Hi All,

There were some cases where U-boats had to turn in their codebooks & Enigma machines and use lesser codes for communication. These were generally mining missions (tube launched magnetic mines) where the U-boat would have to operate close to the enemy coast in shallow water.

When U-26 went on her 1st mining mission at the start of the war (she was already at sea with a load of mines & sealed orders when she got the message that the war had started & they were to execute their sealed orders) they successfully laid their mines but they maintained radio silence longer than Doenitz expected & he started wondering if U-26 had been sunk with her codebooks & enigma machine in those shallow waters where the Brits could retrieve them with commonly available diving equipment. U-26 completed her mission (she laid her mines at the entrance to the Brit anti-submarine school at Portland) & ultimately returned to port safely but after Doenitz realized the problem they came up with special communication procedures for those situations (“They will not receive the signals made to the other boats in Naval Enigma but only the ones essential for themselves, enciphered according to A.F.B. (T.N.: hand code system).” See: [www.uboatarchive.net] Pages 20 & 21.).

Other than these special situations all radio traffic between U-boats and BdU was done with the enigma machine except for a handful of messages sent in the clear during emergencies & a few cases where the messages were intended for the allies (Laconia incident for example).

I have no idea how German shore stations communicated with each other. Especially clandestine ones. I do know there were diplomatic codes but that’s about all I know about them. Breaking the Japanese diplomatic codes is how the allies got a lot of intelligence from communications between Japanese diplomats in Germany and their superiors in Japan. I don’t know if German agents in foreign countries had enigma machines & codebooks but if they did they probably didn’t use the U-boat codebooks for fear of compromising the U-boat war if they were captured.

Regards,

Ken Dunn