Titan could have 'vulnerabilities' due to large window, materials: former sub commander

The submersible owned and operated by OceanGate Expeditions could have had "vulnerabilities,” a former submarine commander says.

David Marquet, a retired United States Navy captain who commanded the nuclear submarine Santa Fe, said the safety standards for the submersible industry are "essentially voluntary."

"The company decides to have their vessel inspected and regulated and insured by going through a process they volunteer to go through. And in this case, the company felt like they're being very innovative, very fast-moving," Marquet told CTV's Your Morning on Thursday, hours before it was announced that the crew is believed to have died.

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• Here's more on the missing submersible

Questions have been raised about the submersible, called the Titan, and its safety, including in a lawsuit that alleged passengers could be endangered.

In 2018, David Lochridge, OceanGate’s former director of marine operations, wrote an engineering report that said the Titan under development needed more testing when it reached "extreme depths," according to a lawsuit filed that year in U.S. District Court in Seattle.

The concerns surrounded the company's decision to rely on sound monitoring for cracking and popping noises made by the hull under pressure to detect flaws rather than a scan.

OceanGate told CTVNews.ca in an email on the subject of the design and build of the Titan: "We are unable to provide any additional information at this time."

Marquet says the design of the Titan and the materials used to construct it concern him.

"It has this big window and that's a vulnerability," he said. "There are no windows on military submarines, for a reason. So the window itself, where the window meets against the vessel is a vulnerability."

According to the lawsuit, the submersible was designed to reach depths of 4,000 metres, but Lochridge said the passenger viewpoint (window) was only certified for depths of up to 1,300 metres. and in the suit he alleged OceanGate would not pay the manufacturer to build a viewpoint cleared for 4,000 metres.

This is a critical factor, Marquet says, due to the pressure on the submersible at that depth.

"The pressure down there was 380 times what we're feeling here at sea level," he said. "And that's like an Empire State Building of lead sitting on top of you."

Marquet said the carbon fibre used in the submersible is "unusual." saying most are made from metal, carbon steel or titanium.

The pressure on submersibles at that depth could also lead to issues, he said.

"For example, you order a certain kind of chromoly bolt, which is sort of a high-tech bolt, but somewhere in the supply chain it gets replaced with a carbon steel bolt, which is now more susceptible to cracking, rusting, degradation," Marquet said. "What happens is you get a lot of stress when it goes deep, and then relaxes when it comes up…that fatiguing of the metal now propagates through the metal in a way that wasn't originally designed."

If there was a leak in the submersible, Marquet says, "it creates the Grand Canyon in 10 seconds."

To watch the full interview click the video at the top of this article.