[UKönig]

An example, I started a new career with a green crew. My sound guy is just a set of ears. Let's say I am trying to attack in the fog, so visibility is crap. I keep popping back to the hydrophones station to listen for my targets to follow them until they get into perfect attack position. My untrained guy can hear the ships, but when I turn the wheel, all I get for an update is "unknown". He cannot identify the sound contact. Back to base, train the PO in radio-electronics, and now he can tell the difference between a lingering merchant and a flank speed destroyer.
This is where SH3 goes back to being a game. With the right kind of crew, you could end up with a wildly inaccurate (to history) U-boat, capable of almost superhuman feats. I can live with that. But it makes a kind of sense that the crew that stays together the longest ends up becoming a very elite group of specialists, so I guess it's not altogether unrealistic.