Ishmael reminds the reader about the man he saw in the inn at New Bedford named Bulkington (you remember, the least rowdy Grampus crew member, way back in New Bedford?).
Now he looks upon the Pequod and sees a vision of Bulkington at the helm.
He’s amazed that a man who just came back from a four-year voyage would immediately set off on another voyage for three years.
Ishmael explains: "this six-inch chapter is the stoneless grave of Bulkington" (23.2). Bulkington’s not dead, but we’re not going to hear any more about him in the novel.
Ishmael uses Bulkington as a means to think about the safety of port and land versus the thrilling danger of landlessness, and then dismisses Bulkington forever.