Kronstadt, the fourth generation diesel-electric attack submarine (Project 677 or Lada class), is to be launched in 2018. It will become the first ever Russian Air-independent propulsion (AIP) boat. The AIP or anaerobic technology allows to operate without access to atmospheric oxygen (by surfacing or using a snorkel). Kronsdadt will be able to operate submerged for a few weeks without coming to surface. Russian shipbuilding industry has achieved a major technological breakthrough to produce the new sophisticated weapon of war.
AIP (battery power) is usually implemented as an auxiliary source, with the traditional diesel engine handling surface propulsion. Conventional submarines running on AIP are virtually silent. Unlike nuclear boats, they don’t have to pump coolant, generating detectable noise. It makes them highly effective in coastal operations and areas where enemy operates many anti-submarine warfare (ASW) assets.
The Russian AIP design is unique because hydrogen required for power generation is obtained by means of diesel fuel reforming onboard the submarine. Hydrogen is not stored onboard and is produced as much as needed, which increases the safety of the propulsion plant. Ordinary diesel fuel, which is standard for all diesel-electric submarines, is used for generating hydrogen. It needs no extra component and, hence, extra reservoir for storage. There is also no need for special infrastructure on shore to generate and store hydrogen. To cap it all, the AIP features low noise and high efficiency.
Project 677 Lada-class diesel-electric submarines are being built by Admiralty Shipyard for the Russian Navy. The Lada-class is an improved version of the Kilo class, fitted with air-independent propulsion and new combat systems. The first Project 677 submarine, Sankt Petersburg, is currently in service with the Russian Baltic Fleet. Kronstadt is the second ship of the class. With the two Lada-class vessels in service, the Navy plans to move on to the much more advanced fifth-generation Kalina-class boats with AIP propulsion.
The Project 677 submarine is an improved version of the Project 636 Kilo Class with much quieter, powerful propulsion and new combat systems. The boat has a trimmed profile equipped with sophisticated torpedo and missile systems.
The submerged displacement is 2,650 tons, the length is 68 meters. The vessel’s surface speed is 10 kt; submerged 21 kt and the surface range is 6000 miles at 7 knots. The submerged cruising range using economic speed is 500 nautical miles at 3 kt. The class is designed for an endurance of 45 days with a complement of 34. Test depth: 300 m (984 ft).
The new diesel-electric propulsion system is arranged in a modular compartment which can be plugged into the basic submarine. The propulsion system – a variable-speed propulsion plant of a new design – integrates two diesel generators, an electric propulsion motor, 2 diesel AIP systems based on oxygen-hydrogen fuel cells and a single shaft driving on a skewed seven-bladed propeller. The power is 2,700 hp (2, 013 kW). The diesel engine operating short time in the snorkeling mode increases the endurance of the submarine. The submarine also has a storage battery with an increased service life.
The hull is covered with a new anti-sonar coating for low acoustic signature on the outer hull. The submarine hull also has a new multi-layered rubber cover providing almost complete absorption of own noises generated by submarine mechanisms and sonar echo signals. The acoustic field of the submarine has been considerably reduced (in comparison with submarines of previous generations – several times).
Admiralty Shipyard’s CEO Alexander Buzakov believes, «The stealth capabilities of Russia’s new Lada-class diesel-electric submarines far exceed those of their predecessors». According to him, the new vessels are even stealthier than Russian Kilo-class submarines, thought to be some of the quietest diesel-electric submarine classes in the world and dubbed «black holes» for their ability to «disappear» from sonars.
Submarines are fitted with sophisticated sonar equipment with bow and flank arrays, as well as towed array. The Lira sonar system with quasi-conformal (abutting the hull of the submarine) antenna can detect low-noise targets located at long ranges.
The submarine has an inertial navigation system for safe navigation and determination of motion parameters during long underwater operation. The system ensures the accuracy of onboard weapons by providing guidance during long underwater operations.
The countermeasures suite includes the electronic support measures (ESM) system, radar warning receiver and direction finder.
The submarine is equipped with Litiy automated combat control system. The propulsion plant, machinery and weapons systems can be controlled either from the main control room or from separate battle stations.
The Amur-class boat is the Lada-class version destined for sale to other countries. Contracts with India and China are under consideration.
It has taken a lot of effort to marry AIP technology with the state-of-the-art conventional submersible. But the problems have been overcome. Now the stealth sea ghost with great underwater endurance will defend Russian shores – a deterrent any potential enemy has to reckon with.