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During the 1930s the Soviet Navy developed and constructed several closed-cycle propulsion submarines, i.e., capable of employing diesel engines while submerged to recharge their batteries, thus extending underwater performance. These submarines were constructed at the Krasnoye Sormovo shipyard No. 112 in Gor’kiy and at the Sudomekh shipyard No. 196 in Leningrad.

After World War II when the Soviet Union resumed warship construction there was renewed interest in closed-cycle submarine systems. Trials with some of these craft were continued after the war. The ten or more small M-class units completed in the late 1940s (most built at Sudomekh) were presumably experimental units, possibly of varying types, and some may have had closed-cycle propulsion plant prototypes. All operated in the Baltic from the late 1 940s through the mid-1950s and appear to have been stricken in the 1950s.

This postwar effort to develop closed-cycle propulsion plants made use of captured German submarine technology as well as building on indigenous Soviet research. By the late 1940s the Soviet Navy simultaneously began building three new submarine classes — known by the NATO code names WIDSK.EY, ZULU, and QUEBEC — as well as several specialized research submarines.

The third submarine class produced in this initial postwar submarine program was the relatively small QUEBEC, known in the Soviet Navy as Project 615. This was a coastal submarine intended to employ a closed-cycle propulsion plant to permit use of diesel engines to charge batteries while submerged without the need to raise a snorkel breathing tube. Details of the QUEBEC’s propulsion plant are sketchy in the open literature. The design provided for three propeller shafts, apparently with the Kreislauf closed-cycle diesel system turning the center shaft. The QUEBEC’s principal designer was A S. Kassatsir, who had worked on closed-cycle propulsion designs in the 1930s and during the war. I

n the Kreislauf process unburned fuel and unused oxygen were recovered from the diesel exhaust gases. These were recycled with small amounts of stored liquid oxygen (lox) being added to permit submerged operation. Developed by the Germans during the war, the Kreislauf system was one of several development efforts intended to permit underwater operation without the need to draw in air from the surface (with the snorkel envisioned by the German Navy as only an interim step in submarine development). On several occasions, while the QUEBECs were being built at the Sudomekh shipyard, ex-German tank trucks were observed discharging their cargo through pipes connected to buildings in the yard. The pipe connections became frost covered, a phenomenon that Jed to speculation that the trucks were off-loading lox or a similar oxidizer necessary for the Kreislauf or the Walter system.

The QUEBEC’s closed-cycle diesel plant was not successful, with several accidents occurring. Some submarines were seen with flames coming from their engineering spaces and their crews were said to call them zazhigalka (lighters) or Zippos, the latter after the popular American cigarette lighter. The closed-cycle plant was to have provided an underwater burst speed of 20 knots. More significant, the submarines would be able to maintain high submerged speed with the Kreislauf system for longer duration than with electric batteries.

Subsequently, the QUEBEC submarines may have been modified to operate as conventional diesel-electric craft, and served into the 1970s in the Baltic and Black Sea areas. However, specialized support barges were said to have been observed near the QUEBECs until their demise, contributing to speculation that some units at least retained the Kreislauf power plant until they were broken up.

The QUEBECs were in several respects the successor to the MALYUJKA coastal submarines built from the early 1930s onward. They had a displacement of 460 tons surfaced and 540 tons submerged, and a n_taximum underwater (electric motor) speed of 16 knots. Armament consisted of four 21inch (533-mm) tubes in the bow plus four reloads for a total of eight torpedoes or 16 tube-launched mines. As in the Mclass submarines, there was no torpedo loading hatch, with reloads being brought in through the torpedo tubes. The first units were completed with a twin 25-mm gun mount, making these the world’s last submarines to be completed with deck guns. (Those with guns beached them in the 1950s.)

The first postwar-generation Soviet submarines, including the QUEBEC class, were intended primarily for the anti-ship role. The principal sonar installation of the period was the Tamir5L High-Frequency (HF) sonar, mounted in the bow, which became operational about 1948. Apparently the last few QUEBEC-class submarines (those completed after 1956) had the Tamir-5L fitted in combination with the new, MediumFrequency (MF) Feniks sonar. The active transducers or “projectors” for the sonars were fitted in wrap-around acoustic “windows” visible on their conning tower or “sail” structure.

A few variants of the QUEBEC were observed, although their exact purpose does not appear to be known in the West. For example, in July 1959 a strangely configured QUEBEC was photographed at Sudomekh with a large “shack” built around the after portion of the modified sail. This conversion — called “shackback” by naval intelligence — had a structure about 26 feet long, 14 feet wide, and 7 1/2 feet high, fitted aft of the sail. A 17-foot vertical pipe was fitted at the after end of the shack. Subsequently, in August 1960, a second “shackback” was observed at the nearby Kronshtadt naval base in the Gulf of Finland. That unit had an additional, smaller shack-like extension fitted aft of the main “shack.”

The vertical pipes may have been exhausts, indicating that the “shackback” submarines operated as either auxiliary power or heating barges, or may have been experimental platforms for closed-cycle propulsion projects.

One other closed-cycle propulsion submarine design was completed at Sudomekh about 1956, being first sighted by Western observers late that year. The one-of-a-kind craft was given the code name “WHALE” in the West; the Soviets designated her Project 617. She had a streamlined hull shape, a small sail structure, and an upper rudder, a feature not usually seen until the advent of nuclear-propelled submarines. The shape of the sail, upper rudder, coupled with the absence of a snorkel installation led to speculation in the West that this was the first Soviet nuclear propelled submarine.

The WHALE was observed to make high-speed runs, albeit for brief periods. This submarine, of approximately 1,500 tons surface displacement and some 250 feet in length, was propelled by the Walter hydrogen-peroxide turbine for highspeed submerged propulsion.

The WHALE apparently conducted trials in the Baltic for several years, with the last Western sighting reported in 1961. According to some sources, S. N. Kovolev developed the design for this submarine; some 30 years later Kovolev served as chief designer for the TYPHOON SSBN.

Soviet interest in closed-cycle propulsion continued parallel to nuclear propulsion. (In the West the U.S. and British efforts into closed-cycle propulsion halted after the successful development of nuclear propulsion.) There was periodic speculation in the West of other Soviet submarines having closed-cycle plants or “boosters,” among them the triple-shaft ZULU and FOXTROT long-range submarines, the JULIETT cruise missile submarine, and, especially, the KILO SSK, which entered service in 1982. But proof that research has continued in this area came in 1987-1988 with the debut of the research submarine BELUGA Thus, the Soviets have demonstrated a long-term and continuing commitment to non-nuclear propulsion, with both conventional diesel-electric plants and closed-cycle propulsion or, as now labeled in the West, Air Independent Propulsion.

[This description of Soviet closed-cycle submarines is abridged from Submarines of the Russian and Soviet Navies. 1718 to 1990 by Nonnan Polmar and Lt.Comdr. Jurrien Noot, Royal Netherlands Navy, to be published later this year by the U.S. Naval Institute.]

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