Previously posted at: https://www.history.com/this-day-in-history/the-laconia-is-sunk
A German U-boat sinks a British troop ship, the Laconia, killing more than 1,400 men on September 12, 1942. The commander of the German sub, Capt. Werner Hartenstein, realizing that Italians POWs were among the passengers, strove to aid in their rescue.
The Laconia, a former Cunard White Star ship put to use to transport troops, including prisoners of war, was in the South Atlantic bound for England when it encountered U-156, a German sub. The sub attacked, sinking the troop ship and imperiling the lives of more than 2,200 passengers. But as Hartenstein, the sub commander, was to learn from survivors he began taking onboard, among those passengers were 1,500 Italians POWs. Realizing that he had just endangered the lives of so many of his fellow Axis members, he put out a call to an Italian submarine and two other German U-boats in the area to help rescue the survivors.
In the meantime, one French and two British warships sped to the scene to aid in the rescue. The German subs immediately informed the Allied ships that they had surfaced for humanitarian reasons. The Allies assumed it was a trap. Suddenly, an American B-24 bomber, the Liberator, flying from its South Atlantic base on Ascension Island, saw the German sub and bombed it—despite the fact that Hartenstein had draped a Red Cross flag prominently on the hull of the surfaced sub. The U-156, damaged by the air attack, immediately submerged. Admiral Karl Donitz, supreme commander of the German U-boat forces, had been monitoring the rescue efforts. He ordered that “all attempts to rescue the crews of sunken ships…cease forthwith.” Consequently, more than 1,400 of the Laconia‘s passengers, which included Polish guards and British crewmen, drowned.