The white stripe is in fact yellow, (Looks white in the w/b pictures of that era) and yes, it means this is a training boat -or at elast a boat during its shakedown period, not yet "frontbereit" i.e. ready for combat action. So I guess you shouldn't have that skin in a combat boat, but only in the academy training missions boat
One question here: I know there was a parameter somewhere to modify the camera position of the captain's view on the bridge. Where is it? I don't want to wait until flakmonkey models his cage to be able to look over at the bow