Soviet submarine L-4

The Soviet Navy decided in the early 1920s on a need for both patrol and minelaying submarines, with the latter derived from the former. Construction of the minelayers was postponed until the submarine design bureaus had time to learn the lessons from building the Dekabrist-class patrol submarines and the British submarine which had been salvaged in 1928. The boats displaced surfaced and submerged. They had an overall length of , a beam of , and a mean draft of . The boats had a diving depth of . Their crew numbered 53 officers and crewmen. For surface running, the Leninets-class boats were powered by a pair of 42-BM-6 diesel engines, one per propeller shaft. The engines produced a total of , enough to give them a speed of . When submerged each shaft was driven by a PG 84 electric motor, giving them a speed of . The boats had a surface endurance of at and at submerged. For submerged cruising the Leninets class were equipped with a pair of electric motors. As completed the boats had problems with stability, excessive diving times (up to three minutes), noisy auxiliary machinery, and poor-quality batteries. These produced excessive amounts of explosive hydrogen gas which could lead to fires. By the end of 1934 the battery compartments had been rendered gas-tight and the ventilation had been improved. == Construction and career ==

L-4 was laid down on 15 March 1930 by the A. Marti Shipyard in Nikolaev (now Mykolaiv), Ukraine, with the name of Garibaldiets. She was launched on 31 August 1931 and completed on 8 October 1933. She was commissioned into the Black Sea Fleet two days later. On 28 August 1934 a build-up of hydrogen caught fire and exploded, killing five men. The boat was repaired and was renamed L-4 on 15 September 1934. She was undergoing a refit when the Axis Powers invaded on 22 June which was completed in early August. During the refit, her 21-K AA gun was replaced by a machine gun. L-4 laid a minefield off Mangalia on 5 October and then made unsuccessful attacks on the Romanian destroyer and the Romanian torpedo boat . The boat relaid her minefield off Mangalia on 24 October. She was refitted from December 1941 to April 1942, after being damaged by a mine off Varna. L-4 laid a minefield south of Cape Sarych on 19 August and off Burnas Lagoon on 19 September. L-4 was awarded the Order of the Red Banner on 23 October. She laid a minefield off Yevpatoria on 18 July without result. The boat was refitted from September to April 1944. In 1944 Michman Ivan Perov was awarded Hero of the Soviet Union. She was renamed B-34 in 1949 and became a training ship in 1953. The submarine was stricken on 17 February 1956 and subsequently broken up. ==Claims==