In the aftermath of the search for the OceanGate sub which went missing on a dive to the Titanic, evidence has emerged that CEO Stockton Rush, who went down with the sub, admitted that the hull of the vessel had been made with carbon fibre from a Boeing aircraft which was past its aeroplane shelf life.
The shocking revelation came from Travel Weekly's editor in chief, Arnie Weissmann, who had been set to travel on the Titan submersible.
Sharing his experiences with the deep-sea diving company, Mr Weissmann said he was due to board the Titan in May to head down to the wreck of the Titanic off the coast of Newfoundland, but the trip was curtailed by weather.
It was a matter of weeks between the trip he had supposed to have been on and the ill-fated trip which ended in tragedy when the vessel imploded, killing the five people onboard.
While he said he was impressed in general by "what appeared to be a risk-averse operation", there was one thing which concerned him.
Mr Weissmann wrote that he was told by CEO Stockton Rush that "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".
He recalled asking Mr Rush whether that was a problem, but said he was told that the shelf-life dates "were set far before they had to be".
Neither OceanGate or Boeing have commented on Mr Weissmann's claims. Previously, OceanGate's website claimed the vessel was designed and engineered "in collaboration" with Boeing.
However, Boeing has denied any involvement in the design of the Titan. A Boeing spokesperson said: "Boeing was not a partner on the Titan and did not design or build it. Boeing has found no record of any sale of composite material to OceanGate or its CEO."
There are still numerous unanswered questions about what happened to the submersible, and how the "catastrophic" implosion happened. The announcement that the five on board were dead came after a debris field was found by the US Coast Guard in their search.
Rear Admiral John Mauger, First Coast Guard District commander, said they had found debris linked to the Titan. He said: "The debris is consistent with a catastrophic loss of the pressure chamber."
Those on board - Hamish Harding, Shahzada and Suleman Dawood, Stockton Rush and Paul-Henri Nargeolet - would have been killed almost instantaneously by the implosion.
With the wreck of the Titanic lying around 3,800m under the ocean's surface, the pressure at that depth is intense, more than 300 times that at the surface. A former Navy doctor has spoken about what would have happened to the crew in their final moments.
Dr Dale Molé said: "It would have been so sudden, that they wouldn't even have known that there was a problem or what happened to them. It's like being here one minute, and then the switch is turned off. You're alive one millisecond, and the next millisecond you're dead."
While an investigation continues, the US Coast Guard has revealed that it's unlikely the bodies will ever be found due to the harsh conditions thousands of metres below the ocean's surface.
Five big pieces of debris were found around 1,600 feet from the RMS Titanic. While it's not clear what caused the implosion, the debris would only have been found if the vessel had suddenly imploded.
