James Cameron reveals he knew Titanic sub imploded on Monday - raising questions over rescue secrecy

Cameron says he told colleagues in a mail on Monday that ‘we’ve lost some friends’

Hollywood filmmaker James Cameron said he received the information within 24 hours of the disappearance of the submersible Titan that it had imploded when it lost communication with its mothership.

"We got confirmation within an hour that there had been a loud bang at the same time that the sub comms were lost," Mr Cameron, who directed the 1997 movie Titanic, said.

"A loud bang on the hydrophone. Loss of transponder. Loss of comms. I knew what happened. The sub imploded," he said, adding that he told colleagues in an email on Monday, "We've lost some friends," and, "It's on the bottom in pieces right now”.

Follow the latest updates on the missing Titanic submarine here

The submersible carrying five people to the Titanic imploded near the site of the shipwreck and killed everyone on board, authorities said on Thursday. The Titan launched on Sunday around 8am EST and was reported overdue that afternoon about 435 miles south of St John’s, Newfoundland.

But after one hour and 45 minutes, the craft lost contact with its mothership, the Polar Prince.

Those on board were British billionaire Hamish Harding, Titanic expert Paul-Henri Nargeolet, Pakistan-born businessman Shahzada Dawood and his son Suleman Dawood, and OceanGate Expedition's chief executive Stockton Rush.

“This was a catastrophic implosion of the vessel,” said rear admiral John Mauger of the First Coast Guard District, adding that the bodies of the victims may never be recovered from the Atlantic.

The decorated director’s statement comes amid reports that secret US Navy underwater microphones detected the Titan sub’s implosion several days ago, but the information was released on Thursday.

The Navy used a top secret acoustic detection system to search for any sign of the OceanGate Expeditions submersible soon after it was reported missing on Sunday, a US defence official told The Wall Street Journal.

The Titan submersible (PA Media)

An implosion was heard near the site where debris was located on Thursday, about 500m from the Titanic shipwreck, soon after the sub disappeared, according to the report.

Mr Cameron, who has made over 30 dives to the Titanic wreckage, said he wishes he had sounded the alarm earlier about the submersible.

He became a deep-sea explorer in the 1990s while researching for his Oscar-winning film Titanic and is part owner of Triton Submarines, which makes submersibles for research and tourism.

When he heard that OceanGate was making a deep-sea submersible with a composite carbon fiber and titanium hull, Mr Cameron said he was skeptical.

From left, Shahzada Dawood, Suleman Dawood, Paul-Henry Nargeolet, Stockton Rush, and Hamish Harding

“I thought it was a horrible idea. I wish I’d spoken up, but I assumed somebody was smarter than me, you know, because I never experimented with that technology, but it just sounded bad on its face,” Cameron told Reuters.

Although the cause of the implosion has not been determined, Mr Cameron presumes the critics were correct in warning that a carbon fiber and titanium hull would enable delamination and microscopic water ingress, leading to progressive failure over time.

OceanGate Expeditions, the company that owned and operated the submersible, said in a statement that all five people in the vessel, including the CEO, “have sadly been lost.”

“These men were true explorers who shared a distinct spirit of adventure, and a deep passion for exploring and protecting the world’s oceans,” OceanGate said in a statement. “We grieve the loss of life and joy they brought to everyone they knew.”

The White House thanked the US Coast Guard, along with Canadian, British and French partners who helped in the search and rescue efforts.“Our hearts go out to the families and loved ones of those who lost their lives on the Titan. They have been through a harrowing ordeal over the past few days, and we are keeping them in our thoughts and prayers,” it said in a statement.