This past week off the Jersey Shore, a humpback whale surfaced to nudge a fishing boat, apparently in a playful way.

In "In the Heart of the Sea," the nudge is not so playful.

Ron Howard's old-fashioned men-at-sea movie tells the apparently true story of a leviathan that rammed and sank a whaling vessel called the Essex in 1820, an incident that inspired Herman Melville to write Moby Dick.

Just to be clear: Howard isn't retelling Melville's story here, as some have implied. He's presenting the story of the Essex as you-are-there history, making use of modern effects to bring the bizarre episode to life.

It's a man-versus-nature yarn that commences as a power struggle between men - Owen Chase (Chris Hemsworth), the experienced and capable first mate, and George Pollard (Benjamin Walker), the green and insecure captain.

In one early scene, a petulant Pollard overrides the advice of Chase and steers into a storm instead of around it. This gives Howard a chance to stage a nicely shot and edited sequence (the first of several) - straining sails, scalding ropes, shattered masts, men sliding across slippery decks.

He saves his best work for the moment when the men encounter a pod of whales, setting out in rowboats, isolating and killing a whale with harpoons.

It's shrewd filmmaking - Howard understands he's showing these grisly images to a modern audience that will recoil, but he also manages to convey the justifiable excitement these men must have felt to accomplish a job so dangerous.

And so essential. They are working in an industry necessary to the American way of life at the time - whale oil helped light the nation's lamps.

Parallels to our present day energy/environmental issues are entirely intentional - men chasing reserves that are increasingly hard to find and extract. Dangerously so. One day "Heart of the Sea" will make an interesting double feature with Peter Berg's "Deepwater Horizon," the oil rig disaster movie set to arrive next year.

Both are sadly familiar stories of expendable men (and in this case, some children) doing dangerous work. When the Essex is sunk - another exciting sequence - the survivors endure many months at sea, and "Heart" becomes a gruesome ordeal of survival.

This gives the movie a curious rhythm - a bracing seafaring adventure slows to a windless crawl - but it does honor the reality of the crew's horrific ordeal (think Donner party).

"In the Heart of the Sea" reunites Howard with Hemsworth, who did some of his best work for the director in "Rush." This role suits the strapping Aussie actor, whose Thor-sized chest plausibly fills out his sailor's blouse.

Not all contemporary actors travel back in time, but Hemsworth does. So does Howard, whose story of courageous, resourceful men fighting to return home plays like a waterborne "Apollo 13."