The pushing is a mode of River transport particular: a specialized boat, the " pousseur" , barge S without pilot nor engine pushes. Appeared in France at the 19th century, pushing especially developed with the the United States. It will replace the " gradually; tractionnage " who consisted in making draw by a river tug from the convoys from several barges who lay thus on several hundreds of mêtres. This principle will be a success growing in the Hexagon after the Second world war. The Poussah is the first pusher built in France, in 1955.

Organized like a propellent element of a floating unit, it is attached by sling S out of steel on the back of a whole of barges which it motorizes strongly. Its cabin, like sight on the photograph, is assembled on Vérin S hydraulics so that the eye of the pilot can see with far in navigation, while assembling the whole of order and, by lowering it, so that it can pass under the bridges.