Dimension Films has acquired N.A. rights to 47 Meters Down, a thriller set at the bottom of the ocean about two sisters trapped in an undersea observation cage who must survive a dwindling oxygen supply and the hungry great whites circling nearby. The contained two-hander is being touted as “Gravity, but underwater.” Copy that. Pic will be directed by Johannes Roberts (Storage 24) with Mark Lane and James Harris producing for their The Tea Shop and Film Company. Dimension’s Matthew Signer, Keith Levine, and Robert Walak are overseeing for the studio. Roberts is repped by WME. Walak and Michal Steinberg negotiated the deal with Altitude Film Sales’ Mike Runagall on behalf of the filmmakers. Altitude is repping worldwide sales.