Missing Titanic submarine: what we know about OceanGate's Titan submersible - as past safety concerns emerge

Five passengers are believed dead after the submersible they were in likely imploded near the shipwreck of the Titanic, as court documents reveal the company has faced a lawsuit over its safety in the past. The US Navy has confirmed a remotely operated vehicle had discovered the nose cone of the Titan around 487m from the bow of the Titanic on the seafloor.

OceanGate's Titan was reported overdue on Sunday evening (18 June) while carrying a crew down to the Titanic's ruins, about 435 miles off the Canadian coast. On Thursday evening UK time, after an enormous and "complex" search and recovery operation, the US Coast Guard said debris from the sub had been found near the shipwreck's hull, which was "consistent with the catastrophic loss of the pressure chamber".

Onboard were OceanGate's CEO, as well as British billionaire explorer and businessman Hamish Harding, well-known French ocean explorer Paul-Henri Nargeolet, British-based Pakistani businessman Shahzada Dawood - one of Pakistan's richest men - and his 19-year-old son.

More details about the doomed voyage and about the ground-breaking vessel itself have come to light since its disappearance. Here's everything you need to know.

What do we know about the Titan submersible?

According to promotional material seen by NationalWorld, the Titan was a manned submersible designed and built by OceanGate, capable of carrying up to five people to depths of 4,000 meters "for site survey and inspection, research and data collection, film and media production, and deep sea testing of hardware and software".

"Once depth validation is complete, Titan will be the only privately owned submersible in the world capable of diving to 4,000 meters," the company claimed. Its operational depth would allow access to up to half of the world's oceans, it said.

A diagram marked "typical seating configuration" demonstrated how five people could fit in the vessel at once, with only one passenger able to fully extend their legs at a time.

Titan was designed to be "the most advanced and mobile deep-sea manned submersible in the world", OceanGate said, built from lightweight carbon fibre and titanium. It features "the largest viewport of any deep diving submersible", as well as "state of-the-art lighting systems, plus internally and externally mounted 4K video and photographic equipment".

OceanGate said the interior provides "ample space for additional monitoring, inspection, and data collection equipment".

Its specifications showed the vessel measured 6.7 by 2.8m by 2.5 metres, weighed 11,340 kg, and was capable of carrying a 1,043 kg payload. Crucially, it had 96 hours of life support for a crew of five.

Like all submersibles, the Titan requires a mother ship that can launch and recover it. Submersibles are launched from support ships which carry the vessel to the site where it will commence its dive - similar to how a boat deposits a scuba diver into an area of the ocean to explore.

Journalist David Pogue travelled aboard OceanGate's Titan submersible last year, and said while the support ship is directly above the submersible after launch, the two vessels can send short, text-based messages to one another - but other forms of communication like GPS or radio did not work that far underwater.

The Titan had seven different functions that could let it resurface, he told the BBC, and that it was "really concerning" none of them appeared to have worked in this case.

He added that it would not be possible for the crew members to escape from the sub themselves either, because they were sealed inside by bolts applied from outside - and had to be freed externally.

Lawsuit over employee allegedly fired for raising 'safety and quality control issues'

The New Republic has revealed OceanGate faced a lawsuit in 2018, after an employee claimed they were fired for raising concerns about the depths its submersible could safely travel to.

Court documents obtained by the US-based magazine revealed OceanGate employee David Lochridge - then the company's director of marine operations - filed a counterclaim against them for alleged wrongful termination. He was also sued by the company for disclosing confidential information about the Titan.

In his counterclaim, Mr Lochridge alleged he initially told OceanGate's executive management team about his safety concerns, which included "potential danger to passengers of the Titan as the submersible reached extreme depths", but was ignored.

The former employee claimed he carried out a thorough quality inspection of the entire vessel at CEO Stockton Rush's request. Mr Rush is one of those onboard the missing sub. Mr Lochridge “identified numerous issues that posed serious safety concerns, and offered corrective action and recommendations for each", according to the court documents.

At a meeting to discuss his findings, he claimed to learn the main viewing window in the submersible was only certified to withstand pressures at depths of up to 1,300 meters - while OceanGate intended to take passengers down to more than three times that depth, and said the manufacturer would only certify to the lower depth due to experimental design of OceanGate's viewport.

Mr Lochridge alleged passengers who paid for a spot on the Titan voyages would not be told about his safety concerns, according to his complaints. The case between him and OceanGate was settled out of court a few months later, The New Republic reported.

What is OceanGate?

OceanGate is a privately-owned company headquartered in Everett, Washington State.

The company was founded by 2009 by current CEO Stockton Rush, also known for once building his own experimental aircraft, according to The Independent. According to OceanGate's website, its focus is on "increasing access to the deep ocean through innovation of the next generation of crewed submersibles and launch platforms".

It operates a range of other Cyclops-class submersibles operating at lesser depths than the Titan, although according to a 2020 press release is currently working with NASA on building a vessel capable of diving to 6,000 meters.