Personally I had never heard of this sinking by a Russian submarine.
See http://www.wilhelmgustloff.com
Makes for an interesting story in my view.
"The Gustloff is not the only lesser-known ship disaster. During the same evacuation operation prompted by German Gross Admiral Dönitz, the Goya was torpedoed and sunk on April 16, 1945 . With estimates of 6,000 to 7,000 lives lost, it is second only to the Gustloff in history. Britain ’s worst maritime disaster of all time is the Lancastria (troopship sunk in June 1940 with up to 5,000 lives lost). Over 4,000 lost their lives in 1987, when the Dona Paz collided with a tanker in the Philippines . The greatest maritime disaster in United States history is the Sultana. On April 27, 1865 , over 1,700 were killed when the steamship exploded. Most of the victims were POW Union soldiers, returning home after the war had ended. "
I’d never heard of the Lancastria either.