I have been checking out TDW's IRAI mod. From what I can see, the range of the passive/active sonar does not appear to differ greatly from stock. The big change is in the search and attack behavior and the length of time the escorts will keep searching for you after they lose contact.
The standard evasion tactic of going as deep as you can and using "silent running" to slowly crawl out of the area should still be the most effective. When you are deep, the escort's passive/active sonar cone is very small, so the escort would have to be practically on top of you to pick you up.
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