1981
Right bloc · C"Whiskey on the Rocks": Soviet submarine U-137 stranded inside Swedish waters.
1981 infographic: U-137 and neutrality crisis
AI-generated infographic using the page's 1981 anchors.
Highlights
- U-137 incident: On 27 October 1981, Soviet Whiskey-class submarine S-363 (Swedish designation U-137) ran aground near Torumskär in the Blekinge archipelago, roughly 10 km from the Karlskrona naval base — Sweden's worst territorial violation since World War II.
- Nuclear weapons suspected: Swedish radiation experts detected uranium-238 in the port torpedo tube, consistent with nuclear warhead cladding. Moscow claimed a navigation error; Stockholm concluded the incursion was intentional.
- Resolution: On 6 November Swedish tugs freed the submarine and escorted it to international waters, where it was handed to the Soviet navy. The crisis strained Swedish–Soviet relations and intensified Sweden's submarine surveillance programme.