The one guy (who got the greasy rag in the face near the beginning) was there as an observer, to take pictures for the propaganda machine (I think).
The other slick faced little boy was the Nazi "make sure they're all thinking right" officer who NObody liked. The photog eventually sort of fit in if I remember right.
Then there's the novel "The Boat" by Buchheim, after which I
think they made the movie. Both are
great in my opinion. 