From the one book I read on a british sub..
They spotted the sub chaser which came directly towards them at high speed. They dived, silent running and settled on the muddy seabed. The subchaser came by blindy dropping a few DCs. and cruised off.
The sonar guy heard the props fade and then dissapeared. The sub Captain wasn't happy and they lay on the bed for an hour. After an hour the Captain ordered scope depth but the sub wouldn't budge - it was stuck.
They tried rocking the boat and blowing the ballast, which all made a lot of noise. Suddenly the sonar guy screamed about high speed screws approaching. The Jap captain was waiting quietly on the surface... and damaged them with the first pass. The sub surfaced and fought it out on the surface and won - the allied aiming was better.
There was another incident where the jap subchaser had radar and was playing cat and mouse with the sub, waiting on the surface for the sub to re-appear, and then the chase was on until the sub dived again. The sub eventually got away on the surface by mixing his radar signal with the shoreline.
In both cases the japanese ships used DC's sparingly, and only when they were literally on target - interesting stuff.
So tactics as mentioned.. silent running with patience and craftiness.
