The Northern Machine-Building Enterprise was still assembling the first designs of the head submarine of Project 664, but it was already clear to everyone that soon they would have to cut them “on needles”. Project 664 had too many problems to get out of the design phase. Without waiting for the final closure of the project, the command of the Soviet naval fleet gave TsKB-16 a new task. Until 1970, from designers led by N.A. Kiselev was demanded to create a submarine designed for covert transportation and landing on unequipped coasts. In addition, military sailors wanted to be able to evacuate or transfer landed units using the same submarine.
The new project with the index “748” was launched in 1965 year, before the official closure of the previous development “664”. According to the available information, at first the 748 project in layout resembled the previous 664. However, by this time all the drawbacks of the circuit with one robust case were already known. With all the desire, it was impossible to enter in it sufficient volumes for the landing, and also to place them so that the equipment and people could quickly and easily disembark. Nevertheless, the variant with one robust case worked. During the verification of the prospects of such a scheme, the General Directorate of shipbuilding proposed to consider two additional versions of the project with various nuclear power plants. The fact is that by this time the low prospects for diesel-electric power plants on amphibious submarines became clear. In addition, the Office requested a survey on the use of a promising submarine as a minelayer.
Within a few months, the TsKB-16 staff immediately prepared six preliminary submarine projects, which differed from each other in a mass of details. Two versions of the project were the main ones and four additional ones were made on their basis. All of them involved the use of different layouts of robust housing, different types of power plant, etc. As a result of the comparison, the option No.4 was chosen, in which it was planned to use two water-cooled reactors and the original layout of robust shells. According to the selected preliminary draft, the 748 submarines were to have three solid hulls at once, horizontally side by side, side by side. In this case, it was possible without special problems to distribute internal volumes between the units of the boat itself and the troop compartments, as well as to ensure a relatively small height of the boat. In addition, when placing an assault force in two side hulls, it was possible to unload and load the assault force twice as fast as when using a scheme like the 621 project.
In the middle of a strong large-diameter casing, it was planned to place all the necessary units. In fact, the central durable hull was the corresponding part of the conventional submarine of that time, divided into ten compartments. In the nose part it was supposed to install a hydro-acoustic complex “Rubicon” or “Kerch”, as well as four torpedo tubes of a caliber 533 millimeter. Due to the fact that all the volumes for the landing force were located outside the central building, it was possible to fit the 14 torpedoes ammunition in the first compartment. If necessary, the boat project 748 could take on board not the torpedoes, but mines. Behind the weapons compartment they placed the living quarters for the crew and the landing force, as well as the central post. The aft part of the central hull of the submarine was given to the elements of the energy system and running engines. The power plant was performed on a two-shaft scheme.
Two more, having a smaller diameter, were placed on the sides of the middle durable case. To increase the survivability of the boat in case of damage to the strong side hulls, each of them was divided into two compartments by a bulkhead with sealed doors. All three corps were interconnected by transitions, thanks to which the landing could expect to land not only in their combat vehicles, but also in equipped cockpits. The terms of reference for project 748 required the ability to transport up to 1200 soldiers or up to 20 pieces of equipment with crews and troops. As a standard load for the landing submarines, the reinforced battalion of the marine corps of 470 people, three light tank PT-76, two armored personnel carriers BTR-60P, as well as six company mortars.
The equipment had to be loaded onto the submarine under its own power. To do this, provided for the ventilation of the cargo buildings, as well as two ramps. Before the nose of the side hulls it was proposed to make two swiveling structures, along which people had to go while the landing was done. In the stowed position, the ramps turned up and back and lay down in the corresponding windows in a lightweight body, closing the ramps for the equipment. Since the cargo strong hull had a sufficiently large diameter, their front cargo hatches, through which it was planned to load and unload the boat, were double: one lid was located outside the hull, the second - inside.
Project 748 shows that in the bow, the light hull of the boat has characteristic contours. Thanks to them, the boat could come close to the shore and even lay on its nose. In view of the peculiarities of amphibious landings - for defense against aviation enemy - it was planned to equip the boat with two anti-aircraft guns of 57 mm caliber. In addition, in the later stages of the project, the possibility of equipping the submarine with an anti-aircraft missile system was considered. The exact type of missiles proposed for use is unknown, but there is information about the location of the launchers. Up to 24 vertical shafts were to be located behind the wheelhouse, in front of the reactor compartment.
In the form of a draft, a promising landing submarine had a length of 153 and a width of 21,2 meters. In the surface position, the displacement of the boat was equal to 11000 tons, in the submerged - 16600 tons. Interestingly, thanks to the use of the original scheme with three solid hulls, a relatively small draft of six meters was achieved. Such a value of this parameter should have a beneficial effect on the amphibious capabilities of the submarine. The maximum speed on the surface, according to calculations, was supposed to be at the level of 10-12 nodes, in the subsea - up to 17. The submarine could operate at depths up to 240 meters, if necessary dropping to 300.
The crew of the promising submarine, according to the project 748, consisted of 80 people. The reserve for him would be enough for a hike lasting 80 days. During the transportation of the assault force, autonomy decreased to one month. If some wounded were taken aboard, the boat could sail no more than 8-10 days.
The development of the 748 project began in August of 1965, and already in December, the designers of TsKB-16 presented to the fleet commanders a preliminary version of the documentation. During the review and careful analysis, the representatives of the Navy found in the project both advantages and disadvantages. With all its advantages, the 748 project was not without its drawbacks. However, a number of questions required additional study, and the CDC-16 by this time was not able to deal with them. Therefore, the command of the Navy decided to close the project in its current form and use the developments on it to form the image of a new universal submarine capable of carrying cargo and troops, as well as to install minefields.
Analysis of existing projects of amphibious submarines lasted for several months. Only in August, 1967, the General Directorate of Shipbuilding prepared the requirements for the new project. This time, the employees of TsKB-16 were required to take into account most of the developments on the 664 and 748 projects, as well as on the minelayers “632”. Using the technical solutions of these projects, it was planned to create a new multifunctional airborne transport submarine. The main objective of the boats of the new project, which received the number "717", was to be the transportation of soldiers, equipment, ammunition, etc. with the possibility of self-unloading, including on the unprepared coast. Thus, the new submarine could be used both as a landing ship and as a weapon transport. Finally, the 717 project meant equipping the submarine with the equipment necessary for setting minefields. In fact, the technical task for the project required to make again a submarine capable of performing several tasks at once. Of course, all previous similar projects were closed, but this time it was supposed to use all the information received and the available technologies. Therefore, the future of the project 717 looked very real.
As before, during the preliminary design, three options for the overall layout were considered. According to the results of their comparison and analysis of the prospects, they chose a scheme with three solid enclosures, as in the 748 project and the power plant like the 664 project. The extensive use of the groundwork for the fairly old 664 project was due to the requirement of the fleet to simplify the development process, including through the use of existing connections with related enterprises. It is worth noting that this approach was justified: the draft version of the 717 project was already ready in the spring of 1968.
Like the 748 project, the 717 project involved the use of three robust enclosures at once. The central one had a larger diameter and contained all the main aggregates of the boat. Overall, its layout was similar to the previous project. Six 533-mm torpedo tubes with ammunition up to 18 torpedoes, the antenna of the Kerch hydroacoustic complex, and nasal horizontal rudders with drives were placed in the nose honor. During the finalization of the conceptual design, instead of the Kerch complex, it was decided to use the Rubicon, which, however, had almost no effect on the layout of the bow of the submarine. Further, in the middle durable hull there were living quarters for the crew of submarines and paratroopers, a central post, etc. Three feed compartments were taken under the equipment of the power plant: in the seventh there were two pressurized water reactors and steam generators; in the eighth, steam turbine installations, the main electric motor and a number of other units; in the ninth aft - some parts of the transmission. The power plant set in motion two propellers. They were protected from external influences by ring nozzles.
On the sides of the central robust hull on the boats of the 717 project, it was supposed to mount two additional ones that had a smaller diameter. They were supposed to place the landed equipment and part of the personnel. The side hulls were connected to the central one with the help of several hatches, so it was possible to move between them. The dimensions of the compartments for the landing equipment, despite the large dimensions of the boat itself, remained at the level of the 748 project. They could accommodate up to 20 units of equipment (10 in each) or several hundred places for soldiers. According to reports, the submarine project 717 could carry up to 800 people without armored vehicles. The side robust hulls received two large-diameter front hatches, as was the case in the previous 748 project. At the same time, these corps were not divided into two compartments and the entire landing force was placed in a single volume.
When creating the 717 project, it was precisely the provision of landing troops to the shore that was put at the forefront. Therefore, several characteristic steps were taken. First of all, it is retractable ramps in front of the front hatches of the side solid hulls. According to him, the technique could move ashore. It is worth noting that, when retracted, the ramp was completely “merged” with the light hull of the boat. Due to this, the flow around the bow of the boat was much better than in previous projects. Of interest is the feed and submarines. In order to protect the propellers from colliding with the bottom near the shore, the lower part of the stern had specific contours. As a result, the screws were slightly higher than the main plane.
In addition, the diagrams show the characteristic form of the stern in the plan. Its sharp “cut” contours were due to the need to place in the same volume not only the steering wheel drives, but also two pipes for dumping mines. A wide feed with a characteristic end allowed to enter into the existing volume all the necessary components and assemblies. Tubes dumping device began in the back of the side of the strong housing. For the submission of mines in the pipes there was a special apparatus. After passing through the pipe, the mine fell out of the aft hatch and anchored. The pipes and side hulls could be loaded up to 378 min. Naturally, at the maximum mine load the submarine could no longer carry troops.
To cover against air strikes, as well as, if necessary, for the fire support of the assault force, the submarine of the 717 project was planned to be equipped with a sufficiently wide range of anti-aircraft weapons. Before felling, there was a paired 57-mm SM-24-ZIF machine gun. Immediately after cutting, the designers provided a place for one single-barreled anti-aircraft gun of the same caliber. In addition, a small-caliber automatic anti-aircraft gun could be installed on the back of the roof of a sturdy felling. All guns in the stowed position were removed in special containers inside the light housing. Missile weapons were not envisaged, but, probably, submarine crews could receive a number of man-portable air defense systems.
The submarine of the 717 project turned out much larger than the 748 submarine. It had an estimated length of 190 and a maximum width of 23 meters. At the same time, the draft of a promising submarine, thanks to the improved coupling of robust hulls and lung configuration, was equal to the entire 6,8 meters. On the surface, the new boat would have a displacement of 17600 tons, and underwater, a 25100. Compared to the 748 project, driving performance has also improved slightly. Having sunk, the new boat could accelerate to 18 knots. Surface speed is up to 12 nodes. The values of the possible immersion depths, due to the use of the previous project, have remained the same: the working depth in 240 meters and the maximum 300. The autonomy of provisions in most situations has decreased slightly.
In July, the fleet command and management of the shipbuilding industry approved the draft version of the 1969 project, but made some remarks. So, it was required to create a special self-propelled underwater vehicle that could be transported on such boats and used in operations to rescue crews of sunken submarines. By the spring of the next 717, all the improvements were completed and the creation of the final version of the project began. By October, the first version of the project was ready. In March, 1970, the project moved to the stage of recent discussions and corrections. In accordance with the needs of the Navy decided to build a series of five submarines. The estimated cost of the main submarine identified at the level of 1972-120 million rubles. Over time, the cost of construction should have dropped to 125 millions. Similarly, the construction time had to be reduced. On the assembly of the head boat allocated 80 months, the fifth - 49.
Interestingly, the order of the Ministry of Shipbuilding Industry about the start of preparation for the construction of the main submarine of the 717 project was issued in the fall of 1969. However, for several reasons, the preparation was delayed, because of which, until the 73 of the year, only a few full-scale mock-ups were produced and the documentation was prepared. According to reports, the reason for such a long delay was the workload of shop No. XXUMX of the Northern Machine-Building Enterprise. Due to the size of the workshops available at the factory, boats like the 50 project could only be assembled in the 717. However, at that time boats of the 50BDR project armed with strategic missiles were being built there. Another large workshop №667 by that time had not yet been built.
Delays in construction time led to the obsolescence of a number of electronic equipment elements of promising submarines. Therefore, in 1976-77, the Malachite SPMBM, the resulting merger of CDB-16 and SKB-143, updated the project in line with current trends. The vast majority of basic electronic systems have been replaced by more modern, corresponding to the third-generation submarines. At the end of 1977, the customer reviewed the updated draft and approved it. However, approval was not followed by any other action. By this time, a new 55 workshop had been used at Sevmash, but it was impossible to build new amphibious submarines there. The fact is, from 1976 of the year, the nuclear rocket carrier TK-208 of the 941 project was built in the new workshop, and preparations were made for laying the second submarine of the same project. It is worth noting that the possibility of starting the construction of the first boat of the 717 project was considered, but such a move would mean a reduction in the volume or pace of assembly of submarines with ballistic missiles. Therefore, naval sailors eventually had to abandon the project already ready for construction.
As we see, all four Soviet projects of amphibious submarines remained on paper or, at best, in the form of several full-scale mockups of various parts of the structure. The reason for this were several factors. First, when creating amphibious submarines, especially early projects, everything had to be done from scratch, because nowhere else in the world did there be such works. Approximately during the development of the 621 project in the United States, the possibility of creating a similar submarine ship was being worked out. According to the most ambitious ideas, a submarine 220 long in meters, 38 wide and with a displacement of at least 10000 tons was to transport up to 2200-2250 marines or several dozen pieces of equipment, including armored ones. In this case, the delivery of the landing force to the coast was planned to be laid on certain boats capable of accelerating to 80-100 miles per hour. After analyzing the possibilities, prospects and - most importantly - the technical difficulties, the command of the US Navy and the International Police Commission decided to continue the existing development of the amphibious fleet.
The second reason why the Soviet Union never built a single amphibious submarine was the limited possibilities of industry. Even brought to mind the project 717, besides created at the peak of the country's power, did not go into the series. The military had to choose what to build: submarines with strategic missiles or amphibious submarines. As a result, the support fell on the first option.
The third reason for the absence of landing craft in the USSR Navy is directly related to the second one and in a sense is a prerequisite for it. The Soviet Union, regularly patrolling remote areas, had no intention of attacking anyone first. Therefore, amphibious submarines, as well as all other classes of amphibious ships, were all the time, as they say, in secondary roles with respect to cruisers, as well as strategic and multi-purpose submarines. Moreover, until a certain time, for obvious reasons, there was no clear and objective concept of the use of landing craft.
In the end, the complexity of the development and construction, limited resources and not quite clear prospects led to the existing result. For many years, the main equipment for the transportation and landing of the marine infantry remained large and small landing ships, as well as ships and hovercrafts. In the eighties, there was a breakthrough in the field of amphibious shipbuilding: Nevskoye PKB created the project of the universal amphibious assault ship "11780". Unfortunately, due to political, economic and social cataclysms, it was not implemented in the metal and added to the list of closed projects of ships for the transportation and disembarkation of marines.
Apalkov Yu.V. Submarines of the Soviet fleet1945-1991 Volume II: The Second Generation of the Premier League - M: Morkniga, 2011