Churchill's life was saved that day when the torpedo that struck his ship failed to detonate
Günther Prien - Wikipedia
How A Submarine Captain Became Known As A Man Who Almost Killed
Frederic John Walker & the German U-Boat - Warfare History Network
Behind new film 'Operation Mincemeat,' the true story of WWII's greatest deception
The Longest Struggle - Warfare History Network
Did Germany lose the submarine war quickly? - Quora
Featured Badass Series: #3 The Mystery Ship – Gear'd Hardware
How A Submarine Captain Became Known As A Man Who Almost Killed
The True Story Behind the 'Greyhound' Movie, History
The U-Boat commander who almost killed Churchill
U-Boats and the Lusitania: The War at Sea
A Soviet Spy Saved Stalin, Churchill and FDR from a Nazi Assassination Plot