The next day dawns, and though the whale has not been spotted the previous night, Ahab knows it is close by. Then, after a few minutes, Ahab himself finds the whale, and the boats are lowered once again, with Starbuck manning the Pequod for the third time. Ahab says goodbye to the ship and shakes Starbuck’s hand, telling his first mate that he thanks him for his service, and saying also that some “ships never return to their harbors.” Starbuck watches Ahab leave in his whaleboat, telling him to be careful of the sharks that are circling the Pequod, and wonders about Ahab’s wife and child—if the captain will ever see them again.
On the first two days Ahab seemed to set forth after Moby Dick with hope of killing him. Now he seems to head out with a sense of his impending doom. Ahab no longer cares at all for the obligations of his command, or his family, or life—he has devoted himself entirely to killing Moby Dick, or even just facing Moby Dick, an action that will give his life meaning, and the prospect of death will not stop him from doing so. Starbuck's advice that he watch out for the sharks seems a final indication of his cautiousness, as he warns a man going to a showdown with Moby Dick about some mindless sharks.
The three boats set off once more, but two of them, manned by Stubb and Flask, come close to the whale and are again broken to bits (these being replacement boats, quickly readied from the previous day). The three harpooners and Stubb and Flask swim with bits of debris back to the Pequod, and quickly try to make the boats ready and water-tight, to continue to attack Moby Dick. Meanwhile, Ahab sees a horrific sight: Fedallah’s body is trapped against the White Whale’s, for he was caught in one of the harpoon lines and drowned when Moby Dick went into a dive.
The horror of Fedallah drowned alive, stuck to Moby Dick only heightens the sense of the whale's dread and possibly malevolent power. Moby Dick himself, is the “first hearse” mentioned in Fedallah’s prophecy, and is a hearse “not made by human hands,” as the whale God’s creation. If this part of Fedallah’s prophecy is correct, then, Ahab seems to have reason to believe that the rest of what he predicted will come to pass. Therefore Ahab awaits the “second hearse,” which will be made of wood.
Ahab realizes this is the first hearse of Fedallah’s prophecy, and wonders what the second will be. Ahab nevertheless orders the crew to once again fly toward Moby Dick, who has appeared to “slacken” in his pace, perhaps because he is tired and wounded after multiple stabs and three days’ chase. But after Ahab throws another “dart” into Moby Dick’s side, the whale thrashes and causes some of the crew to be tipped from Ahab’s boat.
Ahab continues to be able to wound the whale, despite all the thrashing and the tiredness of three days in the whale-boat. As before, Ahab’s power seems only to grow in these scenes, as though the presence of Moby Dick has given him a shot of energy that will not dissipate.
Ahab recovers, orders the crew back into the boat, and realizes that Moby Dick has turned away from attacking the small whaling dinghy, and has instead focused its attentions on the Pequod, seeking to ram into that vessel. Ahab realizes, to his eternal dismay, the second part of Fedallah’s prophecy: that the Pequod itself is the “second hearse,” made of American wood, and that all the sailors on it—who have been hard at work preparing the whale-boats once more for battle—will go down with the ship. Starbuck, Flask, and Stubb each see Moby Dick approaching to ram them—and Starbuck prays for forgiveness earnestly, from heaven, while Flask and Stubb wonder what is to become of them and the ship.
Now the second part of the prophecy is revealed, and fate seems to cling tighter around Ahab and his crew. Ahab;s monomania has doomed his crew. Starbuck, Stubb, and Flask show three men's different reactions to certain death—praying on the one side, a kind of shocked astonishment on the other. And all the while it is left unclear whether Moby Dick actually understands what is happening, or is simply a monstrous animal, doing what large animals do—eating, and attempting to protect itself.
That next instant, Ahab realizes he has one final shot with his harpoon at the whale, and urges the crew onward, toward Moby Dick. Ahab throws the harpoon and strikes the whale, but does not notice that the line is running out quickly, and accidentally steps into its way—the harpoon-line wraps around his neck (the “hemp” of the prophecy) and pulls Ahab into the deep, where he drowns, half hanged by his own line. Moby Dick rams the Pequod and causes it to splinter utterly—the Pequod sinks into the Pacific Ocean. As the boat is sinking, Tashtego remains atop the main mast, hammering to attach a flag to the spar at the top of the mast. And Ishmael notes that, before Tashtego goes down with the ship, he hammers into a bird which has flown between his tool and the main-mast. Ishmael states this is like, in the Biblical story, Satan “dragging a living part of heaven” along on the descent “to Hell.”
Ahab's struggle and death can be seen as a metaphor for that of all men: contending, with imperfect strength and knowledge, against forces that are too big to comprehend or ever hope to defeat (nature, fate, death). Tashtego, who earlier was "reborn" in Chapter 78, now dies. He has gone through the cycle of life on the ship. And his death is similarly metaphoric, as he hammers into place the flag that will identify the ship—to defiantly claim a unique place for him and the ship in the world and in existence—even as the ship is going down, as existence slides soundlessly into the water. And with the accidental killing of the bird the Pequod goes down with a final Biblical interpretation.