Project 671

Project 671
Public domain · source
Name	Project 671
Country	Soviet Union
Type	Attack submarine
Builder	Komsomolsk-on-Amur Shipyard
Laid down	1960s
Launched	1960s
Commissioned	1960s
Status	Decommissioned

Project 671 was a Soviet attack submarine program developed during the Cold War as a response to United States Navy nuclear and diesel threats. Designed by Rubin Design Bureau and built for the Soviet Navy by yards including Komsomolsk-on-Amur Shipyard, the series introduced new nuclear propulsion and sonar concepts into Soviet undersea forces. Commissioned in the 1960s, the class operated alongside contemporaries such as Project 658 and Project 941 while facing NATO scrutiny and analysis from institutions like Naval War College and agencies including the Central Intelligence Agency.

Design and Development

The design originated at the Rubin Design Bureau amid doctrinal debates within the Soviet Navy leadership influenced by figures associated with Admiral Sergei Gorshkov and the Soviet Pacific Fleet. Early studies referenced hull forms from Type 209 assessments and lessons from Project 627 work at Sevmash. Collaboration included technical exchanges at institutes such as the Keldysh Research Center and feedback from operational commands like the Northern Fleet and Baltic Fleet. Engineering decisions weighed reactor concepts tested by the OKB-1 and construction methods promulgated by the Ministry of Shipbuilding Industry (USSR). NATO's Allied Forces Southern Europe analysts classified the class in assessments alongside Foxtrot-class submarine evaluations and POLARIS era countermeasures.

Technical Characteristics

The boats featured a pressurized hull with a single [nuclear] reactor plant based on designs from the Soviet Union nuclear sector, drawing on reactor research from Kurchatov Institute personnel and output comparable to contemporaneous plants in United States designs studied at Naval Research Laboratory. Sonar suites incorporated arrays developed by the Research Institute of Hydroacoustics and were evaluated by NATO acoustic teams from NATO Maritime Command units and the Royal Navy's Admiralty Research Establishment. Armament included torpedo tubes compatible with munitions used by the Soviet Navy and guidance systems influenced by the Stalingrad era weapons engineers; fire-control systems were analogous in concept to systems fielded by the United States Navy on Los Angeles-class submarine prototypes. Maneuvering and stealth characteristics were benchmarked against USS Thresher (SSN-593) and USS Skipjack (SSN-585) hull form advances, with noise-reduction efforts paralleling programs at Admiralty and Naval Ship Research and Development Center.

Operational History

Service began in the 1960s with deployments to the Northern Fleet and patrols in theaters including the Barents Sea and Mediterranean Sea, interacting with NATO units such as NATO Standing Naval Forces Atlantic and carriers like USS Enterprise (CVN-65). Encounters with Western assets were documented in incident reports by the Royal Navy and the United States Sixth Fleet, prompting strategic analyses at institutions like the Congressional Research Service and briefings in WPAFB and GCHQ. Several boats underwent modernization to address sonar and reactor reliability, a process overseen by Sevmash and inspectors from Ministry of Defense (Soviet Union). Accidents and losses during the Cold War prompted inquiries comparable to investigations after K-19 and K-129 incidents, influencing safety protocols at the Russian Navy successor organizations after 1991.

Variants

The program produced subtypes differing in reactor plants, acoustic treatments, and weapon suites, reflecting influence from design bureaus including Malakhit and Lazurit. Modifications paralleled developmental forks seen in Project 705 and Project 667 series programs, with later refits targeting improvements similar to those applied to Victor-class submarine boats. Experimental conversions tested sonar prototypes from the Central Naval Research Institute and noise-reduction technologies trialed by the Soviet Academy of Sciences.

Service and Deployment

Deployments concentrated in Soviet Pacific Fleet and Northern Fleet theaters, with patrol patterns around choke points such as the GIUK gap and passages near Kuril Islands. Operations supported broader Soviet naval strategy articulated by Admiral Sergei Gorshkov and were integrated into tasking alongside surface combatants from fleets including the Black Sea Fleet and units of the Baltic Fleet. Training and crew rotation involved establishments like the Higher Naval School and training centers influenced by doctrine from Frunze Academy instructors. Decommissioning accelerated after the Dissolution of the Soviet Union (1991) with assets paid off under programs administered by the Ministry of Defense of the Russian Federation and shipbreaking conducted at yards such as Sevmash and private contractors contracted under State Committee for Science and Technology guidelines.

Legacy and Evaluation

Analysts at RAND Corporation, Center for Strategic and International Studies, and Western naval staffs assessed the program's impact on antisubmarine warfare and force structure debates in studies influenced by events including the Cuban Missile Crisis and subsequent Cold War maritime tension. The class informed Soviet design philosophy incorporated into successors like Victor-class submarine and Akula-class submarine programs, and its operational record contributed to NATO tactics developed by entities such as the Allied Maritime Command. Historical treatments appear in works published by authors affiliated with Naval Institute Press and academic centers including King's College London and Harvard Kennedy School military studies, which compare the class to contemporaries like USS Nautilus (SSN-571) and Tench-class submarine boats. The program's technical lessons influenced post‑Cold War submarine initiatives within Russian Navy procurement and were cited in retrospectives by institutes such as the Institute of World Economy and International Relations.

Category:Soviet submarines