The movie based on the real story of humanity in the midst of the carnage of WWII. Apart from Das Boot, this is probably the other best u-boat war movie with high marks for accuracy. It is also one of the few movies featuring the Type IX long range u-boats. The U-156 featured was part of group Eisbar which began Admiral Doenitz’s first forrays into the southern region. these early missions ultimately prepared the Kriegsmarine for Far East patrols which culminated in Monsun Gruppe.
On 12 September 1942, RMS Laconia carrying some 2,732 crew, passengers, soldiers and prisoners of war (POWs), was torpedoed and sunk by the German U-boat submarine U-156 off the coast of West Africa. Operating partly under the dictates of the old prize rules, the U-boat commander, Korvettenkapitän Werner Hartenstein, immediately commenced rescue operations. U-156 broadcast their humanitarian intent on open radio channels to all Allied forces in the area, and were joined by the crews of several other U-boats in the vicinity.