SM UC-91

SM UC-91 was a German Type UC III minelaying submarine or U-boat in the German Imperial Navy (Kaiserliche Marine) during World War I. The U-boat was ordered on 12 January 1916 and was launched on 19 January 1918. She was commissioned into the German Imperial Navy on 31 July 1918 as SM UC-91. As with the rest of the completed UC III boats, UC-91 conducted no war patrols and sank no ships. She sank after a collision with the steamer Alexandra Woermann on 5 September 1918 in the Baltic Sea. The salvage vessel SMS Vulkan raised the wreck the following day and was repaired. She was en route to surrender on 10 February 1919 when she foundered in the North Sea.