Actually, that is probably the easiest time for an enemy boomer to go take a swipe at a friendly. Think about it, if you can, the friendly is preoccupied doing whatever they are doing in their exercise and don't have their minds open to recognize any anomalies. For instance the sonar operator may be concentrating on pinging the positions of friendly boomers and just glance to see if they are all in the positions they are supposed to be in.
Another tactic is to draft on a surface ship directly underneath it to hide.
Boomers are boomers because they are stealthy and there has been myriads of tactics developed to enhance their stealthiness.
NKoreans the best? I doubt it.
Oh yeah, and BTW, here's another thread that could have just been added as a post in an existing thread about NK sub issues. Lazy shyte
Mr Gilbert your logic is flawlessly illogical. I have noticed that you are rather free with the personal insults in this thread, perhaps you could tone it down before I am forced to take action and report you to the appropriate authorities.