SM UB-53 was a German Type UB III submarine that served in the Imperial German Navy during World War I. It was commissioned in August 1917 under the command of Kptlt. Hans von Mellenthin. UB-53 conducted several successful patrols in the English Channel and off the coast of Ireland, sinking a total of 12 ships. On 20 October 1917, UB-53 torpedoed and sank the British hospital ship HMHS Rewa, resulting in the deaths of 123 crew members and medical staff. The sinking of a hospital ship violated international laws and outraged the British public. UB-53 was later depth charged and sunk by the British Q-ship HMS Red Gauntlet on 24 November 1917 off the coast of Ireland, resulting in the loss of all 37 crew members. The wreck of UB-53 was discovered in 1989 and rests at a depth of 60 meters. The submarine's discovery shed light on the history of submarine warfare during World War I and provided valuable insights into the tactics and technology used by German U-boats during the conflict.

This description has been generated using GPT-4.1-NANO based on the Vessel's wikidata information and then modified by ShipIndex.org staff.