How, by whom and when Prien and his Uboat were sunk remains a topic of historical debate.
according to the authoritative site: UBoat.net here: Who Sank U-47?
“It had been long supposed that U-47 was sunk with all hands (45) on 8 March 1941. This is now being questioned, as the traditional credit for U-47’s sinking has always gone to the British destroyer HMS Wolverine, but new data suggests that this destroyer actually attacked Eckermann’s UA, which was forced to withdraw with heavy damage.
It is now suspected that U-47 may have been hit by one of her own circling torpedoes. (Two US submarines in the Pacific are also believed to have been lost to the same sort of equipment failure.”
I don’t agree with this conclusion. I maintain that he was sunk by units of the British Royal Navy. American torpedoes were much different than German torpedoes.
Prien – the Hero of Scapa Flow and even better known than Kretschmer – was a jerk and his men hated him. He did the impossible: took his U-Boat (U-47) into the heavily guarded British Fleet anchorage at Scapa Flow and sank a battleship (HMS Royal Oak). He was lionized in Germany to the point of him saying, “I am a U-Boat captain, not a film star.”
When his death at sea on a war patrol was announced, many in Germany refused to believe the news and rumors began that he had criticized the régime in some way and that he and his crew had all been sent to a concentration camp. People swore they had seen him. He was sort of the Elvis of the Third Reich.