[Redmane]

Thermal layers do make it tougher for the ASW guys to pin down your location for an accurate DC attack. It sounds to me like you did things right, getting well enough below it that the entire boat was below it, which is something you always want to make sure of. However, just because you do find a thermal, that won't prevent the enemy AI from continuing to try and locate you. I have often passed through the layer and for a few moments heard them stop active searching, then resume soon after. And sometimes they do get lucky with very close or right on accurate barrages even after you get below one. I will often be diving at high speed, so there are some good knots on the boat, pass the layer, then drop all the way down to 1/3rd to go quiet, and use the momentum to put a turn on the boat and try to throw off any tracking idea they may have on me. This hasn't always worked, but sometimes it has.