Earlier this year, I wrote about Touching the Void and mentioned a similarity it held to Gerry, the movie about two people lost in a desert. Now I've watched Open Water, which is perhaps more like Gerry, because it's about two people lost at sea, in the middle of an ocean, without a boat.

But there is a difference in the similarities between each of the two films to Gerry. Touching the Void is about a man trying so hard to survive an ordeal that it becomes instinctive -- he fights to live without even being conscious about it. Eventually, this happens in Gerry, when the two characters have stopped believing their walk in the sands might just be a walk in the park. Before that point, though, they are somewhat nonchalant about their chances of finding a way out, as if they're taking for granted the inevitability of eventually returning to their normal lives. In Open Water, the two protagonists, a vacationing couple, never progress from that mindset.

It is director Chris Kentis's intention to use the couple, Susan (Blanchard Ryan) and Daniel (Daniel Travis), as an example of the complacency of the civilized being. Showing how ill-prepared the technology-dependent pair are for being stuck in the water (after their boat leaves them when the crew miscalculates the number of tourists who have returned from diving) is fairly easy game. What's more fascinating is the extra step the movie takes to show how the couple is too shiftless and wrongheaded even to try and survive. Relatively early in their time being stranded, the two spot several boats and give up trying to swim toward them after being deterred by the strong current. Instead, they opt to believe a boat will head their way sooner or later.

The most revealing line may be Daniel's nervous utterance about their having a story to tell for years to come. We live in a world so insulated by the modern comforts that we think, by default, everything will be all right in the end. In our societies, that may well be true. But Open Water makes a case for how dangerously ingrained this kind of thinking really is.

However, while the movie provides an opportunity to reflect on this point, it doesn't spend all or even most of its time honing it, and unfortunately the rest of the movie can't find a subject or situation to match it in our thoughts. Most of the movie feels like a low-budget distraction -- part exploitative horror flick, part mundane drama about how good relationships are hurt by pettiness. The early scenes feature Ryan and Travis as a couple who are happily used to each other but may no longer be on the same page. And while this may help in fleshing out the complacency theme, it isn't explored deeply enough (Kentis assumes incorrectly that we can see the depths of the relationship cracks) nor convincingly played. Ryan and Travis only turn in functional performances, and when their line readings are shot in the digital video the director employs, everything feels like a low-grade made-for-cable movie. Some of what's staged helps keep it afloat, though -- for instance, the film uses nudity in a manner more honestly than in any other movie I can remember, to show a couple that behaves realistically and isn't conscious about propriety in front of an invisible movie camera -- so I did have to give it credit for effort.

The two individuals are more effective once they're in the water, but when they're not panicking about jellyfish and sharks (and they did use real sharks!), the movie doesn't know how to fill the minutes. Susan and Daniel have fights and make up, and once in a while Kentis uselessly reminds us how life is continuing unobstructed back at the beach. The film literally treads water for many moments, but it does benefit by reaping the mounting dread it had sown during the daylight hours -- the approaching night may be the scariest element to make an appearance. And though a nighttime ocean would have been greatly enhanced by being shot on film, the mere suggestion of the impending predicament itself is enough to send a viewer visceral chills. After it's all over, the images may haunt you as you give consideration to how complacent you might have been in that very situation.

(Released by Lions Gate Films and rated "R" for language and some nudity.)

Review also posted on www.windowtothemovies.com.