Submarine warfare played a major role in the war, and its tactics and strategies were difficult to overcome due to their discreteness and the mystery surrounding the enigma code. The way Dönitz conducted the U-boat campaign required relatively large volumes of traffic between U-boats and headquarters. This was thought to be safe as the radio messages were encrypted using the Enigma cipher machine, which the Germans considered unbreakable.The rotors were changed every other day using a system of key sheets and the message settings were different for every message and determined from "bigram tables" that were issued to operators. In 1939, it was generally believed at the British Government Code and Cypher School (GC&CS) at Bletchley Park that the Enigma could not be broken.
The capture of the U-505 was one of the greatest intelligence coups of World War II because it gave the Allies a working Enigma code machine. It also produced a complete set of the code books to go along with the machine. Most importantly, the U-505 gave the Allies the current settings for the Enigma machine in use by the U-boat fleet, which allowed the Allies to begin cracking German codes with great success. These finds allowed Allied cryptographers to intercept, decode and read German radio transmissions almost as quickly as the Germans themselves. It also gave the Allies an opportunity to test the capabilities of their German foes, which in turn led to improved tactics to counter the U-boats.
Throughout the summer and autumn of 1941, Enigma intercepts enabled the British to plot the positions of U-boat patrol lines and route convoys around them.
The capture of the U-505 was one of the greatest intelligence coups of World War II because it gave the Allies a working Enigma code machine. It also produced a complete set of the code books to go along with the machine. Most importantly, the U-505 gave the Allies the current settings for the Enigma machine in use by the U-boat fleet, which allowed the Allies to begin cracking German codes with great success. These finds allowed Allied cryptographers to intercept, decode and read German radio transmissions almost as quickly as the Germans themselves. It also gave the Allies an opportunity to test the capabilities of their German foes, which in turn led to improved tactics to counter the U-boats.
Throughout the summer and autumn of 1941, Enigma intercepts enabled the British to plot the positions of U-boat patrol lines and route convoys around them.