As I was reading through chapter 44, I came across this passage, which perfectly encompasses how much Ahab was truly obsessed with the whale he calls Moby Dick. Ahab describes the whale as if he knew the whale personally, and I thought that this bit shows how he has truly made hunting down this whale his entire personality and part of his life.
“That in the broad boundless ocean, one solitary whale, even if encountered, should be thought capable of individual recognition from his hunter, even as a white-bearded Mufti in the thronged thoroughfares of Constantinople? No. For the peculiar snow-white brow of Moby Dick, and his snow-white hump, could not be unmistakable. And have I not tallied the whale, Ahab would mutter to himself, as after poring over his charts till long after midnight he would throw himself back in reveries-tallied him, and shall he escape?” Chapters 44
Amidst the vast ocean, Ahab was in sight of one whale, which caused him to lose a part of himself, which then caused him to want to take vengeance upon the massive creature for the pain that he went through. That piercing whiteness of the whale, he will never forget, and will be part of how he can identify Moby Dick out traversing the seas. He knows the anatomy of this whale whale so well that it has been haunting him ever since. This causes him to even believe that he can spot the menacing white whale even if he is trying to blend in with other sperm whales that could be traveling nearby.
He details the anatomy of the whale, which he could spot from and knows is his nemesis, in the blink of an eye. The vengeance that is built up in him as he has traveled the oceans seeking out Moby Dick, with the marks he has left on him in the past encounters, to identify the creature to hunt him down to kill him. Ahab, with his charts, knows where this whale has gone, and he can still know this whale apart from the rest, and the image of this large ocean creature has not left his mind since that first sighting.
Ahab has shown us that his dedication to seeking out Moby Dick to kill him has the same mentality as when someone says I put my heart and soul into it. He has dedicated his life to hunting down this whale, and now he has encouraged his crew of the Pequod to help him seek out his ocean nemesis.