The Kilos were Soviet, and later mostly Russian, diesel-electric (SS) fighter submarines whose production began in 1982. Units were built in the cities of Leningrad (today's St. Petersburg), Gorky (today's Nizhny Novgorod) and Komsomolsk-on-Amur. It is estimated that a total of about 60-65 units of this class were built. The Kilo-class ship is 72.6 m long, 9.9 m wide, and has a displacement of 3,200 tons. The maximum underwater speed is approx. 16 knots. The main armament of units of this class is 6 bow 533 mm torpedo tubes.
The Kilo-class ships (project 877) were designed to replace the Whiskey-class units, i.e. medium-range ships, intended to operate at a relatively close distance from their own bases. Compared to their predecessors, the new Soviet submarines had a completely different hull shape, which provided much better hydrodynamic properties. They also have better soundproofing of the drive unit and are generally much quieter. They also feature a much more perfect reloading system, which works much faster, with torpedo tubes. Generally, Kilo-class ships are successful ships, with a potential similar to that of Western units of that period. The Kilo class (Project 877) has been modernized (Project 636) for the needs of the Russian Navy and features higher underwater speeds of up to 19 watts, reduced noise and improved electronics. Kilo-type units were or are operated by the fleets of the USSR / Russian Federation, the PRC, Algeria, India, Iran, Romania, Vietnam and Poland. In our Navy, a ship of this class is used under the name ORP Orzeł.