According to reports from Russian state media the Black Sea Fleet's Project 636.3 diesel-electric submarine Rostov-on-Don is headed to Syria to join the Russian Navy's permanent Mediterranean task force. A source in Russia's defense industry told TASS that the boat was expected to transit the Black Sea straits on Monday evening.

However, it wasn't clear if the Rostov-on-Don would replace the same-type submarine Krasnodar, which is currently on a deployment with the Russian Navy's Mediterranean Squadron. Krasnodar, along with the Stary Oskol, had joined the Russian Navy's Mediterranean task force in April 2019 and replaced the Veliky Novgorod and Kolpino submarines, which had joined the task force after inter-fleet transit from the Black Sea. Stary Oskol recently returned to the Kronshtadt Marine Plant for repairs.

Typically two of the Project 636.3 convention submarines are deployed in the Mediterranean, with deployments lasting an average of 18 months – while crews are rotated every three months. The Admiralty Shipyard has built a  series of six of the diesel-electric submarines for the Black Sea Fleet.

"The B-237 Rostov-on-Don is a Russian diesel-electric submarine of project 636.3 Varshavyanka, which is part of the 4th separate submarine brigade of the Russian Black Sea Fleet," the Russian publication Avia.Pro reported, which noted  that this was "the second ship of the project 636.3 Varshavyanka, named after the Russian city of Rostov-on-Don."

The Rostov-on-Don was first sent to Syria in December 2015, and had been used to deliver strikes with Kalibr cruise missiles against ISIS. Veliky Novgorod and Kolpino have also delivered numerous strikes against terrorist targets within Syria. The third generation diesel-electric submarines are considered to be among the world's most noiseless vessels.

The boats have a speed of up to 20 knots, can dive to a depth of about 300 meters and have a sea endurance of 45 days. The subs displace 4,000 tons and have a crew of 52 men.

The Rostov-on-Don is the latest Russian vessel to head to Syria. In February two Black Sea Fleet frigates, Admiral Makarov and Admiral Grigorovich passed through the Turkish Bosporus and Dardanelles straits to join the Mediterranean task force.  Russia has positioned a considerable naval armada near Syria in recent years, and naval experts have noted there could be up to 13 Russian Navy vessels in the region.

In 2017, Moscow struck a deal with Syria to extend its lease on the Russian naval base in Tartus for 49 years. Under the agreement Russia is allowed to keep up to 11 warships at its base in Syria including nuclear-powered ones. Russia has also moved to modernize and expand the naval facilities.

Support from Russia, as well as Iran, has helped the Syrian government in its efforts to gain an upper hand in the nearly nine-year-long civil war. The assistance from Russia has allowed the Syrian regime under President Bashar Assad to retake nearly all opposition-held territory with the exception of the northwestern province of Idlib along with strips of land near the Turkish border.

Peter Suciu is a Michigan-based writer who has contributed to more than four dozen magazines, newspapers and websites. He is the author of several books on military headgear including A Gallery of Military Headdress, which is available on Amazon.com.

Image: Reuters.