[Sledgehammer427]

I guess I'll bite

okay.
from your diagram I notice two things right off the bat.
a. where's the rest of the watch crew?
b. the forward bunks in the torpedo room are empty. but that's because of the torpedoes, even on the surface the bunks are folded up so the torpedoes can be loaded.

but here's my theory.
if memory serves me right, the U-boats had a two-watch system. that would split the boat in half while some crew rested, the other would be on watch. I'm not sure how the watch rotation was set up, (I know for Fleet boats, it was 8 hours sleep, 8 hours maintenance or what have you, and 8 hours on watch)
so I'm guessing the dev's set it up so it looks like only the crew on active watch was visible, I'm not sure how 40 men would impact performance, but, I can't blame them for their decision.