In my opinion, the climax occurs on the third day of battle with Moby Dick, when the whale rams the Pequod and sinks it. Ahab is caught in a harpoon line and dragged out of his boat to his death. Thus, Ahab’s maniacal pursuit of the white whale, which is the main plot of the novel, comes to a climax. The conflict man against nature is resolved, and man loses. While Ahab believes the unnaturally white whale Moby Dick is the incarnation of evil, Ahab’s mad obsession to pursue and kill the whale is also unnatural and turns Ahab evil.
Ahab’s men are caught in a whirlpool created by the Pequod when it is sinking and they all drown. The only survivor is Ishmael, who was thrown out of his boat earlier and is too far away to have been caught in the whirlpool. Ironically, he saves himself by clinging to Queequeg’s coffin, an item usually associated with death. Ishmael is picked up by another ship, the Rachel, still searching for its own lost crewman, whom Ahab refused to help the day before. Thus Ishmael (in the Bible, Ishmael was a wanderer because he was cast out by his father, Abraham) is the only one that the Rachel finds in the end (in Jeremiah 31:15, the prophet speaks of 'Rachel weeping for her children'). This also resolves a major theme of the novel, that God’s ways are above man’s ways, and who can fathom them?