Technically the HMT Olympic at the time of the sinking. Re-purposed as a troop carrier.
In the early hours of 12 May 1918, the surfaced *U-103* sighted *Olympic*, the older sister of RMS *Titanic* and HMHS *Britannic*, which was carrying U.S. troops to France. The crew prepared to launch torpedoes from her stern torpedo tubes but was unable to flood them in time before the submarine was spotted by *Olympic*, whose gunners opened fire as the transport ship turned to ram.
SM *U-103* started to crash dive to 16 fathoms (96 ft; 29 m) in an attempt to turn to a parallel course to the liner. But there was not enough time before the bow of *Olympic* rammed the submarine, cutting into its pressure hull just aft of the conning tower. The crew of *U-103* blew ballast tanks before scuttling their sinking submarine. Nine crewmen lost their lives. *Olympic* did not stop to pick up the survivors but continued on to Cherbourg. USS *Davis* later sighted a distress flare and took 35 survivors to Queenstown (now Cobh) in Ireland. #history