Herman Melville, around age 66
"God, God is against thee, old man; forbear!"
A persistent criticism of director John Huston's 1956 Moby Dick is that Gregory Peck was too young to play Captain Ahab. Born in 1916, Peck was about 40 when the film was released -- more than ten years younger than Leo Genn, the actor who played Starbuck. As some pointed out, it would have made more sense if Peck and Genn had switched roles. Genn, however, while an accomplished British film actor with a splendid voice, had no star power.
A few remarks by Ahab in Chapter 132 ("The Symphony") enable the reader to pinpoint his age at the end of the novel's action as 58. Ahab there tells Starbuck that he struck his first whale 40 years earlier, as "a boy-harpooneer of eighteen!" But Ahab's all-around agedness is noted throughout the novel. He is, among other things, a "scornful old man," "the queerest old man," a "monomaniac old man," an "ungodly old man," an "insane old man," a "wondrous old man," a "frantic old man," a "crazed old man."
(Others aboard the Pequod described as "old men" are the blacksmith, the cook, and most intriguingly, Fedallah (in Ch. 48).)
To Melville, who (mirabile dictu) was in his very early 30s while writing Moby-Dick, 58 must have seemed quite old. To me, who hit 58 recently, it doesn't seem old at all. Granted, I'm a landsman, "pent up in lath and plaster," not running around a ship on a peg leg and throwing lances at sperm whales. Moreover, 58 was indeed old for a whaling captain. The authors of In Pursuit of Leviathan gathered age data for 275 whaling voyages out of New Bedford between 1842 and 1858. The oldest recorded man on any of those voyages was 62, and only 12 men were over 50. (See the tables on pp. 94-96.) As the authors point out (p. 90), "on 50 percent of the voyages for which we have [New Bedford] Port Society lists, the oldest man aboard was thirty-five or younger." (Emphasis added.)
The significance of Ahab's being an old man has been much discussed. From a purely practical standpoint, it helps make more believable that Ahab could bend the entire crew to his will, notwithstanding repeated bad omens and his occasionally dotty behavior. The reader has to be willing to accept that even the intrepid whale-hunter Starbuck could not withstand the "spiritual terrors" that menaced him "from the concentrating brow" of the "enraged and mighty man." (Ch. 26.)