SM U-8 was one of 329 U-boatss which served in the Imperial German Navy during World War I.
A Type U 5 submarine, she was built at Germaniawerft in Kiel between 1909 and 1911. The boat was launched on 14 March 1911 and commissioned into the Navy on 18 June. The boat was scuttled in the English Channel in March 1915.
At the beginning of World War I, U-8 was commanded by Kapitänleutnant Konrad Gansser. In August 1914 she took part in the first U-boat operation of the war, sailing from Heligoland in a coordinated attack on the Royal Navy base at Scapa Flow.
Kapitänleutnant Alfred Stoàtook over the boat on 1 September 1914, with Gansser moving to command . During February 1915 she sank five British steamers in the English Channel. On 4 March, however, U-8 became trapped in anti-submarine nets in the Channel and was forced to surface. After coming under gunfire from and , the crew scuttled the boat at position . The crew were taken prisoner.
In June 2015 the submarine's propeller, which had been illegally removed from the wreck, was recovered and presented to the German Navy. It is exhibited at the Laboe Naval Memorial near Kiel. In July 2016 the wreck was officially designated as a protected site managed by Historic England.
U-8 sank five British steamers with a combined Gross Register Tonnage of 15,049 GRT.