@JScones
I know Das Boot does not show a "real strom" but look at this one if you not already know it.
IMO these qualifiy to create a Das Boot-
like situation as in this vid the ship is much larger than a u-boat. Of course I won't expect Leutnant Werner to magically appear next to me on the bridge screaming at the sea.

And it does not need to look exactly the same.
When seeing this and other vids I realise that huge waves must affect hydrophone at periscope depth right? I think this is not modelled in SH4 or is it?