All five people aboard the Titan were killed when the submersible imploded.
The fatal accident aboard the Titan submersible, which was on its way to the Titanic wreckage, has once against brought the focus the need for additional safety regulations. The concerns are being raised after the use of carbon fibre hull in the submersible, which was meant to go to the depth of 3,700 metres. For vessels that undertake expeditions like these, the preferred material is titanium, as it is elastic and can readjust to different pressures below and above the sea. But titanium is expensive compared to carbon fibre, prompting the CEO of vessel operator OceanGate to go for it.
All five people aboard the Titan were killed when the submersible imploded. The accident led to the launch of a multinational search and captured the world's attention.
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Industry experts say they were the first known fatalities in more than 60 years of civilian deep-sea submergence.
Explorers, including James Cameron, had sounded the alarm earlier with the filmmaker saying he had found the hull design risky.
"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," Mr Cameron told news agency Reuters.
The cause of the submersible's implosion has not been determined, but Mr Cameron presumes the critics were correct in warning that a carbon fibre and titanium hull would enable delamination and microscopic water ingress, leading to progressive failure over time.
Mr Cameron said he would support regulation to require certification of vessels, but it would have to be passed in every country where submersibles operated.
"If it's taking passengers, whether they're science observers or citizen explorers, it should be certified," he said. "We celebrate innovation, right? But you shouldn't be using an experimental vehicle for paying passengers that aren't themselves deep ocean engineers."
Of roughly 10 submersibles that exist in the world and are capable of diving to the depth of the Titanic - nearly 4,000 metres below the surface - only OceanGate's Titan was uncertified.
Most tourist submersibles explore coral reefs and other natural phenomenon at 500 metres or less.
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In 2018, an OceanGate employee had authored a letter warning CEO Stockton Rush that forgoing third-party certification for the Titan could result in a "catastrophic" outcome.
Travel Weekly's editor in chief, Arnie Weissmann, said when he met Mr Rush he said "he had gotten the carbon fibre used to make the Titan at a big discount from Boeing because it was past its shelf life for you in airplanes".
When Mr Weissmann pointed out to Mr Rush that it could be a problem, the CEO said the shelf-life dates "were set far before they had to be".
Mr Weissmann also said he had planned to board the Titan in May to the wreck of the Titanic but the trip was cancelled due to adverse weather.
Just weeks later, the submersible's trip ended in tragedy when it imploded, killing all five people - including OceanGate's CEO - on board.