SM U-103

SM U-103 was an Imperial Germany Navy Type U 57 U-boat of the First World War. U-103 was built on AG Weser in Bremen, launched on 9 June 1917 and commissioned 15 July 1917. She completed 5 tours of duty under Commander Claus Rücker and sank eight ships totalling.

Loss
In the early hours of 12 May 1918, U-103 prepared to launch torpedoes from her stern tubes at RMS Olympic, the sister ship of the ill-fated RMS Titanic, which was en route for France with US troops on board. The crew was unable to flood the two stern torpedo tubes, and the submarine was sighted on the surface by Olympic, whose gunners opened fire as Olympic turned to ram.

U-103 started to crash dive to 30 m and turned to a parallel course, but almost immediately afterwards was struck just aft of her conning tower and Olympic's port propeller sliced through U-103 ' s pressure hull. The crew of U-103 blew her ballast tanks and scuttled and abandoned their sinking submarine. Olympic did not stop to pick up the survivors, but continued on to Cherbourg. USS Davis (DD-65) later sighted a distress flare and took on board the 31 survivors. This was the only known sinking of a warship by a merchant vessel during the First World War.

U-103 ' s wreck lies at position 49.26667°N, -4.85°W.