Soviet submarine S-363 was a Soviet Navy Whiskey-class submarine of the Baltic Fleet, which became notable under the designation U137 when it ran aground on 27 October 1981 on the south coast of Sweden, approximately 10 km (6.2 mi) from Karlskrona, one of the largest Swedish naval bases. U137 was the unofficial Swedish name for the vessel, as the Soviets considered names of most of their submarines to be classified at the time and did not disclose them. The ensuing international incident is often referred to as the Whiskey on the rocks incident.