When trying to figure out where to find, and how to use, this form of public transport, we couldn't figure out why so many of the street hawkers were so keen to get us on board. When they followed us on we twigged - they were hawkers from the other side who wanted to sell us camel rides, etc., on the far bank.
It must have puzzled them no end when we got to the other side and we just stayed on board and chugged back. We'd been to the west bank the previous day; we just fancied a trip across the Nile!