'walrus') were built for the Black Sea Fleet of the Imperial Russian Navy shortly before World War I.

The procurement was heavily cut back and delayed; in 1910, the Russian State Duma agreed to a portion of the naval plan to reinforce the Black Sea Fleet, including the construction of the six submarines.

The design of the Morzh class was based on Akula, a vessel that was considered to be the most successful of the Russian-designed submarines built to date.

[1][2] The Morzh submarines were well-armed for the time, having a deck gun, four internal torpedo tubes and eight Dzhevetskiy torpedo-launching collars.

An additional problem was that twin 1,140 horsepower (850 kW) diesel engines to power the vessels had been ordered from Germany, but were not delivered by the time the war broke out.

After 24 patrols Nerpa went into refit in 1917 in Nikolayev but had to be laid up due to a shortage of essential parts and did not rejoin the war effort.

Nerpa remained in the shipyard at Nikolayev until 3 June 1922, when it was recommissioned by the Soviet Navy under the new name Politruk ("political instructor") and in 1923 it was given the designation of No.