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fighting ships of the world

SOVIET / RUSSIAN NAVY (USSR / RUSSIA)

SUBMARINES

K-3 nuclear powered attack submarine (project 627) (1958)

K-5 nuclear powered attack submarines (project 627A) (1959 - 1964)

K-3 1958

K-5 1959

B-5 1990

Project history: This first Soviet nuclear submarine was conceived to deliver a strategic weapon, a 1550mm diameter T-15 torpedo (24m long) with a range of at least 40km. A parallel diesel submarine project (probably 630 or 631) was abandoned before the boat could be built. T-15 itself was abandoned when the alternative ballistic missile proved successful, and in 1954-55 the design was recast as a torpedo-attack submarine.

    Under a 9 September 1952 directive, separate design groups were formed to develop the nuclear submarine and its powerplant. SKB-143 (Malakhit), which had been working on Walter submarines, was assigned to this project. It formally began the submarine design in March 1953; it would carry a single strategic attack torpedo and a pair of 53cm torpedoes for self-defence. The submarine was provided with a targeting radar for use with T-15 (presumably mainly to confirm its position off an enemy coast). Each tube carried only a single torpedo.

    Initial estimates (1952-53) called for a 2650-2700t (surfaced) submarine with an operating depth of 250-300m, capable of 22-24kts, with a stores endurance of 50-60 days and a crew of 70. The first sketch design (1953) showed 2896t/4500t, operating depth 275-300m, 24-25ks, 60 days' stores, and a crew of 75. The final version of the strategic attack submarine design (1954) showed 3050t/4746t, 300m depth, 24-25kts, 50-60 days' stores, and a crew of 76. Then the mission was changed; armament was switched to 8 bow tubes (in vertical rows) with 20 torpedoes. Displacement was almost unchanged (3050/4750t), as were speed, diving depth, and stores endurance; but crew increased to 85. Surfaced speed was 15.2kts.

    Once the basic design had been recast, it was ordered developed into a production attack submarine, Project 627A (directive 22 October 1955). SKB-143 began work in August 1956. The prototype, K-5, was launched in September 1958 and was accepted on 27 December 1959. The most obvious difference between 627 and 627A was in their sonars. Probably mainly to achieve high speed, 627 lacked the Feniks chin array of contemporary diesel ™ submarines, such as Project 611. Instead, she had the simpler flush-mounted Mars-26KP, an earlier-generation set. Her Arktika searchlight sonar was behind a big window in the forward face of her sail (which was quite small by contemporary Russian standards). As yet there was no associated Leningrad system; the boat had a Prizma torpedo fire control system. The underwater communications set was Svet and the echo-sounder was Luch. Torpedoes could be fired at depths down to 100m. Unusually for Russian submarines, there was only a single periscope. Other masts carried two HF whips, HF/DF (actually for underwater radio reception), an ESM array, and radar.

    On trials, K-3 made 23.3kts at 65% power, and 28-30kts at full power. Each of the two independent power trains comprised a 70MW VM-A reactor and a 17500shp turbine set turning a motor-generator, as in a direct-drive diesel submarine. Also as in diesel boats, each shaft carried a 450hp creep motor. One unusual feature of these and later Soviet submarine reactors was a quench baffle within the reactor pressure vessel, to be used to quickly shut the reactor down (it was also used during refuelling). There was a substantial battery, needed partly to start up each reactor. The submarine could, therefore, either drive her propellers directly from the turbine or use one turbine, operating as a generator, to turn both shafts. Each reactor was connected to several heat exchangers. Reportedly heat exchangers were, initially at least, quite unreliable, so boats often ran on part of the output of only one reactor and rarely at full power. As these problems were solved, the operational speed of the class improved dramatically through the 1960s, one demonstrating her full power when chasing USS Enterprise in February 1968. Her unexpectedly good performance helped sell the Los Angeles class to the US Navy. Rated speed was 15/29kts. The same machinery arrangement was used on other first-generation submarines of Project 658 and 659.

Because 627A was conceived from the outset as an attack submarine, it was provided with a full attack submarine sonar suit, Arktika. active sonar was moved into a large chin fairing projecting below the keel, and passive sonar was placed behind a sonar window on the upper part of the bow. The big sonar window in the sail was eliminated. A new narrow window covered elements of the high-frequency sonar intercept array. Medium-frequency intercept arrays were arranged to either side of the torpedo tubes, with a large window on either side at die waterline. At 80% power K-5 made 28kts on trials.

    The sixth unit of the class, K-27 was redesigned with a new liquid-metal (lead-bismuth) powerplant (as Project 645). Contract design began m 1955 because the hull very nearly duplicated that of Project 627, there was no need for a concept or preliminary design. The only important differences were that the bow of Project 645 was spherical (like that of 627) only below the waterline, it was conical above. Furthermore, unlike 627, 645 was designed to standard navy requirements. It added ship-service turbo-generators, tike than of Western nuclear submarines. There was some internal rearrangement The reactor room replaced the auxiliary machinery space of the 627; the turbo-generators and diesel generators replaced the reactor space of the 627.

    Compared with Project 627A, this design needed 23% less battery capacity because its higher-temperature reactor needed much less electricity to start up. The ship's combat system was also improved: a device tor rapid torpedo loading was installed, it could simultaneously load any four tubes. Like a 627A, 645 had Arktika-M and the Leningrad system which allowed attacks without using a periscope. The usual second (air search) periscope was added. Non-magnetic steel was used in the outer hull, superstructure, and sail to reduce magnetic signature (degaussing weight and power were halved). However, as in contemporary German submarines, the new steel caused problems.

Modernizations: 1973, K-52; 1980, K-42: - MG-200 Arktika-M sonar; + MGK-400 Rubikon sonar

1970s, K-42, K-115: + wake detector

Naval service: K-8 was sunk after fire 12.4.1970 in Northern Atlantic off Cape Finisterre. B-159 was foundered under tow 30.8.2003 off Kildin (Barents Sea).

Project 627A 1978

© Ivan Gogin, 2015