On 25 October 1918 submarine UB-116 left Heligoland under the command of Oberleutnant zur See Joachim Emsmann. As part of the German Navy's last-ditch naval operation of the war, Emsmann’s task was to enter the British Naval Base at Scapa Flow, Scotland, off the north coast of Scotland, and attack larger ships, so as to weaken the British fleet prior to the attack by the German High Seas Fleet.
On 28 October Emsmann’s submarine entered Hoxa Sound, Scapa Flow. The British had laid a minefield in Hoxa Sound. The minefield had underwater microphones called hydrophones, allowing shore-based operators to pick up the sound of an approaching submarine. UB-116 was picked up by hydrophone at 2121. At 23:32 an electrical cable laid in loops on the seabed sent a signal to a device called a galvanometer, indicating the UB-116 was in the minefield. The operator flipped a switch and a row of mines exploded. The next morning the surface was covered with oil and air bubbles were rising steadily. Patrol boats dropped depth charges that brought debris to the surface, including a jacket. British divers visited the wreck on 29 October and on 4 November they returned and recovered UB-116’s logbook.
Hans Joachim Emsmann and all of his crew were killed. Due to mutinies on board the ships of the High Seas Fleet, the German surface ships were unable to put to sea.
Text written by Mr. Philip Lecane, taken from his book Torpedoed!