The Schnellboot S31 was equipped with three Daimler-Benz diesel engines and three propellers, allowing it to reach a maximum speed of 38 knots. Its armament included two 533mm torpedo launchers and two 20mm anti-aircraft guns. The crew consisted of 24 individuals. During World War II, the S31 operated in various regions, including around Malta. On May 9, 1942, it participated in an operation to intercept the Allied minelayer Welshman. To accomplish this mission, German ships laid a minefield at the entrance to the port. A total of 28 depth charges and explosive buoys were deployed.
Tragically, shortly after the minefield was set, one of the bombs broke free from its moorings and drifted, ultimately detonating and destroying the S31 submarine. Sadly, half of the 26-person crew lost their lives. The wreckage of the S31 was discovered on September 6, 2000, approximately one nautical mile from the Grand Harbour, resting at a depth of 73 meters. The wreck stands upright on the sandy seabed, displaying a significant hole in its middle caused by the mine explosion, which effectively divides the wreck into two sections. The torpedo tubes still contain visible torpedoes. This captivating wreck holds historical significance and will be remembered for many years to come.