Sovetsky Soyuz Class Battleship - Design and Development

Design and Development

Design work began in 1935 on new battleships in response to the existing and planned German battleships, and the Soviets made extensive efforts in Italy and the United States to purchase either drawings or the ships themselves in the late 1930s. The Italian firm of Gio. Ansaldo & C. proposed a ship of 42,000 long tons (43,000 t) standard displacement with nine 16-inch (406 mm) guns, in size and appearance similar to the Italian battleship Littorio then under construction by the company. 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. 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 TTZ) for the large battleship design was issued on 21 February 1936 but proved too ambitious, specifying nine 460 mm guns and a speed of 36 knots (67 km/h; 41 mph) on a displacement of 55,000 tons. The TTZ was revised in May 1936 by Admiral Orlov, Commander of the Soviet Navy, reducing speed to 30 knots (56 km/h; 35 mph), and weakening the secondary and 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 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 152-millimeter (6.0 in), twelve 100-millimeter (3.9 in), and forty 37-millimeter (1.5 in) guns, a maximum armor thickness of 380 mm (15 in) and a speed of 30 knots.

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 Premier 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.

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 Shipbuilding Administration the next month. A number of details remained to be worked out, including the final design of the machinery plant, the 152 mm guns and the 100 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 rubles 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 500-kilogram (1,100 lb) bombs, proving that such ordnance would generally penetrate both the 40-millimeter (1.6 in) upper and 50-millimeter (2.0 in) 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 barges. These tests proved that the torpedo belt system of multiple bulkheads was superior to the 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.

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 launches suggested that the hull's propulsive efficiency would be 1 knot (1.9 km/h; 1.2 mph) less than planned, and this was accepted in the November 1938 revision as a maximum speed of 27.5 knots (50.9 km/h; 31.6 mph). However, a new propeller design proved to be more efficient and was predicted to increase speed to 28 knots (52 km/h; 32 mph). 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 trim, or front-to-back angle in the water. To remedy this, the two 100 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 also 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.