K-21

At the outbreak of war in September 1939, the Soviet Union deployed the world’s largest submarine force, with 168 boats in service. Soviet mass production of submarines began early and produced a wide variety of different types. There were two basic series of M-type coastal submarines, two basic medium submarine series (the S-type, derived from the same basic design as the German Type VII, and the Shch or Piketype of indigenous origin), minelayers of the L-type, and long-range boats of the K-type.

The final M-type displaced 283 tons when surfaced, had a range of 4,500 miles at 8 knots on the surface or 36 hours at 3 knots submerged, could dive to 295 feet, and had a battery of 2 torpedo tubes with 4 torpedoes and a 45 mm antiaircraft gun. The S-type displaced 856 tons surfaced, had a range of 9,500 miles at 9 knots on the surface or 45 hours at 3 knots submerged, could dive to 330 feet, and had a battery of 6 torpedo tubes with 12 torpedoes and a 4-inch deck gun. Their indigenous rivals displaced 587 tons, had a range of 3,650 miles at 7 knots on the surface or 50 hours at 2.5 knots submerged, could dive to 295 feet, and carried 6 torpedo tubes with 10 torpedoes. The minelayers displaced 1,108 tons, had a range of 10,000 miles at 8.6 knots on the surface or 60 hours at 2.5 knots submerged, could dive to 330 feet, and carried 8 torpedo tubes with 14 torpedoes and 20 mines. The K-type were very popular with their crews and were regarded as the best Soviet submarines of the war. These displaced 1,480 tons, had a range of 15,000 miles at 9 knots on the surface or 50 hours at 2.5 knots submerged, could dive to 330 feet, and carried 10 torpedo tubes with 24 torpedoes. Despite this variety, the Soviet Union’s yards produced a great many submarines, completing some 200 boats during the course of the war.