Syntax

The Wilhelm Gustloff was a passenger ship built by the Blohm and Voss shipyards, and was named after the Nazi functionary Wilhelm Gustloff. The ship was launched on 5 May 1937. While evacuating Germans trapped by the Red Army in East Prussia, it was hit by three torpedoes from a Soviet submarine in the Baltic Sea during the night of 30 January 1945. The sinking remains the worst disaster in maritime history — it left over 9,000 people dead, more than half of them children.
-http://en.wikipedia.org/wiki/KdF_Ship_Wilhelm_Gustloff

A disaster is something that's an accident. Torpedoing an enemy ship is deliberate and falls within the actions permissable during war.