The Foxtrot boats were intended as a follow-on to the Zulu class, but only 62 of an anticipated programme of 160 were completed as the change to nuclear boats took effect. These diesel-electric submarines were built at Sudomekh between 1959 and 1983 and formed the bulk of the Soviet submarine force in the Mediterranean in the 1960s and 1970s. These boats were also exported to Cuba, India and Libya.
A Foxtrot attack submarine belonging to the Cuban navy. These boats were intended to replace the earlier Zulu class derived from the German Type XXI U-boat.
A Foxtrot at speed, showing the clean lines of these submarines. The red-and-white buoy recessed into the deck forward of the sail is the tethered rescue buoy. The bow diving planes retract into the hull almost level with the long row of limber holes, which provided free flooding between the double hulls.
In the Cold War era, that commitment began with the massive submarine construction programs initiated immediately after World War II-the long-range Project 611/Zulu, the medium-range Project 613/Whiskey, and the coastal Project 615/Quebec classes. Not only did these craft serve as the foundation for the Soviet Navy’s torpedo-attack submarine force for many years, but converted Zulus and Whiskeys were also the first Soviet submarines to mount ballistic and cruise missiles, and several other ships of these designs were employed in a broad range of research and scientific endeavors.
These construction programs were terminated in the mid-1950s as part of the large-scale warship cancellations that followed dictator Josef Stalin’s death in March 1953. But the cancellations also reflected the availability of more-advanced submarine designs. Project 641 (NATO Foxtrot) would succeed the 611/Zulu as a long-range torpedo submarine, and Project 633 (NATO Romeo) would succeed the 613/Whiskey as a medium-range submarine. There would be no successor in the coastal category as the Soviet Navy increasingly undertook “blue water” operations. Early Navy planning provided for the construction of 160 Project 641/ Foxtrot submarines.
Designed by Pavel P. Pustintsev at TsKB-18 (Rubin), Project 641 was a large, good-looking submarine, 2991/2 feet (91.3 m) in length, with a surface displacement of 1,957 tons. Armament consisted of ten 21-inch (533-mm) torpedo tubes-six bow and four stern. Project 641/Foxtrot had three diesel engines and three electric motors with three shafts, as in the previous Project 611/Zulu (and smaller Project 615/Quebec). Beyond the increase in range brought about by larger size, some ballast tanks were modified for carrying fuel. Submerged endurance was eight days at slow speeds without employing a snorkel, an exceptional endurance for the time. The Foxtrot introduced AK-25 steel to submarines, increasing test depth to 920 feet (280 m). The large size also provided increased endurance, theoretically up to 90 days at sea.
The lead ship, the B-94, was laid down at the Sudomekh yard in Leningrad on 3 October 1957; she was launched-64 percent complete-in less than three months, on 28 December. After completion and sea trials, she was commissioned on 25 December 1958. Through 1971 the Sudomekh Admiralty complex completed 58 ships of this design for the Soviet Navy.
Additional units were built at Sudomekh from 1967 to 1983 specifically for transfer to Cuba (3), India (8), and Libya (6). The Indian submarines were modified for tropical climates, with increased air conditioning and fresh water facilities. Later, two Soviet Foxtrots were transferred to Poland. The foreign units brought Project 641/Foxtrot production to 75 submarines, the largest submarine class to be constructed during the Cold War except for the Project 613/Whiskey and Project 633/Romeo programs.
(Two Project 641 submarines are known to have been lost, the B-37 was sunk in a torpedo explosion at Polnaryy in 1962 and the B-33 sank at Vladivostok in 1991.)
The Soviet units served across the broad oceans for the next three decades. They operated throughout the Atlantic, being deployed as far as the Caribbean, and in the Pacific, penetrating into Hawaiian waters. And Foxtrots were a major factor in the first U. S.-Soviet naval confrontation.