Since the cinematic oeuvre of Troy Donahue is mostly forgotten to everyone besides camp aficionados of a certain age, it’s unlikely that the target demographic of “Charlie St. Cloud” will sense the shadow of Troy over almost every frame of this would-be tearjerker, which seems clearly designed to vault Zac Efron into non-franchise leading-man territory.

But the shadow of Troy Bolton, the character that Efron played in the mega-successful “High School Musical” trilogy, looms just as much, since “Charlie St. Cloud” confirms that the toothy actor – who has proven to be quite proficient at musicals and light comedy – lacks the gravitas to play a young man haunted by loss and guilt.

Like the working-class characters so often played by Donahue – they were poor, but they had both integrity and great cheekbones – Efron’s Charlie is a proletarian townie in an upper-crust seaside town where sailing is everything. With his scruffy skiff and the assistance of his adoring kid brother Sammy (Charlie Tahan), Charlie becomes captain of the school sailing team and wins the annual regatta over his snotty opponents. (It perhaps represents some kind of non-traditional casting coup that the film’s one arrogant preppy a-hole is also the film’s one African-American character.)

Charlie’s prowess on the water has earned him a scholarship to Stanford, but on the night of his graduation, a drunk driver hits his car, killing both Charlie and Sam. Charlie is brought back to life by a presumably Catholic paramedic (Ray Liotta), while Sam isn’t so lucky. Consumed by guilt, Charlie runs away from Sam’s funeral to go to the woods, where he had promised to meet Sam every day at sunset that summer to throw around a baseball. Sam, having not crossed over to the other side, is there to meet him.

And he keeps that appointment every day for five years. Charlie defers his ambitions, retreats into private grief, works as a groundskeeper at the local cemetery, and becomes the dreamiest, most approachable town weirdo on Earth. When his high-school classmate Tess (Amanda Crew) returns to town, poised to compete in a solo round-the-world sailing race, Charlie flirts with the idea of returning to sailing and to the real world, although the pull of his rendezvous with Sam continues to tug at his conscience.

At this point, “Charlie St. Cloud” takes a plot turn so outlandish that it shouldn’t be spoiled in a movie review. Suffice it to say it involves Charlie’s ability to see and speak to the not-quite-dead. It will also prompt lots of tasteless jokes, but you can make your own once you’ve seen the movie.

Those looking for evidence on how casting can shape an entire film could certainly start here – had director Burr Steers (“Igby Goes Down,” “17 Again”) placed, say, Jesse Eisenberg or Michael Pitt or Joseph Gordon-Levitt in the title role, this could have been a brooding meditation on the inability to let go of a lost loved one. But “Charlie St. Cloud” couldn’t be sunnier – Efron’s Charlie never looks like he’s missed a day of shaving or moisturizing, and Enrique Chediak’s cinematography is bright and swoopy when sailboats are racing and gently autumnal in the forest scenes with Sam.
 
Perhaps no haunted, grieving character in the history of cinema has had his abs lingered over as much as Efron here – whether he’s getting wet (so that his shirt can cling to his chiseled body) or half-disrobing, the camera can’t get enough of him. Between “Charlie St. Cloud” and “The Twilight Saga: Eclipse,” it’s a big summer for fans of taut, hairless torsos. (The rest of us can amuse ourselves with the observation that Efron’s hair remains so casually bedhead-y, even when he’s soaking wet.)

If this review dwells more on Efron’s appearance than on his acting, it’s because the movie does, too. The final result of his performance suggests angst far less than it does a photo spread in the newly-revived A&F Quarterly.

The supporting cast doesn’t really pick up the slack, either: Amanda Crew (whose very name suggests casual separates for women) seems to have been cast for her blankness, so that every straight girl and gay boy in the audience can put themselves in her deck shoes when she’s clinching with Efron, and Tahan’s Sammy veers between cutesy and irritating. Liotta gets little to do besides a very on-the-nose “you survived for a reason” speech, and poor Kim Basinger has what amounts to a glorified walk-on as Charlie’s mom.

Zac Efron is young, and there’s certainly no reason why he can’t still blossom into the kind of actor who can handle all kinds of roles. For the time being, however, “Charlie St. Cloud” suggests he stick to quips and kick-ball-changes instead of dramatic heavy lifting.

"Charlie St. Cloud" opens nationwide Friday, July 30.

Alonso Duralde is a member of good standing in the Los Angeles Film Critics Association.  You can follow him on Twitter @Aduralde.