The drunken ferryman is an incidental but amusing character in the short story "A Little Sacrifice". Geralt, Dandelion and Essi Daven meet him as they are leaving Bremervoord and about to cross the Adalatte.
The trio is forced to pull the rope-operated ferry across the river themselves as the ferryman is near paralytic and clinging to one of the posts on the dock. He's clearly in no shape whatsoever to do the job himself. When they try to speak with him, all the man can manager are a few unintelligible syllables.