IT'S BEING DESCRIBED as Jaws meets The Blair Witch Project - and those sharks you see circling and bumping into the actors as they try to stay afloat are real. Little wonder there were more than a few moments of panic. 'I never got used to being in the water with all those sharks,' says Blanchard Ryan, who plays a strong-willed adventure tourist who becomes stranded at sea. 'There were moments when I was completely terrified. I remember I was so scared I cried for two days solid at one point.' Open Water, which was made by Chris Kentis and Laura Lau for a mere US$130,000, is certainly an effective thriller, despite some technical shortcomings. Inspired by a true story, the film takes every water-borne tourist's biggest nightmare and spins it into a taut 79-minute story. It starts with yuppie Susan (Ryan) and her boyfriend Daniel (Daniel Travis) taking a scuba-diving trip on a small boat. When they surface, the boat has left without them. As night falls, fear sets in - and a number of uninvited guests turn up. The story is tight, and the actors work hard to make their floating conversations credible. But the film's main attraction is those real-life sharks, even if they take up a minimum of screen time. The reason for using real sharks was simple: they work cheap. Given their small budget, Lau and Kentis decided they couldn't afford to use model sharks. And anyway, they say, they were bored with computer-generated monsters onscreen. So, they headed for the Bahamas, where a company that specialises in sharks kept the actors safe by diverting the killers with chunks of raw tuna. That's not to say it wasn't dangerous - but the danger was part of the attraction for Travis. He says he couldn't wait to jump in and mix it with the sharks. Ryan wasn't as enthusiastic 'As soon as I saw those sharks, I just went white,' she says. 'I was quite happy for him to jump in first and do some scenes on his own. I thought, hmm, those are real sharks. Let's just see how it all goes for a bit. I figured if someone was going to be eaten, I'd prefer it to be him than me.' But the pair were well prepared - and protected - for their encounter, Travis says. 'We took a full orientation course with the shark handlers to find out what movements were safe to make in the water,' he says. 'We took every safety precaution we could. You shouldn't splash or make jerky movements, for instance. It's actually best not to move at all.' As well, they wore light chain mail suits under their diving outfits. Which didn't seem like much comfort to Ryan, since they weren't separated from the sharks by nets or cages. 'She kept complaining I was kicking her,' says Travis, with a laugh. 'This went on for ages. She was, like, 'Can't you keep your big feet to yourself?' Then I got up on the boat, and the kicking didn't stop. So she figured out the awful truth: it was the sharks bashing into her, not my feet!' Kentis and Lau took just as many risks as the actors - if not more. 'Chris never asked us to do anything he wasn't doing himself,' says Travis. 'He was in the water with us, shooting. Plus, he didn't wear the chain mail because he had this big camera to lug about. That kept our whining to a minimum.' The film was inspired by - but not based on - the story of two American divers who disappeared during a tour off the Australian coast in 1998. At first, it was thought they'd somehow been left behind. Then, stories began circulating that they may have faked their own deaths, or even committed suicide together. However, Open Water focuses on the emotions of the couple, rather than clever plot twists. Much of the time, the filmmakers used the actors' real reactions. 'Chris and Laura just put us there and said, 'What would you do?'' says Travis. 'Then they filmed it.' That personal approach is the real strength of the film. Watching the two divers try to deal with their situation, viewers can't help but wonder how they'd deal with it themselves - and whether they'd be able to cope. 'Everybody reacts differently,' says Ryan. 'It's like the Titanic - try to put yourself on the deck of the Titanic when it was going down. Would you be the one pushing five-year-old children out the way to get on the lifeboat? Or would you be selflessly helping old ladies? You can think that you'd be all strong and noble in the situation, but until it happens, you just don't know. We decided we'd just see what came naturally to us. It was important to see how we'd react - and the audience likes to think about how they'd do it, too.' The film inadvertently raises questions about the safety of adventure holidays. Travis says dive companies have become more safety conscious during the past few years. GPS transmitters can be fitted inside wet suits, and inflatable markers allow stranded divers to be spotted at sea. But accidents still happen. Recently, a diver was stranded at sea in a similar incident off the US coast. He was saved by a passing boat-load of boy scouts. 'I think that the buzz about adventure holidays has made us lose touch with the fact that there's danger involved,' says Travis. 'The danger has simply become part of the excitement.' Especially as far as Open Water is concerned. Open Water opens on September 16.