Sanctum: Depths of despair

Achieving the claustrophobic atmosphere of Sanctum involved shooting in often challenging environments. Photo / Supplied

As the director of 3D cave diving thriller Sanctum, Alister Grierson had some pretty big flippers to fill.

After all, read the movie's poster and the one name that pops out is that of one James Cameron. He's the Australian-American film's executive producer.

Cameron also knows a thing or two about making movies involving large amounts of water (The Abyss, Titantic various deep sea docos, and not to forget his first feature, 1981's Piranha 2) and putting his actors through the wringer.

"You don't want to kill your actors is the mantra," laughs Grierson echoing the reputation of his mentor. "At least until the final day of the shoot ..."

The other big flippers Grierson had to fill were those of Sanctum producer Andrew Wright. The Australian diver-adventurer worked with Cameron on his undersea docos Ghosts of the Abyss, Expedition: Bismarck and Aliens of the Deep.

The premise for Sanctum - a team of cave divers trapped as flash floodwaters pour in from above - came from one of Wright's early experiences while exploring caverns 3km below South Australia's Nullarbor Plain in 1989 and which Wright recounted in his documentary Nullarbor Dreaming.

Here, that has become a story about a team, led by master diver Frank McGuire (Richard Roxburgh) and including his son (Home and Away alumni Rhys Wakefield) and their dubious expedition boss (Ioan Gruffudd), finding the only way out of the flooding cave system is an uncharted tunnel to the sea. Not all of them make it out in one piece.

Which brings us to the other big webbed footprints Sanctum is following. Grierson says though the film may use state of the art Cameron-developed underwater 3D camera technology, its story harks back to 70s big screen survival tales. Just without the banjos or the upside down cruise ships ...

"What we tried to do is hark back to those great 70s kind of survival movies, everything from The Poseidon Adventure to whatever. The idea that you focus on a group of people in extreme circumstances who have to survive and what happens within the group in that kind of environment.

"Deliverance was a big model for us in terms of man versus nature. It's an old-fashioned genre in a lot of ways."

And at an old-fashioned budget too. Sanctum was made for an estimated modest amount of US$30 million ($39.6 million).

Though set in the fictitious Esa'ala caves in the Papua New Guinea highlands, it was shot mostly in Queensland - with local rainforests doubling for the Avatar-like jungles of its northern neighbour - and in the huge heated tanks at the Village Roadshow Studios on the Gold Coast.

Grierson's previous feature, the acclaimed World War II drama Kokoda, about the legendary efforts of outnumbered Aussie troops to hold off the Japanese, was also set in New Guinea.

Sanctum not only shares a (pretend) geography with Kokoda but a tense sense of claustrophobia, enhanced by the 3D. Having got the gig, Grierson spent a week with Cameron on the Wellington set of Avatar boning up on how he might best shoot the film, often below the surface and in tight confines.

"Jim's philosophy with 3D is different to most in a sense that he likes subtle 3D - he doesn't want to exploit it in a sense of throwing things at the audience all the time. When you are in a cinema and experiencing the 3D it is an illusion your own mind creates and you are looking into a window of a new world. So we grabbed that philosophy and ran with it.

"I think that really does enhance that experience of being in the cave, there is no doubt about it.

Grierson's describes Cameron as a "arm's length mentor" on his film - Sanctum started shooting a month out from Avatar's release so he was otherwise occupied anyway. He visited the Gold Coast set on the final week of underwater scenes. "We could basically send various versions of the cut to him for his feedback and I would travel to LA and have meetings with him. He was very, very supportive and very creative. It was great having an executive producer who is a director. He understood very much what my problems were and issues about storytelling stuff".

Cameron would have also known not only the challenges of shooting in a very big tank, but lighting an environment where the only light source is supposedly carried by the divers. Which means, says Grierson, getting some scenes on film would require a strange underwater ballet. "Those shots you see - even if it is just a close up of an actor in a squeeze there are probably about 30 people around them making that happen - you've got doubles, stunt co-ordinators, special effects guys, camera operators, electrics guys and safety supervisors and you're in there in the water with the actor.

"The trickiest one was trying to do a tracking shot through water - you've got this bizarre dance of 15 people on the soundstage all trying to stay out of shot and because they are charging through water, you have a safety guy to stop them from drowning because the stage is fully rigged with electrical equipment and if you tripped over you would go under."

Grierson says no actors were drowned in the making of his movie, though a few haven't forgiven him for how many hours he made them stay in their clammy wetsuits. And though there were a few minor injuries, the biggest dent was to his own pride when he found that despite being the director, he couldn't actually walk on water.

"I am the only one who made an idiot of himself. One day I was walking along explaining how the shot was going to work and literally stepped into this 2m pit. And by all accounts the only thing that was left was my baseball cap floating on the surface of the water".

LOWDOWN

Who: Alister Grierson, director of Sanctum
Where and when: In cinemas today.

-TimeOut