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fighting ships of the world

SOVIET / RUSSIAN NAVY (USSR / RUSSIA)

SUBMARINES

K-38 nuclear powered attack submarines (project 671) (1967 - 1974)

K-314 nuclear powered attack submarines (project 671V) (1972 - 1974)

K-38 1967

K-147 1990

Project history: Project 671 emerged from a larger programme of follow-ons to the Project 627. The Malakhit KB (SKB-143), which had designed Project 627, conducted numerous studies of possible future nuclear submarines during 1956-59. In May 1958 the new Bureau Chief, Dubovichenko, decided to offer one of the sketch designs to the State Committee on Shipbuilding. It was a US-style single-hull submarine (with a cylindrical, rather than a curved, pressure hull) with a single reactor, a single turbine, and a single propeller, ballast tanks only at the ends, and a boxlike superstructure. Unlike US nuclear submarines, the design carried some ballast between internal transverse bulkheads. The double bulkheads also accommodated escape hatches leading into escape capsules in the superstructure. Unlike earlier Soviet submarines, this one would not be designed to the usual three-compartment standard, ie, to survive surface collisions. The designers argued that surface considerations were irrelevant to a submarine designed to spend most of its time submerged.

    The State Committee showed no interest in the proposal, but it did announce a competition for four next-generation submarines: Project 667, an SSBN;     Project 669, a large torpedo submarine (a direct successor to Project 627); Project 670, a small torpedo submarine for mass production; and Project 671, an ASW submarine. Three design bureaus competed: SKB-143, TsKB-18 (Rubin), and TsKB-112 (Malakhit). SKB-143 would be assigned Project 671; Malakhit would get Project 670, and Rubin would get Project 667. Project 669 was amalgamated with Project 671.

    Project 671 seems to have been inspired by the contemporary US Tullibee class. The competition requirement called for a powerful new sonar, four torpedo tubes (eight torpedoes), a speed of about 30kts, and a test depth of 300m, all within a normal displacement of about 2000t.

    By this time SKB-143 had designed three nuclear submarines: Project 627, Project 645, and the abortive Project 639 (an SSBN). The latter had introduced AC rather than DC electric power, and a larger-diameter pressure hull. Project 645 introduced self-contained turbogenerators (in Project 627 and its contemporaries, they were driven directly by the main turbines).

SKB-143 proposed a derivative of its proposed SSN, with a single shaft. At about the same time, the main naval staff developed standards for new SSNs. It assumed that the usual surface survivability standard would be maintained, and it asked for two shafts and two reactors, for reliability. SKB-143 argued instead that underwater performance should be paramount. Presumably its designers had reached much the same conclusions as their US counterparts (after a series of model tests, culminating in the construction of the Albacore). They pressed for a single-screw design with a body-of-revolution hull, for minimum ballast tankage (to minimise wetted surface) and for choosing the number of reactors only on the basis of required power. The State Committee agreed, but the naval staff and its own technical experts resisted.

    Meanwhile Project 669 was dropped; clearly Project 671 would have to be a dual-purpose submarine. To provide it with sufficient speed and armament, the TTZ was revised: maximum displacement could rise to the limit set by the capacity of the White Sea-Baltic Canal. The SKB won its argument for a single shaft, on the basis that it would minimise noise and overall displacement while providing the greatest possible speed on the available power. Admiral Gorshkov personally approved the single shaft as a one-time exception, but in fact the same principle was applied to the parallel Project 670. In retrospect, the designers were particularly proud that they had been able to choose dimensions based on hydrodynamics, rather than adopting the usual practice of adding up the lengths of compartments. For example, to minimise length they placed the reactors side by side, a practice repeated in later Soviet SSNs. As in contemporary US SSNs, the new hull form drastically reduced wetted surface compared to displacement: Protect 671 displaced about 30% more than Project 627, but had about the same wetted surface.

    The bow presented a particular problem. Standard practice, as in other navies, was to run the torpedo tubes in two vertical rows. That would have let little space for the big sonar array required. The solution adopted for Project 671 was to turn the two rows horizontally (two above four), with the sonar in the chin position. Coincidentally, this was much the solution adopted in the US Skipjack class a few years earlier. The Russians went further, adopting power loading from a moving tray (as in later US designs). Soviet practice apparently differed from US practice in that four of the torpedo tubes were accommodated in an inner hull tube extending towards the bow, two more (the lower outer pair) were apparently non-reloadable tubes outside the extended inner hull. In later versions of the design, the reloadable quartet of tubes was increased in diameter and length to accommodate 65cm weapons.

    As for power, all of the second-generation submarines had new reactors which had nearly the same output as the two reactors of the Project 627. The SKB-143 designers estimated that one such reactor would give good speed, but they chose two in order to provide a margin for future growth. Slightly earlier the US submarine designers had made the opposite choice in the Skipjack and Thrasher classes. They would regret it in the 1960s, as the submarines had to grow to accommodate new equipment, and lost too much speed in the process. The main propeller of Project 671 has five blades, and there were two auxiliary propellers for maneuvering.

    The technical design was approved on 3 November 1959.

    Apparently this submarine, already in production, was hurriedly adapted to take the 81R Vyuga ASW missile (equivalent to the US SUBROC, the design of which had been compromised); the modified design was Project 671V.

Modernizations: 1978, K-69; 1979, K-38: - MG-509 Radian-1 sonar; + MG-519 Arfa sonar

1980, K-147; 1981, K-438: + MNK-100 Kolos wake detector

1984, K-53: - MGK-300 Rubin sonar; + MGK-400 Rubikon radar

1986, K-323 50 Let SSSR - under Project 671K: - MGK-300 Rubin, MG-509 Radian-1 sonars; + 3M10 Granat CruM (launch from TT), MGK-400 Rubikon, MG-519 Arfa radars

Naval service: No significant events.

Project 671 1979

© Ivan Gogin, 2015