Acoustic torps are wonderful!
Just killed another escort with it.
September 1943, off the coast near Halifax.
Convoy sighted despite bad visiblity.....as I was picking off merchants one by one I saw a dd coming up right behind me, about 1 km away.....
LOS!, out goes acoustic torp.... a true fire and forget weapon.... a couple of minutes later....BOOM! no more escort!
Gotta love 'em.
But remember two things.....
1) target needs two move ar 12 knts minimum in order to be picked up by the sensor.
2) If you happen to be the noisiest vessel around the torp is coming back for you!
I believe it was standard practice among U-boats to dive 60 mtrs or deeper after firing such a torp!
Finally:I think an acoustic torp is a bad investment: they cost about 250, I believe the amount of renown for sunk DD is less...
I still 'buy' one sometimes just for the fun of it...