DECIZE, France - It would be hard to invent a more limited way to see Europe than on a rented canal barge. You have a choice of two directions, forward or back. Most towns on the map are completely out of reach. Your maximum speed doesn't quite break 5 m.p.h., and every couple of miles you need to stop completely and wait to be let through a lock. There is some chance you will get your timing wrong and spend the night in an industrial port.