The MO (Russian: МО, an initialism for Малый охотник, Malyj okhotnik, 'Small Hunter'; nickname Мошка, Moshka, 'Midge') is a class of naval boats produced before and during World War II for the Soviet Navy and NKVD Border Troops.

During the war they carried out many additional roles from supporting landing operations to escorting convoys.

[1] In early 1930s, the main focus of Soviet shipbuilding was building small patrol ships and boats with various duties.

The boat had no armor and had a wooden structure, but consisted of nine sections isolated from each other, allowed to stay afloat even after suffering heavy damage.

[3][4] MO-class boats carried out a very large number of duties during the war, serving in all fleets.

Their duties included patrolling naval bases perimeter, hunting submarines, escorting convoys, laying and disarming mines, supporting amphibious landings and fighting small enemy ships.

On July 30, 1944 she sank the German submarine U-250 in shallow waters of the Baltic Sea.

The boat was mobilized by the Black Sea Fleet during the Great Patriotic War and it was named the "Guards Boat" on July 25, 1943 for distinguished services in battle (Commanding Officer, Senior Lieutenant Pavel Sivenko, received a lot of Soviet military decorations and was also awarded the Navy Distinguished Service Medal of the United States).

[7] Survived until the end of the war and was returned to the NKVD Border Troops in July 1945.