Theoretically you are right but in reality this is not what happens!LWD wrote:I seam to recall reading that the British got a lot of info by df'ing u-boat radio transmissions. Hunter killers can be very effective if you are getting this sort of data. Even if they aren't sinking huge numbers if they are forcing them down especially at night so they can't recharge batteries, exchage air, and such. EAlso even a little damage can impact the rest of the cruise for a U-boat.
The British did their best to break the Enigma code and they almost got to good results for breaking up the code before 1941! But it would take 48 hours to a week to decrypt the code!
After the German/Donitz suspected the decryption followed by the introduction of the advanced Enigma called Shark by the British (Called Triton by German) in 1942 it became difficult and not useful to decrypt the message.
http://www.ilord.com/enigma.html
The period of decryption might take around one month to decrypt the message which was not practical!
It is not worth it to know Donitz order to attack the convoy after one month! It is faster to know that in German newsreel when the covoyed is destroyed!
http://everything2.com/title/Enigma
However in WWII Documentary one British official mentioned that we didn't realize that all our Atlantic radio messages was fully recognize and decrypted by the German unless the war is over!!
The Most reason for making the life of the U-boat missirable is the conitnues and enormous Airplanes scanners equipped with radar which stopped the U-boat to travle at surface and re-charge the battery !
The German succeeded to make Long life battery that would last longer under surface but I am not sure wither it was used in any type other than the XXI !?