I've seen some good stuff on this recently from level-headed Nordic defense observers - will share when I find the links
...Very little is known about the nine X-Craft built by the Soviet Union in the 1970s, and operated through the 1980s. The Project 1015 SPLC type was analogous to the British X-Craft midget submarine and appears to have had similar capabilities. SPLC stands for Special-purpose submarines (СПЛЦ - Специальные подводные лодки-цели), although the boats are also described as SPLT and SPLTS. The 9 SPLCs were distributed across all fleets: 2 in the Northern, 2 in the Pacific, 2 in the Baltic, 2 n the Black Sea and 1 in the Caspian. At least one was converted to an uncrewed craft and known as the Haddock.
After World War Two the Russians became interested in naval Special Forces capabilities and paid particular attention to British wartime exploits and equipment. It is natural therefore that they might seek to emulate the X-Craft, which was still in service throughout the 1960s. The Italian CB Class and German Seehund may also have been influences.
The SPLC is about the same size as an X-Craft but likely smaller on the inside thanks to its double-hull construction. In line with post war design philosophy, the bow was more rounded than on the original X-craft, which would have optimized the SPLC for submerged performance. It retained the short fixed snort mast similar to postwar X-craft however, allowing her to run on the surface on just below, while running on her diesel engine. Combined with the dry interior, this would have increased range considerably over similar sized all-electric SDVs. In the Baltic, Black Sea and Caspian Sea this would have translated into a shore-to-shore capability without the need for a mother ship. For longer missions he SPLC could be towed like X-Craft were, and there is evidence of towing attachments on some examples.
The craft had two access hatches in the sail which suggests that one of them, likely the aft one, provided a diver lock-out capability. Although it is not confirmed, there is no other obvious explanation for having two hatches on such a small craft. This capability would be in line with the British X-Craft and Italian CA Class.
In service these midget subs kept out of the public eye and are rarely even listed among Soviet submarine classes. They were likely employed for testing harbor defenses, acting as inshore anti-submarine warfare (ASW) targets and for equipment trials.
covert_shores said:Thanks, great article (sorry!)
I have more on tracked submersibles coming soon to Covert Shores
Soviet mini-sub discovered in Jarfjord by Norwegian special forces in 1990. A former officer from the Headquarters of the Armed Forces in Northern Norway told about the surfacing submarine in a TV documentary by NRK about the Cold War.
After receiving reports about suspicious activities in the area in June 1990, military divers first discovered tracks on the seafloor. Coming back a few months later for more thorough investigation, the divers could see new tracks that were not there on the previous dives.
The incident in Jarfjord was, however, not the only discovery of tracks on the seafloor. The NRK documentary also featured an interview with Jon Røkenes, a diver in Alta that could tell about video-recordings he made just outside the harbor on February 21st, 1991.
Also Røkenes has a background from the Navy Special Operations Command. After showing the video recordings of the tracks on the seafloor to the military command headquarters, he was told not to talk about what he had seen.
NRK Finnmark has posted the video of the seafloor crawler tracks and the interview with Jon Røkenes.
KRONSHTADT, RUSSIA - MAY 20, 2019: Placing the MTK 200 Submersible uninhabited remotely operated robotic marine complex at the Kronshtadt Bathyscaphes and Deep Submergence Vehicles Museum at a quay by Petrovsky Park. The complex was in service of the Soviet Navy in the 1980s allowing to examine and take pictures of underwater objects, to bring oxygen to a submarine in distress and pull objects under 100kg from water. Anton Vaganov/TASS (Photo by Anton Vaganov\TASS via Getty Images)