The Soviet Navy converted a Romeo-class submarine, S-49, into a test platform for anti-submarine missile systems in 1971.

The conversion created the Project 633RV variant, which added external 650mm launch tubes for the RPK-7 Veter missile and internal 533mm tubes for the RPK-6 Vodopad missile.

Engineers removed standard equipment and installed specialized launch mechanisms, programming gear, electrical connections, fire‑control systems, sealing arrangements and guide tracks, turning the forward section into a test laboratory.

After conversion, S-49 conducted 24 launches between 1973 and 1974 at depths of 50 to 150 meters, and 22 additional launches from 1975 onward, including a test at 240 meters, as well as trials of the 3M10 Granat cruise missile starting in 1977.

The vessel remained in service after an overhaul from 1986 to 1991, was redesignated PZS-50 as a floating battery charger in 1995, and was retired around 2019; it is now displayed in an underground museum in Balaklava.

Its testing contributed data that helped integrate the Vodopad and Veter missiles into Soviet submarine arsenals, and its current status as a museum exhibit is uncertain given the ongoing conflict in Crimea.