Watch any surfing documentary, from “Whipped!” to “Riding Giants,” and you’ll hear the dudes speak — in hushed tones — about the treacherous and epic waves that show up off the coast of Northern California when the conditions are just right.

The Mavericks break is legendary, and for years was considered some sort of myth by those who surfed and had never seen it.

“Chasing Mavericks” is about the days when that break was acknowledged as real, and the teenager — Jay Moriarity — who became famous there.

Jonny Weston is Jay, a curly-headed blond who has gotten the surfing bug from his somewhat standoffish neighbor, Frosty. The older surfer, played by Gerard Butler at his most gruffly charming, has a job — roofing — a gorgeous wife (Abigail Spencer) and a growing family. But his passion is surfing. All flowing locks, a regular Adonis-on-a-long-board, Frosty is one of the “children of the tides,” he poetically narrates. And his secret is Mavericks.

In a brief prologue, we learn of Jay’s working-poor background — his alcoholic, semi-employed divorced mom (Elisabeth Shue) and his absent father. Cooper Timberline plays the 8-year old Jay, who tapes together a busted board, braves bullies and gets his nose bloodied by the surf. But he sticks with it to become the best surfer kid on the block by the time he’s 15.

He lionizes Frosty and stows away on the guy’s ancient Ford Econoline van when Frosty sneaks off to Mavericks, of which only a quartet of veteran surfers are aware. They know what the conditions are and are skilled enough to handle waves as high “as five-story buildings, a thousand tons of water pounding you, holding you down.”

Those are Frosty’s warnings to the boy. But when his wife points out that “there are all kinds of sons,” Frosty mentors the kid — trains him for that magical three-month window when conditions make Mavericks an epic ride.

The dynamic here is that Jay is the more grown up of the two. He’s keeping his lonely, depressed mother afloat and employed. Frosty is missing his daughter’s childhood, ditching work, lying to the wife to surf.

Jay’s high school years are as tough as anybody’s — part-time pizza joint job, a surfing pal (Devin Crittenden) who is dabbling in drugs, bullies in and out of the water, an older teen girl (Leven Rambin) he has worshiped since childhood, but who seems embarrassed by his attentions now. With kids sneaking into beach clubs after hours, breaking into backyards to skateboard in the empty pools of the rich folk, the film gives a PG, edges-rubbed-off taste of surfing/ skateboarding culture of the era.

“Chasing Mavericks” tends toward the cute, as Jay’s guru, his sensei, makes him practice holding his breath for four minutes, makes him ride a paddleboard 36 miles across Half Moon Bay, takes him on dives to explore the deadly reef that causes the wave break and assigns him essays on “the power of observation.”

But the mentor-student relationship works. The sense of a time and place is very strong. And the surfing footage is awe-inspiring. The film captures the majesty and violence of the big waves and gives us a taste of their allure.

Built with “Soul Surfer” in mind, the film’s emotional punches are saved for the third act, and it never really sells its “Live Like Jay” — on the edge and for each moment — ethos. It’s a bit overlong, for the limited scope of the story and narrow vision of the characters. That’s probably due to initial director Curtis Hanson getting ill and being replaced by the equally accomplished Michael Apted in the last chunk of the shooting. Either one, on his own, might have ensured those issues were addressed.

But “Chasing Mavericks” is still an entertaining dip into a world many talk about but few have ever sampled firsthand.