Soviet submarines of the Lin type (model 55) of the Baltic Fleet sighted in July 1936according to report No. 9697 dated 8 February 1937

An item referred to the report 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. Six boats of the Lin type were seen while operating at the same time, 7 boats could be identified namely Lin (SHCH-305), Piksha (SHCH-306), Treska (SHCH-307), Semga (SHCH-308), Delfin (SHCH-309), Beluga (SHCH-310) and Kumya (SHCH-311).

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.