It is okay, did not take it as complaining, just trying to figure out why keep getting detected, because that does not happen to me.
Unseen aircraft spotted you? They can spot you under water at certain depths, depending on various factors. They will alert nearby escorts. Periscope spotted at some point during observation? Perhaps detected by merchants when obseeving them, they will "report" your presence to the nearby patrol vessels, which will come out to "greet" you. Depending on time of war, some merchants get hydrophones for self defense purposes, their range is limited but if they pick up a submarine, will report you. In new version, some merchants will carry defensive depth charges, so if detect you, are close enough, and depending on skill level that particular ship is set, may drop a ash can or two on you. They won't hunt you like a escort, but will take the opportunity to drop on you.
Yea, tell your boys to pipe down when enemy are nearby lol.