I think you are referring to the phrase \"walking up the river\" which is found in Chapter two. This is a way to move a ship that has been stalled by the weather. After seven days of no wind, Captain Eaton had two sailors in a rowboat row ahead of the Dolphin and drop a small anchor. On the Dolphin, ten men pulled on the rope attached to the anchor by grasping it, then walking to the rear of the ship. As each man reached the end of the rope, he ran back to grab it again. This pulled the ship ever-so-slowly toward the anchor. After reaching it, the rowboat set out again to begin the process anew. This was a miserable way to creep upriver during the hot spring weather. The men strained and sweated hour after hour to move the ship a small distance. Kit, too, was miserable as she could only watch them struggle and suffer. The next morning a breeze came up that sent them on their way.
"Walking upriver" means walking against the current (usually next to the river on the riverbank), toward the river's source.
Walking up the river means to go against the way the current is going. to do that they would throw like an anchor or somthing and pull the rope. they would do that repeatedly so thats what walking upriver mean. i hope this answered your question.