The Kilo class is the diesel-electric submarine designed by St. Petersburg-based Rubin Central Maritime Design Bureau. It is intended mainly for anti-submarine warfare (ASW) and anti-surface warfare (ASuW) roles, and is also capable of general reconnaissance, water mine laying and patrol missions. There are three variants in the Russian Navy service: Project 877, Project 877K, and Project 877M. The Project 877EKM was the early export variant with reduced features. The Project 636 is a follow-on development of the former with reduced noise level and increased underwater speed.
The PLA Navy ordered two Project 877EKM submarines from Russia in 1994, and they were delivered in 1995. In 1996 the PLA Navy became the first foreign customer for the improved Project 636 submarines with two boats of this variant ordered from Russia. These boats were delivered in 1997 and 1998. All four Kilo class submarines are deployed in the submarine base of the East Sea Fleet at Zhoushan, Zhejiang Province near the Taiwan Strait.
In 2002, the PLA Navy signed a US$1.5 billion deal with the Russian state arms export agency Rosoboronoexport to purchase eight more Project 636 submarines. In May 2002, the Russian news agency Itar-Tass confirmed that construction on two units of the eight Project 636 submarines for the PLA Navy was to begin during the first quarter of 2003 at the Severodvinsk Shipyard. Follow-on units of the class will be built at Admiralteyskiye Verfi Shipyard in St. Petersburg (five units) and at Krasnoye Sormovo Shipyard in Nizhniy Novgorod (one unit). Delivery of these submarine began in 2005 and was completed by 2007.
The PLA Navy reportedly experienced some mechanical problems with the Kilo class submarines due to insufficient crew training, and more constantly because of the material problems including the troublesome batteries and generators. The first two Project 877EKM submarines were said to be out of operation for several months due to technical problems. As the PLA Navy gets more efficient in operating the submarine, these problems are likely to be solved.
The purchase of additional Kilo class submarine reflects the PLA Navy’s urgency to build a modernised underwater force that capable of supporting its military actions against Taiwan and deterring any intervention by the U.S. Navy. It also reflects the incapability of China’s indigenous shipbuilding industry to fulfil the navy ’s requirements, which forced the Chinese military planners to look elsewhere for a solution.
The Kilo class submarines features a water-drop shape double hull with a T-shape stern rudder and a single large shaft. A pair of bow planes are located close to the midship on the upper hull in front of the sail. With a reserve buoyancy of 32%, the submarines consists of six watertight compartments separated by transverse bulkhead in a pressured double hull, which increases the survivability of the submarine, even with one compartment and adjacent ballast tanks flooded. The command and control and fire-control systems are located in the main control room which is sealed off from other compartments.
To reduce the submarine’s acoustic signature, the flooding ports are removed from the forebody, and the hull is covered with rubber anti-sonar protection tiles to reduced the risk of detection. The improved Project 636 has more powerful diesel generators, but with a lowered speed main shaft, which provides a substantial reduction in the acoustic signature of the submarine.
The Project 877EKM has a displacement of 2,300t when surfaced and 3,950t submerged. The Project 636 has a extended hull with slightly larger displacement. The maximum diving depth is 300m. The surface speed is 11 knots and the underwater speed is 20 knots. The personnel onboard total 52, and the submarine has an endurance at sea of 45 days.
The submarine's propulsion system consists of two diesel generators, a main propulsion motor, a fuel-economic motor and a single shaft driving a seven-blade fixed-pitch propeller. There are two additional stand-by motors for running in shallow waters, at mooring and in cases of emergency. Two 120-cell storage batteries are installed in the first and third compartments of the submarine. The main machinery is equipped with an automatic control system.
