In the 1984-1996 period the Soviet and Russian shipbuilding industry built 16 Akula class (Project 971) nuclear attack submarines. They were built in Severodvinsk and Komsomolsk-on-Amur shipyards and were commissioned tD the Northern and Pacific fleets of the Russian Navy. These submarines and four Project 945 titanium submarines (E.d. Note: NATO designation ls Sierra) are the most advanced Russian SSNs and they are approximately comparable tD the American improved-688 class attack nuclear submarines. These submarines together with 26 Project 671 RTM and seven Project 671 RT submarines (Victor classes), which are comparable tD the initial 688 class U.S. submarines, are the backbone of the Russian SSN force.
The Project 971 submarine is earmarked, first of all, for sweeping, detection, and shadowing of an adversary’s ballistic missile nuclear submarines and aircraft carriers and destroying them with beginning-of-war actions. She also can destroy other submarines and surface ships by her torpedoes, missiles and mines. The second very important mission, which was really first implemented on this SSN, is her ability to strike land targets on ranges up to 3000 kilometers by her 533mm caliber Granat cruise missiles.
The submarine was designed by the St. Petersburg’s Central Design Bureau Malachite which designed the first Soviet attack nuclear submarine November class (Project 627 A), first serial production attack: submarines of the Victor class (Projects 671, 671RT, and 671RTM) of the second generation and some other submarines. The Chief Designer of Akula was Georgy Tchemyshev; the Chief Navy Supervisor was Captain 1 rank Igor Boganchenko.
In principle, weapons of the Project 971 submarines are similar to weapons of Project 945 titanium attack nuclear submarines which were designed and built in Sormovo (Nizhny Novgorod).
The submarine has eight bow torpedo tubes (four 650mm and 4 533mm) with a total number of 40 torpedoes and cruise missiles (12 650mm and 28 533mm). Torpedo tubes are installed in two horizontal rows: 533-65~0-533mm in the upper part of the first compartment.
She also has six bow 400mm outside tubes for decoys.
It should be noted that Russian submarine torpedoes and missiles have a number of sizes and weights. Their lengths are up to 8.2m for 433 and 12m for 650mm caliber. Until recently Russian submarines had no wire guided torpedoes.
The main category of Russian 533mm torpedoes are of the homing variety with electric batteries and propulsion. The newest of them are: 53-65 KE anti-ship wake homing (speed 45 knots, range 19 km) and TEST-71M anti-5Ubmarine acoustic homing, wire guided (speed 24 or 40 knots, range 20 or 15 km) and also rocketpropelled Shkval torpedo (speed 200+ knots, range 7-10 km). Torpedoes have several warheads-the largest a high explosive one of up to 500 kg. Nuclear warheads are also fitted; submarine torpedoes having been the first Sovie, naval weapon with nuclear capability.
Anti-ship 650mm torpedoes entered service in the 1980s. They have an advanced closed-cycle thermal propulsion system (speed of 50 knots with a range of SO km and 30 knots with a range of l 00 km), warhead weight up to 1000 kg and the guidance is wake homing.
The first Soviet anti-submarine, submarine-launched missile SSN-15 was deployed in 1972 and is fired from standard 533mm torpedo tubes and carries a nuclear warhead (like the U.S. Navy Subroc) with a range up to SO km.
A further development of the SS-N-15 was the 650mm caliber SS-N-16 missile which carries an anti-submarine 500mm homing torpedo in lieu of the nuclear warhead. A parachute lowers the torpedo into the water for the torpedo to home in on a target. Its range is up to 100 km.
The first Soviet advanced land-attack cruise missile SS-N-21 (Granat) is launched from standard 533mm torpedo tubes, much like the U.S. Navy Tomahawk Land-Attack Missile (TLAM). Deployed in 1988, on 671RTM, 945 and 971 Project submarines. Its weight is 1700 kg and length is 8.1 m. The propulsion is turbofan with a speed of Mach 0. 7, and a range of up to 3000 km.
The warhead is nuclear at 200 300 kt, and guidance is inertial with Terrain Contour Matching (TERCOM). It is possible to install a conventional high explosive warhead.
Readiness of an Akula class submarine to fire torpedoes and missiles in a duty condition is 15 seconds. The fast recharge device lets it fire the next salvo after six minutes.
Instead of torpedoes and missiles, the submarine can carry mines of 533mm caliber with one to one ratio.
The submarine has a storage and reloading system which allows automatic transfer of any torpedo or missile from a torpedo tube to any storage place in the torpedo compartment and back.
She also has 18 air defense portable Strela missiles.
Hydroacoustics and Other Electronics
For illumination of underwater and surface situations and targeting, the submarine has the newest hydroacoustic complex, SCA T-3, with digital information processing which has several full spectrum modes:
- passive regime
- active regime
- regime of hydroacoustic signal detection
- regime of hydroacoustic communication
- infrasound passive regime
- regime of target classification
- passive regime of target range measuring
The main passive hydroacoustic antenna (cylindrical with a height approximately 4.Sm and diameter up to 7m) is placed under the torpedo tubes. The active antenna is also in the bow part. They have fiberglass fairing.
In addition to this antenna, there are two side passive antennas in the area of the first compartment with sizes approximately 10m vertically and 6m horizontally and also a stem towed passive infrasound hydroacoustic antenna in the capsule on the vertical stabilizer.
Owing to reduction of noise levels and hindrances to the hydroacoustic complex work, the range of target acquisition was increased more than three times in comparison with submarines of the second generation.
The submarine’s other electronic equipment includes a battle information control system (BICS), automatic radio communication, radar systems and a navigational complex.
The main power plant (MPP) of the submarine is almost identical to the MPP of Project 945 submarines. It consists of one 190mw pressured water reactor with pressure in the first contour of 1150 atmospheres, and one turbine with 50,000 shp, one 7 bladed propeller (6m diameter, maximum 200 rpm) with extensive mechanism reservation.
The steam generating system has one reactor, two steam generators, two pumps of first contour, three pumps of third contour and two pumps of fourth contour.
The steam turbine plant consists of one turbo-toothgearing agregate and two autonomous turbo-electro generators of alternating current (each 3000 kwt, 380 v, 50 hz), two feed water pumps and two condemers with two circulation pumps. The last ones on this submarine are in the reactor compartment. Steam pressure is 32 atmospheres.
In case of a withdrawal of the MPP from action and for putting it into operation, the submarine bas emergency sources of electric energy and reserve propulsion means. For users of direct current there are two reversible convertors and two groups of storage batteries.
The submarine has two submerged electric motors of alternating current (each are 400 lcwt) with two propellers which are retractable from their niches between the pressure and light hulls. With these propellers she can sail with speeds up to four knots underwater and on the surface. In the latter case, electromotors get energy from a diesel generator (800 hp). Fuel reserve for it provides for 10 days of power.
Naval Architectural Elements
Submarine designers put special attention to increasing her propulsion qualities. The outer hull is made as a body of revolution with a slightly elliptical bow. All of its holes are covered by automatic drain hole covers. The submarine’s speed is up to 33 knots with a propulsion coefficient of 0.8.
The submarine has classical stem empennage with horizontal and vertical stabilizers and planes. The bow planes are retractable.
Speed-of-depth change at 30 knots with a 30 degree angle is up to Sm/sec. The turning circle in a horizontal plane is about 5.5 times the submarine’s length.
The test diving depth of an Akula is the same as that of a Sierra: 600m. Collapse depth is 840m. Operating depth is 480m. The pressure hull has a simple form (cylindrical in the middle parts and cones at the ends). The maximum diameter of the pressure bull is 10.9m with a thickness of 46 mm. The bow and stem bulkheads are spherical. Intercompartment bulkheads are flat (10 atmospheres) except the second compartment’s bulkheads which are also spherical (20 atmospheres). The material of the pressure hull is steel, Alc-32, with a yield strength of 100 kg/sq mm.
Damage control surface unsinkability is provided for flooding of any one of six compartments with two adjacent ballast tanks. The submarine has 26 percent reserve buoyancy having 17 main ballast tanks with kingstons.
A new measure of the submarine’s surfacing from underwater is the system of emergency blowing up of the three middle main ballast tanks by products of solid fuel burning in addition to usual blowing of ballast tanks by high pressure air. For rescuing the whole crew from test depth, the submarine has a life-saving chamber.
Owing to a high degree of automatization, the submarine’s crew consists of 73 officers, petty officers and men.
The submarine has six compartments plus a bow part, a stem part, 17 ballast tanks, a superstructure and a sail. For unsinkability, the first compartment is divided into two parts by the horizontal 10 atmospheres watertight deck. In the bow part there are torpedo and decoy tubes and a hydroacoustic antenna. The first compartment has torpedoes, hydroacoustic and storage batteries; second compartment-control room and living accommodations; third compartment-radio, radar, navigational, some electrical equipment and diesel generator; fourth compartment-reactor and its equipment; fifth compartment-turbine, turbogenerators and their components; sixth compartment-thrust bearing, rudders and planes machinery and the device for the retractable towed hydroacoustic antenna. In the stem part-propeller, stabilizers, planes and rudders and reel for the hydroacoustic antenna. The surfacing escape chamber, bridge, retractable masts and towed radio antenna are in the superstructure and sail.
Surfaced displacement, t 8,140
Submerged displacement, t 12,770
Length, beam, draft, m 110.3xl3.6×9.7
Torpedo tubes bow, 4-650mm and 4-533mm
Weapons 12-6SOmm and 28-S33mm torpe does and missiles or 40 mines
Sonar/fire control SCAT-3 and BICS
Test depth, m 600
Speed, submerged, knots 33
Reactor 1 OK-650, 190 mgwt
Turbine 1 50,000 sbp
Builders Komsomolsk and Severodvinsk Shipyards
Cost 300 million rubles in 1984
In comparison with the Project 945 submarine, the increasing volume displacement of the Project 971 submarine reduced her speed but allowed the implementation of the newest weapons and electronics that broadened the spectrum of submarine missions. The most important of them was the installation of new cruise missiles (Granat) to strike land targets from S33mm torpedo tubes at ranges up to 3000 km and new hydroacoustic complex SCAT-3 with digital processing.
But the main test was providing for minimum noise of the submarine. It was done by arranging of all that is on a submarine on intermediate rafts which are fixed to the pressure hull and bulkheads on pnaunatic shock absorbers. It is the second cascade of noise insulation. The first one is on rubber struts and mechanism fuundations. Thick anti-echoing coating (64mm) on the outer bull and thin anti-noise coating on the pressure bull also play their role. As a result, this submarine is the quietest in the Russian Navy.