Symbolism, Imagery, Allegory
We're not sure if even Batman himself could stand toe-to-toe with the sperm whale depicted in In the Heart of the Sea. After all, what chance do humans have against the natural world if the natural world starts fighting back?
To Chase, the most horrifying part of the ordeal is how human the whale acts. Unlike the crew of the Essex, this beast isn't fighting out of greed or anger—it attacks the ship only after the ship "struck three of his companions, as if fired with revenge for their sufferings" (5.57). See, it's not just that sperm whales are huge and intimidating (even though they are). It's that this proves (in Chase's mind) that sperm whales have intelligence that rivals that of the men who hunt them.
Basically, this challenges Chase's notion of human superiority. First, he has to reckon with the ethical ramifications of hunting intelligent beings. Well, okay: he isn't overly concerned with that one. Instead, he has his mind on practical matters: "if other sperm whales should start ramming ships, it would be only a matter of time before the island's whaling fleet was reduced to so much flotsam and jetsam" (5.50). Though this prophecy remains unfulfilled, its shadow hangs over poor Owen Chase for the rest of his life.