The Imperatritsa Mariya-class () battleships were the first dreadnoughts built for the Black Sea Fleet of the Imperial Russian Navy. All three ships were built in Nikolayev during World War I; two of the ships were built by the Rossud Dockyard and the third was built by the Associated Factories and Shipyards of Nikolayev (). Two ships were delivered in 1915 and saw some combat against ex-German warships that had been 'gifted' to the Ottoman Empire, but the third was not completed until 1917 and saw no combat due to the disorder in the navy after the February Revolution earlier that year.
was sunk by a magazine explosion in Sevastopol harbor in 1916. , having been renamed Svobodnaya Rossiya in 1917, was scuttled in Novorossiysk harbor in 1918 to prevent her from being turned over to the Germans as required by the Treaty of Brest-Litovsk. The crew of Volia, as had been renamed in 1917, voted to turn her over to the Germans. They were only able to make one training cruise before they had to turn her over the victorious Allies in 1918 as part of the armistice terms. The British took control of her, but turned her over to the White Russians in 1920 who renamed her General Alekseyev. She only had one operable gun turret by this time and she provided some fire support for the Whites, but it was not enough. They were forced to evacuate the Crimea later that year and sailed with Wrangel's fleet to Bizerte (Tunisia) where she was interned by the French. She was eventually scrapped there during the 1930s to pay her docking fees.
Design and development The Naval Ministry began planning a class of dreadnoughts for the Black Sea Fleet in 1910 when they learned that the Ottomans were on the verge of ordering dreadnoughts of their own from the British. This rumor proved to false, but the Russians had decided that they should continue the design process for the time when the Ottomans did procure dreadnoughts of their own. Preliminary specifications were issued on 12 August 1910All dates used in this article are New Style for a design based on that of the s then being built for the Baltic Fleet. was thought to be excessive in the confined environs of the Black Sea so the new design was capable of only which allowed more weight to be devoted to more guns or heavier armor. A main armament of a dozen guns in four triple turrets was specified in the same 'linear' non-superfiring arrangements as the Ganguts. The sixteen anti-torpedo boat guns of the Ganguts were replaced by twenty /55 B7 Pattern 1913 guns to counter the ever-increasing size of torpedo boats. The maximum elevation of the 12-inch guns was to be increased to 35°, 10° more than in the Gangut-class ships, and turret armor was to be increased from to .McLaughlin, p. 229–230
A design competition was announced in July 1911, but there were not many contenders. The Naval Ministry favored the design from the Russud Works and gave preliminary orders for three ships on 2 September, even before the competition was concluded in November. Russud's design was unsurprisingly selected and the government transferred designers from the government-owned Baltic Works as well as a complete set of drawings for the Gangut-class to speed up the detailed design process.McLaughlin, pp. 230–231
General characteristics The ships of the Imperatritsa Mariya-class were long overall, had a beam of and at full load a draft of . They displaced at (standard). High-tensile steel was used throughout the hull with mild steel used only in areas that did not contribute to structural strength. The hull was subdivided by 18 transverse watertight bulkheads. The engine room was divided by two longitudinal bulkheads and a double bottom was provided. Their designed metacentric height was .McLaughlin, pp. 233, 235–236
Imperatritsa Ekaterina Velikaya was slightly larger than her half-sisters because ONZiV enlarged her in an effort to counter the usual problem Russian battleships had with weight. She was long at the waterline and had a beam of ; longer and wider than her half sisters. Her exact draft is not known, but she had a draft of on trials. Her displacement was at load, over more than her designed displacement of .McLaughlin, p. 228
Imperatritsa Mariya proved to be very bow-heavy in service and tended to ship large amounts of water through her forward casemates.Budzbon, p. 303 The ammunition for the forward 12-inch guns was reduced from 100 to 70 rounds each while the 130 mm ammunition was reduced from 245 to 100 rounds per gun in an attempt to compensate for her trim. This did not fully cure the problem, but Imperatritsa Mariya was lost before any other changes could be implemented. This did not fully cure the problem so Volias, as she was known by then, forward pair of 130 mm guns were removed while she was fitting out. Imperatritsa Ekaterina Velikaya did not suffer from the same degree of trim by the bow by virtue of her greater size and retained her forward guns.McLaughlin, p. 237
Propulsion The two Russud-built ships were fitted with four Parsons-type steam turbines imported from John Brown & Company of the United Kingdom while Imperatritsa Ekaterina Velikayas turbines were built by ONZiV with technical assistance from Vickers Limited. They were designed for a total of ( in Imperatritsa Ekaterina Velikaya), but produced over on trials. 20 mixed-firing triangular Yarrow water-tube boilers powered the turbines at a working pressure of . Their designed speed was 21 knots. Their maximum coal capacity ranged from plus of fuel oil which gave them a range of approximately at full speed or at economical speed. All of their electrical power was generated by three main Curtis 360 kilowatt turbo generators and two 200 kilowatt auxiliary units.McLaughlin, pp. 229, 235–237
Armament
The main armament of the Imperatritsa Mariya-class consisted of a dozen Obukhovskii Pattern 1907 52-caliber guns mounted in four triple turrets distributed the length of the ship. The guns were identical to those used in the Gangut-class ships, but the turrets were of a new and roomier design. The fore and aft turrets could traverse a total of 310° while the middle turrets covered an arc of 130° on each side.McLaughlin, pp. 233–234 The guns could be depressed to −5° and elevated to 25° and could be loaded at any angle between −5° and +15°; their rate of fire was supposed to three rounds per minute up to 15° of elevation. The turrets could elevate at 3–4° per second and traverse at a rate of 3.2° per second. 100 rounds per gun were carried at full load. The guns fired projectiles at a muzzle velocity of ; this provided a maximum range of .
The secondary armament consisted of twenty /55-caliber B7 Pattern 1913 guns mounted in casemates. They were arranged in two groups, six guns per side from the forward turret to the rear funnel and the remaining four clustered around the rear turret. Three guns per side were situated to fire ahead as that was the most likely direction of attack by torpedo boats as anticipated by the Naval General Staff.McLaughlin, p. 261 Their rate of fire ranged from five to eight rounds per minute and they were provided with 245 rounds per gun. They had a maximum range of about with a shell at a muzzle velocity of .
No anti-aircraft (AA) armament was originally planned. In October 1916, the Naval Ministry specified that four 37-caliber guns of a new design were to be fitted, but they never entered service. The two older ships had three or four 50-caliber Pattern 1892 guns mounted on turret roofs.McLaughlin, p. 234 The 75 mm gun had maximum elevation of 50°. It fired a shell at a muzzle velocity of at a rate of fire of 12–15 rounds per minute. It had a maximum ceiling of less than . Volia used four of the newer 30-caliber 'Lender' AA guns, mounted on the fore and aft turrets. This had a maximum depression of 5° and a maximum elevation of 65°. It fired a shell at a muzzle velocity of . It had a rate of fire of 10–12 rounds per minute and had a maximum ceiling of .
Four underwater torpedo tubes were also fitted, two on each broadside in a compartment immediately abaft the forward magazine. Imperatritsa Mariyas trials revealed problems with her magazine cooling systems where the heat generated by the ventilation system mostly negated the cooling effects of the refrigeration system. Her sisters shared this problem, which may have contributed to the magazine fire suffered by Imperatritsa Mariya that led to her loss in 1916.McLaughlin, p. 233
The two older ships mounted Zeiss rangefinders on each conning tower, but Volia was given four Barr and Stroud rangefinders, one for each turret. These would provide data for the central artillery post to calculate, using the standard Geisler mechanical computer, and then transmit to the guns for the gun crew to follow.Friedman 2008, pp. 273–275
Armor The full-scale armor trials with the hulk of the old pre-dreadnought battleship greatly affected the armor protection of the Imperatritsa Mariya-class ships. The Krupp cemented armor plates were sized to match the frames to provide support for their joints and they were locked together by a type of mortise and tenon joint to better distribute the shock of a shell's impact. The waterline belt had a maximum thickness of . It was continued forward and aft of the citadel by plates and thick. These reduced to and then to 75 millimeters just before the bow. Aft the belt thinned to 125 millimeters all the way to the stern. It had a total height of , of which was above the design waterline and below. It was backed by 75 millimeters of wood to make a better fit between the hull and the armor. The forward end of the citadel was protected by other armor and the transverse bulkhead was therefore only thick, barely enough to consider as splinter protection. However, the rear bulkhead had no other protection and was thick. These thin bulkheads left the end magazines very vulnerable to shells fired from bearings in front of or behind the ship. The upper belt was thick and had a height of . It thinned to 75 mm forward of the casemates all the way to the bow. The casemates were also protected by a transverse bulkhead from axial fire as well as a 25 mm screen between each casemate. Behind the side armor was an inboard longitudinal splinter bulkhead that was thick, but the casemates had their own separate 25 mm splinter bulkhead.McLaughlin, pp. 234–235
The main gun turrets had sides thick with 125 mm roofs. 50 mm plates protected the gun ports and bulkheads separated each gun. The barbettes were 250 mm thick, but reduced to 125 mm below the upper deck, except in the forward and rear turrets which thinned only to . The forward conning tower sides were thick with a roof and 250 mm supporting tube which reduced to 100 mm below the upper deck. The rear conning tower also had 300 mm sides and a 250 mm support tube, but the roof was only 100 mm thick. The funnel uptakes were protected by 75 mm of armor above the upper deck, but this reduced to below it. The upper deck was thick while the middle deck was 25 mm thick over the armored citadel. Outside the citadel the middle deck was 37.5 mm thick and the lower deck was 25 mm thick. Underwater protection was minimal as there was only an unarmored watertight bulkhead behind the upwards extension of the double bottom.
Construction