Sub's carbon-fiber composite hull was the 'critical failure,' James Cameron says

Renowned Hollywood director and Titanic researcher James Cameron said he believes the carbon-fiber composite construction of the submersible's hull was the "critical failure" that led to its implosion during a deep-sea tour of the Titanic wreckage.

"You don't use composites for vessels that are seeing external pressure. They're great for internal pressure vessels like scuba tanks, for example, but they're terrible for external pressure," Cameron, who famously directed the Oscar-winning film "Titanic," told ABC News' George Stephanopoulos in an interview Friday on "Good Morning America."

"This was trying to apply aviation thinking to a deep-submergence engineering problem. We all said that it was, you know, a flawed idea and they didn't go through certification," he continued. "I think that was a critical failure.

"The thing that's insidious here," Cameron added, is the way these materials "fail at pressure."

SEE ALSO: Titanic submersible: Underwater cinematographer says excursion was 'disaster waiting to happen'

Experienced underwater cinematographer Al Giddings who also worked on the film "Titanic," says the sub excursion was a "disaster waiting to happen."

"They fail over time, each dive adds more and more microscopic damage," he said. "So, yes, they operated the sub safely at Titanic last year and the year before, but it was only a matter of time before it caught up with them."

OceanGate CEO Stockton Rush, who was among the five crew members killed on the submersible, had previously defended the decision to manufacture the Titan with the material, saying he believed a sub made with carbon fiber would have a better strength-to-buoyancy ratio than titanium.

Bob Ballard, the oceanographer and explorer who discovered the Titanic wreckage in 1985, told ABC News that he expects the investigation into what happened "will go on for quite some time."

"There will be now a very systematic survey. I've done this before," he said during the interview Friday morning. "The (remotely operated vehicles) are going to do a very, very precise, systematic mapping that will collect the photography and high-definition imagery and they'll also be recovering the objects."

SEE ALSO: Missing Titanic sub experiences 'catastrophic implosion.' Here's what may have happened

Coast Guard officials said the tail cone and other pieces of the missing submersible Titan were found about 1,600 feet from the wreckage of the Titanic on the sea floor.