Foxtrot Class (Project 641 Class) Russian Diesel-Electric Patrol Submarine

The Foxtrot Class (Project 641 Class) Russian Diesel-Electric Patrol Submarine is a class of diesel-electric patrol submarines that were built in the Soviet Union. The Soviet designation of this class was Project 641 and was designed to replace the earlier Zulu class, which suffered from structural weaknesses and harmonic vibration problems that limited its operational depth and submerged speed. The first Foxtrot keel was laid down in 1957 and commissioned in 1958 and the last was completed in 1983. A total of 58 were built for the Soviet Navy at the Sudomekh division of the Admiralty Shipyard (now Admiralty Wharves), Saint Petersburg. Additional hulls were built for other countries. The Foxtrot class was comparable in performance and armament to most contemporary designs. However, its three screws made it noisier than most Western designs. Moreover, the Foxtrot class was one of the last designs introduced before the adoption of the teardrop hull, which offered much better underwater performance. Also, although the Foxtrot was larger than a Zulu class submarine, the Foxtrot class had 2 of its 3 decks dedicated to batteries.