Hi Jimboy,

Keep in mind that many writers simply ASSUMED that the intelligence that caused some action at sea to occur or not occur came from ULTRA. Sometimes this information came to them from the men who fought those battles but in fact the men at sea who fought the U-boat war were simply not on the list to know that ULTRA even existed.

The actual source of Allied intelligence was a closely guarded secret during the war and for some time after. As Bruce correctly points out intelligence from several sources including ULTRA, traffic analysis, Huff/Duff, sightings at sea (visual sightings, radar contacts, ASDIC contacts etc.), and other sources was funneled into a central location where it was analyzed and orders formulated accordingly. Many times the orders were simply based on an educated guess based on the limited intelligence available at the time – especially when intelligence sources conflicted with each other. Even the existence of an unusual amount of U-boat radio traffic from one location that couldn’t be decrypted was enough to alert them that a wolfpack was probably operating in that area.

The men who took action on the intelligence weren’t even necessarily told what was going on or what kind of intelligence was involved – they were simply ordered to patrol a certain area where low and behold they stumbled on the enemy. They might even have been purposely misled as to where the intelligence came from as they didn’t have a need to know the actual source and it was undesirable for them to know if they were captured etc. Simply “intelligence indicates the enemy is here or his intentions are such and such” or even “the enemy has been sighted at this location” (never mind that the plane that sighted them was sent to patrol that area based on ULTRA or Huff/Duff etc.) was perfectly adequate for tactical use. The actual source of military intelligence has to be kept from the enemy at all costs and the fewer people that knew the truth the better.

Actually Huff/Duff could in some cases be far more accurate in determining the actual location of a U-boat at sea than ULTRA. ULTRA could tell you where a U-boat was ordered to go or where it said it was or where it said it was going if the messages could be intercepted and decrypted in time to do any good but Huff/Duff could tell you where it was at the time of its last transmission and fingerprint information could sometimes even tell you which boat it was even when the message couldn’t be decrypted. Additionally, a lot of U-boat transmissions were garbled when they reached U-boat Command and when they weren’t acknowledged had to be retransmitted. Huff/Duff might well have pinpointed the boat’s location (well, its general location anyway) on the first transmission.

Huff/Duff was especially critical during the many times intercepted messages couldn’t be decrypted in time to have a tactical value.

It difficult to research the actual piece of intelligence that resulted in a specific action today because it was so secret at the time that either it wasn’t recorded for posterity or the records were destroyed or they are still stuck in some classified file. It is also quite easy to assume any signals intelligence came from ULTRA because of this confusion when in fact it may have not played any part in a specific event or if it did it might have even been a minor part. Keep in mind that grid square (map coordinate) information was double encrypted in U-boat transmissions and was as a result sometimes not able to be decrypted by the Allies in a timely manner. There was a completely separate code book (Adressbuch) for it.

The bottom line is that the people making the decisions based them on experience and the best evidence from as many sources as possible that was available at the time. Sadly it is very difficult now to know all of the sources of intelligence that went into a given decision or which was given the most weight. Was it just ULTRA or was it just Huff/Duff or was it both or was it a combination of even more sources? Even with all of the records that still exist today it might still not be possible to know for a given event.

Perhaps asking about “signals intelligence” which would include ULTRA, Huff/Duff, traffic analysis, fingerprinting, etc. would be a bit easier to answer though.

Regards,

Ken Dunn