A very significant submarine.
The 20,000 ton British Cunard Star Liner "Laconia" had been converted into a troopship, armed with deck guns, depth charges and asdic equipment. This made her a legitimate military target. U-156 attacked and sank this target.
As it turned out, she was carrying 2,732 passengers; 136 crew, 285 British soldiers, 80 civilians including women and children, 160 Polish guards and 1,800 Italian prisoners of war.
Realizing his error, Hartenstein immediately launches a rescue operation. Hundreds of survivors were picked up, including civilian women and children, with many crammed inside the submarine, on the upper deck and a further 200 survivors in tow aboard four lifeboats. He also called for assistance from nearby U-boats and broadcasted a radio message in plain English, providing his position and requesting aid from any nearby vessels, promising a suspension of hostilities while rescue operations were underway. U-156 remained on the surface for two and a half days providing aid to the beleaguered survivors.
Donitz was startled by Hartenstein’s actions. Although he ordered for no such rescues to take place, this time he not only allowed it, but supported it. Donitz would explain many years later, “to give them an order contrary to the laws of humanity would have destroyed it (the crews morale) utterly”.
Four submarines shepherded the survivors, with lifeboats in tow and hundreds standing on the decks of the U-boat, they made towards the African coastline for a rendezvous with Vichy French warships dispatched as part of the rescue.
September 16, at 11.25am, this concentration of U-boats was spotted by an American B-24 Liberator bomber operating out of Ascension island. The survivors waved and the U-boats signaled for help. As Red Cross flags were draped over their decks, the pilot Lieutenant James D. Harden turned away and radioed back to base for instructions. The officer on duty that day Captain Robert C. Richardson III replied with the order to attack
They were attacked with a concentration of bombs and depth charges. One bomb landed amidst a lifeboat and hundreds perished during that attack. U-156 was slightly damaged and forced to submerge, leaving hundreds of victims struggling in the water.
In total, there were about 1,621 deaths with 1,111 survivors, including those already taken aboard the overcrowded U-boats.
As a result of this incident, Admiral Donitz issued an order forbidding U-boats from attempting any rescues and furthermore, from providing any assistance whatsoever to survivors of submarine attacks. He was quoted to say “no attempt of any kind must be made to rescue the crews of ships sunk”. This order became to be known as the “Laconia Order”.
After the war, Donitz stood trial for war crimes and the Laconia order was used as a basis of indictment against him.
Sunk in 1943 by USN aircraft.