Hollywood director James Cameron's sub reaches deepest point of the ocean

Hollywood director James Cameron has completed his journey to the deepest point of the ocean.

The director of Titanic, Avatar and other films used a specially designed submarine to dive nearly seven miles.

He spent time exploring and filming the Mariana Trench, about 200 miles south west of the Pacific island of Guam, according to members of the National Geographic expedition.

Cameron returned to the surface of the Pacific Ocean this morning, according to Stephanie Montgomery of the National Geographic Society.

He spent a little more than three hours under water after reaching a depth of 35,756 feet (10,898 metres) before he began his return to the surface, according to information provided by the expedition team.

He had planned to spend up to six hours on the sea floor.

Cameron's return aboard his 12-tonne, lime-green sub called Deepsea Challenger was a “faster-than-expected 70-minute ascent”, according to National Geographic.

There were no immediate reports regarding Cameron's well-being. A medical team was present when Cameron, 57, emerged from the sub, according to the expedition.

Expedition physician Joe MacInnis told National Geographic News before the journey that recent test dives, including one that went more than five miles deep, had gone well and that he expected Cameron would be fine.

“Jim is going to be a little bit stiff and sore from the cramped position, but he's in really good shape for his age, so I don't expect any problems at all,” said Dr MacInnis, a long-time Cameron friend, according to National Geographic.

The scale of the trench is hard to grasp - it is 120 times larger than the Grand Canyon and more than a mile deeper than Mount Everest is tall.

“It's really the first time that human eyes have had an opportunity to gaze upon what is a very alien landscape,” said Terry Garcia, the National Geographic Society's executive VP for mission programmes, via phone from Scotland.

Swiss engineer Jacques Piccard and Don Walsh, a US Navy captain, are the only others to reach the spot.

They spent about 20 minutes there during their 1960 dive but could not see much after their sub kicked up sand from the sea floor.

One of the risks of a dive so deep was extreme water pressure. At 6.8 miles below the surface, the pressure is the equivalent of three SUVs sitting on your toe.

Cameron said in an interview after a 5.1 mile-deep practice run near Papua New Guinea earlier this month that the pressure “is in the back of your mind”.

The submarine would implode in an instant if it leaked, he said.

But while he was a little apprehensive beforehand, he was not scared or nervous while underwater.

“When you are actually on the dive you have to trust the engineering was done right,” he said.

The film director has been an oceanography enthusiast since childhood and has made 72 deep-sea submersible dives.

Thirty-three of those dives have been to the wreckage of the Titanic, the subject of his 1997 hit film, which is being released in a 3-D version next month.

AP