They only had to hold it back to prevent its running down too fast, and to keep it properly guided.
"It goes down pretty easy," said Marco; "but I don't see how you are ever going to get it back again." It was, in fact, a long and rather steep descent.

The boys thought that it would require far more strength than they could exercise, to bring the boat _up_ such an inclination.

Forester told them not to fear.

He said that a good commander never put too much upon his men, or voluntarily got them into any difficulty without planning beforehand a way to get out.
They soon got down to the water's edge again.

Here, instead of the broad and smooth pond which they had above the dam, they found a stream eddying, and foaming, and flowing rapidly down between rocks and logs.