One might wonder how Herman Melville was able to write a story such as Moby Dick so realistically. It is because he spent time on a whaling ship that sailed out of the same port from which Ahab's ship departs. The element of realism in this novel of adventure and obsession is born of personal experience.
On January 3, 1841, he sailed from New Bedford, Massachusetts, on the whaler Acushnet, which was bound for the Pacific Ocean. He was later to comment that his life began that day.
The larger-than-life Captain Ahab is an intimidating persona who eventually loses his reason in his pursuit of a white whale with which he has a personal grudge to settle: the loss of his leg.
When Ishmael (the narrator) considers signing on the whaler, Pequod, at the beginning of the story, Ahab is described as “a grand, ungodly, godlike man.” It is not until Chapter 28 that "Old Thunder" (Ahab) "makes a proper appearance." And little information is provided about the captain prior to this voyage. Ahab was orphaned as an infant—at twelve months old. Ahab, ironically, is a Quaker—Quakers are pacifists or peacemakers. Ahab is anything but peaceable. His name comes from the Old Testament. Ahab is married with a child, though he does not provide their names.
Ahab has lost his leg in a recent whaling encounter, and his artificial leg is made of bone: from the jaw of a whale. Melville writes about Ahab's steely dedication to the task at hand, and an unswerving concentration:
There was an infinity of firmest fortitude, a determinate, unsurrenderable wilfulness, in the fixed and fearless, forward dedication of that glance.
Captain Ahab is presented as a man of dignity, but the reader is surprised at Ahab's assertion that rather than being attacked by an animal based upon its instinct, Ahab personifies the whale as malicious. He is also a man who "takes no prisoners." Ahab seems slightly unhinged when he states that he would attack the sun if it had insulted him.
In light of Ahab's need for revenge, his obsession seems to have a life of its own, and it eats away at him.
Ahab’s obsession is presented as a ravenous monster...
The more his fixation takes hold of him, the less rational he becomes. As the story progress, Ahab is presented as one who has lost control of his mind; he is ...
a possessed man at the mercy of his obsession...
In an almost Shakespearean light, Ahab fights his demons alone; they rule his every move. Along with his departure from reason and sanity, he ultimately seals his fate, and that of his crew. Thinking of no one but himself, his actions cause the death of every member of the Pequod's crew, except for Ishmael.
Ahab is destroyed by the very obsession that drives him. As he attacks Moby Dick at the end of the story, he becomes entangled in the whaling gear he is using to kill the whale, and when the whale submerges, it takes Ahab with him. Ahab is presented as a strong man, with a weak mind that give in to his obsession with an element of nature. Like Icarus, who loses sight of his limitations, Ahab loses sight of the fact that he is merely a man, and no match for the white whale.