design of Izmail.
The upper deck was made 37.5 mm, which was supposed to guarantee the detonation of the projectile (at least 305 mm), but the middle deck was reinforced from 20 to 60 mm - the deck had such a thickness up to vertical 25 mm of armor bulkheads located along the sides, which were, concurrently, the rear walls of the casemates. There, the thickness of the middle deck decreased to 12 mm, increasing to 25 mm only near the side (apparently, reinforcements for 130-mm guns).
As a result, it should have turned out that if an enemy shell hit the upper deck closer to the center of the ship, then it exploded, and 60 mm armor was on the way of the fragments. If the projectile hit closer to the side, then its fragments "met" only 12-25 mm floor of the casemate, which, of course, could not hold them in any way, but, having pierced it, the fragments ended up in the "armored bag" formed by a 50 mm vertical armored partition and 75 mm bevel. Such protection was considered sufficient, so the horizontal part of the lower deck remained unarmored at all (the thickness of the flooring was 9 mm). The only exception was the area of the well of the large rudder, where 50 mm of armor plates were laid, and a small section between the two aft 75 mm traverses (60 mm) - since they were spaced, the absence of a deck reservation behind the fourth tower would be an "open road" to the ammunition cellar … As for the "platforms", they retained the originally assumed thickness of 49 mm and 20 mm for the stern and bow sections, respectively, and the forecastle deck had 37.5 mm protection only in the area of the main caliber turret and casemates.
The artillery of the main caliber received very serious protection - the thickness of the vertical walls of the towers was 300 mm, the roof was 200 mm, and the floor was 150 mm. The thickness of the barbet in the section 1.72 m (upper tier) was 247.5 mm (and not 300 mm, as indicated in some sources), while the barbet had such a thickness not only above the upper deck (for the bow tower - the forecastle deck), but even below it, although the 247.5 mm upper tier did not reach the middle (for the bow tower - upper) deck. This was done so that if a projectile hit the deck and pierced it in the immediate vicinity of the turret, it would be met by thick 247.5 mm armor. The second tier was different for different towers - the middle (second and third) towers here had an armor thickness of 122.5 mm - this is not much, but in order to hit the barbet in this part, the enemy shell first had to overcome 100 mm of the upper armor belt. The lower 122.5 mm tier of the barbet at the middle towers reached the middle deck, below the barbets were not armored. The bow tower, due to the forecastle, rose one interdeck space above the rest and was armored like this - the upper tier (above the forecastle deck and, probably, about a meter with a small one below it) was protected by 247.5 mm armor, then up to the upper deck the barbet had 147, 5 mm. From the upper to the middle deck, the part of the barbette, facing the bow, had the same 147.5 mm of armor, and the aft one - 122 mm. The aft tower had exactly the same 1.72 m upper tier, and the lower one, extending to the middle deck, had 147.5 mm from the stern, and 122.5 mm towards the bow. As for the protection of mine artillery, its casemates received 100 mm side armor, their roof was the upper deck 37.5 mm thick, the floor (middle deck) of the guns had 25 mm further - 12 mm, the rear wall of the casemate formed by the longitudinal armored bulkhead of the ship - 25 mm, and in addition, the guns were separated from each other by separate 25 mm armored partitions.
Initially, the project provided for two conning houses with walls of 300 mm and a roof of 125 mm, but after the Black Sea tests, this thickness was considered insufficient. As a result, two wheelhouses were replaced with one bow, which was supposed to have a wall thickness of 400 mm and a roof thickness of 250 mm. Below the upper deck, between the upper and middle decks, the conning tower continued, having protection of 300 mm, from it below there was a 75 mm "well" to the central post, which was at the level of 237.5 mm of the armor belt and protected by 50 mm armor plates from the sides and from the top.
From the rest, the shafts of the head of the large rudder (vertical walls 50 mm) received protection, the chimneys - from the upper to the lower deck 50 mm, and the pipes themselves - 75 mm at a height of 3.35 m above the upper deck. Also, the elevators for feeding 130-mm projectiles and boiler fan shafts (30-50 mm) were protected by armor.
Due to the fact that the author is limited by the size of the article, we will not give an assessment of the Izmailov reservation system now, but we will leave it until the next materials, in which we will consider in detail the fighting qualities of domestic battle cruisers in comparison with their modern warships.
Power plant
The Ishmaels had a four-shaft power plant, while the turbines, in essence, were an enlarged and more powerful copy of the turbines of the Sevastopol-class battleships. Their work was provided by 25 boilers, of which 9 (three boilers in three bow compartments) were purely oil, and the remaining 16 (four boilers in each of the four compartments) had mixed heating. The rated power of the installation was supposed to be 66,000 hp, while it was expected to reach a speed of 26.5 knots.
A small mystery is the statement of almost all sources that when forcing the mechanisms it was planned to reach a power of 70,000 hp. and a speed of 28 knots. Such an increase in power (4,000 hp) looks too small for forcing, and besides, it would not have been able to provide an increase in speed by 1.5 knots - the simplest calculations (through the Admiralty coefficient) suggest that for this it was necessary to bring power up to approx. 78,000 hp. The author of this article assumes that there was some mistake in the documents of those years - perhaps it was still not about 70,000, but about 77,000 hp? In any case, and taking into account the fact that the battleships of the "Sevastopol" type significantly exceeded the "passport" capacity of their power plants, it can be assumed that the same would have happened with the "Izmail", and the speed of 28 knots. afterburner would be quite achievable for them.
