Hi Krzysztof,

Here is the answer to part of your question. From “U-Boats The Illustrated History of The Raiders of The Deep” by David Miller (ISBN: 1-57488-246-5):

“The first weapon - T IV (G7es) Falke (= falcon) - entered testing in 1940 and was originally meant to enter service in 1942, but development problems caused long delays and the early models were not tested at sea until early 1943. Then, however, two out of three successes resulted in the weapon being declared satisfactory and it was cleared for service from July 1 1943. Falke had a contact pistol, a 6041b (274kg) warhead\', the relatively low speed of 20 knots and a range of 8,200yd (7,500m).

It was in service for a brief period only and a few U-boats were adapted to take it, before it was replaced by the much better Zaunkdnig. Approximately 100 Falke were manufactured, of which some 30 were launched in anger.”

From “U-Boats Under the Swastika” by Jak P. Mallmann Showell (ISBN: 0-87021-970-7):

“The Zaunkdnig or T5 was an acoustic torpedo introduced to operational boats during October 1943……………

Unfortunately, some of the faults which caused the torpedo crisis of 1939/40 had not been recognized at the time and started to reappear when the T5 came into service. Consequently the German Navy suffered a torpedo catastrophe. Some 700 acoustic torpedoes were shot, but only produced 77 definite hits, meaning this highly rated anti-destroyer weapon had a miserable success rate. (The U-boat Command guessed there was a considerable discrepancy between actual sinkings and figures given by commanders, but their estimate was nowhere near these figures, which came to light much later during the 1970s, when Prof Dr. Jürgen Rohwer researched the subject.).”

As to the Foxer, it worked but I don’t know how much it had to do with the lack of success of the T5. I do know that improvements were made (Zaunkdnig II) to make the acoustic torpedo more attuned to the propeller noise when it was discovered that the Foxer was being used, however, it was never deployed. I also think (but am not sure) that another sound-generating buoy was also used against the T5.

Also see [www.uboat.net].

Regards,

Ken Dunn