Donitz and the Code Breakers
By 1943, Donitz’s work with the Navy had achieved him the rank of Grand Admiral and he was now commander in chief of the navy. But he did not believe in delegating- let alone trusting his submarine commanders to make their own decisions. Donitz was notorious for micro managing his crews. He believed in keeping a close eye on the daily operations of his U-boats, often contacting them up to 70 times a day to establish their position, and fuel supply- despite the fact that these were details he could easily have left to their commanders.
This practice actually did more harm than good because it weakened the security of communications. Donitz’s constant questions had to be answered. The steady flow of constant messages between the subs and command meant that the allies were more likely to intercept them. This meant the allies had a better chance of deciphering them. As Donitz was often inquiring into the U-boats position, the allies found this out too, which made it much easier to attack the subs and remove their threat to ships.
As the allied successes against U-boat operations increased, the admiral decided to investigate. Although he believed espionage was responsible for the leaks, Donitz still improved the coding of his messages. In 1942, he installed an improved version of the Enigma machine of his submarines. The Kriegsmarine was the only force to use this new, four-wheeled version of the machine. Donitz was once again on top-for ten months at least- before the allies also cracked the new code.