A submersible expert who took a trip on the Titan sub with OceanGate CEO Stockton Rush in 2019 says the hull made terrifying creaking sounds during their descent.
Karl Stanley said he warned Rush to slow down his Titanic plans after their 12,000-foot descent in the Caribbean.
Rush invited Mr Stanley, who runs an undersea tourist business in Honduras, on the dive in the Bahamas to showcase his Titan sub which had a carbon fiber hull he had designed himself.
Rush, 61, founded OceanGate in 2009 and was among five people killed when the Titan lost contact on Sunday morning during a dive to the wreck of the Titanic.
After a frantic search debris consistent with an implosion was discovered on the sea bed on Thursday, 1,600 feet from the bow of the Titanic.
Speaking about his 2019 trip to CNN Karl Stanley recalled that Rush, who was piloting the sub, warned him about the creaking sounds coming from the hull so he was not overly concerned at the time.
But after returning from the trip he was worried enough to email the OceanGate founder warning him that the noise was likely dangerous.
The day after the dive he wrote that the noise heard during their descent “sounded like a flaw/defect in one area being acted on by the tremendous pressures and being crushed/damaged.”
The email, obtained by the New York Times, warns that the loud creaking sounds indicated "an area of the hull that is breaking down."
In the email he urges Rush to take the development of his sub slowly and ensure it was safe, but he received no response.
Stanley wrote: 'A useful thought exercise here would be to imagine the removal of the variables of the investors, the eager mission scientists, your team hungry for success, the press releases already announcing this summer's dive schedule.
'Imagine this project was self funded and on your own schedule. Would you consider taking dozens of other people to the Titanic before you truly knew the source of those sounds??'
In 2018 more that three dozen dustry leaders, deep-sea explorers and oceanographers warned Rush in a letter that the company's 'experimental' approach could have ‘catastrophic’ consequences.
The first tourist trip took place in 2021.
The implosion on Sunday killed Stockton Rush alongside French Titanic expert Paul-Henri Nargeolet, 77; British billionaire businessman Hamish Harding, 58; and British-Pakistani father and son Shahzada Dawood, 48, and his son Suleman.
Some submersible experts have suggested that the sub's composite hull, made from a cylinder of carbon fiber with two titanium end caps, was the cause of the implosion.
It is possible experimental carbon fiber hull was unable to stand the repeated cycles of pressurization caused by multiple trips to the sea floor.
