Kronshtadt class battlecruiser
Encyclopedia
The Kronshtadt-class battlecruiser
s, with the Soviet
designation as Project 69 heavy cruisers, , were ordered for the Soviet Navy
in the late 1930s. Two ships were started but none were completed due to World War II
. These ships had a complex and prolonged design process which was hampered by constantly changing requirements and the Great Purge
in 1937. They were laid down in 1939, with an estimated completion date in 1944, but Stalin's naval construction program proved to be more than the shipbuilding and armaments industries could handle. Prototypes of the armament and machinery had not even been completed by 22 June 1941, almost two years after the start of construction. This is why the Soviets bought twelve surplus 38 centimetres (15 in) SK C/34 guns, and their twin turrets, similar to those used in the s, from Germany
in 1940. The ships were partially redesigned to accommodate them, after construction had already begun, but no turrets were actually delivered before Operation Barbarossa
.
Only Kronshtadts hull survived the war reasonably intact and was about 10% complete in 1945. She was judged obsolete and the Soviets considered converting her into an aircraft carrier, but the idea was rejected and both hulls were scrap
ped in 1947.
, to which the Soviets were not a signatory. Several designs were submitted by the end of 1935, but the Navy was not satisfied and rejected all of them. It asked for another design, displacing 23000 tonnes (22,637 LT) and armed with 254 millimetres (10 in) guns, in early 1936, eventually designated Project 22, but this design was cancelled after the Soviets began negotiations in mid-1936 with the British that ultimately resulted in the Anglo-Soviet Quantitative Naval Agreement of 1937 and agreed to follow the terms of the Second London Naval Treaty
which limited battleships to a displacement of 35000 LT. The Soviets had been working on a small battleship design (Battleship 'B') for service in the Baltic
and Black Sea
s and had to shrink it as a result of these discussions to a size close to that of the Project 22 large cruiser so that the latter was cancelled. Battleship 'B' was redesignated as Project 25 and given the task of destroying Treaty cruisers and German pocket battleships
. The Project 25 design was accepted in mid-1937 after major revisions in the armor scheme and the machinery layout and four were ordered with construction to begin in late 1937 and early 1938. However, this decision occurred right before the Great Purge began to hit the Navy in August 1937 and two of the ship's designers were arrested and executed within a year. The Project 25 design was then rejected on the grounds that it was too weak compared to foreign ships and the whole program was cancelled in early 1938 after an attempt to modify the design with larger guns had been made.
However the Soviet Navy still felt a need for a fast ship that could deal with enemy cruisers and the original concept was revived as Project 69. They wanted a ship not to exceed 23,000 metric tons with a speed of 34 knots and an armament of nine 254 mm guns, but the requirement proved to be too ambitious for the specified size and it increased to 26200 tonnes (25,786 LT) in the design submitted in June 1938. By this time, however, details were becoming available for the s and the ship was deemed inferior to the German ships. The State Defense Committee revised the requirements and specified a size about 31000 tonnes (30,510 LT), an armament of nine 305 millimetres (12 in) guns, an armor belt
250 mm (9.8 in) thick and a speed about 31 knots. A revised design was finished by October which was wargamed against the Japanese s, the French s as well as the Scharnhorst-class. It was deemed superior to the Kongos at medium range and inferior to the Dunkerques at the same range, but generally superior to the Scharnhorsts, although it is doubtful that the Soviets were fully aware of the true specifications of the Kongos as rebuilt or of the Scharnhorsts as the displacement of the latter had been given as 26000 tonnes (25,589 LT), more than 5000 tonnes (4,921 LT) short of their true displacement. The Navy's Shipbuilding Administration thought that the original secondary armament of 130 millimetres (5.1 in) guns was too small and that the armor on the turrets, conning tower and the forward transverse bulkhead was too thin. A revised, 35,000-ton design with 152 millimetres (6 in) guns and extra armor was submitted to the State Defense Council in January 1939.
This was approved and the detailed design work began with the basic concept that the ship should be superior to the Scharnhorst-class ships and able to outrun the s. At this time the horizontal protection was revised after full-scale trials revealed that a 500 kilograms (1,102.3 lb) bomb would penetrate both a 40 millimetres (1.6 in) upper deck and a 50 millimetres (2 in) middle deck to burst on the main armor deck. So the middle deck was thickened to 90 millimetres (3.5 in) with the lower deck intended to catch any splinters penetrating the armor deck. This mean that the main belt had to be extended upwards to meet the main armor deck at a significant penalty in weight. The Defense Committee approved the sketch design on 13 July 1939, but the detailed design was not approved until 12 April 1940, after construction had already begun on the first two ships.
It was already apparent that the 305 mm guns and turrets were well behind schedule when Joseph Stalin
asked the German representatives in Moscow
on 8 February 1940 to negotiate a trade agreement if it would be possible to use the triple 283 millimetres (11.1 in) turrets in lieu of the triple 305 mm turrets of the Project 69 ships. They replied that the turrets were out of production, but new ones could be built. He then asked if twin 380 millimetres (15 in) turrets could be used instead. The Germans said that they would have to check back for the technical details. Krupp
had six incomplete turrets on hand that had originally been ordered before the war to rearm the Scharnhorst-class battleships, but they were cancelled after the start of World War II when the Germans decided that they could not afford to have the ships out of service during the war. A preliminary purchase agreement was made to buy twelve guns and six turrets later that month, well before any studies were even made to see if the substitution was even possible. The Shipbuilding Commissariat reported on 17 April that it was possible so the agreement was finalized in November 1940 with the deliveries scheduled from October 1941 to 28 March 1943. The order also included 10 metres (32.8 ft) rangefinder
s and 150 centimetres (59.1 in) searchlights.
The Soviets never did get the detailed data required to redesign the ship's barbettes and magazine
s, but they did know that the 380-mm barbettes was bigger in diameter than that of the 305 mm turret as well as taller than the Russian turrets. So the barbette of turret number two had to be raised to clear turret number one and the height of the conning tower had to be raised to clear turret number two. Similarly the 37 millimetres (1.5 in) anti-aircraft
guns behind turret number three had to raised as well. The new turrets required more electrical power which meant that the output of the turbo generator
s had to be increased to 1,300 kilowatts. All of these changes added over 1000 tonnes (984 LT) to the ships' displacement and the sketch design was completed by 16 October 1940, as Project 69-I (Importnyi—Imported), even though they still lacked data for the turrets and their barbettes. This was presented to the State Defense Committee on 11 February 1941, but the design was not approved until 10 April when it ordered that the first two ships be completed with German guns while the others would continue to use the 305 mm guns. The detailed design was supposed to be completed by 15 October 1941, but it was rendered pointless when the Germans invaded the Soviet Union
in June.
of 240 metre. They had a beam
of 31.6 metre and at full load a draft of 9.45 metre. As designed they displaced 35240 tonnes (34,683 LT) at standard load and 41539 tonnes (40,883 LT) at full load. The displacement of the two Project 69-I-class ships increased to 36250 tonnes (35,677 LT) at standard load and 42831 tonnes (42,154 LT) at full load which increased the draft to 9.7 metre at full load while the waterline length grew to 242.1 metre simply because the extra draft submerged more of the sharply raked stem and spoon-shaped stern. The speed remained the same as the deeper draft was offset by a more efficient propeller form.
The hull form was very full with a block coefficient
of 0.61 which compared badly to the 0.54 of the Dunkerque, the 0.52 of the German or the 0.5266 of the American . This meant that a lot of horsepower was necessary to achieve even modest speeds. Stalin's decision that the Project 69 ships would use three shafts increased the shaft loading and reduced propulsive efficiency, although it did shorten the length of the armored citadel and thus overall displacement. The riveted hull was subdivided by 24 transverse bulkheads and used longitudinal framing in the citadel, but transverse framing for the structure fore and aft of the citadel. The metacentric height
was 2.8 metre for the 305 mm gunned ships, but dropped to 2.58 metre in the 380 mm gunned ships. The tactical diameter was estimated at about 1200 metres (1,312 yd).
The Kronshtadt-class ships were provided with two KOR-2
flying boat
s which would be launched by the catapult
mounted between the funnels.
s were an imported Brown Boveri
design shared with the , but the factory in Kharkiv
that was to build them never finished a single turbine before the Germans invaded. They produced a total of 210000 shp. Twelve 7u-bis water-tube boiler
s worked at a pressure of 37 kg/cm2 and temperature of 380 °C (716 °F). There were two other small boilers for harbor service and to power the auxiliary machinery. The electrical plant originally consisted of four 1200 kW turbo generators and four 650 kW diesel generators, but these were upgraded for the Project 69-I ships.
Maximum speed was estimated at 31 knots (16.9 m/s), using the revised propeller design, although forcing the machinery would yield an extra knot. The normal fuel oil
capacity was 2920 tonnes (2,874 LT), which provided an estimated endurance of 1100 nautical mile at full speed. Maximum fuel capacity was 5570 tonnes (5,482 LT) which gave a range of 8300 nautical mile at 14.5 knots (7.9 m/s) and 6900 nautical mile at 16.5 knots (9 m/s).
305 mm B-50 guns. The turrets were based on the MK-2 turrets planned for the Project 25 large cruiser. The guns could be depressed to −3° and elevated to 45°. They had a fixed loading angle of 6° and their rate of fire varied with the time required to relay the gun. It ranged from 2.36 to 3.24 rounds per minute depending on the elevation. The turrets could elevate at a rate of 10 degrees per second and traverse at 5.1 degrees per second. 100 rounds per gun were carried. The gun fired 470 kilograms (1,036.2 lb) armor-piercing
projectiles at a muzzle velocity
of 900 m/s (2,952.8 ft/s); this provided a maximum range of 47580 metres (52,034.1 yd).
The secondary armament consisted of eight 57-caliber B-38 152 mm guns mounted in four dual MK-4 turrets concentrated at the forward end of the superstructure. The forward turrets were inboard and above the outer turrets which provided both turrets with good arcs of fire. 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. 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 30000 metres (32,808.4 yd) with a 55 kilograms (121.3 lb) shell at a muzzle velocity of 950 m/s (3,116.8 ft/s).
Heavy anti-aircraft (AA) fire was provided by eight 56-caliber 100 mm B-34 dual-purpose guns in four twin MZ-16 turrets mounted at the aft end of the superstructure with the aft turrets mounted inboard of the forward turrets. They could elevate to a maximum of 85° and depress to -8°. They could traverse at a rate of 12° per second and elevate at 10° per second. They fired 15.6 kilograms (34.4 lb) high explosive shells at a muzzle velocity of 895 m/s (2,936.4 ft/s); this provided a maximum range of 22241 metres (24,323.1 yd) against surface targets, but their maximum range against aerial targets was 9895 metres (32,463.9 ft), the limit of their time fuse.
Light AA defense was handled by six quadruple, water-cooled, 46-K mounts fitted with 37 mm (1.5 in) 70-K guns. Two mounts were abreast the forward funnel, two just abaft the rear funnel and the last two on the centerline of the aft superstructure superfiring
over the rear main gun turret. Initially seven mounts were planned, but the one above the conning tower
was exchanged for a director for the 100 mm guns in early 1940 when the Navy realized that the other directors were blocked by the superstructure. The guns fired 0.732 kilograms (1.6 lb) shells at a muzzle velocity of 880 m/s (2,887 ft/s). Their effective anti-aircraft range was 4000 metres (13,123 ft).
The Germans sold the Soviets twelve 52-caliber 38 centimetres (15 in) SKC/34 guns and their associated Drh LC/34 turrets as part of the Molotov–Ribbentrop Pact. Their elevation limits were -5.5° to +30° with a fixed loading angle of 2.5°. Their rate of fire was 2.3 rounds per minute. The turrets could elevate at a rate of 6° per second and traverse at 5° per second. They had a maximum range of 36520 metres (39,938.8 yd) with a 800 kilograms (1,763.7 lb) shell at a muzzle velocity of 820 m/s (2,690.3 ft/s).
The main turrets had 305 mm faces and backs and 125 millimetres (4.9 in) sides and roofs. Their barbettes were protected with 330 mm of armor. The secondary turrets had 100 mm faces with 50 millimetres (2 in) sides and roofs and 75 millimetres (3 in) barbettes. The dual-purpose mountings had 50 mm armor with 40 millimetres (1.6 in) barbettes. The conning tower had 330 mm sides and a 125 mm roof with a 230 mm communications tube running down to the armor deck. The admiral's bridge was protected with 50 mm armor. Each of the directors had 14 mm of armor as did the 37 mm gun mounts. The funnels had 20 mm armor for their entire height above the deck and a 50 mm box protected the smoke generators.
and Nikolayev
had less than half the workers intended. Shipbuilding steel proved to be in short supply in 1939–1940 and a number of batches were rejected because they did not meet specifications. An attempt to import 14000 long tons (14,225 t) of steel and armor plate from the United States in 1939 failed, probably as a result of the Soviet invasion of Poland on 17 September 1939. Armor plate production was even more problematic as only 27438 tonnes (27,005 LT) were delivered in 1940 of the anticipated 30000–32000 t (29,526.1–31,494.5 LT) and 30–40% of that was rejected. Furthermore the armor plants proved to be incapable of making cemented plates over 230 mm and inferior face-hardened
plates had to substituted for all thicknesses over 200 millimetres (7.9 in).
Machinery problems were likely to delay the ships well past their intended delivery dates of 1943–44. The Kharkhovskii Turbogenerator Works never completed a single turbine before the German invasion in June 1941. Another problem were the 305 mm guns and turrets as the armament factories were focused on the higher-priority guns for the Sovetsky Soyuz-class battleships. Prototypes of neither had been completed by the time the Germans invaded. The situation was not much better for the smaller guns as mountings for both the 152 mm and 100 mm guns were still incomplete on 22 June 1941 and all of these programs were terminated quickly afterwards.
Kronshtadt was built by the Shipyard No. 194, Marti
in Leningrad. She was laid down 30 November 1939 and judged 10.6% complete when the Germans invaded. Her building slip was too short for her entire length so her stern was built separately. Some of her material was used during the Siege of Leningrad
to repair other ships and in defensive works, but she could have been finished after the end of the war. Proposals were made to complete her as an aircraft carrier and as a base ship for a whaling flotilla, but both ideas were rejected and she was ordered scrapped on 24 March 1947. Her dismantling began shortly afterwards and was completed the following year.
Sevastopol was built by Shipyard No. 200, 61 Communards
in Nikolayev. She was laid down on 5 November 1939 and estimated as 11.6% complete on 22 June 1941. She was captured by the Germans when they occupied Nikolayev in late 1941, but the Germans did little with her other than to use some of her material for defensive positions and some was apparently shipped to Germany. Before the Germans evacuated the city they damaged her building slip and hull with explosives and made her a constructive total loss. She was ordered scrapped on 24 March 1947 and her dismantling began shortly afterwards. It was completed in 1948.
Battlecruiser
Battlecruisers were large capital ships built in the first half of the 20th century. They were developed in the first decade of the century as the successor to the armoured cruiser, but their evolution was more closely linked to that of the dreadnought battleship...
s, with the Soviet
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
designation as Project 69 heavy cruisers, , were ordered for the Soviet Navy
Soviet Navy
The Soviet Navy was the naval arm of the Soviet Armed Forces. Often referred to as the Red Fleet, the Soviet Navy would have played an instrumental role in a Warsaw Pact war with NATO, where it would have attempted to prevent naval convoys from bringing reinforcements across the Atlantic Ocean...
in the late 1930s. Two ships were started but none were completed due to World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. These ships had a complex and prolonged design process which was hampered by constantly changing requirements and the Great Purge
Great Purge
The Great Purge was a series of campaigns of political repression and persecution in the Soviet Union orchestrated by Joseph Stalin from 1936 to 1938...
in 1937. They were laid down in 1939, with an estimated completion date in 1944, but Stalin's naval construction program proved to be more than the shipbuilding and armaments industries could handle. Prototypes of the armament and machinery had not even been completed by 22 June 1941, almost two years after the start of construction. This is why the Soviets bought twelve surplus 38 centimetres (15 in) SK C/34 guns, and their twin turrets, similar to those used in the s, from Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
in 1940. The ships were partially redesigned to accommodate them, after construction had already begun, but no turrets were actually delivered before Operation Barbarossa
Operation Barbarossa
Operation Barbarossa was the code name for Germany's invasion of the Soviet Union during World War II that began on 22 June 1941. Over 4.5 million troops of the Axis powers invaded the USSR along a front., the largest invasion in the history of warfare...
.
Only Kronshtadts hull survived the war reasonably intact and was about 10% complete in 1945. She was judged obsolete and the Soviets considered converting her into an aircraft carrier, but the idea was rejected and both hulls were scrap
Scrap
Scrap is a term used to describe recyclable and other materials left over from every manner of product consumption, such as parts of vehicles, building supplies, and surplus materials. Unlike waste, scrap has significant monetary value...
ped in 1947.
Design
The Kronshtadt-class battlecruisers had their origin in a mid-1930s requirement for a large cruiser capable of destroying 10000 long tons (10,161 t) cruisers built to the limits imposed by the Washington Naval TreatyWashington Naval Treaty
The Washington Naval Treaty, also known as the Five-Power Treaty, was an attempt to cap and limit, and "prevent 'further' costly escalation" of the naval arms race that had begun after World War I between various International powers, each of which had significant naval fleets. The treaty was...
, to which the Soviets were not a signatory. Several designs were submitted by the end of 1935, but the Navy was not satisfied and rejected all of them. It asked for another design, displacing 23000 tonnes (22,637 LT) and armed with 254 millimetres (10 in) guns, in early 1936, eventually designated Project 22, but this design was cancelled after the Soviets began negotiations in mid-1936 with the British that ultimately resulted in the Anglo-Soviet Quantitative Naval Agreement of 1937 and agreed to follow the terms of the Second London Naval Treaty
Second London Naval Treaty
The Second London Naval Disarmament Conference opened in London, the United Kingdom, on 9 December 1935. It resulted in the Second London Naval Treaty which was signed on 25 March 1936.- Description :...
which limited battleships to a displacement of 35000 LT. The Soviets had been working on a small battleship design (Battleship 'B') for service in the Baltic
Baltic Sea
The Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...
and Black Sea
Black Sea
The Black Sea is bounded by Europe, Anatolia and the Caucasus and is ultimately connected to the Atlantic Ocean via the Mediterranean and the Aegean seas and various straits. The Bosphorus strait connects it to the Sea of Marmara, and the strait of the Dardanelles connects that sea to the Aegean...
s and had to shrink it as a result of these discussions to a size close to that of the Project 22 large cruiser so that the latter was cancelled. Battleship 'B' was redesignated as Project 25 and given the task of destroying Treaty cruisers and German pocket battleships
Deutschland class cruiser
The Deutschland class was a series of three panzerschiffe , a form of heavily armed cruiser, built by the Reichsmarine officially in accordance with restrictions imposed by the Treaty of Versailles...
. The Project 25 design was accepted in mid-1937 after major revisions in the armor scheme and the machinery layout and four were ordered with construction to begin in late 1937 and early 1938. However, this decision occurred right before the Great Purge began to hit the Navy in August 1937 and two of the ship's designers were arrested and executed within a year. The Project 25 design was then rejected on the grounds that it was too weak compared to foreign ships and the whole program was cancelled in early 1938 after an attempt to modify the design with larger guns had been made.
However the Soviet Navy still felt a need for a fast ship that could deal with enemy cruisers and the original concept was revived as Project 69. They wanted a ship not to exceed 23,000 metric tons with a speed of 34 knots and an armament of nine 254 mm guns, but the requirement proved to be too ambitious for the specified size and it increased to 26200 tonnes (25,786 LT) in the design submitted in June 1938. By this time, however, details were becoming available for the s and the ship was deemed inferior to the German ships. The State Defense Committee revised the requirements and specified a size about 31000 tonnes (30,510 LT), an armament of nine 305 millimetres (12 in) guns, an armor belt
Belt armor
Belt armor is a layer of heavy metal armor plated on to or within outer hulls of warships, typically on battleships, battlecruisers and cruisers, and on aircraft carriers converted from those types of ships....
250 mm (9.8 in) thick and a speed about 31 knots. A revised design was finished by October which was wargamed against the Japanese s, the French s as well as the Scharnhorst-class. It was deemed superior to the Kongos at medium range and inferior to the Dunkerques at the same range, but generally superior to the Scharnhorsts, although it is doubtful that the Soviets were fully aware of the true specifications of the Kongos as rebuilt or of the Scharnhorsts as the displacement of the latter had been given as 26000 tonnes (25,589 LT), more than 5000 tonnes (4,921 LT) short of their true displacement. The Navy's Shipbuilding Administration thought that the original secondary armament of 130 millimetres (5.1 in) guns was too small and that the armor on the turrets, conning tower and the forward transverse bulkhead was too thin. A revised, 35,000-ton design with 152 millimetres (6 in) guns and extra armor was submitted to the State Defense Council in January 1939.
This was approved and the detailed design work began with the basic concept that the ship should be superior to the Scharnhorst-class ships and able to outrun the s. At this time the horizontal protection was revised after full-scale trials revealed that a 500 kilograms (1,102.3 lb) bomb would penetrate both a 40 millimetres (1.6 in) upper deck and a 50 millimetres (2 in) middle deck to burst on the main armor deck. So the middle deck was thickened to 90 millimetres (3.5 in) with the lower deck intended to catch any splinters penetrating the armor deck. This mean that the main belt had to be extended upwards to meet the main armor deck at a significant penalty in weight. The Defense Committee approved the sketch design on 13 July 1939, but the detailed design was not approved until 12 April 1940, after construction had already begun on the first two ships.
It was already apparent that the 305 mm guns and turrets were well behind schedule when Joseph Stalin
Joseph Stalin
Joseph Vissarionovich Stalin was the Premier of the Soviet Union from 6 May 1941 to 5 March 1953. He was among the Bolshevik revolutionaries who brought about the October Revolution and had held the position of first General Secretary of the Communist Party of the Soviet Union's Central Committee...
asked the German representatives in Moscow
Moscow
Moscow is the capital, the most populous city, and the most populous federal subject of Russia. The city is a major political, economic, cultural, scientific, religious, financial, educational, and transportation centre of Russia and the continent...
on 8 February 1940 to negotiate a trade agreement if it would be possible to use the triple 283 millimetres (11.1 in) turrets in lieu of the triple 305 mm turrets of the Project 69 ships. They replied that the turrets were out of production, but new ones could be built. He then asked if twin 380 millimetres (15 in) turrets could be used instead. The Germans said that they would have to check back for the technical details. Krupp
Krupp
The Krupp family , a prominent 400-year-old German dynasty from Essen, have become famous for their steel production and for their manufacture of ammunition and armaments. The family business, known as Friedrich Krupp AG Hoesch-Krupp, was the largest company in Europe at the beginning of the 20th...
had six incomplete turrets on hand that had originally been ordered before the war to rearm the Scharnhorst-class battleships, but they were cancelled after the start of World War II when the Germans decided that they could not afford to have the ships out of service during the war. A preliminary purchase agreement was made to buy twelve guns and six turrets later that month, well before any studies were even made to see if the substitution was even possible. The Shipbuilding Commissariat reported on 17 April that it was possible so the agreement was finalized in November 1940 with the deliveries scheduled from October 1941 to 28 March 1943. The order also included 10 metres (32.8 ft) rangefinder
Rangefinder
A rangefinder is a device that measures distance from the observer to a target, for the purposes of surveying, determining focus in photography, or accurately aiming a weapon. Some devices use active methods to measure ; others measure distance using trigonometry...
s and 150 centimetres (59.1 in) searchlights.
The Soviets never did get the detailed data required to redesign the ship's barbettes and magazine
Magazine (artillery)
Magazine is the name for an item or place within which ammunition is stored. It is taken from the Arabic word "makahazin" meaning "warehouse".-Ammunition storage areas:...
s, but they did know that the 380-mm barbettes was bigger in diameter than that of the 305 mm turret as well as taller than the Russian turrets. So the barbette of turret number two had to be raised to clear turret number one and the height of the conning tower had to be raised to clear turret number two. Similarly the 37 millimetres (1.5 in) anti-aircraft
Anti-aircraft warfare
NATO defines air defence as "all measures designed to nullify or reduce the effectiveness of hostile air action." They include ground and air based weapon systems, associated sensor systems, command and control arrangements and passive measures. It may be to protect naval, ground and air forces...
guns behind turret number three had to raised as well. The new turrets required more electrical power which meant that the output of the turbo generator
Turbo generator
A turbo generator is a turbine directly connected to an electric generator for the generation of electric power. Large steam powered turbo generators provide the majority of the world's electricity and are also used by steam powered turbo-electric ships.Smaller turbo-generators with gas turbines...
s had to be increased to 1,300 kilowatts. All of these changes added over 1000 tonnes (984 LT) to the ships' displacement and the sketch design was completed by 16 October 1940, as Project 69-I (Importnyi—Imported), even though they still lacked data for the turrets and their barbettes. This was presented to the State Defense Committee on 11 February 1941, but the design was not approved until 10 April when it ordered that the first two ships be completed with German guns while the others would continue to use the 305 mm guns. The detailed design was supposed to be completed by 15 October 1941, but it was rendered pointless when the Germans invaded the Soviet Union
Operation Barbarossa
Operation Barbarossa was the code name for Germany's invasion of the Soviet Union during World War II that began on 22 June 1941. Over 4.5 million troops of the Axis powers invaded the USSR along a front., the largest invasion in the history of warfare...
in June.
General characteristics
The Project 69-class ships were 250.5 metre long overall and had a waterline lengthWaterline length
The Waterline length is a measurement of ships and boats. The term denotes the length of the vessel at the point where it sits in the water. It excludes the total length of the boat, such as features that are out of the water...
of 240 metre. They had a beam
Beam (nautical)
The beam of a ship is its width at the widest point. Generally speaking, the wider the beam of a ship , the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position...
of 31.6 metre and at full load a draft of 9.45 metre. As designed they displaced 35240 tonnes (34,683 LT) at standard load and 41539 tonnes (40,883 LT) at full load. The displacement of the two Project 69-I-class ships increased to 36250 tonnes (35,677 LT) at standard load and 42831 tonnes (42,154 LT) at full load which increased the draft to 9.7 metre at full load while the waterline length grew to 242.1 metre simply because the extra draft submerged more of the sharply raked stem and spoon-shaped stern. The speed remained the same as the deeper draft was offset by a more efficient propeller form.
The hull form was very full with a block coefficient
Hull (watercraft)
A hull is the watertight body of a ship or boat. Above the hull is the superstructure and/or deckhouse, where present. The line where the hull meets the water surface is called the waterline.The structure of the hull varies depending on the vessel type...
of 0.61 which compared badly to the 0.54 of the Dunkerque, the 0.52 of the German or the 0.5266 of the American . This meant that a lot of horsepower was necessary to achieve even modest speeds. Stalin's decision that the Project 69 ships would use three shafts increased the shaft loading and reduced propulsive efficiency, although it did shorten the length of the armored citadel and thus overall displacement. The riveted hull was subdivided by 24 transverse bulkheads and used longitudinal framing in the citadel, but transverse framing for the structure fore and aft of the citadel. The metacentric height
Metacentric height
The metacentric height is a measurement of the static stability of a floating body. It is calculated as the distance between the centre of gravity of a ship and its metacentre . A larger metacentric height implies greater stability against overturning...
was 2.8 metre for the 305 mm gunned ships, but dropped to 2.58 metre in the 380 mm gunned ships. The tactical diameter was estimated at about 1200 metres (1,312 yd).
The Kronshtadt-class ships were provided with two KOR-2
Beriev Be-4
-External links:* at Century of Flight* at Russian Aviation Museum...
flying boat
Flying boat
A flying boat is a fixed-winged seaplane with a hull, allowing it to land on water. It differs from a float plane as it uses a purpose-designed fuselage which can float, granting the aircraft buoyancy. Flying boats may be stabilized by under-wing floats or by wing-like projections from the fuselage...
s which would be launched by the catapult
Aircraft catapult
An aircraft catapult is a device used to launch aircraft from ships—in particular aircraft carriers—as a form of assisted take off. It consists of a track built into the flight deck, below which is a large piston or shuttle that is attached through the track to the nose gear of the aircraft, or in...
mounted between the funnels.
Propulsion
The power plant was laid out on a unit system. The forward boiler room contained eight boilers and was followed by an engine room for the two wing propeller shafts. The second boiler room contained four boilers and was followed by a turbine room for the central shaft. The single-reduction, impulse-reduction geared steam turbineSteam turbine
A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Sir Charles Parsons in 1884....
s were an imported Brown Boveri
Brown, Boveri & Cie
Brown, Boveri & Cie was a Swiss group of electrical engineering companies.It was founded in Baden, Switzerland, in 1891 by Charles Eugene Lancelot Brown and Walter Boveri who worked at the Maschinenfabrik Oerlikon. In 1970 BBC took over the Maschinenfabrik Oerlikon...
design shared with the , but the factory in Kharkiv
Kharkiv
Kharkiv or Kharkov is the second-largest city in Ukraine.The city was founded in 1654 and was a major centre of Ukrainian culture in the Russian Empire. Kharkiv became the first city in Ukraine where the Ukrainian Soviet Socialist Republic was proclaimed in December 1917 and Soviet government was...
that was to build them never finished a single turbine before the Germans invaded. They produced a total of 210000 shp. Twelve 7u-bis water-tube boiler
Water-tube boiler
A water tube boiler is a type of boiler in which water circulates in tubes heated externally by the fire. Fuel is burned inside the furnace, creating hot gas which heats water in the steam-generating tubes...
s worked at a pressure of 37 kg/cm2 and temperature of 380 °C (716 °F). There were two other small boilers for harbor service and to power the auxiliary machinery. The electrical plant originally consisted of four 1200 kW turbo generators and four 650 kW diesel generators, but these were upgraded for the Project 69-I ships.
Maximum speed was estimated at 31 knots (16.9 m/s), using the revised propeller design, although forcing the machinery would yield an extra knot. The normal fuel oil
Fuel oil
Fuel oil is a fraction obtained from petroleum distillation, either as a distillate or a residue. Broadly speaking, fuel oil is any liquid petroleum product that is burned in a furnace or boiler for the generation of heat or used in an engine for the generation of power, except oils having a flash...
capacity was 2920 tonnes (2,874 LT), which provided an estimated endurance of 1100 nautical mile at full speed. Maximum fuel capacity was 5570 tonnes (5,482 LT) which gave a range of 8300 nautical mile at 14.5 knots (7.9 m/s) and 6900 nautical mile at 16.5 knots (9 m/s).
Armament
The main armament consisted of three electrically powered MK-15 triple turrets, each with three 54-caliberCaliber (artillery)
In artillery, caliber or calibredifference in British English and American English spelling is the internal diameter of a gun barrel, or by extension a relative measure of the length....
305 mm B-50 guns. The turrets were based on the MK-2 turrets planned for the Project 25 large cruiser. The guns could be depressed to −3° and elevated to 45°. They had a fixed loading angle of 6° and their rate of fire varied with the time required to relay the gun. It ranged from 2.36 to 3.24 rounds per minute depending on the elevation. The turrets could elevate at a rate of 10 degrees per second and traverse at 5.1 degrees per second. 100 rounds per gun were carried. The gun fired 470 kilograms (1,036.2 lb) armor-piercing
Armor-piercing shot and shell
An armor-piercing shell is a type of ammunition designed to penetrate armor. From the 1860s to 1950s, a major application of armor-piercing projectiles was to defeat the thick armor carried on many warships. From the 1920s onwards, armor-piercing weapons were required for anti-tank missions...
projectiles at a muzzle velocity
Muzzle velocity
Muzzle velocity is the speed a projectile has at the moment it leaves the muzzle of the gun. Muzzle velocities range from approximately to in black powder muskets , to more than in modern rifles with high-performance cartridges such as the .220 Swift and .204 Ruger, all the way to for tank guns...
of 900 m/s (2,952.8 ft/s); this provided a maximum range of 47580 metres (52,034.1 yd).
The secondary armament consisted of eight 57-caliber B-38 152 mm guns mounted in four dual MK-4 turrets concentrated at the forward end of the superstructure. The forward turrets were inboard and above the outer turrets which provided both turrets with good arcs of fire. 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. 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 30000 metres (32,808.4 yd) with a 55 kilograms (121.3 lb) shell at a muzzle velocity of 950 m/s (3,116.8 ft/s).
Heavy anti-aircraft (AA) fire was provided by eight 56-caliber 100 mm B-34 dual-purpose guns in four twin MZ-16 turrets mounted at the aft end of the superstructure with the aft turrets mounted inboard of the forward turrets. They could elevate to a maximum of 85° and depress to -8°. They could traverse at a rate of 12° per second and elevate at 10° per second. They fired 15.6 kilograms (34.4 lb) high explosive shells at a muzzle velocity of 895 m/s (2,936.4 ft/s); this provided a maximum range of 22241 metres (24,323.1 yd) against surface targets, but their maximum range against aerial targets was 9895 metres (32,463.9 ft), the limit of their time fuse.
Light AA defense was handled by six quadruple, water-cooled, 46-K mounts fitted with 37 mm (1.5 in) 70-K guns. Two mounts were abreast the forward funnel, two just abaft the rear funnel and the last two on the centerline of the aft superstructure superfiring
Superfire
The idea of superfire is to locate two turrets in a row, one behind the other, but with the second turret located above the one in front so that the second turret could fire over the first...
over the rear main gun turret. Initially seven mounts were planned, but the one above the conning tower
Conning tower
A conning tower is a raised platform on a ship or submarine, often armored, from which an officer can con the vessel; i.e., give directions to the helmsman. It is usually located as high on the ship as practical, to give the conning team good visibility....
was exchanged for a director for the 100 mm guns in early 1940 when the Navy realized that the other directors were blocked by the superstructure. The guns fired 0.732 kilograms (1.6 lb) shells at a muzzle velocity of 880 m/s (2,887 ft/s). Their effective anti-aircraft range was 4000 metres (13,123 ft).
The Germans sold the Soviets twelve 52-caliber 38 centimetres (15 in) SKC/34 guns and their associated Drh LC/34 turrets as part of the Molotov–Ribbentrop Pact. Their elevation limits were -5.5° to +30° with a fixed loading angle of 2.5°. Their rate of fire was 2.3 rounds per minute. The turrets could elevate at a rate of 6° per second and traverse at 5° per second. They had a maximum range of 36520 metres (39,938.8 yd) with a 800 kilograms (1,763.7 lb) shell at a muzzle velocity of 820 m/s (2,690.3 ft/s).
Fire control
Two KDP-8-III fire-control directors were used to control the main armament. These had two 8 metre stereoscopic rangefinders, 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 20 mm (0.78740157480315 in) of armor and were mounted atop the rear superstructure and the tower-mast. Two KDP-4t-II directors, with two 4 metre rangefinders each, controlled the secondary armament. The dual-purpose guns were controlled by two, later three, stabilized directors, each with a 3 metre rangefinder.Protection
The ships had relatively light armor. The main belt was 230 millimetres (9.1 in) thick, with a taper to the lower edge, and inclined outwards six degrees. It was 5 metre high of which 1.6 metre was intended to be submerged as originally designed. The belt was 185 metre long and covered 76.8 percent of the waterline; forward of this was a 20 mm belt that extended all the way to the bow. The forward transverse 330 millimetres (13 in) bulkhead was 330 mm thick while the rear bulkhead was 275 millimetres (10.8 in) thick. The upper deck was only 14 millimetre (0.551181102362205 in) thick and was intended to initiate shell and bomb fuzes. The main armor deck, which was even with the top of the waterline belt, was 90 millimetres (3.5 in) thick and a 30 millimetres (1.2 in) splinter deck was underneath it, although it tapered to 15 millimetre (0.590551181102362 in) in thickness over the torpedo protection system. The underwater protection was an American-style design with a bulge and four longitudinal bulkheads intended to withstand a 500 kilograms (1,102 lb) warhead of TNT. It covered 61.5% of the ship's length and had a total depth of 6 metre, that reduced to 4 metre forward and aft where the hull lines became finer.The main turrets had 305 mm faces and backs and 125 millimetres (4.9 in) sides and roofs. Their barbettes were protected with 330 mm of armor. The secondary turrets had 100 mm faces with 50 millimetres (2 in) sides and roofs and 75 millimetres (3 in) barbettes. The dual-purpose mountings had 50 mm armor with 40 millimetres (1.6 in) barbettes. The conning tower had 330 mm sides and a 125 mm roof with a 230 mm communications tube running down to the armor deck. The admiral's bridge was protected with 50 mm armor. Each of the directors had 14 mm of armor as did the 37 mm gun mounts. The funnels had 20 mm armor for their entire height above the deck and a 50 mm box protected the smoke generators.
Construction
The Soviet shipbuilding and related industries proved to be incapable of supporting the construction of the four Sovetsky Soyuz-class battleships as well as the two Kronshtadt-class battlecruisers at the same time. The largest warships built in the Soviet Union prior to 1938 were the 8000 tonnes (7,874 LT) s and even they had suffered from a number of production problems, but the Soviet leadership preferred to ignore the industrial difficulties when making their plans. The shipyards in LeningradSaint Petersburg
Saint Petersburg is a city and a federal subject of Russia located on the Neva River at the head of the Gulf of Finland on the Baltic Sea...
and Nikolayev
Mykolaiv
Mykolaiv , also known as Nikolayev , is a city in southern Ukraine, administrative center of the Mykolaiv Oblast. Mykolaiv is the main ship building center of the Black Sea, and, arguably, the whole Eastern Europe.-Name of city:...
had less than half the workers intended. Shipbuilding steel proved to be in short supply in 1939–1940 and a number of batches were rejected because they did not meet specifications. An attempt to import 14000 long tons (14,225 t) of steel and armor plate from the United States in 1939 failed, probably as a result of the Soviet invasion of Poland on 17 September 1939. Armor plate production was even more problematic as only 27438 tonnes (27,005 LT) were delivered in 1940 of the anticipated 30000–32000 t (29,526.1–31,494.5 LT) and 30–40% of that was rejected. Furthermore the armor plants proved to be incapable of making cemented plates over 230 mm and inferior face-hardened
Case hardening
Case hardening or surface hardening is the process of hardening the surface of a metal, often a low carbon steel, by infusing elements into the material's surface, forming a thin layer of a harder alloy...
plates had to substituted for all thicknesses over 200 millimetres (7.9 in).
Machinery problems were likely to delay the ships well past their intended delivery dates of 1943–44. The Kharkhovskii Turbogenerator Works never completed a single turbine before the German invasion in June 1941. Another problem were the 305 mm guns and turrets as the armament factories were focused on the higher-priority guns for the Sovetsky Soyuz-class battleships. Prototypes of neither had been completed by the time the Germans invaded. The situation was not much better for the smaller guns as mountings for both the 152 mm and 100 mm guns were still incomplete on 22 June 1941 and all of these programs were terminated quickly afterwards.
Ships
The ships were originally intended to be laid down 1 September 1939, but they were delayed until November to allow improvements to the shipyards to be completed. A total of sixteen ships were planned in the August 1939 building program, but this was scaled back to four in July 1940 and two in October 1940 when it became clear just how unprepared the Soviets were for any large-scale naval construction program. Work on these ships ceased shortly after the German invasion.Kronshtadt was built by the Shipyard No. 194, Marti
Admiralty Shipyard
The Admiralty Shipyard is one of the oldest and largest shipyards in Russia, located in Saint Petersburg. The shipyard's building ways can accommodate ships of up to , 250 meters in length and 35 meters in width...
in Leningrad. She was laid down 30 November 1939 and judged 10.6% complete when the Germans invaded. Her building slip was too short for her entire length so her stern was built separately. Some of her material was used during the Siege of Leningrad
Siege of Leningrad
The Siege of Leningrad, also known as the Leningrad Blockade was a prolonged military operation resulting from the failure of the German Army Group North to capture Leningrad, now known as Saint Petersburg, in the Eastern Front theatre of World War II. It started on 8 September 1941, when the last...
to repair other ships and in defensive works, but she could have been finished after the end of the war. Proposals were made to complete her as an aircraft carrier and as a base ship for a whaling flotilla, but both ideas were rejected and she was ordered scrapped on 24 March 1947. Her dismantling began shortly afterwards and was completed the following year.
Sevastopol was built by Shipyard No. 200, 61 Communards
Shipyard named after 61 Communards
Shipyard named after 61 Communards is a major shipyard located in Mykolaiv, Ukraine. In modern times, the shipyard has been most commonly referred to as Nikolaev North Shipyard but was also known as Soviet Shipyard No. 200.- History :...
in Nikolayev. She was laid down on 5 November 1939 and estimated as 11.6% complete on 22 June 1941. She was captured by the Germans when they occupied Nikolayev in late 1941, but the Germans did little with her other than to use some of her material for defensive positions and some was apparently shipped to Germany. Before the Germans evacuated the city they damaged her building slip and hull with explosives and made her a constructive total loss. She was ordered scrapped on 24 March 1947 and her dismantling began shortly afterwards. It was completed in 1948.