Function: Nuclear powered attack submarine.





History: The Delfin class attack submarines (SSN) were originally conceived in 1972 as Project 971/971U "Bars", a strategic cruise missile launch platform (SSGN) capable of launching the S-10 Granat missile, a Soviet copy of the American Tomahawk cruise missile. Originally designed along the same lines of the Pr. 671RTM (NATO Victor III) submarines, and armed with six 53cm torpedo tubes (to fire the S-10) and 2 65cm tubes (to launch defensive torpedoes and missiles), when the Soviet navy realized that its production facilities were not capable of producing titanium hulled Pr. 945 (NATO Sierra I and II) submarines, the 971 was redesigned to take advantage of the advanced sensor, command, communication, and weapons systems of the Zubatka and Karp class boats, yet made from steel. This redesign also increased the number of 53cm and 65cm torpedo tubes to four apiece. Additionally, the Pr. 971 submarines incorporated the active countermeasures suite found on the Pr. 945 boats. This system would use acoustic sensors to detect, classify, and automatically prioritize these contacts and display this information to an operator who then could take more precise action. Furthermore, in the case of torpedoes, the system could automatically take action, launching decoys and initiating barrage and deception jamming of the threat sensors. Surprisingly, when the 971 series entered production, it was found to offer performance similar to the 945 but at a fraction of the cost,with lower maintenance requirements, and the only real drawback being the reduction of the basic load from 40 weapons to 32. Consequently, the 971, and not the 945, was adopted as the follow on general purpose submarine to replace the aging 671 fleet.



Improvements to the basic Delfin design were incorporated into a more advanced production model designated the 971U. These improvements included the installation of 6 external 53cm torpedo tubes (for launching the S-10 Granat) and the non acoustic sensor system from the Pr. 945 submarines, which uses infrared sensors to detect the thermal gradients produced in submarine wakes. As production of the 971U was initiated, attempts to reduce the noise signature to levels comparable with the early Los Angeles class boats were made, which necessitated the redesign of the engine spaces. These modifications were incorporated into a new design designated Project 971A.



Deployed roughly at the same time as the American Improved Los Angeles class fast attack submarines, the 971 boats produce more noise than the early Los Angeles class, though their performance is far superior to earlier Soviet designs. The 971U is comparable to the early Los Angeles submarines in radiated noise levels at low speeds, becoming progressively noisier as speed increases. Additionally, the 971 series are far inferior to their US counterparts in terms of sonar sensitivity and combat capabilities. Production was limited to twelve 971U submarines before the collapse of the Soviet Union. Additionally, production was initiated on two 971A submarines but discontinued for lack of funding. Eleven of the surviving 971U submarines are currently in limited service with the Russian navy.





General Characteristics, Delfin Class



Builders:

Krasnoye Soromovo Zavod 112, Nizhniy Novgorod





Power Plant:

One OKB-650B-5 rated at 190 Megawatts, two steam turbines, one shaft with one VRSh-7 controllable pitch screw, 47,000 shaft horsepower





Length, Overall:

354.2 feet (107.9 meters)





Beam:

44.3 feet (13.5 meters)





Draft:

31.4 feet (9.6 meters)





Displacement:

7,900 tons submerged





Speed:

35 knots submerged





Crew:

31 Officers; 31 Enlisted





Maximum Safe Diving Depth:

1,475 feet





Armament:

Two internal 53cm torpedo tubes



Two external 53cm torpedo tubes (8 on 971U series)



Four internal 65cm torpedo tubes



S-10 Granat (NATO SS-N-21 SAMPSON) strategic cruise missiles



Two RPK-6 Vodopod (NATO SS-N-16 STALLION) rocket delivered nuclear depth charges



RPK-7 Vodopei (NATO SS-N-16 STALLION) rocket delivered homing torpedoes



BA-111 Shkval underwater rockets



Type 53-65K torpedoes



SET-65 torpedoes



TEST-68 torpedoes







Sensors:

Vspletsk combat direction system





Radar:

One Chiblis surface search radar



One Medvyedista-945 navigation radar





Sonar:

One MGK-503-M Skat active/passive sonar suite



One Pelamida towed sonar array



Two Akula flank arrays



One MG-70 mine detection sonar





Countermeasures:

Bukhta ESM/ECM system



Two MG-74 Korund noise simulation decoys



One MT-70 sonar intercept reciever



Nikhrom-M IFF system









Ships:

K.239 Karp, Commissioned June 1987, decommissioned 1997.

K.276 Krab, Commissioned September 1984, decommissioned 1997