Character Analysis
The chief mate in this story basically serves one purpose: to act totally surprised whenever the narrator says anything to him. Even when the narrator mentions something normal, like the fact that there's another boat nearby, the chief mate answers:
Bless my soul, sir! You don't say so! (1.6)
And again, later, we hear:
The stare of extreme surprise imparted an air of ferocity also to his eyes, and he looked truly terrific for a moment . (2.122)
Sheesh, dude. Take it down a notch.
On top of his incredulity, the chief mate tends to make the narrator feel insecure about his authority as captain of the ship. After all, the chief mate is the next in command and he is much more familiar with the ship than the narrator. We can see how much the chief mate questions the narrator in passages like this:
There was a sort of curiosity in his eye that I did not like. I don't know whether the steward had told them that I was 'queer' only, or downright drunk, but I know the man meant to have a good look at me. (1.9)
Then again, it's impossible to know how much of this is the chief mate's doing and how much of it is the narrator's paranoia and insecurity. It's like high school all over again.