Sure if no ones knows where to start looking... but in my game experience evading becomes important once you've launched that first salvo, then everyone knows almost *exactly* where you are and where to start looking. Your cover is blown because everyone has a clear datum to prosecute. 1-2 ASW aircraft are no doubt blazing at 100 knots to your exact location (if the AI is any good). If you say still too long, a active dipping sonar is about to drop right down on your head to ping you and a torp will soon follow. You have to move and move fast, because they are coming for ya and coming quickly at that.
Soo.....trying to slink away at 3-5 knots is suicide, you have to move fast to clear datum. After a strike your sleath is already blown, and location are already given away. Its just a matter of hoping that you have caused enough confusion to force the enemy to break contact for just an few minutes while you run for the hills.
