If you ever wondered what “Jaws” would have been like had it been directed by Ron Howard instead of Steven Spielberg, this adaptation of Nathaniel Philbrick’s 2000 book provides something of an answer: it would have been handsomely mounted and shot but ponderously earnest, dramatically inert and remarkably dull.

“In the Heart of the Sea” is about a whaling voyage out of Nantucket in the early 1920s that ended in disaster when the ship, the Essex, was sunk by a whale the crew attempted to harpoon in the middle of the South Pacific. The sailors not killed in the initial encounter took to three small boats, but only eight of them survived the brutal three-month ordeal across the huge expanse of ocean they had to navigate to safety—and then only by resorting to a decision regarding their dead comrades that would appall polite society.

This story was previously told on screen in a 2013 BBC TV movie “The Whale,” where it was presented as the recollection of Tom Nickerson, a cabin boy on the ship. Here, employing a script by Charles Leavitt, Howard frames it as a long flashback related some three decades later, in a completely imaginary scene, by Nickerson (Brendan Gleeson), a reclusive drunkard, to Herman Melville (Ben Whishaw), who would use the material as inspiration for his masterpiece “Moby Dick.” The historical Nickerson had in fact served on the Essex as a teen (played in the flashback by Tom Holland) but in this telling he had been unwilling to discuss the experience at all until approached—with a wad of cash—by Melville. (In reality he penned an account of it, though not until 1876, as also did the ship’s first mate Owen Chase much earlier—the work that was in fact used by Melville. But whatever the source by which Melville was inspired, Howard’s reimagining of it is distinctly uninspired.)

As Leavitt constructs the tale, it begins as something that could turn into an American variant of “Mutiny on the Bounty,” though with a class reversal. Chase (Chris Hemsworth) is an experienced seaman of low station who has been promised a captaincy. But instead he’s offered the position of first mate on the Essex, serving under a greenhorn captain, George Pollard (Benjamin Walker), who’s gotten the call on the basis of his distinguished family’s long history of maritime service. The two men don’t hit it off, and Pollard’s attempt to demonstrate his authority by recklessly sailing the vessel into a storm—with near catastrophic results—poisons their relationship further, despite the efforts of second mate Matthew Joy (Cillian Murphy) to calm the waters, so to speak. Meanwhile Nickerson clearly comes to idolize Chase for his brawny expertise, even if he forces the boy to overcome his seasickness by threatening to toss him overboard and later orders him to crawl down into the malodorous blow-hole of the first whale they kill to extract the last remnants of precious oil from it.

Unfortunately, that’s the sole whale they encounter until they reach a port in Ecuador, where a Spanish captain tells them of a spot far into the Pacific where there are a great many to be found; but it’s a thousand leagues away, and the creatures are protected by a “devil” white whale that capsized his ship. The one thing that Pollard and Chase share is the ambition to fill their cargo holds and sail home, and so they proceed to that distant, dangerous place, only to encounter the precursor of Melville’s Moby.

And in this telling the whale is just as determined as Bruce the Shark was in Spielberg’s movie. Not only does it methodically destroy the Essex, but it pursues the three little whaling boats the crew are forced to use for their escape (a completely invented addendum to the record). The men do stop briefly at a small uninhabited island, but shortly set out again and will not be rescued until some three months after the loss of their ship; Howard spends much of the latter portion of the film on their ordeal, in which some perish while the remaining men grow increasingly weak and emaciated. He adds a postscript dealing with the survivors’ return to Nantucket, where the bigwigs in charge of the whaling operations try to suppress word of how the Essex was destroyed, afraid that the truth will undermine their business interests; that’s presumably designed as a slap at the present-day oil industry, which (as alluded to in old Nickerson’s final comment, will eventually supplant the use of whale oil.

This is an old-fashioned seafaring story that frankly seems rather out of place in today’s cinematic landscape, particularly since it’s told so lethargically. Howard tries to ramp up the energy level in some of the action scenes—and the crew’s first encounter with a whale is staged fairly excitingly, with no little emphasis on the brutality of the process befitting today’s anti-whaling attitudes. But frankly the encounter with the Great White Whale and the sinking of the Essex don’t possess the punch they need; the combination of live action and CGI work is decently handled, and Howard, cinematographer Anthony Dod Mantle and editors Mike Hill and Dan Hanley work hard to invest them with visceral power—but to no avail. The movie seems to flounder as badly as the damaged ship does, and the prolonged voyage back to civilization is taxing for the audience as well as the stranded sailors.

That’s largely because the cast never manage to give the characters much personality, to a great extent because Leavitt’s dialogue is so stilted. Hemsworth strikes the right strutting he-man poses, but hardly comes across as authentically nineteenth-century, while Walker can do little with the part of Pollard, who remains until a turnabout at the end an arrogant, elitist prig. (Not even an emotional scene toward the close involving Frank Dillane as his cousin—which, one should note, has been altered from the record for heightened dramatic effect—works especially well.) The scenes between Gleeson and Whishaw, to whom the picture returns periodically, are even clumsier, with lines that are occasionally unintentionally risible.

And then there’s young Holland, who here undergoes his second unfortunate encounter with the sea after his run-in with a tsunami in 2012’s “The Impossible.” He’s an agreeable lad and fine here, even if the material doesn’t offer him nearly the opportunity to shine that the earlier film did; one can look forward to him assuming the role of Peter Parker. But despite Howard’s effort to make the destructive whale a frightening creature, the scariest thing about “In the Heart of the Sea” is probably the notion that this handsome young man is supposed, in thirty years, to turn into Brendan Gleeson.