Soviet Dekabrist type submarines underway towards Onega Lake of the Baltic Fleet in 1934 according to report No. 9711 dated 19 February 1937

An item referred to the report dealing with the training exercises of the Soviet Baltic Fleet in August 1936. It supplemented the reports 9697-7040 and 9699-7040. An unverified source reported that three Dekabrist type (model 51) were seen in summer 1934 transported on wooden pontoons passing the Svir River power plant destined for the Onega Lake. Estimated length about 70 metres.The transport operated in the night with covered up boats. If the source was correct were the involved boats Kebarist (31), Narodovolets (32) and Krasnogvardeets (33).

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.