Believe it was a German Passenger/cruise liner(loaded with refugees & troops) torpedoed by a Russian Sub at the end of WWII

I recently saw the movie, The Imitation Game, about Allan Turing's early computer, which cracked the German code about where their U-boats. Some estimate his work saved over 1 million passengers worth of ships from being sunk and preventing other war casualties. Unfortunately, his personal life story is rather tragic.

"Ultra would never have got off the ground if we had not learned from the Poles, in the nick of time, the details both of the German military Enigma machine, and of the operating procedures that were in use."
— Gordon Welchman British Code Breaker

The British Navy also had captured an enigma machine off of a Fishing Trawler that was a spy vessel.That was also an essential factor in code breaking efforts