An item described a submarine in the area of Leningrad nowadays St. Petersburg] towed by a small vessel, fitted out with a square shaped sail of 1/7 of the length of the submarine which had on the aft edge a protuberance. Her machinery was at the moment of sighting running.
Source
The report was published on www.archive.org, document number CIA-RDP80T00246A033200070001-5
