"You can give orders to trail oars." "I don't know any thing about that," said Forester.
"That's a beautiful manoeuver," said Marco, "only it is hard to do.
You see, you order them to give way hearty, so as to get a good headway, till just as you get to the narrow place, and then _trail_ is the word.

Then the oarsmen all whip their oars out of the row-locks in an instant, and let 'em trail alongside under the boat's counters, and she shoots through the narrow place like a bird." Marco became very enthusiastic in describing this manoeuver, but Forester did not get a very clear idea of it, after all.
"You'll teach it to us," said Forester, "when we get our oars and a good boat's crew of boys.

At any rate, a boat can be paddled continuously through a narrow space, better than it can be rowed.
Therefore, paddles are generally used on rivers, where there are many narrow places to pass through.

Indians and savages almost always use paddles, for they navigate many intricate and narrow passages of water." By this time they began to draw near the mill.

They landed near some great logs which were floating in the water, ready to be drawn up into the mill and sawed.