What omens appear as ahab's whaleboat pulls away from the ship and when moby-dick surfaces

A recurring theme throughout Moby Dick is the appearance of harbingers, superstitious and prophecies that foreshadow a tragic end to the story. Even before Ishmael boards the Pequod, the Nantucket strangers Elijah warns Ishmael and Queequeg against traveling with Captain Ahab. The Parsee Fedallah also has a prophetic dream concerning Ahab's quest against Moby Dick, dreaming of hearses (although he misinterprets the dream to mean that Ahab will certainly kill Moby Dick). Indeed, the characters are bound by superstition and myth: the only reason that the Pequod kills a Right Whale is the legend that a ship will have good luck if it has the head of a Right Whale and the head of a Sperm Whale on its opposing sides. An additional harbinger of doom found in Moby Dick occurs when a hawk takes Ahab's hat, thus recalling the story of Tarquin and how his wife Tanaquil predicted that it was a sign that he would become king of Rome.

The purpose of these omens throughout Moby Dick is to create a sense of inevitability. Even from the beginning of the journey the Pequod's mission is doomed by Captain Ahab, and the invocation of various omens serves to endow this mission with a sense of grandeur and destiny. It is no suicide mission that Ahab undertakes, but a grand folly of hubris.