Class overview
Operators	Soviet Navy  Polish Navy  People's Liberation Army Navy
Preceded by	None
Succeeded by	Quebec class
In service	1933
In commission	1933
Planned	141
Completed	141
Lost	33
Retired	108
General characteristics
Type	Submarine
Displacement	VI: 158 tons surfaced; 198 tons submerged VI-bis: 161 tons surfaced; 201 tons submerged XII: 206 tons surfaced; 256 tons submerged XV: 281 tons surfaced; 351 tons submerged
Length	VI to XII: 37.50 m (123 ft 0 in) XV: 50.0 m (164 ft 1 in)
Beam	VI and VI-bis: 3.1 m (10 ft 2 in) XII: 3.3 m (10 ft 10 in) XV: 4.9 m (16 ft 1 in)
Draft	VI and VI-bis: 2.6 m (8 ft 6 in) XII: 2.9 m (9 ft 6 in) XV: 3.6 m (11 ft 10 in)
Speed	VI and VI-bis: 13.1 knots (24 km/h) surfaced; 7.4 knots (14 km/h) submerged XII: 14.1 knots (26 km/h) surfaced; 8.2 knots (15 km/h) submerged XV: 15 knots (28 km/h) surfaced; 10 knots (19 km/h) submerged
Complement	VI to XII: 16-19 XV: 32
Armament	VI to XII: 2 × 533 mm (21 in) bow torpedo tubes XV: 4 × 533 mm (21 in) torpedo tubes (2 bow, 2 stern) All series: 1 × 45 mm (2 in) semi-automatic gun

The M-class submarines, also Malyutka class (Russian: Малютка; baby or little one), were a class of small, single-, or 1½-hulled submarines built in the Soviet Union and used during World War II. The submarines were built in sections so they could easily be transported by rail. The production was centered in the Gorky Shipyard on the Volga River, after which the sections were transported by railway to Leningrad for assembly and fitting out. This was the first use of welding on Soviet submarines.

History

1930s to 1940s

Submarines of this class were in four series: VI, VI-bis, XII, XV. The number of VI and VI-bis series boats were almost equal. Series XII was a re-developed project with equivalent tactical characteristics. The first series were powered by one diesel engine and one electric motor. Series XV had developed separately with improved characteristics, including the main ballast in light hull and two shafts. These vessels were mainly used by the Black Sea Fleet and the Baltic Fleet.

Although the design was satisfactory, only limited results were obtained and losses were heavy with 33 submarines sunk between 1941 and 1945. M-103 disappeared in the Baltic Sea in mid-August 1941. The wreck was discovered in the late 1990s during a NATO minesweeping training exercise.^[1] Seven submarines were lost in the Black Sea, four depth-charged and sunk by Romanian warships (M-31 by the flotilla leader Mărășești,^[2] M-58 by the destroyer Regina Maria,^[3] M-59 by the destroyer Regele Ferdinand^[4] and M-118 by the Romanian gunboats Ghiculescu and Stihi^[5]) (both M-58 and M-59 however are also reported as lost on Romanian laid mines,^[6] while M-31 was also claimed by mines or a German vessel^[7] ) and three were sunk in minefields laid by the Romanian minelayers Amiral Murgescu, Dacia and Regele Carol I.^[8] By 1945, some 111 M-class submarines had been completed, with another 30 XV-series completed between 1945 and 1947.

Cold War

Two submarines of the early series of this class, along with two Soviet S-class submarines, (S-52 and S-53) and two Shchuka-class submarines (under lease, S-121 and S-123) were sold to the People's Republic of China in June 1954 as the foundation of the People's Liberation Army Navy Submarine Force. Both the M- and S-class submarines were sold to China, and two more M-XV series of this class (M-278 and M-279) were sold to China a few years later in 1956.Those purchased by China were renamed, but the two leased Shchuka-class submarines were not. The four M-class submarines bought by China were renamed National Defense # 21, 22, 23 (ex M-278) and 24 (ex M-279) respectively.^[9]

Modern times

An M-class submarine was discovered near Tallinn in May 2012. The submarine is located in Tallinn Bay between the islands of Aegna and Naissaar, at an approximate depth of 65 to 66 metres (213 to 217 ft). It is believed to be M-216, which was intentionally sunk in the area in 1962 for training purposes. Divers have confirmed that many components, including the periscope, are missing. It is also believed that the training exercise may have been ordered as a result of several deadly submarine accidents in the 1950s. One such accident happened near Paldiski, where the entire crew of M-200 died during a failed rescue operation.^[10]

In July 2015, another M-class (series XII) submarine was found in the Black Sea by divers off the Romanian coast at Costinești, at an approximate depth of 40 metres (130 ft).^[11][12] It is believed to be either M-34 or M-58, both being lost to Romanian minefields. The submarine is buried in sand up to the deck level and also completely filled with sand, making any further identification almost impossible. The upper part of the hull shows a pretty high level of damage - many ribs are exposed. The aft hatch was partially opened. The hull is in one piece, with the conning tower and deck gun intact.

Versions

Series VI

30 submarines constructed between 1932 and 1934 were 37.5 m long and displaced 201 tons submerged (158 tons surfaced).^[13]

Series VI-bis

19 submarines built in four sections between 1934 and 1936) were 37.5 m long and displaced 202 tons submerged (161 tons surfaced).

Series XII

45 submarines built in six sections between 1936 and 1941 were 44.5 m long, and displaced 258 tons submerged (206 tons surfaced).

Series XV

4 submarines built in seven sections during World War II while other 11 built after it, until 1953 were 53.0 m long, and displaced 420 tons submerged (350 tons surfaced).

Both series VI and VI-bis were constructed by A. N. Asafov. Series XII was made by P. I. Serdyuk and series XV was created by F. F. Polushkin.

• 
  Series VI
• 
  Series VI-bis
• 
  Series XII
• 
  Series XV