Recounting the basic plot of “47 Meters Down” doesn’t do the film many favors, since any detailed synopsis likely will make it sound like one of those cheesy “Jaws” knock-offs that served as drive-in fodder in the 1970s. Indeed, it’s ridiculously easy to imagine the sort of breathless taglines and lurid poster art that might have been used decades ago to hard-sell this scenario about two vacationing sisters who are stranded in a shark-cage way below the waves while hungry Great Whites loom large all around them. (“Lynn Lowry and Claudia Jennings are … ‘Shark Bait!’”) But credit must be given where it is due: Director Johannes Roberts’ mostly underwater thriller is a compact and sturdily crafted B-movie that generates enough scares and suspense to qualify as — well, maybe not a pleasant surprise, but a reasonably entertaining one.
Mandy Moore and Claire Holt star as two attractive sisters who try hard to enjoy themselves during a Mexico holiday that Lisa, Moore’s character, had originally planned to share with her boyfriend. Shortly before the departure date, however, the lout dumped her for being too “boring” — which, truth to tell, Lisa fears she actually may be, especially when compared to Katie (Holt), her more worldly and adventurous sibling.
Dead set on bringing a little excitement into Lisa’s life, Katie goes overboard, literally as well as figuratively, by more or less browbeating her sister into joining her and two hunky locals (Yani Gellman, Santiago Segura) for a shark-diving expedition aboard the Sea Esta, a boat skippered by a salty dog portrayed by a credibly seasoned Matthew Modine.
As soon as she sees the ramshackle condition of the Sea Esta, Lisa has second thoughts — and, once on board, third and fourth thoughts — about sightseeing below sea level. But after she and Katie are outfitted in scuba gear and lowered into the water inside a protective cage, her trepidation gives way to exhilaration. (An amusing touch: After donning her wetsuit, the insecure Lisa asks Katie: “Does my butt at least look cute in this?”) Both sisters are thrilled to see sharks swimming all around them, and take great delight in what obviously is a bonding experience.
And then, of course, something goes terribly wrong: The crane used to lower the cage snaps from the boat, and the sisters plummet — yes, you guessed it! — 47 meters down, to the bottom of the ocean. With limited air supplies. And sharks, lots of sharks, hovering nearby.
Working from a serviceably schematic screenplay he co-wrote with Ernest Riera, Roberts efficiently establishes the rules of the game early in his movie: Each of the sisters has only an hour’s worth of air in her tank. They can talk to each other because their masks are rigged with microphones and speakers — but, because they’re down so deep, it’s difficult to communicate with people on the boat above them. Even if the sharks temporarily leave the vicinity, Katie and Lisa would have to swim to the surface very, very slowly, lest they suffer a fatal case of the bends. Trouble is, such a measured ascent would leave them in a vulnerable position if the sharks changed their minds and returned for a snack or two.
Most of the underwater scenes were shot — extremely well, by DP Mark Silk — inside a massive tank at the Underwater Studio in Basildon, England. (Something like an hour of this 89-minute feature is supposed to take place in the dark depths of the ocean.) And the sharks, while adequately menacing as they sporadically appear from out of nowhere, are CG contrivances. But everything looks and sounds more than believable enough to encourage a willing suspension of disbelief, even during a few scenes that, dramatically speaking, strain credibility.
Moore and Holt comes across as sympathetic and resourceful as their characters register varying degrees of stark terror, desperate determination and teary optimism. They bring impressive conviction to the sometimes bluntly simplistic dialogue (“The shark almost got me!” Oh, really?) and help the movie pass the Bechdel Test with flying colors. Except for a brief scene in which they talk about Lisa’s ex-boyfriend, the two women have many conversations that have nothing to do with men, and everything to do with survival, once they’re alone together 47 meters down.