Did anyone see last weeks TimeTeam ? -> [www.channel4.com]

It was the oldest Rhine river barge found, in good condition and unusually used mortise and tenon joints for the thin base sheets;



Having done a bit of sailing - I'm confused how this barge highway worked. As far as I can see there was one sail mast (no one even mentioned a rudder). Also there was nothing to hold, or suggest, the use of oars. I can easily imagine a 35m barge like this working okay when going downstream, or even with a heavy wind behind going upstream. But what about getting back in either circumstance ? Surely they didn't wait around for the wind, and just stop on the side when it calmed down and wait. And there was no suggestion of what was used here far more recently in terms of horses pulling them. So what am I missing ?