The Kilo-class submarine was laid down by the Central Design Bureau for Marine Engineering and officially commissioned in April of 1982. 57 total vessels of the class were ultimately completed and 47 remain in active service as of this writing (September 2013). Two have been formally retired from service while a single boat was lost. The Kilo-class replaced the outgoing Tango-class boats while the Kilo-class itself was succeeded by the Lasa-class series. The boats have been exported beyond Soviet/Russian territories and have served with Algeria, China, India, Iran, Poland, Romania and Vietnam. The class is designed primarily for anti-ship/anti-submarine duties.
Design-wise, the Kilo-class displaces at 2,300 tons when surfaced and nearly 4,000 tons when submerged. She features a running length of up to 74 meters with a beam measuring 9.9 meters and a draught of 6.5 meters. The vessel has been tested to depths of 300 meters while oeprational service is typically at 240 meters. The Kilo-class is outfitted with a conventional powerplant arranged as a diesel-electric configuration. This includes 2 x diesel generators outputting 1,000kW of power and tied to 1 x motor delivering up to 6,800 shaft horsepower to a single, multi-bladed, fixed-pitch propeller held along a shaft at the stern. This arrangement allows the vessel a to surfaced speed of 12 knots with a submerged speed nearing 25 knots. Operational range is approximately 7,500 miles when cruising at seven knots along the surface. Range is reduced when submerged to 400 miles heading at 3 knots. The Kilo-class holds enough stores to supply a crew up to 45 days at sea before replenishment is required. Her crew consists of 52 personnel made up of officers and sailors.
As an attack submarine, the craft is outfitted with 6 x 533mm torpedo tubes with 18 x torpedo reloads. Some versions are outfitted further with the Club S anti-ship missile system. The craft can also disperse up to 24 naval mines if required (in place of the torpedo load). Russian variants are defensed on the surface through 8 x SA-N-8 "Gremlin" or 8 x SA-N-10 "Gimlet" surface-to-air missile systems.
The modern Russian Navy is believed to operate some 17 Kilo submarines today (2013). China, India and Vietnam represent the next largest operators with 12, 10 and 6 respectively. In the Russian Navy nomenclature, the Kilo-class is recognized as "Project 877 Paltus", Paltus meaning "Halibut".