This boat, built in 1906 - 1911, was considered by the Imperial Russian Navy to be their most successful pre-1914 design. She had unusually heavy armament for her day - two bow torpedo tubes, two stern tubes, and four torpedoes carried externally in drop collars.

The AKULA served in the First Division of the Baltic Fleet. In 1915 she was based on Reval and operated with British submarines under commander Max Horton. Although she was one of the more active Russian submarines, she achieved no successes. She left Reval on November 27, 1915 to lay four mines south of Libau; she was reported off Ösel the following evening but that was the last time she was seen. She probably ran into a German mine field northwest of Lyserort.

Displacement 370/468 tons
Dimensions 187 x 12 x 11 feet
Power three-shaft diesel/electric
Power (diesel) 900bhp
Power (electric) 300ehp
Speed (diesel) 10.65 knots
Speed (electric) 6.39 knots
Guns one 47mm gun
Crew unknown
NOTE - about 1914 or 1915, they added three more torpedo tubes, probably 17.7 inch tubes.