TORONTO -- If you think directing a movie is hard, try doing it while you're swimming the backstroke.

That's how it went for Baltasar Kormakur, who shot his new Icelandic survival picture "The Deep" while he was on, and sometimes in, the water.

"I wanted to get shots looking at the actor head-on, and if you're in the boat you're looking down on him," Kormakur said during an interview at the Toronto International Film Festival, where his movie premiered. "So I got into the water with the camera and started doing the backstroke. I had to tie myself to him with a rope so he would stay in the frame."

That Ryan Lochte moment was hardly the only ocean-bound or other dangerous outdoor act that Kormakur -- best-known in the U.S. for Mark Wahlberg thriller "Contraband" -- undertook for the sake of his new Icelandic-language movie, which tells the true story of the lone survivor of a fishing-boat accident off the coast of Iceland's Westman Islands in 1984.

Kormakur also found himself swimming through crashing waves to rescue said actor (Olafur Darri Olafsson, playing the hero Gulli) after Olafsson got stranded on the rocks.

The director bought a boat with his own money because he had to sink it and, well, no one wants to lease you a boat you plan on sinking.

And he commissioned a helicopter pilot to fly him over the top of a volcano, getting as close as possible to the mouth so he could shoot into it.

"When the helicopter really started shaking," Kormakur said, making a trembling motion with his hands, "we knew we probably should fly out of there." (Insurance requirements on film productions, apparently, are more lax in Iceland.)

Kormakur didn't set out to become an extreme-sports auteur. But in crafting his tale of existential survival he wanted to avoid the artifice of many Hollywood movies in similar settings. So he said no to water tanks and green screens, and yes to putting on swimming trunks and doing the backstroke.

The real-world conditions also made for some uncertainty about the shooting schedule. A movie like "The Deep" needs a steady series of massive waves. And those are, well, kind of unpredictable. Kormakur became very acquainted with nautical weather reports.

The director was motivated to make “The Deep” because the Westman incident is an iconic moment in his country’s history -- everyone over the age of 35 remembers it -- and ran counter to the usual assumptions about heroism.  "Here was a guy who would not seem like a hero and didn't want to be one -- he was a little overweight, he was drunk a lot, he didn't seem to be the one who would survive." (The second half of the movie explores the human consequences of that survival as Gulli returns to shore.)

Even Kormakur's land-bound efforts were fraught. To research the film he wanted to interview many of the people familiar with the story. But that group included families of the victims, some of whom were resentful at Gulli for surviving and all of whom still carried around some grief (think Paul Greengrass making "United 93").

Kormakur has a rugged thoughtfulness -- with his salt-and-pepper beard, he looks like Viggo Mortensen if Mortensen were a sea captain -- and appreciates the kind of wisdom that comes from grappling with the outdoors. He spends two weeks every summer leading a small group of friends into the Icelandic wilderness with little but horses and some basic supplies to keep them company.

"What makes me really excited is when it's just you and the elements, and no one packed sandwiches and you can’t go home to Mommy and you just have to deal with the loneliness," he said, Icelandically.

Kormakur has had a strange career even by international-director standards.

Coming from a nation of barely 300,000 people, he started out making offbeat slacker comedies like the indie darling "101 Reykjavik." He branched out to thrillers with well-regarded foreign-language pieces like "Jar City." Then he made the jump to Hollywood, as he helmed the Central American drug thriller  "Contraband" and was signed by the same manager who represents Oscar-winner Mark Boal.

Kormakur said he wants to continue pursuing a career in the North Atlantic as well as in Hollywood. He just finished shooting "2 Guns," a crime thriller with Wahlberg and Denzel Washington, which he will edit as "The Deep" rolls out around the world. "The Deep" is seeking distribution in the U.S.; despite the unfamiliarity of the tale, agents hope the survival story and the spectacle will be a selling point.

Kormakur, meanwhile, said he feels there’s a universality to his story. “It’s about what makes someone survive when there’s no reason he should. I can't imagine anyt