Fire long range...
Ok.
But the problem is that they wan't !
The escort is increasingly close to the convoy and force me to stay out of range of fire...(this sentence has been entirly translated by Google, I'm not sure you can understand lol).
And if I fire an acoustic topedos (T5) after 400m she follows the nearest destroyer and never hit a merchant...
Thanks to your ideas, I like the spirale system and try it next opportunity.
PS: to all players, don't forget: maximum depth is estimated with 100% integrity hull ! If lowest...maximum depth decrease(unknow values...). I can just tell you that with 30% integrity hull my IX/D2 had imploded at +/- 250 meters...
Last screen taken at 249m:
PS: note that the official values found on google says max depth at 230m...
http://fr.wikipedia.org/wiki/Unterseeboot_178
(On the right side in a square, watch "Profondeur: 230m")