\">Pretty good intelligence work ensured those towed buoys to be aboard the escorts practically at the same time, when the first T5\'s were delivered to the boats.<\" It was not intelligence work, but treason which gave away the plans for the early Zaunkoenig work. The so called \"Oslo Report\" was a compendium of German military technology which was thrown over the fence of the British embassy in Oslo in early 1940 by an unknown traitor on his own initiative. He had previously sent a note to the British asking for a certain phrase to be broadcast by the BBC if they were interested. They were and they got detailed technical information on acoustic torpedoes, various Luftwaffe radio navigation systems which were used for night bombing and other items.

\">Only the T11 (Geier = Vulture) was able to ignore the buoys and go for the sounds of the ship.<\" T XI was Zaunkoenig II, not Geier. Geier did not have a T designator, but only the designation G 7es 47. It was an electric torpedo with a combined passive/active sonar seeker which apparently used the Zaunkoenig II passive set.

The other torpedo which could discriminate between a real ship and a decoy was Lerche (G 7es 48), basically a wire guided Zaunkoenig II, since the sonarman could hear the noises through the wire.

Regards,
SuperKraut