SM UB-86

SM UB-86 was a German Type UB III submarine (U-boat) of the German Imperial Navy (Kaiserliche Marine) during World War I. She was commissioned on July 21, 1917, under the command of Oberleutnant zur See Wilhelm Bartenwerfer.

UB-86 conducted several war patrols, primarily in the waters around the British Isles. Her operational area included the English Channel and the Western Approaches. She was credited with sinking a number of Allied ships, contributing to the German U-boat campaign aimed at disrupting British maritime trade and supply lines.

One of the most notable and controversial incidents involving UB-86 occurred on June 27, 1918, when she sank the Canadian hospital ship HMHS Llandovery Castle. The sinking was particularly reprehensible because hospital ships were supposed to be protected under international law. After the sinking, UB-86 surfaced and its crew, under the command of Bartenwerfer, fired upon the lifeboats and surviving medical personnel and crew in an attempt to eliminate witnesses.

After the war, the actions of Bartenwerfer and his crew were investigated as war crimes. Bartenwerfer and two other officers were put on trial in Germany in 1921 for their involvement in the Llandovery Castle incident. Bartenwerfer claimed he had acted under orders from higher command, though this was never substantiated. He was ultimately convicted and sentenced to four years in prison. The other two officers were also found guilty.

SM UB-86 surrendered to the Allies following the Armistice in November 1918. She was later scuttled in the Atlantic Ocean by the Royal Navy as part of the terms of the Treaty of Versailles. Her wreck lies off the coast of Ireland. The Llandovery Castle incident remains a significant and somber example of the brutality and moral complexities of unrestricted submarine warfare during World War I.