Several types of Soviet submarines of the Baltic Fleet sighted in July 1936 according to report No. 9697 dated 8 February 1937

An item referred to the report of the US Marine Attaché  Riga, Latvia dealing with the training exercises of the Soviet Baltic Fleet in July 1936 and which was based on a reliable source. It supplemented the report dealing with June 1936 No. 9680-7040. Totally 35 submarines were sighted namely the 260, 266,6 Bolshevik-class, 3 Dekabrist-class, 4-Shchuka-class, L 55, Spartakovets, 6 Lin-class, 6 M-class with a length of 35 meters and 3 P-class with a lengthof 75 metres.

Source

National Archive. Record Group 165: Records of the War Department General and Special Staffs Series: Security Classified Correspondence and Reports. File Unit. Russia: Navy - MID 2503-16 THRU 2503-265. Roll 1443.