39-10-17 German U-47 Raid at Scapa Flow

German U-47 Raid at Scapa Flow > . 

24-5-19 Detection Advances vs Future of Ballistic, Attack Submarines - Perun > .

The German Submarine branch of the Kriegsmarine was one of the most fear-inducing branches of the German military apparatus during the Second World War. It wasn’t always that way though. As a matter of fact, Adolf Hitler preferred to put emphasis on the Wehrmacht and Luftwaffe, rather than the Kriegsmarine during the initial stages of the war. He simply didn’t realize the potential of the U-boats against the Allied fleet. Admiral Karl Dönitz put a change to that: within 2 months of the outbreak of the war he launched a daring operation with merely 1 U-boat that would rapidly sway the minds of everyone involved in the second world war: U-boats from then on would be a force to be reckoned with.

https://en.wikipedia.org/wiki/German_submarine_U-47_(1938) .
https://en.wikipedia.org/wiki/HMS_Royal_Oak_(08) .