Then, each manning a clumsy oar, they pulled up-stream.

Along shore were whirling, slow eddies, and there rowing was possible.

Out in that swift current it would have been folly to try to contend with it, let alone make progress.

The method of crossing was to row up along the shore as far as a great cape of rock jutting out, and there make into the current, and while drifting down pull hard to reach the landing opposite.
Heavily laden as the boat was, the chances were not wholly in favor of a successful crossing.
Lucy watched the slow, laborious struggle of the boatmen with the heavy oars until she suddenly remembered the object of her visit down to the ford.

She appeared to be alone on her side of the river.