Russia launched its sixth and final Project 636.3 (Improved Kilo-class) diesel-electric submarine (Kolpino) on order for the Black Sea Fleet on May 31.

At the ceremony, Vice Admiral Alexander Fedotenkov, deputy chief of the Russian Navy, revealed that Russia is now planning to order Project 636.3 submarines for the Pacific Fleet, and will later build more Improved Kilo-class boats for Russia’s Northern and Baltic Fleets.

The Varshavyanka-class (Project 636.3) is an improved version of Kilo-class submarines that features advanced stealth technology, extended combat range and the ability to strike land, surface and underwater targets.

Russia currently has four Project 636.3 vessels commissioned into service with the Black Sea Fleet and launched a fifth in March that is due to soon begin sea trials. While in the eastern Mediterranean Rostov-Na-Donu notably fired 3M14 Kalibr land attack cruise missiles at targets in Syria.

The diesel-electric submarine has a maximum speed of 10–12 knots surfaced (18–22 km/h) and 17–25 knots submerged (31–46 km/h). A submerged displacement is around 4,000 tons. Fifty-two sailors are needed to operate the sub, which displaces 3,100 tons and can maintain continuous patrol for 45 days. The ship’s length is70.0–74.0 m (229 ft 8 in–242 ft 9 in), beam 9.9 m (32 ft 6 in), draft 6.5 m (21 ft 4 in). Range: with snorkel 6,000–7,500 nmi (11,100–13,900 km; 6,900–8,600 mi) at 7 kn (13 km/h; 8.1 mph), submerged 400 nmi (740 km; 460 mi) at 3 kn (5.6 km/h; 3.5 mph), full run 12.7 nmi (23.5 km; 14.6 mi) at 21 kn (39 km/h; 24 mph). Depth: operational 240 m (790 ft), maximum 300 m (980 ft). Endurance 7,500 nautical miles (13890 km). The cruising range under electric propulsion is 400 miles.

The new submarine has unique noise characteristics. Its immediate predecessor – the Project 877EKM Kilo class – was nicknamed «black hole» by Western naval experts due to the very low noise emission and visibility. The increased length of the Project 636.3 permits increasing the power of diesel-generators and mounting them on improved shock-absorbing support, and reducing twofold the main propulsion shaft speed. Owing to these improvements, the submarine speed and sea endurance are increased, while the noise level is radically decreased. The low noise level has been achieved with the selection of quiet machinery, vibration and noise isolation and a special anti-acoustic rubber coating applied on the outer hull surface.

The submarine consists of six watertight compartments separated by transverse bulkheads in a pressurized double-hull. This design and the submarine’s good reserve buoyancy lead to increased survivability if the submarine is holed, even with one compartment and two adjacent ballast tanks flooded. The foreplanes are positioned on the upper hull in front of the fin or sail.

The boat is equipped with a multi-purpose combat and command system which provides information for effective submarine control and torpedo firing. The system’s high-speed computer can process information from the surveillance equipment and display it on the screen; determine submerged and surface target data and calculate firing parameters; provide automatic fire control; and also provide information and recommendations on manoeuvres and deployment of weapons.

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.

Intended primarily for anti-shipping and anti-submarine warfare in relatively shallow waters the ship packs a powerful punch to carry the missions out. The armament includes:

- air defense: 8 SA-N-8 Gremlin or SA-N-10 Gimlet surface-to-air missiles (export submarines may not be equipped with air defense weapons). The Gremlin is a man-portable system with infra-red homing seeker head and an operational range of 4100m (2.5mi).

The SA-N-10 Gimlet is a short-range man-portable air defense system with a range of 5.2 km (3.2 mi).

- Six 533 mm torpedo tubes with 18 ASW torpedoes. The tubes can be used for launching VA-111 Shkval supercavitating «underwater missiles», or 24 mines. All torpedo tubes and their service systems provide effective firing from periscope to operational depths. The computer-controlled torpedo system is provided with a quick-loading device. It takes only 15 seconds to prepare stand-by torpedo tubes for firing: The first salvo is fired within two minutes and the second within five minutes.

- Kalibr-PL (export name Club-S) anti-ship, anti-submarine and land attack cruise missile.

The missile can strike land targets at 1500 km (over 917 miles). Last year, the Russian Navy said the Rostov-Na-Donu successfully fired the missiles from a submerged position in the Mediterranean Sea hitting two objectives in Syrian Raqqa province on December 8.

The 636.3 boats are equipped with improved MGK-400EM sonar system, which provides: detection of submarine and surface ship targets in sonar listening mode; echo-ranging in a ±30° sector of the target relative bearing; telephone and telegraph communication in both long and short-range modes; detection of underwater sound signals and determination of the signal bearing. The submarine’s radar works in periscope and surface modes and provides information on the underwater and air situation, radar identification and navigational safety.

The MGK-400 design features extremely low volume of hardware accommodated inside the submarine hull and low power consumption owing to a number of brilliant engineering solutions, including hull-mounted high-strength capsule housing part of the sonar equipment. Anechoic tiles are fitted on casings and fins to absorb the sound waves of active sonar, which results in a reduction and distortion of the return signal. These tiles also help attenuate sounds that are emitted from the submarine, thus reducing the range at which the sub may be detected by passive sonar. To reduce submarine sonar crew, MGK-400EM incorporates the MG-519EM mine-hunting system with presentation of its data on the MGK-400EM’s common information display.

Featuring low noise, advanced hull architecture, optimal level of control process automation, the submarines provide high reliability and are low maintenance. The optimum combination of acoustic stealth and target detection range, the latest inertial navigation system, modern automated information management system, powerful high-speed torpedo and missiles provide this world-class ships with superiority in the field of non-nuclear submarines.

According the National Interest report, the 636.6 Varshavyanka is one of the 5 most lethal Russian submarines.

After years of inattention, Russia has embarked on an ambitious submarine-building program as part of its larger military modernization. As Defense News reported earlier this year, «Four different kinds of submarines are under construction and more are coming».

By comparison, the US only recently returned to building two nuclear attack submarines per year.