The Battle of the Atlantic forms a backdrop to my WW2 spy story, The Black Orchestra. This battle was critical to the outcome of the war. As an island nation, Britain needed constant supplies of imported materials to sustain and support her war effort. Convoys of supply ships from North America had to run the gauntlet of German U-boats in a deadly game of cat and mouse. For the early years of the war the U-boats were winning this game hands down, but by mid-1943 the Allies had begun to prevail and the U-boat menace was largely neutralized.

Perhaps even more remarkable than the raid was that the U47 managed to escape undetected from the British naval base and return safely to her base in Wilhelmshaven. The commander and crew were instant celebrities, and Gunther Prien became a hero of the Third Reich.
U47 continued its attacks on Allied shipping, sinking a total of 30 merchant ships. It vanished on March 7, 1941 and is still officially missing.
Over the 6 years of the war, 3,500 Allied merchant ships and 175 naval vessels were torpedoed and sunk by the “wolfpacks” of German U-boats.
There’s lots of information and photos available on the web. Try any of these sites:
http://www.uboataces.com/battle-scapa-flow6.shtml
http://www.u47.org/english/
http://www.wrecksite.eu/wreck.aspx?14018