Project 678 / Project 1851
Nelma class / X-Ray class

There is considerable obscurity concerning this small class of small submarines, starting with the project designation. According to NATO classification they are given the designation X-Ray. Some sources reference the X-Ray class as Project 678, while more authoritative sources reference it as Project 1851. Both project numbers seem to be associated with this program, though what difference they make is opaque.

In total, according to projects 1851 and 18511, three AGS were built, which are part of the 29th SSBM of the Northern Fleet. The information and their service history are classified. Some sources suggest that this class consists of a single unit, while other sources suggest that this class consists of three units. By one account this submarine was built at the Admiralty Yard in St. Petersburg in 1982, while others have starting in 1981 and running through 1995. The most authoritative sources tend toward a multi-unit class, consisting of an initial 1851 and follwed by a pair of 18511 units.

In June 1979, the formation of the 29th separate submarine brigade of the Red Banner Northern Fleet began in Oleny Bay for basic maintenance and operation of deep-water vehicles and their carriers. To perform exits to the sea, the crews of the hydronauts of the stations went to the Northern Fleet, received equipment from technical crews, made an exit to the sea and handed over the equipment back. The first deep-water assets of the Russian Navy were the towed bathyscaphes "Archipelago" and "Seliger", which gained invaluable experience in working with objects on the seabed.

In fact, even before the start of operation of the Seliger- type devices , it became clear that they have disadvantages. First, it is the limitation of the area of operations by communication with the carrier boat. Secondly, limited autonomy in terms of energy and resources of the crew life support system. And, thirdly, extremely poor maneuverability. Then the idea arose of creating an autonomous modification of the "Seliger" -type bathyscaphes by installing a nuclear reactor on the apparatus, increasing the size, life support system, speed and maneuvering capabilities. Of course, the new type of apparatus should have received significant autonomy and significantly increased capabilities for the types of work that it could carry out at the bottom of the World Ocean.

The ships are equipped with a reactor capacity of 10 MW. One of the questions that immediately arises: how was a nuclear power plant placed in such a small underwater vehicle? In the preliminary design of the AGS project 18510, it was assumed to use a light power plant, similar to those used on spacecraft. The reactor was planned to be installed in a capsule without special heavy biological protection. The role of such protection was to be performed by seawater, i.e. the reactor compartment was made in the form of a separate block of a robust body, which is separated from the manned robust body by a washed space inside the outer lightweight body of the AGS.

The peculiarity and main disadvantage of the first nuclear power plant was the continuity of the design from the Seliger type bathyscaphes. In fact, the new type of submarines was an apparatus similar to tethered bathyscaphes, but without a connecting cable and noticeably large in size, with its own small-sized nuclear power plant, as well as with more developed main and auxiliary propellers.

So in the 1970s, the design of a new deep-water complex of project 1851 was started, which included a nuclear deep-water station (AGS) of project 18510 "Nelma" and a nuclear submarine carrier of project 675N. The initial 1851 unit was a design some 40 meters long with a submerged displacement of 1,000 tons, while the subsequent 18511 units were some 63 meters long with a submerged displacement of 1,450 tons. Initially, in 1980 Sudomech in Leningrad began construction of a series of nuclear submarines special project 1851, deprived of weapons. The ships were intended, in particular for deepwater operations using divers equipped with a pressure chamber. The first submarine AS-23, was laid Sept. 25, 1981, launched on 30 October 1983 and joined the Northern Fleet on Dec. 30, 1986 It was followed by AS-21 (incorporated December 26, 1984, launched 29 April 1991, came into operation on Dec. 28, 1991). Completed a series of AS-35 (incorporated December 20, 1989, launched 29 September 1994 and came into operation on Oct. 12, 1995).

The entrance hatch to the AGS was located in the same place as on the first device "Archipelago" - on the upper part of the hull, without a wheelhouse and any kind of railing. The transfer of the crew to the AGS was to be carried out from a special transition compartment of the carrier boat, and in the event of an emergency, the exit in the event of an emergency could occur after the vehicle surfaced to the surface in the same way as on the Archipelago. During operation, the design of the AGS AS-23 was modified: the station received a railing that provides a safer exit to the AGS deck in case of surfacing. This is how the final appearance of the AGS project 18510 "Nelma" was formed.

Project 18510 autonomous deep-water stations, code "Nelma" - Nuclear autonomous deep-water stations (AGS), are part of a complex consisting of a carrier (modified serial nuclear submarines) and a portable vehicle, the AGS itself. According to NATO classification X-Ray / Nelma - class nuclear special-designation submarine (DSV). They are special nuclear submarines / deep-water technology assets. They belong to the Main Directorate for Deep Sea Research (GUGI) of the Ministry of Defense of the Russian Federation.

The inconnu (Stenodus leucichthys) is a species of freshwater whitefish of the family Salmonidae. It is also known as the "coney", nelma, belorybitsa, or sheefish. It is the only species in the genus Stenodus. Salmo Nelma is a silvery white Salmon, with greatly elongated head, and lower jaw much longer than the upper. Length from three to six feet: snout depressed: mouth rather large, and furnished with large lateral laminae: scales large: tail forked. Inhabits the larger rivers of Siberia.

The complex was created for reconnaissance operations, jamming on the routes of combat patrols of nuclear-powered ships of the Russian Navy, solving scientific and technical problems, rescuing people in extreme situations, lifting various equipment from the military equipment of a potential enemy sunken in the sea and for carrying out other special operations. According to other sources, the complex is designed to collect from the bottom of the wreckage of ships, aircraft and satellites sunk in the ocean and conduct underwater reconnaissance at depths of up to 1 km. This class was designed for operations with divers equiped with a pressure chamber. The Project 678 X-Ray class submarine is a small, nuclear-propelled boat that is geneally generally similar in concept to the US Navy's NR-1 submersible. It was probably designed for covert underwater intelligence collection [ "research" or "ocean engineering").

Deep diving enclosures that provide an environment at normal or near normal atmospheric pressure include diving suits, diving chambers and other occupant enclosure devices, as well as crewless enclosure devices falling within the term "submersibles." A wall structure in accordance with the invention is also suited for use in forming at least a part of an enclosure for containing vacuum conditions.

At depths below 1,200 feet a diver needs almost all his energy to breathe, and consequently his work effort diminishes with depth. Furthermore, long-term operations at pressure create several immediate problems, such as rescue in the event of injury, and the long-term effects under such conditions are still not fully known. A diving suit capable of providing internal pressure equivalent to one atmosphere would enable a diver to carry out a high percentage of his normal duties at depths below 1,200 feet, whilst reducing many of the dangers that are at present inherent.

It is essential to produce a one atmosphere diving suit with a good strength to weight ratio. This is particularly true of the limb portions of the suit, since having commenced movement of a limb portion, such as an arm, the momentum of the moving mass of the limb tends to cause it to move beyond its objective, or overshoot, thus making the accomplishment of intricate tasks difficult, time-consuming, and tiring if moved by the physical effort of the diver. In present-day diving suits high strength to weight ratios are obtained by the use of magnesium with, however, the constant risk that in an undersea environment any break in the protective treatment of the metal will lead to corrosion followed by rapid disintegration.

By decree No. 722-271 of the Central Committee of the CPSU and the Council of Ministers of the USSR dated September 25, 1965, it was planned to start sketch work on the design of an autonomous deep-water research station at TsKB-18. ES Korsukov and his deputy, SM Bavilin, became the main developers in the development group. The preliminary design work was completed by 1970, and the project itself was presented to the Ministry of Justice Industry and the command of the USSR Navy.

The development of a technical design for special-purpose nuclear deep-water stations in 1972, by the Decree of the Council of Ministers of the USSR, was transferred to the Central Design Bureau "Volna" of the Ministry of the USSR Ministry of Industry. Bavilin S.M. was appointed the chief designer of the new complex , Tereshkin V.M., Dubnitsky D.N., Uvarov V.A., Deshkin E.A. were also included in the design group, and Romanov B.L became the chief designer of the power plant. The design group developed and prepared two draft designs - an autonomous deep-water station (AGS) / project 1910 "Kashalot" / and a complex consisting of a carrier and a habitable vehicle / project 1851 "Nelma".

For development of design solutions and as an experimental vessel, the K-170 project 675 SSGN from the 11th division of the 1st flotilla of the KSF of the USSR Navy was allocated from the Navy . By 1973, rough technical projects were completed, and in January 1973 the K-170 was delivered to the Zvezdochka shipyard in Severodvinsk for revisions. The work was carried out jointly with LPMB Rubin. The boat received a new tactical number - BS-86, then K-86, later KS-86. In 1974 SPMB Mashinostroyenia and Central Design Bureau "Volna" were merged, the new association was named SPMBM "Malakhit". In the course of the work, at the suggestion of SM Bavilin, the technical project was changed in terms of the AGS power plant.

In accordance with the Order of the Commander-in-Chief of the USSR Navy, a detachment of hydronauts was formed in October 1976 for the operation of deep-water stations. The detachment was selected by people who served on submarines for at least 5 years and are members of the CPSU. Medical requirements were similar for astronauts. The first officer of the detachment was PA Chebotayev, and he took up the further formation of the detachment on the territory of the 39th brigade of submarines under construction on Rimsky-Korsakov Avenue in Leningrad.

Some sources indicate that further development of the project and detailed refinement submarine Project 675 to type "carrier vessel AGS" (draft 675N / 06754) mandated Nizhny Novgorod CDB "Lapis" , a project manager - the Hero of Russia Kvasha NI Partly, this may be true, since SPMBM "Malachite" was engaged in the 1910 "Kashalot" project. But this information has not been confirmed in official open sources.

At the beginning of 1980, the Leningrad Admiralty Association (now the Admiralty Shipyards ) began preparing for the construction of the first AGS for the Twice Orders of Lenin, Orders of the Patriotic War of I degree and the Order of the Red Banner of Labor . AS-23 was laid down on September 25, 1981 (serial number 01429). Launching took place on 30 October 1983. Responsible deliverer - Suslennikov M.E., representatives from the USSR Navy - Semyonov V.S. and Popilnukh G.A.In 1984, during the tests, for the first time the Western services were noticed by the AGS. In 1986, underwater docking was carried out for the first time. The AGS-carrier complex was enlisted in the 29th submarine brigade of the Red Banner Northern Fleet of the USSR (military unit 13090) based on Olenya Guba (Snezhnogorsk-1) on December 30, 1986. The commander of the AGS - Terekhov Yu. A. Information about the further service of the AS-23 is classified and has not been published in open sources. AS-23 - KS-86 is the only complex built according to the project 18510 "Nelma". In 1991, another KS-411 carrier ship (project 09774) came to replace KS-86 . June 24, 1991KS-86 was excluded from the Navy's combat strength and was put on a sludge in Olenya Bay until the 2000s, then dismantled for metal. Presumably, since 2009, the AS-23 - KS-411 complex has been located in Severodvinsk at the Zvezdochka shipyard.

AS-23 had a total displacement of about 1000 tons and is equipped with one 10 MW reactor. The case is made of titanium alloy. During the design, the wheelhouse was not provided, but due to the fact that the airlock hatch was flooded with water even with a slight roughness of the sea, it was later mounted during the next repair. AGS has no weapons. For deep-sea diving operations, it is equipped with a pressure chamber. Based on the results of the trial operation of the AS-23 AGS, a number of modifications were proposed to be included in the serial construction project, after implementation the project received a new designation 18511 (1851.1), code "Halibut". According to NATO classification Paltus-class Two AGSs - AS-21 and AS-35 were built under this project. On December 4, 2012, information appeared that at the Zvyozdochka shipyard in Severodvinsk, work is underway on the construction of a modernized AGS based on the hull laid in the 1990s at the Admiralty Shipyards in St. Petersburg with adaptation to a new generation of carrier boats of the BS type -64 "Moscow region". But there is an opinion that in fact the AS-23 was undergoing modernization during the overhaul, but there is no 4th building.

AS-21 was laid down on December 26, 1984. Completed according to project 18511. Launched on April 29, 1991. Adopted on December 28, 1991 as part of the 29th KSF SLBM (military unit 13090) based at Olenya Bay (Snezhnogorsk-1). Responsible deliverer - Suslennikov M.E., representative from the Navy - Mikhailov A.I., chairman of the state commission - Kholod V.V. First commander of the AGS - Gritsko M.V.

AS-35 was laid down on December 20, 1989 according to project 18511. Launched on September 29, 1994. Adopted on November 12, 1995 into the 29th KSF brigade (military unit 13090) based at Olenya Bay (Snezhnogorsk-1). Responsible deliverer - Suslennikov M.E., representative from the Navy - Mukhin V.M., chairman of the state commission - Khmyrov V.L. stage of the State deep-sea tests AS-35 . On July 24, 2012, NIPTB Onega and TsS Zvezdochka signed an agreement No. 92-44 / 12, which provides for the development of design and technological documentation for work at the AGS AS-35directly in the transport dock TPD-70. On December 5, another contract No. 92-20 / 12 was signed for the development of a project for the average repair of the order of the head. No. 431 in the conditions of JSC "TsS" Zvezdochka ".

The small 'X-Ray' class special missions submarine had become inoperable by 1997 and would not return to service. Further development of the projects of nuclear deep-water stations 1851 "Halibut" and 1910 "Kashalot" was the project 10831 "Kalitka".