[John Pancoast]

I've come to the conclusion that the sensors in the stock game are whacked too.
Without binos I can clearly see the destroyer's bow wake and/or camo paint long, long before it reacts. If I can see it's, it should see mine when I'm at flank speed going directly at it, regardless of crew rating. "Sorry sir, even though it's my job and I have incredible optics, I didn't see that sub charging at us until it was only 800 meters away"

Especially in the clear weather/calm seas of the Scapa mission. Maybe the mission is tweaked to make it easy, don't know.
But the distances aren't much different in stock or any mod, this mission or in mod campaign convoy.
If nothing else, it can lead to very ahistorical and unrealistic tactics. Not many u-boat commanders would risk staying on the surface/or in the area with an escort in easy visual sight at close range when one shell from a destroyer can ruin their day, regardless of whether the destroyer saw it or not.
As is, a player can do that in stock, rub, gwx, and nygm. Or at least I can on my installs.