Moby Dick

Does this question relate to Chapter 100? I've found mention of Captain Boomer but haven't yet found any mention of an allusion to Ahab's mental state.

Chapter 100:

"Bless my soul, and curse the foul fiend's," cried Bunger, stoopingly walking round Ahab, and like a dog, strangely snuffing; "this man's blood—bring the thermometer!—it's at the boiling point!—his pulse makes these planks beat!—sir!"—taking a lancet from his pocket, and drawing near to Ahab's arm.

"Avast!" roared Ahab, dashing him against the bulwarks—"Man the boat! Which way heading?"

"Good God!" cried the English Captain, to whom the question was put. "What's the matter? He was heading east, I think.—Is your Captain crazy?" whispering Fedallah.

But Fedallah, putting a finger on his lip, slid over the bulwarks to take the boat's steering oar, and Ahab, swinging the cutting-tackle towards him, commanded the ship's sailors to stand by to lower.