Originally Posted by Saquist
No doubt...over 1200 U boats constructed and held of the allied fleets and supplies untill the code was broken and they began sinking them by the hundreds.
Bad play by Hilter.
He really was insane.
The cypher actually had to be broken numerous times. I think it was sometime in 1942, the Kreigsmarine introduced a new version of Enigma that had a fourth rotor added to it. Also the U-boats began to limit the length of their transmissions to evade radio direction finders which gave the Allies limited number of characters to analyze. Took nearly a year before regular deciphering of U-boat message traffic could resume.
On top of cracking Enigma, the US Navy began deploying hunter killer squadrons consisting of escort carriers and destroyer escorts. The aircraft from these squadrons were outfitted with sonobuoys and acoustic homing torpedoes in addition to bombs and depth charges. These squadrons were devastating to the U-boats. None the less, the fact that such a small boat often required large amounts of resources to combat speaks to the magnitude of just the threat of a single submarine. To this day, submarines and mines still are the weapon of choice for nations that for whatever reason cannot afford to build and maintain a large navy.
In the end the loses reached the point where it wasn't an issue of being able to build enough U-boats, but rather finding enough personnel to crew them.