The tiny compartment that the film-maker sits in is made from thick steel, which is able to resist the 1, 000 atmospheres of pressure he experienced at full ocean depth.

BBC: James Cameron back on surface after deepest ocean dive

"I started to think about what would it take to go deeper, what would it take to go to full ocean depth - that was kind of the holy grail from an engineering standpoint, " he told BBC News.

BBC: James Cameron gets ready to dive to the Mariana Trench

The rig was aground in an area of Ocean Bay, where water depth is 32 feet to 48 feet.

CNN: STORY HIGHLIGHTS

But Maria Celina Rodrigues, the Brazilian consul in Paris, said the depth of the ocean would make it difficult for searchers.

BBC: Atlantic searched for lost plane

He also holds the world-record depth for a solo ocean dive in a submersible, at 3, 000 feet--"People think it's interesting there, but you're just sitting, " he says.

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The Thresher sank toward the ocean floor after losing power, until it imploded below crush depth into thousands of pieces.

WSJ: Work stalled on Thresher memorial park in Maine

Locating a ship resting on the floor of the ocean for many decades is somewhat different than finding a submersible to get to that depth and plugging many leaks in a riser pipe and in a blowout preventer.

WHITEHOUSE: Press Briefing