In this chapter, Ahab considers how he will keep his men from mutiny, given his irrational and monomaniacal purpose (killing Moby Dick), which is at odds with the normal purpose of a whaling voyage (making a profit). Melville writes, "To accomplish his object Ahab must use tools; and of all tools used in the shadow of the moon, men are most apt to get out of order." Ahab knows that Starbuck will be must difficult to keep in check: "Starbuck would ever be apt to fall into open relapses of rebellion against his captain's leadership, unless some ordinary, prudential, circumstantial influences were brought to bear upon him."
Ahab's plan to keep his men in check is to keep them busy with more immediate tasks. He compares his sailors to knights of the Crusads: "For even the high lifted and chivalric Crusaders of old times were not content to traverse two thousand miles of land to fight for their holy sepulchre, without committing burglaries, picking pockets, and gaining other pious perquisites by the way." Abab will use the men's greed and hopes of cash to keep them loyal to his real purpose.
