AP shells - as posted - will make no difference to anything below a cruiser as not armoured
Not 100% certain they are much different ingame than the HE anyway

Not sure RE your problems in the naval academy as never done it :oops:

Because the game is wrong in that area, and all the mods in the world don't seem to be able to fix it.

Corvettes only carried a single deck gun, true, but they carried a 40mm AA gun aft and it would very quickly kill the entire u-boat crew on deck in a matter of seconds (and did in at least one case).

Part of the problem is that the game lets the player be much more accurate with the deck gun than the AI can be, which leads to the second problem, that of the gunsight wandering to the left.

Simply put, it's unrealistic for the captain to be shooting the deck gun at all. And if he did, he would almost certainly be less qualified at it than a trained gunner (though another thread mentions that the Ubootwaffe didn't have a gunner rating).

Bottom line: The game lets us play unrealistically, and only our own self-monitoring can fix that.

Yeah, I definitely don't plan on doing it again. I just did it because I'd surfaced by accident (blew ballast), so I figured I was a goner anyway. I was very, very surprised when I turned out to be the terror of the surface fleet.