Project 670 Skat

Project 670 Skat
Name	Project 670 Skat
Other names	Charlie I class
Builders	Krasnoye Sormovo Shipyard, Sevmash
Country	Soviet Union
In service	1968–1992
Displacement	4,000–6,500 tonnes
Length	91.3 m
Beam	9.5 m
Draught	8.1 m
Propulsion	PWR, turbo-electric drive
Speed	33 kn (submerged)
Test depth	300 m
Complement	~100
Armament	SS-N-7 Starbright, torpedoes, mines
Sensors	MG-13, MG-335, sonar suites

Project 670 Skat

Project 670 Skat was a Soviet nuclear-powered cruise-missile submarine class introduced in the late 1960s, known in NATO reporting as the Charlie I class. Designed during the Cold War arms competition, the class reflected Soviet assessments of threats posed by NATO carriers and maritime task forces, and incorporated nuclear propulsion, cruise missiles, and advanced sonar and fire-control systems.

Design and Development

Design work on the Skat concept was carried out by Rubin Design Bureau and TsKB-16 in the context of Cold War naval programs involving Marshal Nikolai Kuznetsov-era priorities and guidance from the Ministry of Shipbuilding Industry. The program paralleled projects at Admiralty Shipyards and Sevmash and drew on experience from earlier classes such as November, Echo, and Hotel, while responding to assessments from the General Staff and the Soviet Navy's Northern Fleet and Pacific Fleet commanders. Key industrial partners included Baltic Shipyard, Krasnoye Sormovo, and Zvezda, with technological input from OKB-16 and research conducted at TsNII VMF institutes and the Krylov Shipbuilding Research Institute. The design trade-offs balanced missile payload, reactor type developed at OKB Gidropress, acoustic signature reductions informed by Malakhit design studies, and requirements set during Strategic Rocket Forces discussions and Politburo oversight.

Technical Specifications

The design incorporated a pressurized water reactor core derived from earlier Alfa and Victor studies, coupled to a turbo-electric transmission influenced by work at Leningrad's Electrosila and Moscow Institute of Thermal Technology. Hull form and hydrodynamics were tested at the Krylov Institute and addressed cavitation concerns raised by NATO intelligence and by planners in the Northern Fleet. Displacement varied with loadout; internal arrangements reflected Soviet standards for habitability defined by the Ministry of Defense and influenced by lessons from Project 627. Machinery spaces were laid out to facilitate maintenance by Sevmash crews and dock trials supervised by officials from the Ministry of Shipbuilding.

Operational History

Charlies entered service with the Northern Fleet, Pacific Fleet, and Black Sea Fleet under commanders who had previously served on November- and Echo-class boats. Deployments included patrols aimed at NATO carrier battle groups and participation in large-scale exercises such as Okean and Zapad, often coordinated with units from the Northern Fleet, Baltic Fleet, and Soviet naval aviation. Encounters with US Navy carrier groups involved units from Carrier Strike Groups and tracking by platforms such as USS Enterprise (CVN-65), USS Nimitz (CVN-68), and Hank-class destroyer-type escorts, and featured in NATO reporting and assessments by the RAND Corporation, the Royal Navy, and the United States Sixth Fleet. Skat boats were subject to port visits and overhauls at facilities like Sevmash, Admiralty Shipyards, and Baltiysky Zavod, with technical cooperation limited by Cold War secrecy and monitored by Western intelligence agencies including the CIA, MI6, and Bundesnachrichtendienst.

Variants

The baseline Charlie I class spawned design evolutions influenced by research from Malakhit and Rubin bureaus, leading to iterations that paralleled developments in Victor and Sierra programs and later Soviet projects such as Oscar. Variants differed in missile launch systems, sonar suites supplied by institutes like NII Rubin, and reactor modifications based on OKB Gidropress proposals. Proposed export versions were discussed in intergovernmental talks with Warsaw Pact navies and allies such as India and Egypt, while decommissioning options considered transfer, scrapping at facilities like Nerpa, and disposal under treaties influenced by discussions at SALT and later arms-control dialogues involving the United States and United Kingdom delegations.

Armament and Sensors

Armament centered on the P-70 Ametist (NATO SS-N-7 Starbright) anti-ship cruise missile system integrated into the fire-control architecture developed by TsNII Gidropribor and Malakhit. Torpedo systems and mine-laying capabilities were provided by design houses with components manufactured at Krasnoye Sormovo and PO Sevmashremont; weapons were compatible with torpedoes used across Soviet fleets and with munitions cataloged by the Soviet Navy's Main Staff. Sensor suites included bow and flank arrays developed by NII Korund and hydroacoustic systems similar to MG-13 and MG-335 series, commanders relying on data fusion with airborne assets such as Tu-95RTs and Il-38s, and coordination with coastal units at Sevastopol and Vladivostok.

Service Record and Incidents

Charlie-class boats participated in numerous Cold War operations monitored by NATO and logged in assessments by institutions including the Royal United Services Institute and the Center for Naval Analyses. Documented incidents included collisions, reactor repairs, and mechanical failures addressed during repairs at Admiralty Shipyards and Sevmash drydocks. Several boats were retired or scrapped during the post-Soviet drawdown overseen by the Russian Navy and ministries in Moscow, with decommissionings subject to oversight by the State Duma and reported in press outlets ranging from Pravda to Jane's Defence Weekly. International diplomatic incidents involved shadowing by US and NATO units and publicized sonar and radar contacts noted by analysts at RAND, SIPRI, and the International Institute for Strategic Studies.

Influence and Legacy

Project 670's legacy influenced later Soviet and Russian submarine concepts, contributing to design features in classes such as Victor III, Sierra, and Oscar, and informing doctrine debated within the General Staff, the Northern Fleet, and the Pacific Fleet. Technical lessons on missile integration, reactor layouts, and acoustic management were cited by Rubin and Malakhit in subsequent projects, and analyses appeared in publications from the U.S. Naval War College, Royal Navy think tanks, and the Center for Strategic and International Studies. The class figures in Cold War naval historiography alongside events like the Cuban Missile Crisis, the Yom Kippur War-era naval deployments, and later post-Cold War force transformations discussed in forums including the Munich Security Conference and the Valdai Discussion Club. Its operational history continues to be studied by historians at institutions such as the Hoover Institution, the Wilson Center, and the Russian Academy of Sciences.

Category:Soviet submarine classes