Download and watch the "In-game Footage" video (#3) from
here (not that most of us have seen it already

).
I liked how you could target the various compartments of ships in that movie. It sounds like a rather nice thing to add to the lower realism levels.
Anyone know why it was taken out? And do you want it in
Silent Hunter IV?
Either way, it'd be nice to have an overview of the compartments in the
Silent Hunter IV manual.