View source for Sovetsky Soyuz-class battleship

{{short description|Planned class of Soviet battleships}}
{|{{Infobox ship begin}}
{{Infobox ship image
|Ship image=File:Sovietsky Soyuz 1 June 1942.jpg
|Ship caption=German reconnaissance picture of ''Sovetsky Soyuz'' taken in June 1942
}}
{{Infobox ship class overview
|Builders=
|Operators={{navy|Soviet Union|1935}}
|Class before={{ship|Russian battleship|Imperator Nikolai I|1916|2}}
|Class after=''[[Project 24]]''
|Cost=1,180,000,000 [[Soviet ruble|ruble]]s (for all 4 ships laid down)
|Built range=1938–1941
|Total ships planned=16 (4 laid down before cancellation)
|Total ships cancelled=16
}}
{{Infobox ship characteristics
|Hide header=
|Header caption=after 1941 modifications
|Ship type=[[Battleship]]
|Ship displacement=*{{cvt|59150|t|LT|lk=on}} ([[Displacement (ship)#Standard displacement|standard]])
* {{convert|65150|t|LT|abbr=on}} ([[Full-load displacement|full load]])
|Ship length={{convert|269.4|m|ftin|abbr=on}} ([[o/a]])
|Ship beam={{convert|38.9|m|ftin|abbr=on}}
|Ship draft={{convert|10.4|m|ftin|abbr=on}}
|Ship power=* 6 triangle-type [[boiler (steam generator)|boilers]]
*{{cvt|201000|shp|kW|lk=on}}
|Ship propulsion=3 shafts; 3 geared [[steam turbine]]s
|Ship speed= {{convert|28|kn|lk=in}}
|Ship endurance={{convert|7680|nmi|lk=in|abbr=on}} at {{convert|14|kn}}
|Ship complement=
|Ship sensors=
|Ship EW=
|Ship armament=*3 × triple {{convert|406|mm|adj=on|abbr=on|0}} guns
* 6 × twin {{convert|152|mm|adj=on|abbr=on|0}} guns
* 6 × twin {{convert|100|mm|in|abbr=on|1}} [[dual-purpose gun|DP]] guns
* 10 × quadruple [[37 mm automatic air defense gun M1939 (61-K)|{{convert|37|mm|in|abbr=on}}]] [[AA gun]]s
|Ship armor=*[[Belt armor|Waterline belt]]: {{convert|180|-|420|mm|in|abbr=on|1}}
* [[Deck (ship)|Deck]]: {{convert|25|-|155|mm|in|abbr=on|1}}
* [[Gun turret|Turrets]]: {{convert|230|-|495|mm|in|abbr=on}}
* [[Barbette]]s: {{convert|425|mm|in|abbr=on}}
* [[Bulkhead (partition)|Bulkheads]]: {{convert|75|-|365|mm|in|1|abbr=on}}
* [[Conning tower]]: {{convert|425|mm|in|abbr=on}}
|Ship aircraft=4 [[Beriev Be-4|KOR-2]] [[flying boat]]s
|Ship aircraft facilities=2 [[aircraft catapult]]s
|Ship notes=
}}
|}

The '''''Sovetsky Soyuz''-class battleships''' ('''Project 23''', {{langx|ru|Советский Союз}}, {{gloss|Soviet Union}}), also known as "Stalin's Republics", were a class of [[battleship]]s begun by the [[Soviet Union]] in the late 1930s but never brought into service. They were designed in response to the {{sclass|Bismarck|battleship|2}}s being built by Germany. Only four hulls of the sixteen originally planned had been [[laid down]] by 1940, when the decision was made to cut the program to only three ships to divert resources to an expanded army rearmament program.

These ships would have rivaled the [[Imperial Japanese]] {{sclass|Yamato|battleship|4}} and America's planned {{sclass|Montana|battleship|4}} in size if any had been completed, although with significantly weaker firepower: nine {{convert|406|mm|adj=on|sp=us|0}} guns compared to the nine {{convert|460|mm|adj=on|sp=us|1}} guns of the Japanese ships and a dozen {{convert|16|in|adj=on|sp=us|0}} on the ''Montana''s.  The failure of the Soviet armor plate industry to build [[Krupp cemented armour|cemented armor]] plates thicker than {{convert|230|mm|sp=us}} would have negated any advantages from the ''Sovetsky Soyuz'' class's thicker armor in combat.

Construction of the first four ships was plagued with difficulties as the Soviet shipbuilding and related industries were not prepared to build such large ships. One battleship, ''Sovetskaya Belorussiya'', was cancelled on 19 October 1940 after serious construction flaws were found. Construction of the other three ships was suspended shortly after [[Operation Barbarossa|Nazi Germany invaded the Soviet Union]] in June 1941, and never resumed. All three of the surviving hulls were [[ship breaking|scrapped]] in the late 1940s.

==Design and development==
Design work began in 1935 on new battleships in response to the existing and planned German battleships,<ref>Westwood, p. 202</ref> and the Soviets made extensive efforts in Italy and the United States to purchase either drawings or the ships themselves in the late 1930s.<ref>McLaughlin 2003, pp. 362–372</ref> The Italian firm of [[Gio. Ansaldo & C.]] proposed a ship of {{convert|42000|LT|t}} [[Displacement (ship)#Standard displacement|standard displacement]] with nine 16-inch (406&nbsp;mm) guns, in size and appearance similar to the {{ship|Italian battleship|Littorio||}} then under construction by the company.<ref>Ireland, p. 93</ref>  The U.S. firm of [[Gibbs & Cox]] provided four designs; one for a conventional battleship, and three hybrid designs which combined battleship main armament with a raised flight deck on the central superstructure capable of operating up to 30 aircraft.<ref>Ireland, pp. 92–93; Braynard, p. 66</ref>  While these projects proved useful to the Soviets, they decided to proceed with their own designs.

The first Tactical-Technical Requirement (abbreviated in Russian as ТТZ) for the large battleship design was issued on 21 February 1936 but proved too ambitious, specifying nine 460&nbsp;mm guns and a speed of {{convert|36|knots}} on a displacement of 55,000 tons.<ref group=Note>Aside from the ship's specifications themselves the type of ton is not specified by McLaughlin.</ref> The TTZ was revised in May 1936 by Admiral [[Vladimir Mitrofanovich Orlov|Vladimir Orlov]], Commander of the [[Soviet Navy]], reducing speed to {{convert|30|knots}}, and weakening the secondary and [[Anti-aircraft warfare|anti-aircraft]] batteries. A few months later Admiral Orlov further reduced the size of the battleship to 45,000 tons and set the size of the main guns at 406&nbsp;mm. Shortly afterward, the Soviet Union signed the Anglo-Soviet Quantitative Naval Agreement of 1937 and agreed to follow the terms of the [[Second London Naval Treaty]] that limited battleships to a displacement of 35,560 metric tons (35,000 long tons), although they did add a proviso that allowed them to build ships of unlimited size to face the [[Imperial Japanese Navy]] if they notified the British. Yet another TTZ was approved by Orlov on 3 August for ships of 41,500 tons with an armament of nine 406-millimeter, twelve {{convert|152|mm|adj=on|sp=us|0}}, twelve {{convert|100|mm|adj=on|sp=us|1}}, and forty {{convert|37|mm|adj=on|sp=us}} guns, a maximum armor thickness of {{convert|380|mm|abbr=on}} and a speed of 30 knots.<ref>McLaughlin 2003, pp. 380–382</ref>

The design of KB-4, the surface ship design bureau of the [[Baltic Shipyard]], was selected for further development although the lead designers were convinced that only a larger ship could fulfill the ambitious requirements. They did manage to get agreement on 22 November 1936 for a thickening of the deck armor that raised the displacement to about 47,000 tons. Design work continued on this basis and technical work was completed for a ship of 47,700 tons in April 1937, but the designers continued to press their case for larger ships. The issue was resolved by [[General Secretary of the Communist Party of the Soviet Union|General Secretary]] [[Joseph Stalin|Stalin]] at a meeting on 4 July when he agreed to increase displacement to about 56,000 tons. This forced the project to begin again.<ref>McLaughlin 2003, pp. 383–384</ref>

The timing of the redesign proved to be inauspicious as the [[Great Purge]] was spreading through the ranks of the military and related industries. The original deadline for completion of design work by 15 October was missed, and an incomplete version was presented to the navy's [[Ministry of the Shipbuilding Industry (Soviet Union)|Shipbuilding Administration]] the next month. A number of details remained to be worked out, including the final design of the machinery plant, the 152&nbsp;mm guns and the 100&nbsp;mm gun mounts. In the meantime, extensive and expensive testing was conducted on the ship's hull form, deck armor and torpedo protection; 27 million [[ruble]]s were spent on experimental work in 1938 alone. Over 100 models of the hull were tested in a [[ship model basin]] to find the best hull form and two one-tenth-scale launches were built at [[Sevastopol]] to test the hull's maneuverability. An old steamship was fitted with a replica of the design's armor decks and tested against {{convert|500|kg|adj=on|sp=us}} bombs, proving that such ordnance would generally penetrate both the {{convert|40|mm|adj=on|sp=us}} upper and {{convert|50|mm|adj=on|sp=us|0}} middle decks before exploding on the armored deck. The main armor deck was raised one deck in consequence and a [[splinter deck]] added underneath it to stop any bomb or shell fragments that might penetrate the armor deck. The underwater protection system was tested on fifteen one-fifth scale models and two full-sized experimental [[barge]]s. These tests proved that the [[torpedo belt]] system of multiple [[bulkhead (partition)|bulkheads]] was superior to the [[Pugliese torpedo defense system|Pugliese system]] of a large tube filled with smaller sealed tubes, but it was too late to incorporate these test results into the design as construction was well underway by the time they were completed in late 1939.<ref>McLaughlin 2003, pp. 384–385</ref>

A revised design was approved on 28 February 1938 and the first ship was to be laid down on 15 July, but even this design was incomplete and would be revised later. Trials with similarly shaped [[motor launch]]es suggested that the hull's propulsive efficiency would be {{convert|1|knot}} less than planned, and this was accepted in the November 1938 revision as a maximum speed of {{convert|27.5|knots}}. However, a new propeller design proved to be more efficient and was predicted to increase speed to {{convert|28|knots}}. Another change was the deletion of the centerline rudder when tests showed that the two wing rudders would not be able to counteract its effects if it jammed. The weight toward the stern of the boat was calculated to be too great, producing a substantial stern-down trim. To remedy this, the two 100&nbsp;mm turrets mounted on the quarterdeck were deleted and the height of the armor belt abreast the rear turret was lowered, but this decision was reversed and they were restored by a decision of the State Defense Committee on 14 January 1941. This forced a revision of the aircraft arrangements as the [[aircraft catapult]] had to be removed from the centerline of the quarterdeck; two catapults were added to the sides of the quarterdeck instead.<ref>McLaughlin 2003, pp. 385–386, 389</ref>

===General characteristics===
[[File:BalticShipyard26June1941.jpg|thumb|right|upright=1|Luftwaffe aerial reconnaissance photo of the Ordzhinikidze Yard (Shipyard 189), Leningrad, showing the battleship ''Sovetsky Soyuz'' (top) and the cruiser ''Chkalov'' under construction, 26 June 1941]]
As designed, the Project 23-class ships, as ''Sovetsky Soyuz'' and her sisters were designated, were {{convert|269.4|m|ftin|sp=us}} long [[length overall|overall]]. They had a [[beam (nautical)|beam]] of {{convert|38.9|m|ftin|sp=us}} and a [[draft (ship)|draft]] of {{convert|10.4|m|ftin|sp=us}} at [[deep load]]. They displaced {{convert|59150|t|LT|sp=us|lk=on}} at [[Displacement (ship)#Standard displacement|standard load]] and {{convert|65150|t|LT|sp=us|0}} at full load, although weight estimates made in 1940 show that they would have exceeded {{convert|60000|t|LT|sp=us|0}} standard and {{convert|67000|t|LT|sp=us|0}} at full load.<ref>McLaughlin 2003, pp. 379, 386</ref>

The hull form was very full-bodied, especially at the forward [[magazine (artillery)|magazines]], where the torpedo protection system added width to the beam. Coupled with the relatively low length-to-beam ratio of 7.14:1, this meant that very powerful turbines were necessary to achieve even modest speeds. Stalin's decision that the Project 23-class ships would use three shafts instead of four increased the [[structural load|load]] on each shaft and reduced propulsive efficiency, although it did shorten the length of the [[armored citadel]] and thus overall displacement. [[Metacentric height]] was designed at {{convert|3.4|m|ftin|sp=us}} and the tactical diameter was estimated at about {{convert|1170|m|sp=us}}.<ref name=m8>McLaughlin 2003, p. 388</ref>

The ''Sovetsky Soyuz''-class ships were provided with facilities to handle two to four [[Beriev Be-4|KOR-2]] [[flying boat]]s which would be launched by the two [[aircraft catapult|catapults]] mounted on the stern. Two [[hangar]]s were built into the after end of the [[forecastle]] deck to house two of them and [[crane (machine)|cranes]] were provided at the forward end of the [[quarterdeck]] to hoist them out of the water.<ref>Gribovskii, p. 167</ref>

===Machinery===
The machinery arrangement "provided good dispersal of the machinery spaces, but at the cost of very long runs for the wing shafts (ca. {{convert|105|m|ft|1|sp=us}}). The turbine compartments for the wing shafts were located forward of boiler room No. 1 and aft of the No. 2 turret magazines. The engine room for the center shaft's turbine was between boiler room No. 2 and No. 3. This meant that the wing propeller shafts had to run underneath the boilers.<ref>{{cite book|last=McLaughlin|first=Stephen|title=Russian and Soviet Battleships: Errata, Corrections and Additions|date=26 December 2005|url=http://www.gwpda.org/naval/russian_and_soviet_battleships_errata.pdf|page=3|publisher=gwpda.org|access-date=19 May 2010}}</ref>

The [[steam turbine]]s, and a license to build them, were originally going to be ordered from [[Cammell Laird]] in the United Kingdom, but their £700,000 cost was more than the Soviets wanted to pay. Instead they bought them from [[Brown, Boveri & Cie|Brown Boveri]], using the technical information acquired from Cammell Laird in the process, for £400,000. Four single-reduction, impulse-reduction geared turbines were ordered from the [[Switzerland|Swiss]] firm, three to equip ''Sovetskaya Rossiya'' and one to serve as a pattern for the factory in [[Kharkiv|Kharkov]] that was to build the remainder. The three produced a total of {{convert|201000|shp|kW|lk=on|0}}. Six triangle-type [[water-tube boiler]]s—two in each boiler room—powered the turbines at a working pressure of {{cvt|37|kg/cm2|kPa psi|0|lk=on}} and a temperature of {{convert|380|°C|°F}}.<ref>McLaughlin 2003, pp. 393–394</ref>

Maximum speed was estimated at 28 knots, using the revised propeller design, although forcing the machinery would yield an extra knot. The normal [[fuel oil]] capacity was {{convert|5280|t|LT|sp=us|0}}, giving an estimated endurance of {{convert|6300|nmi|lk=in}} at {{convert|14.5|knots}} and {{convert|1890|nmi}} at full speed. Maximum fuel capacity was {{convert|6440|t|LT|sp=us|0}} which gave a range of {{convert|7680|nmi}} at 14.5 knots and {{convert|2305|nmi}} at full speed.<ref>McLaughlin 2003, p. 380</ref>

===Armament===
[[File:Guns mp10-4.jpg|thumb|406&nbsp;mm B-37 gun in MP-10 test mount, 1940]]
The main armament consisted of three electrically powered MK-1 triple turrets, each with three 50-[[caliber (artillery)|caliber]] 406&nbsp;mm B-37 guns. The guns could be depressed to −2° and elevated to 45°. They had a fixed loading angle of 6° and their rate of fire varied with the time required to re-aim the guns. It ranged from 2.0 to 2.6 rounds per minute depending on the elevation.<ref name=m8/> The turrets could elevate at a rate of 6.2 degrees per second and traverse at 4.55 degrees per second. 100 rounds per gun were carried. The guns fired {{convert|1108|kg|lb|adj=on|sp=us}} projectiles at a [[muzzle velocity]] of {{convert|830|m/s|ft/s|abbr=on}}; this provided a maximum range of {{convert|45600|m|yd|sp=us}}.<ref>{{cite web|url=http://www.navweaps.com/Weapons/WNRussian_16-50_m1937.htm|title=Russian 406 mm/50 (16") B-37 Pattern 1937|date=9 October 2006|publisher=navweaps.com |access-date=3 January 2010}}</ref>

The secondary armament consisted of twelve 57-caliber B-38 152&nbsp;mm guns mounted in six twin-gun MK-4 turrets. Their elevation limits were −5° to +45° with a fixed loading angle of 8°. Their rate of fire also varied with the elevation from 7.5 to 4.8 rounds per minute. They were provided with 170 rounds per gun.<ref name=m99>McLaughlin 2003, pp. 379, 389</ref> The turrets could elevate at a rate of 13 degrees per second and traverse at 6 degrees per second. They had a maximum range of about {{convert|30000|m|0|sp=us}} with a {{convert|55|kg|lb|adj=on|sp=us}} shell at a muzzle velocity of {{convert|950|m/s|ft/s|abbr=on}}.<ref>{{cite web|url=http://www.navweaps.com/Weapons/WNRussian_6-57_m1938.htm|title=Russian 152 mm/57 (6") B-38 Pattern 1938 |date=23 May 2006|access-date=3 January 2010|publisher=navweaps.com}}</ref>

Heavy anti-aircraft (AA) fire was provided by a dozen 56-caliber 100&nbsp;mm B-34 [[dual-purpose gun]]s in six twin-gun MZ-14 turrets with 400 rounds per gun. The ships began construction with only four turrets, but two additional turrets were restored to the quarterdeck in January 1941. They could elevate to a maximum of 85° and depress to −8°.<ref name=m99/> They could traverse at a rate of 12° per second and elevate at 10° per second. They fired {{convert|15.6|kg|lb|adj=on|sp=us}} [[high explosive]] shells at a muzzle velocity of {{convert|895|m/s|ft/s|abbr=on}}; this provided a maximum range of {{convert|22241|m|yd|sp=us}} against surface targets, but their maximum range against aerial targets was {{convert|9895|m|sp=us}}, the limit of their time fuse.<ref>{{cite web|url=http://www.navweaps.com/Weapons/WNRussian_39-56_m1940.htm|title=Russia / USSR 100 mm/56 (3.9") B-34 Pattern 1940|date=15 November 2008|access-date=3 January 2010|publisher=navweaps.com}}</ref>

Light AA defense was handled by ten quadruple, water-cooled, 46-K mounts fitted with [[37 mm automatic air defense gun M1939 (61-K)|{{convert|37|mm|abbr=on}} 70-K]] guns with 1800 rounds per gun. Initially only eight mounts were planned when the ships began construction, but two more were added later, probably in January 1941, one on each side of the forward superstructure. Each mount was fully enclosed to protect the crew from the muzzle blast of the larger guns and against splinters.<ref name=m99/> The guns fired {{convert|.732|kg|lb|adj=on|sp=us}} shells at a muzzle velocity of {{convert|880|m/s|ft/s|abbr=on}}. Their effective anti-aircraft range was {{convert|4000|m|sp=us|0}}.<ref>{{cite web|url=http://www.navweaps.com/Weapons/WNRussian_37mm-67_70-K.htm|title=Russia / USSR 37 mm/67 (1.5") 70-K|date=19 November 2008|access-date=3 January 2010|publisher=navweaps.com}}</ref>

===Fire control===
Each main gun turret was given a DM-12 {{convert|12|m|ftin|adj=on|sp=us}} [[Rangefinding telemeter|rangefinder]] for use in local control, but they were generally controlled by one of three KDP-8 [[Fire-control system#Naval fire control|fire-control directors]]. These had two {{convert|8|m|ftin|adj=on|sp=us}} [[stereoscopic rangefinder]]s, one to track the target and the other to measure the range to the ship's own shell splashes. Two of these were protected by {{convert|20|mm|abbr=on|1}} of armor and were mounted atop the rear superstructure and the tower-mast. The other was mounted on top of the [[conning tower]] and was protected by 50&nbsp;mm of armor. They used a TsAS-0 mechanical computer to generate firing solutions. Four KDP-4t-II directors, with two {{convert|4|m|ftin|adj=on|sp=us}} rangefinders each, controlled the secondary armament. One pair was on either side of the tower-mast and the aft pair was on each side of the aft funnel. Three SPN-300 stabilized directors, each with a 4-meter rangefinder, controlled the heavy anti-aircraft guns. There was one on each side of the forward funnel while the other was atop the rear superstructure.<ref>McLaughlin 2003, pp. 388–389</ref>

===Protection===
Soviet armor plate plants proved incapable of producing plates of [[Krupp armour|cemented armor]] thicker than {{convert|230|mm|abbr=on}} which forced the decision to replace cemented plates thicker than {{convert|200|mm|abbr=on}} with [[Case hardening|face-hardened]] ones with less resistance in November 1940. The plants tended to compensate by making the thicker plates harder, but this often made them more brittle and large numbers did not pass the acceptance tests. This would have significantly reduced the level of protection enjoyed by the ''Sovetsky Soyuz''-class ships in combat.<ref>McLaughlin 2003, pp. 387, 390</ref>

The ''Sovetsky Soyuz''-class ships devoted a total weight of {{convert|23306|t|LT|sp=us|0}} to armor protection, a slightly greater weight than that of the larger Japanese ''Yamato'' class ({{convert|23262|t|LT|sp=us}}). Their armor was intended to resist 406&nbsp;mm shells and 500&nbsp;kg bombs, specifically shells fired from forward bearings between 35° and 50° from the centerline. This led to the very unusual situation where the [[Belt armor|armor belt]] thickened toward the bow to compensate for the narrowing of the ship near the forward magazines, which had to be compensated for by thicker armor. The belt was {{convert|148.4|m|ftin|sp=us}} long and covered 57% of the total waterline length. It was inclined 5° to increase its resistance to flat-trajectory shells. Over the machinery spaces it was {{convert|375|mm|abbr=on}} thick and increased in steps until it was {{convert|420|mm|abbr=on}} thick over the forward magazines. It was {{convert|380|mm|abbr=on}} over the rear magazine. The belt armor was carried forward of the magazines at a thickness of {{convert|220|mm|abbr=on}} and terminated in a steeply sloped (30°) transverse {{convert|285|mm|abbr=on}} bulkhead that reduced to {{convert|250|mm|abbr=on}} at the lower deck where it was continued down to the inner bottom by a {{convert|75|mm|adj=on|sp=us|0}} bulkhead. Forward of this bulkhead was a 20&nbsp;mm splinter belt that continued all the way to the bow. The main armor belt dropped down to the main deck from the upper deck abreast the aft turret to reduce weight. This "step" was protected by {{convert|180|mm|adj=on|sp=us}} plates. A {{convert|365|mm|adj=on|sp=us}} transverse bulkhead separated the rear turret and the ship's sides. The main part of the armored citadel was closed off by a 230&nbsp;mm forward bulkhead and a 180&nbsp;mm rear bulkhead, both of homogeneous armor. Splinter armor {{convert|25|mm|abbr=on}} thick covered the upper portion of the citadel.<ref>McLaughlin 2003, pp. 190–192</ref>

The [[forecastle]] deck was 25&nbsp;mm thick while the upper deck was {{convert|155|mm|abbr=on}} over the citadel. Below it, the 50&nbsp;mm middle deck acted as a splinter deck. The upper deck was 100&nbsp;mm thick above the 220&nbsp;mm waterline belt extension. The bottom edge of the forward splinter belt met with a {{convert|65|mm|abbr=on}} arched deck. Another arched deck of the same thickness covered the stern aft of the rear transverse bulkhead.<ref name=m23>McLaughlin 2003, pp. 392–393</ref>

The main gun turrets had faces {{convert|495|mm|abbr=on}} thick with sides and roofs 230&nbsp;mm thick. {{convert|180|mm|adj=on|sp=us}} thick plates protected the gun ports and {{convert|60|mm|adj=on|sp=us}} bulkheads separated each gun. The barbettes were {{convert|425|mm|abbr=on}} thick above the upper deck. The MK-4 turrets had 100&nbsp;mm faces and 65&nbsp;mm sides. Their barbettes were 100&nbsp;mm in thickness, but reduced to 65&nbsp;mm on their inboard sides. 100&nbsp;mm of armor protected the faces, sides and backs of the MZ-14 turrets for the 100&nbsp;mm guns, but their roofs and barbettes were 100&nbsp;mm thick. The forward conning tower had walls 425&nbsp;mm thick while the rear conning tower had only {{convert|220|mm|abbr=on}}. The flag bridge in the tower-mast had {{convert|75|mm|abbr=on}} of protection.<ref name="m23" />

The [[torpedo]] defense system was designed to withstand torpedoes with warheads equivalent to {{convert|750|kg|abbr=on|0}} of [[Trinitrotoluene|TNT]]. The ships were intended to be able to remain afloat with any five adjacent compartments flooded or with three torpedo hits and the destruction of the unarmored above-water side. The [[Pugliese torpedo defense system|Pugliese system]] protected {{convert|123|m|ftin|sp=us}} of the ships' midsection. At the aft end was a multi-bulkhead protection system that extended another {{convert|33|m|ftin|sp=us}} to the rear from the Pugliese system. The depth of the system was {{convert|8.2|m|ftin|sp=us}} amidships, but it reduced to {{convert|7|m|ft|sp=us}} fore and aft. The outer plating ranged from {{convert|11|to|14|mm|abbr=on}} in thickness while the inner bottom was {{convert|7|mm|abbr=on}} thick. The cylinder of the Pugliese system was also 7&nbsp;mm thick while the semi-circular main bulkhead was {{convert|35|mm|abbr=on}} thick with a flat {{convert|10|mm|adj=on|sp=us}} bulkhead behind it. The {{convert|3.15|m|ftin|adj=on|sp=us}} diameter cylinder was intended to be immersed in [[fuel oil]] or water.<ref>McLaughlin 2003, p. 393</ref>

==Construction==
The August 1938 shipbuilding plan envisioned a total of 15 Project 23-class battleships, and this grandiose scheme was only slightly revised downward to 14 ships in the August 1939 plan. Eight of these were to be laid down before 1942 and the remaining six before 1947. However, only four were actually laid down before the outbreak of World War II forced the Soviets to reassess their ambitious plans. On 19 October 1940 an order was issued, signed by Stalin and [[Vyacheslav Molotov|Molotov]], that no new battleships would be laid down in order to concentrate on smaller ships' building (and also, probably, because more resources were required for the Army), one ship was to be scrapped, and priority should be given to only one of the three remaining battleships.<ref>Rohwer & Monakov, pp. 95, 120</ref>

The Soviet shipbuilding and related industries proved to be incapable of supporting the construction of so many large ships at the same time. The largest warships built in the Soviet Union prior to 1938 were the {{convert|8000|t|LT|adj=on|sp=us|0}} {{sclass|Kirov|cruiser|2}}s, and even they had suffered from a number of production problems, but the Soviet leadership appeared to ignore the difficulties encountered in the construction of the ''Kirov'' class when ordering 14 much more ambitious ships. Construction of two more ships planned for [[Saint Petersburg|Leningrad]] and [[Mykolaiv]] had to move to the brand-new [[Sevmash|Shipyard Nr. 402]] in [[Severodvinsk|Molotovsk]] because the existing shipyards could not be expanded to handle so many large ships. Components for these two ships had to be manufactured at Leningrad and shipped via the [[White Sea – Baltic Canal]] to Molotovsk. Also, the turret shop at Mykolaiv proved to be too poorly equipped to assemble the 406&nbsp;mm mountings and the propeller shafts had to be ordered in 1940 from Germany and the Netherlands as the domestic plants were already overburdened with orders. Shipbuilding steel proved to be in short supply in 1940, and a number of batches were rejected because they did not meet specifications. Armor plate production was even more problematic as only {{convert|1800|t|LT|sp=us|0}} of the anticipated {{convert|10000|t|LT|sp=us|0}} were delivered in 1939, and more than half of that was rejected. Furthermore, the armor plants proved to be incapable of making cemented plates over 230&nbsp;mm, and inferior [[Case hardening|face-hardened]] plates had to substitute for all thicknesses over 200&nbsp;mm.<ref>McLaughlin 2003, pp. 386–387</ref>

Machinery problems were likely to delay the ships well past their intended delivery dates of 1943–1944. Three turbines were delivered by Brown Boveri in 1939 to [[Arkhangelsk]] for ''Sovetskaya Rossiya'', but the Kharkhovskii Turbogenerator Works never completed a single turbine before the German invasion in June 1941. A prototype boiler was supposed to have been built ashore for evaluation, but it was not completed until early 1941, which further complicated the production plan.<ref>McLaughlin 2003, p. 387</ref>

Construction of all three ships was ordered halted on 10 July 1941, and ''Sovetsky Soyuz'' was placed into long-term conservation as the most advanced ship. However, all three were officially stricken from the Navy List on 10 September 1941.<ref name=m8/>

===''Sovetsky Soyuz''===
''Sovetsky Soyuz ({{lang|ru|Советский Союз}}–Soviet Union)'' was formally laid down 15 July 1938 in [[Baltic Shipyard|Shipyard Nr. 189 (Ordzhonikidze)]] in Leningrad, although evidence suggests that construction actually began in January 1939 after her slipway was completed, the necessary cranes were in place, and working drawings had been completed.<ref>Gribovskii, p. 166</ref> When the war began she was estimated to be 21.19% complete, with {{convert|15818|t|LT|sp=us|0}} of steel assembled on the slip. She was only lightly damaged by German air attacks and bombardments, and, as some material had been used during the [[siege of Leningrad]], she was estimated to be 19.5% complete after the end of the war. Some thought was given to completing her, but this was opposed as she was regarded as obsolete in light of the experience gained during the war. Stalin's expressed desire to see one of the Project 23-class ships completed only delayed the decision to scrap her; this was ordered on 29 May 1948 and was well underway by April 1949.<ref>McLaughlin 2003, pp. 411–413</ref>

===''Sovetskaya Ukraina''===
''Sovetskaya Ukraina ({{Lang|ru|Советская Украина}}–Soviet Ukraine)'' was laid down 31 October 1938 at [[Black Sea Shipyard|Shipyard Nr. 198 (Marti South)]] in Mykolaiv. When the war began she was 17.98% complete, with {{convert|13001|t|LT|sp=us|0}} assembled on the slipway. Some effort was made to launch the hull, but little work had been done to dredge the river at the foot of the slipway, and she was captured on 18 August 1941, although retreating Soviet troops slightly damaged her hull. The Germans dismantled {{convert|200|ft|0}} of her bow and {{convert|100|ft|0}} of her stern for use in fortifications. They were forced to evacuate Mykolaiv on 17 March 1944 and demolished the supporting blocks under her port side before they left, which gave her a [[list (watercraft)|list]] between 5 and 10 degrees and made her a total loss. She was ordered scrapped on 27 March 1947.<ref name=m4>McLaughlin 2003, pp. 379, 411, 413</ref>

===''Sovetskaya Rossiya''===
''Sovetskaya Rossiya ({{Lang|ru|Советская Россия}}–Soviet Russia)'' was laid down on 22 July 1940 in [[Sevmash|Shipyard Nr. 402]] in [[Severodvinsk|Molotovsk]]. After the end of the war she was only 0.97% complete, with {{convert|2125|t|LT|sp=us|0}} of steel assembled. She was ordered scrapped on 27 March 1947.<ref name=m4/>

===''Sovetskaya Belorussiya''===
''Sovetskaya Belorussiya ({{lang|ru|Советская Белоруссия}}–Soviet Belorussia)'' was laid down 21 December 1939 at Shipyard Nr. 402 in Molotovsk, but construction was suspended in mid-1940 when it was discovered that 70,000 [[rivet]]s used in her hull plating were of inferior quality. This fact probably influenced the decision to cancel her on 19 October 1940.<ref>McLaughlin 2003, pp. 379, 387</ref>  Material intended for her construction was used to construct a [[floating battery]] for the [[Siege of Leningrad|defense of Leningrad]].<ref name = Ireland94>Ireland, p. 94</ref>

===''Sovetskaya Gruziya''===

''Sovetskaya Gruziya'' ''({{lang|ru|Советская Грузия-Soviet Georgia}})'' was planned to be laid down in 1941 at the Baltic Works, but this was cancelled due to the invasion of the Soviet Union.<ref>McLaughlin 2021, p. 28</ref>

==See also==

* [[K-1000 battleship]], a purported class of Soviet battleships to succeed ''Sovetsky Soyuz'', promulgated hoax of the Soviet government.

==Notes==
{{reflist|group=Note}}

==References==
{{Reflist}}

==Bibliography==
* {{cite book|last=Braynard|first=Frank O.|author-link=Frank Braynard|title=By Their Works Ye Shall Know Them, The Life and Ships of William Francis Gibbs 1886–1967|publisher=Gibbs & Cox|year=1968|oclc=1192704|location=New York}}
*{{cite book|title=Conway's All the World's Fighting Ships 1922–1946|editor-last=Chesneau |publisher=Conway Maritime Press |location= Greenwich, UK|year=1980|isbn=0-85177-146-7 |last=Budzbon|first=Przemysław|pages=318–346|chapter=Soviet Union|editor-first=Roger}}
*{{cite book |last1=Budzbon |first1=Przemysław |last2=Radziemski |first2=Jan |last3=Twardowski |first3=Marek |title=Warships of the Soviet Fleets 1939–1945 |date=2022 |publisher=Naval Institute Press |location=Annapolis, Maryland |isbn=978-1-68247-877-6|volume=I: Major Combatants|name-list-style=amp}}
* {{cite book|last=Friedman|first=Norman|title=Naval Weapons of World War One: Guns, Torpedoes, Mines and ASW Weapons of All Nations: An Illustrated Directory|publisher=Seaforth |location=Barnsley, UK|year=2011|isbn=978-1-84832-100-7 |authorlink=Norman Friedman}} 
* {{cite journal|last=Gribovskii|first=V. Iu.|year=1993|title=The "Sovietskii Soiuz" Class Battleships|journal=Warship International |volume=XXX|issue=2|pages=150–169|issn=0043-0374}}
* {{cite book|last=Ireland|first=Bernard|author-link=Bernard Ireland|title=Jane's Battleships of the 20th Century|publisher=HarperCollins |location=London|year=1996|isbn=0-00-470997-7}}
* {{cite book|last=McLaughlin|first=Stephen|title=Russian & Soviet Battleships|publisher=Naval Institute Press |location=Annapolis, Maryland|year=2003|isbn=1-55750-481-4}}
*{{cite book |last1=McLaughlin |first1=Stephen |editor1-last=Jordan |editor1-first=John |title=Warship 2021 |date=2021 |publisher=Osprey Publishing |location=Oxford, UK |isbn=978-1-4728-4779-9 |chapter=Stalin's Super-battleships: The ''Sovietskii Soyuz'' Class|pages=8–28}}
*{{cite book|last1=Rohwer|first1=Jürgen|last2=Monakov|first2=Mikhail S.|title=Stalin's Ocean-Going Fleet: Soviet Naval Strategy and Shipbuilding Programs 1935–1953|publisher=Frank Cass |location=London |year=2001|isbn=0-7146-4895-7|name-list-style=amp|author-link1=Jürgen Rohwer}}
* {{cite book|last=Westwood|first=J. N.|title=Russian Naval Construction, 1905–45|publisher=Macmillan |location=London |year=1994 |isbn=0-333-55553-8}}


==External links==
* [https://web.archive.org/web/20060704210410/http://web.ukonline.co.uk/aj.cashmore/russia/battleships/sovietskysoyuz/sovietskysoyuz.html Class specifications]
* [http://ship.bsu.by/main.asp?id=100157 Article from ship.bsu.by] {{Webarchive|url=https://web.archive.org/web/20080110163757/http://ship.bsu.by/main.asp?id=100157 |date=2008-01-10 }} {{in lang|ru}}
* [http://www.battleships.spb.ru/0796/history.html Article from www.battleships.spb.ru] {{in lang|ru}}

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[[Category:Battleship classes]]
[[Category:World War II battleships of the Soviet Union]]
[[Category:Abandoned military projects of the Soviet Union]]
[[Category:Proposed ships]]
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