Vanity unit from German Fleet

Orkney Museum Exhibition '1919: The Scuttling of the German Fleet' 

"This vanity unit is a compact and practical piece of furniture for an officer’s cabin on a German naval ship.  It has two tin water tanks and a fold-down basin.  The upper tank could be filled with fresh water poured into the funnel in the top of the unit, and waste water would empty into the lower tank when the basin was folded back in.  The lower cupboard would have given access to a waste water container which could be removed and emptied.
The front of the basin compartment folds down separately and doubles as a writing surface."