One of the peculiarities of Moby-Dick is that it includes large quantities of information about the science of whales and the practice of whaling. Whole chapters are dedicated to describing the technicalities of life aboard a whaling vessel in the most minute detail.
These make the novel read oddly: they interrupt the telling of the tale and many readers find them boring. What was Melville's reason for including so many technical chapters and going into such detail?
There are multiple purposes behind the novel structure of Moby-Dick.
In the first instance the author was himself a whaleman, having spent 18 months as an ordinary seaman aboard the whaler Acushnet in 1841–42. In his experience the literature of the day, such as Miriam Coffin or The Whale-Fisherman by Joseph Hart, did not portray whaling accurately but rather sensationalised it. He wished to provide his readers with a more realistic account.
In doing so, he also gave the reader the information necessary to better understand and appreciate the passages of whaling described in the novel. With the reader forewarned, he is able to keep the narrative passages tense and exciting. It is interesting that, early in the novel, the Pequod meets virtually no whales and that the chases become longer and more involved as the story progresses. This may be because Melville felt he needed to give the reader more and more technical information before they could fully appreciate these encounters, but understood the science would need to be spaced out among the narrative.
In describing it to the reader, the science also serves another useful narrative function. It indicates that on whaling voyages, long periods of time pass when nothing much happens at all. By padding out of the story with scientific digressions serves as a useful narrative metaphor for waiting.
The level of detail provided also mirrors one of the novel's central themes: obsession. Although Ishmael is the narrator and Ahab the obvious obsessive, the amount of science indicates that Ishmael is also an obsessive. His obsession is the business of whaling itself.
Finally, Melville made good use of these passages in serving as metaphors for other themes of the novel where he felt it appropriate. For example in the chapter The Line, which describes how the whale line is stored and used in the boat, it ends by using the line as a metaphor.
"All men live enveloped in whale-lines. All are born with halters round their necks; but it is only when caught in the swift, sudden turn of death, that mortals realize the silent, subtle, ever-present perils of life."
That’s not a 'peculiarity'. To most who enjoy the genre that's much, if not most of the point.
Melville's reason for including so much technicality was simply to show realism. Consider how Hollywood did the same in the 1956 film adaptation, the major difference being simply the time taken to watch a movie or to read a book…
Isn’t the real question, to what genre does Moby Dick belong? Adventure? Seafaring? Whaling? Something else?
For a quite separate, singular example consider Seven Pillars of Wisdom, the autobiography of TE Lawrence (of Arabia) who at one point spends three pages describing nothing more 'interesting' than the different kinds of gravel found along the sides of a valley.
Still, Seven Pillars was called the best adventure story ever written in English by both Sir Winston Churchill and Sir Edward Bulwer-Lytton, both military heroes, literary giants and political masters.
Consider CS Forrester’s Hornblower; Patrick O'Brian's Aubrey–Maturin; Bernard Cornwell’s Sharpe. Go back 100 years to Talbot Mundy’s Tros.
All those, and many others, simply would not work without their technical details. Any good writer could translate exactly the same stories into current or future fiction, except that the technical details you ask about would need to be re-invented.
All those stories could be switched to Star Trek and I suggest the reason that hasn’t happened is not the copyright fees, but the technical details…
James T. Kirk or Jean-Luc Picard need only to say “Set course…” or “Make it so…” because the writers want the audience not to concentrate on details they couldn't possibly understand because basically, those "details" are nonsense.
Horatio Hornblower or Richard Sharpe need to explain what’s required not only to their men but also to their readers because the technicalities will seem strange… who doesn't see the difference?
In Moby Dick every reader has and in Star Trek almost no-one has an opportunity to study the technicalities.
What’s vitally interesting to one reader is boring to another and why would the other finish reading the work, including you?
Had excellent literature professor who reasoned that the technical sections gave the reader the option of exhaling following the intense pressure of Melville’s narrative. The reader could choose to read as much or little as deemed necessary.
