While investigators work to piece together what happened on board OceanGate's Titan submersible, the little evidence available makes one thing clear: Whatever happened, happened fast.
"It would have been immediate," David Mearns, an expert on sea rescues who lost two friends in the incident, said. "Literally in milliseconds, and the men would have had no idea what was happening."
It's not clear exactly how deep underwater the vessel was when it imploded, but a ship on the surface tracking its movements lost contact with it an hour and forty-five minutes into its dive Sunday. Deep underwater, the Titan was under enormous pressure. At 12,500 feet underwater, where the wreck of the Titanic — the Titan's destination — sits, pressure per square inch is more than 5,000 pounds. That's well more than 300 times what it is at the surface, and 12 times more pressure than any human has experienced outside a submersible.
The design of the Titan had been criticized for being vulnerable to failure under extreme pressure, like that at the Titanic site. Stockton Rush, the CEO and founder of OceanGate, built the Titan using a combination of carbon fiber and titanium. That combination left it vulnerable to something called "delamination." It alarmed filmmaker and deep-sea explorer James Cameron.
"They call it delamination when water ingress starts to force the layers of the fibers apart," Cameron said on CNN. He went on to describe a submersible similar in design to the Titan that caught his attention years ago, when he was working on a separate dive.
"There was another sub design that was competing with ours at the time that was based on a wound filament, composite cylinder with two titanium endcaps," he said, describing a design remarkably similar to that of Titan. "I told those guys, point blank, 'You're gonna get killed in that thing.' And they ultimately never dove it."
Cameron says he never warned Rush directly about the design of the Titan, assuming the vulnerabilities of the mixed-material design had been resolved.
Rush acknowledged he'd "broken some rules" building the Titan. In 2021, he told a Mexican YouTuber, "I think it was General McArthur [who] said, 'You're remembered for the rules you break.' And you know, I've broken some rules to make this. I think I've broken them with logic and good engineering behind me. The carbon fiber and titanium, there's a rule you don't do that. Well, I did."
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The Titan also raised eyebrows for its cylindrical shape, foregoing a sphere or vertically oriented design, like Cameron used on his Deepsea Challenger sub, that would have limited the amount of pressure on the hull at great depth.
Whatever the craft's failure, experts agree that the implosion would have killed Titan's passengers far too quickly for them to have registered the pain or panic of the experience.
"I actually believe they heard it with their ears, not through the sensor system, in the last moments of their lives and that's quite a horrifying prospect," Cameron said, describing the Titan's body beginning to crumble.
Still, once the pressure chamber, which carried the passengers, failed, medical experts say all five would have been killed almost instantaneously.
"That massive pressure, up to 360 atmospheres, the inrush of water would have been extremely fast," Dr. Kenneth LeDez, an expert on hyperbaric medicine, said. "Anyone who's a diver knows that the deeper you go the more narcotic and impaired you get just from the nitrogen in the air, so it would have been a very rapid increase in the nitrogen pressure in the people's brain and it would have been like a massive anesthetic overdose, to be honest. I mean, it would have been instant loss of consciousness for that reason."
LeDez said at the same time, the rapid and massive increase in pressure would have crushed the passengers' chest cavities and stopped their hearts. All of it would have happened too fast to feel, experts say.
While the sea-exploring community waits for clearer answers about what happened, some ex-passengers of the Titan admit it wasn't safe. The vessel's design and lack of certification are prompting calls for better regulation of deep-sea exploration. But defenders of Stockton Rush argue he shouldn't be remembered as a reckless laughingstock.
"James Cameron, I have great respect for, and if he says the carbon fiber is not the appropriate shell, then I will agree with him," Alfred Hagan, who visited the Titanic wreckage with some of the crewmembers killed, said. "We're going to learn from that and move on. But Stockton Rush was also correct: The oceans are fundamental to our future. The elements that will power the green economy are all on the seafloor. We have to explore this last great frontier on Earth. It's critical to survival and life on earth. And he was a trailblazer."
'A catastrophic implosion': All 5 on board missing sub presumed dead
OceanGate said all five on board are presumed dead after officials found a debris field in the search area for the missing submersible.
