This is the EX "Barbara Kessel", The bridge wing is mounted on the barge as far as I know. This is the US system to sail rather big "ships" as one unit like here it is one ship and therefore would need 25 crew or something like that if welded together.
With the tug detacheable they need only a rather small crew as per regs for the tug. In one way it is not really a "true/correct" thing, because operating like this on a river or in good weather at sea it would have to have higher crews. Question is then,, why not for the time on the river a bigger crew. It,s a kind of loophole created for US ships/tugs to keep crews small.

Nice one! I like that outer parts of the bridge wings belong to the barge.