The Natya-class were a group of minesweepers built for the Soviet Navy and export customers during the 1970s and 1980s (58 ships were built). The Soviet designation was Project 266M Akvamarin. The ships were used for ocean minesweeping.

The design evolved from the Yurka class minesweeper with new demining equipment including more advanced sonar and closed circuit TV. A stern ramp made recovering sweeps easier. The hull was built of low magnetic steel. To protect against acoustic mines the foundations main engines and diesel generators were padded with rubber, installation of mechanisms for isolating dampers; installation of flexible inserts in pipes; application of low-noise propellers controlled step large-diameter, as well as the installation of low-noise machinery and equipment. An electrical field compensator was also installed.

Seagoing Minesweeper Torpedist laid down on 20 May 1971 at the Sredne-Nevsky Shipyard, Pontonny (yard No.909), launched on 25 December 1971, commissioned on 12 July 1972 and assigned to the Black Sea Fleet.

From 1990 - OS-99 trial ship, all armament were removed.

On 01 September 1995 OS-99 was decommissioned and excluded from the lists of the Black Sea Fleetand scrapped.