Ahab takes out his quadrant a few days later, attempting to determine the ship’s location, whether it is close to the equator, and whether it is therefore time to search for Moby Dick in earnest—for Ahab is now convinced that Moby Dick will be found along the equator line in the seas near Japan. But, after using the quadrant to orient himself, Ahab realizes that the quadrant “can tell him nothing of where he is,” and that he will need to find Moby Dick himself, without the aid of any instrument or “toy.” Ahab smashes the quadrant against the deck of the ship, and Starbuck, observing this from the deck, wonders if Ahab won’t “burn himself to ashes” in his quest to find the whale. But Stubb believes that Ahab is merely “seeing his quest through” until its bitter end.
Just as Ahab cast his pipe over the side of the boat and into the water, as an indication that he no longer had any time for enjoyment, so too does Ahab throw over the navigational instruments of the ship. This signals that Ahab is no longer concerned with finding land, or with getting home at all. The ship will no longer follow standard navigational tools. Its only course is Ahab's course.—to find Moby Dick. Starbuck, understandably, is alarmed by Ahab’s cavalier attitude and believes Ahab may end up destroying himself. Stubb, as usual, is more willing to follow his captain's orders.