The mystery submersible spotted in Swedish waters near Stockholm on Friday could be one of a handful of Soviet-era midget submarines operating from a mother ship in the Baltics and not likely a larger Russian Navy submarine.
Since Friday, the Swedish Navy has been operating a large-scale search following reports of “foreign underwater activity,” near the Swedish capital employing several patrol craft and a Visby-class corvette.
The Swedes have doubled down on the hunt expanding the search area for the mystery craft that could be, “a submarine, or a smaller submarine… It could be divers using some form of moped-like underwater vehicle and it could be divers that do not have any business on our territory,” said Swedish Navy Rear Adm. Anders Grenstad earlier this week.
Though the Russians have denied any involvement, the presence of a Russian-owned cargo ship, NS Concord, acting suspiciously in the Baltic and reports of encrypted transmissions on a Russian emergency channel toward the Russian naval base at Kaliningrad originating near Sweden point toward the operation of a Russian midget sub.
“Speculation that the suspected Swedish contact could be a midget submarine is certainly plausible. Midget submarines can be launched covertly from beneath larger vessels ,” according to a Tuesday analysis in Jane’s Defence Weekly.
Concord was spotted moving in a zigzag pattern in Swedish waters, “as if in a search or rendezvous pattern,” reported Jane’s.
“When the situation became more publicly known, NS Concord turned about and headed northeastwards towards Russian waters.”
Concord was off the coast of Estonia and steaming in the direction of St. Petersburg, Russia as of Tuesday afternoon, according to MarineTraffic.com.
One possible suspect is a Soviet-era midget submarine used for insertion of special operations forces (SOF) that Russia has been marketing for export.
“Russia has renewed its interest in midget submarines, including the Project 865 Piranha-class (NATO reporting name Losos) vessel, two of which have been based in the Baltic in the past. They are exceptionally quiet, stealthy, and with a low detection signature,” wrote Jane’s.
The Piranhas displace a mere 390 tons submerged and can carry a compliment of nine crew and six combat divers, according to the U.S. Naval Institute’s Combat Fleets of the World.
The diesel-electric submarines have a reported ten-day endurance.
The Soviet-era Piranhas were built in the 1980s and stricken from the Russian fleet in 1997, however at least one may have been upgraded for use as a technology demonstrator for potential foreign sales, according to Combat Fleets.
Other experts have speculated the submersible could be a Project 908 Triton II swimmer delivery vehicle (LSDV), a 6-ton craft capable of delivering six combat divers with a range of 60 nautical miles.
But as the search continues, the prospect of a Triton as the suspected craft is less likely given the sub’s 12-hour endurance.
The suspected craft was first spotted on Oct. 17 and again on Oct. 20.
Since then the Swedes have expanded the search pattern to include a wider swath of territory toward the South.
