Russia’s Navy in the Asia-Pacific will soon be getting a boost in the form of two new diesel-electric submarines.

On June 25, the state-run TASS media outlet reported that two Project 636.3 Varshavyanka-class diesel-electric submarines will be handed over to Russia’s Pacific Fleet in November 2020. The article cited an annual report from the Admiralty Shipyard, the firm that builds the submarines, as the source for the information.

“The Project 636.3 diesel-electric submarine designed by the Rubin Central Design Bureau (two subs) - November 2020," TASS quoted the Admiralty Shipyard report as saying.

Project 636.3 subs displace 4,000 tons when submerged and have a crew of fifty-two sailors. The TASS article said they have a speed of 20 knots and a diving depth of only 300 meters. An upgraded version of Russia’s classic Kilo-class subs, the 636.3 vessels have “been modified to include upgraded combat characteristics, to enhance the Russian Navy in anti-submarine warfare and anti-surface-ship warfare, general reconnaissance and patrol missions,” according to the website, Naval Technology.

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Meanwhile, Kyle Mizokami has noted that “It features improved quietness due to further isolation of the machinery, moving other machinery to areas where they would make less noise.”

The Wall Street Journal has further clarified that each sub is “wrapped in echo-absorbing skin to evade sonar; its propulsion system is mounted on noise-cutting dampers; rechargeable batteries drive it in near silence, leaving little for sub hunters to hear.” They also have roughly 25 percent greater range.

Russian media outlets have previously emphasized that the upgraded Kilos are primarily designed for anti-ship and anti-submarine missions, although they do have a land attack capability (see below).

“Armed with 18 torpedoes and eight surface-to-air Club missiles, Project 636.3 submarines are mainly intended for anti-shipping and anti-submarine missions in relatively shallow waters. They have an extended combat range and can strike surface, underwater and land targets,” Russia Today, another state-run media outlet, previously reported. The torpedoes are launched out of six 533-mm bays, which automatically reload every fifteen seconds.

Russia has billed the Varshavyanka-class diesel-electric submarines as the “quietest submarines in the world,” the boats have without question posed challenges to NATO. In a November 2017 article in the Wall Street Journal, Julian Barnes details the enormous lengths the alliance went to over the course of three months to one 636.3 submarine in a journey that took it from the North Sea to the Mediterranean.

NATO’s efforts began with the Dutch following it while it was in the North Sea, before a British ship took over when it approached the English Channel. A Spanish patrol boat temporarily helped out before the submarine reached Gibraltar, when an American cruiser assisted by P-8 Poseidon aircraft followed the vessel into the Mediterranean. Once there the submarine launched missile attacks on Syria and lingered for weeks in a cat and mouse game with NATO.

It’s unclear from the article how well the Western naval forces fared in keeping tabs on the Russian sub when it was submerged. A U.S. naval officer said that the submarine’s second missile salvo into Syria was monitored by a French frigate and U.S. Navy aerial surveillance.

What is clear from the article is that the United States and its allies devoted extensive resources in trying to track the submarine. This included using an American carrier task force in the region at the time, along with plenty of other helicopters and ships.

Construction of the lead vessel of the Varshavyanka-class, the Novorossiysk, began back in August 2010. It was launched in November 2013. So far Russia has built six of the 636.3 submarines, the last one of which was launched in February 2016.

The first six boats have all been assigned to Russia’s Black Sea Fleet. Most of them will be stationed in Sevastopol in Crimea but some are expected to be based at Russia’s new naval base in Novorossiysk once it opens.

Originally, Moscow only planned to build six Varshavyanka-class submarines total. After those were completed Russia was scheduled to begin transitioning to the Project 677 Lada-class diesel-electric attack submarines. But the Project 677 program has suffered a number of delays prompting Moscow to order six additional Varshavyanka-class boats for its Pacific Fleet. A contract for these six was signed in September 2016.

At that time, the head of Admiralty Shipyard, Alexander Buzakov, said “The term of delivery of the six boats [is] two in 2019, two in 2020 and two in 2021.” Thus, it appears the first two vessels have already been delayed and it’s unclear when all six will be completed.

Russia has also had success selling the 636 submarines abroad. Its first customer was China, followed by Algeria. Vietnam has also purchased six of them, and Venezuela and Indonesia have shown varying degrees of interest at certain times.

Zachary Keck (@ZacharyKeck) is a former managing editor of the National Interest.

Image: Reuters