The Petya class was the NATO reporting name for a class of light frigates designed in the 1950s and built for the Soviet Navy in the 1960s.

They were the first gas turbine-powered ships in the Soviet navy. The role of these ships was anti-submarine warfare in shallow waters. The specification was issued in 1955 and design approved in 1956. A total of 56 ships were built in four shipyards.

Displacement was 910 tons under standard load and 1050 tons under full load. The ship's profile saw the mass of the superstructure contained forward of midships with low-profile funnels aft of this. A main mast was set along the aft section of the superstructure. Power was from a CODAG (COmbined Diesel And Gas) arrangement which paired 2 Gas turbines of 30000 horsepower with 1 Diesel unit of 6000 horsepower - providing speeds reaching 33 knots and ranges out to 2000 nautical miles. A three shaft machinery layout was chosen with the central shaft powered by diesel engines for economical cruising and the two wing shafts powered by gas turbines for speed. Gun armament was two twin 76 mm gun turrets which were controlled by a single radar director. Anti-submarine armament consisted of four RBU-2500 anti-submarine rocket launchers and a launcher for 400 mm anti-submarine torpedoes.

Frigate PLK-37 laid down 28 October 1960 at the Shipyard No.820, Kaliningrad (yard No.166), launched 18 November 1961, commissioned 30 June 1964 and was assigned to the Black Sea Fleet.

In 1964-66 - added MG-325 Vega sonar instead of AK-726 and RBU-2500 at the aft. From 19 May 1966 - SKR-40.

Frigate SKR-40 was excluded from the lists of the Black Sea Fleet on 25 January 1994 and scrapped.