But for hunting UBoats it was not as successful because the information being passed to sub hunters was already hours old and subs rarely sit bobbing up and down on the ocean for very long.
ASW was very rudimentary in WWII. If the convoys knew they were going to be attacked by subs then the destroyers could fire their ASW weapons. Most subs survived this but they had to dive deep and keep silent. The convoy was saved, and that was most important.
If you want to know how life was in subs being attacked, watch the movie "Das Boot". It's excellent.