Portuguese aircraft detects Russian submarine in the Baltic sea

Advanced equipment was installed on the Portuguese reconnaissance and patrol aircraft, the P-3C Orion, designed for anti-submarine warfare, and enabled the detection of a Russian submarine in the Baltic Sea. According to Russian media, it was most likely the B-608 Mozhaysk, belonging to the Baltic Fleet. What kind of submarine is it?

The submarine was spotted in the Baltic Sea at the end of June. As reported by Bulgarian Military, the vessel was not in combat mode and was on the surface, which made the task significantly more straightforward for the pilots of the Portuguese P-3C Orion. The service also reminds us that submarines like the B-608 Mozhaysk must surface at least once a day due to their air-dependent propulsion system. At such times, they become vulnerable to detection by conventional radars, optoelectronic reconnaissance systems, or AESA radars.

The B-608 Mozhaysk is a Project 636.3 (06363) Varshavyanka-class submarine, based on the Soviet Project 877 submarine. It has a length of 240 feet and a width of about 33 feet. It displaces nearly 3,410 tons when submerged. The vessels are unofficially called "acoustic black holes" due to their low noise levels.

The Russians have managed to minimize the acoustic signature parameters in these submarines. Introduced modernizations have also improved target detection capabilities, enabling them to carry modern armaments. Varshavyanka-class submarines can carry Kalibr missiles.

It is worth mentioning that Kalibr is a Russian weapons system consisting of anti-ship cruise missiles, cruise missiles intended for land targets, and rocket torpedoes for anti-submarine warfare. They have common vertical launch system launchers. In addition to Kalibr missiles, Project 636.3 submarines are equipped with 6 torpedo tubes and—in total—18 torpedoes of 21-inch caliber.