Oxygen reserves run out for five people aboard missing Titanic submersible

According to OceanGate, the company that own the vessel, Titan had 96 hours of oxygen when it went missing on Sunday.

Those reserves were depleted at 9.08pm (AEST), confirming the worst fears of the families of the five passengers on board.

British billionaire Hamish Harding, 55, Pakistani businessman Shahzada Dawood, 48, and his son Suleman, 19, paid $US250,0000 each to explore the Titanic shipwreck on board Titan.

They were accompanied by OceanGate CEO Stockton Rush, 61, and Titan’s pilot Paul-Henri Nargeolet, 77.

Titan lost communication shortly after being launched into the North Atlantic and it is somewhere in the vicinity of the famous shipwreck which is located 640 kilometres off the coast of Newfoundland, Canada, 3800 metres below the waves.

Despite an enormous multinational search effort involving US, Canadian and French vessels covering 40,000 square kilometres — and reports of “banging” sounds detected in the search area on Tuesday and Wednesday raising hopes of a last-minute miracle — rescuers have so far failed to locate the craft.

It is not known how long officials will continue to look for Titan now oxygen reserves are known to have been depleted.

Lost communication

The submersible launched from the Canadian research vessel Polar Prince at 8am local time on Sunday and was expected to resurface at 3pm that afternoon. But communication was lost with the Titan just one hour 45 minutes into its descent.

At 5.40pm on Sunday, the US Coast Guard received a report of the “overdue” vessel, sparking a frantic and complex rescue mission.

Company officials had been criticised for waiting eight hours after they lost communication with the Titan to alert authorities.

One of OceanGate’s previous Titanic expeditions had also gotten lost for several hours, because there is no GPS underwater, according to CBS News correspondent David Pogue, who was along for the harrowing ride.

The sub’s disappearance and desperate search sparked international headlines and multiple theories as to its fate, as well as scrutiny on the safety record of OceanGate and past statements of Mr Rush.

Enormous search

By Wednesday five specialist vessels backed by deep-sea robots and search-and-rescue aircraft were involved, with underwater remotely operated vehicles (ROV) deployed in an attempt to pinpoint the origin of the “underwater sounds” picked up on sonar.

That number doubled as the deadline approached, with a US Navy CURV21 among robot subs joining the last-ditch bid.

Canada’s CGS Ann Harvey, CGS Terry Fox, Motor Vessel Horizon Arctic and French research ship L’Atalante were all steaming at full speed to join the “needle in a haystack” hunt before dawn on Thursday local time.

The late arrivals to the fleet — carrying the world’s most advanced undersea search technology — provided the best hope of an incredible last-gasp rescue.

The L’Atalante carries the Victor 6000, which is capable of reaching depths of 6100 metres. The three-metre-long robot has arms that can be operated to cut cables or perform other manoeuvres to release a stuck vessel.

The CURV21 can salvage wreckage and craft up to 6100 metres down — and last year pulled off a world record recovery of a Seahawk helicopter at a depth of 5814 metres off Japan.

“If anything can bring them up, it’s this kit,” former UK Royal Navy Rear Admiral Chris Parry said on Wednesday.

Two of the trapped men’s wives were on ships at the surface monitoring the operation.

Oxygen runs out

Dr Kenneth Ledez, director of Centre for Offshore and Remote Medicine (MEDICOR) and Medical Director of Hyperbaric Medicine in St John’s, Newfoundland, explained what would happen when the oxygen on the sub ran out.

“Let’s say they are rescued after the oxygen levels drop too low, they are not going to be able to rescue themselves, they will have to be carried out,” he told the BBC.

“And depending on how long and how low the oxygen has been will determine, you know, what the long-term outcome is. Can people survive after exposure to those conditions? Yes, they could have damage to the nervous system or heart … so really it’s going to be a gradual deterioration.”

But Dr Ledez said he didn’t think rescuers should give up.

“I think they should keep their efforts going to see if they can get them up in time, absolutely,” he said. “If they’re still alive they are doing everything they possibly can do now to survive. They’re smart and they know the steps that they [have] got to make.”

Possible fate

Experts had previously suggested the submersible may have suffered a “catastrophic failure”, immediately crushing all five men under the pressure of the water above.

“The worst case scenario is that it has suffered a catastrophic failure to its pressure housing,” wrote University of Sydney professor of marine robotics Stefan Williams.

“Although the Titan’s composite hull is built to withstand intense deep-sea pressures, any defect in its shape or build could compromise its integrity — in which case there’s a risk of implosion.”

John Mixson, a retired US Coast Guard lieutenant commander who was involved in long-range search and rescue missions, also feared the worst.

“It’s hard to say whenever you just lose total communications in a situation like that what actually happened until you find the vessel,” he told Fox News. “This isn’t a common occurrence at all. Obviously, something very rapid and very tragic took place. I would say it is extremely serious. It’s a dire situation.”

Assuming the sub was still intact, other scenarios facing rescuers were that it was floating somewhere on the surface, somewhere underwater, or stuck in the 111-year-old wreckage of The Titanic.

“In a best-case scenario, the Titan may have lost power and will have an in-built safety system that will help it return to the surface,” Prof Williams wrote.

“Alternatively, the vessel may have lost power and ended up at the bottom of the ocean. This would be a more problematic outcome.”

Underwater noises

US Coast Guard captain Jamie Frederick on Wednesday confirmed “underwater noises” had been heard which were being analysed by sonar experts to establish if they came from the missing craft.

“There is an enormous complexity associated with this case, due to the location being so far off shore and the co-ordination between multiple agencies and nations,” he said.

“There were multiple reports of noises and every one of them is being analysed. The noises have been described as banging noises. The noises were heard yesterday and this morning, experts are analysing the data but at the moment it is inconclusive. We need to have hope … what I can tell you is we are searching in the right area. We have to remain optimistic and hopeful when we are in a search-and-rescue case.”

Carl Hartsfield, another expert involved in the search, told reporters it was very tough to discern what the noises were.

“We have multiple sensors in the area taking the data back to the best people in the world and feeding this back to the team so they can make decisions,” he said. “They have to eliminate potential man-made sources other than the Titanic.”

Rear Admiral John Mauger of the US Coast Guard on Monday afternoon said that it was possible the submarine had become stuck in the wreckage of The Titanic.

“We don’t have equipment onsite that can do a survey of the bottom,” he said. “There is a lot of debris … so locating will be difficult. We don’t have the capabilities at this time. Right now, we’re focused on trying to locate it.”

Five victims

Mr Harding, a British businessman, aviator and space tourist known for his incredible adventures, sent his friend a chilling last text message a day before the expedition.

“Hey, we’re headed out tomorrow, it looks good, the weather’s been bad so they’ve been waiting for this,” he wrote.

Mr Dawood is one of Pakistan’s richest men. He has strong links to the UK, having studied law and the University of Buckingham and owning a mansion in Surrey where Shahzada lives with Suleman, his wife Christine, and daughter Alina.

“We are very grateful for the concern being shown by our colleagues and friends and would like to request everyone to pray for their safety,” the family said in a statement.

Mr Nargeolet is a veteran submarine pilot and longtime researcher of the wreck of the Titanic.

He had previously spoken about the extreme dangers of deep sea travel.

“If you are 11m or 11km down, if something bad happens, the result is the same,” he said in a resurfaced interview. “When you’re in very deep water, you’re dead before you realise that something is happening, so it’s just not a problem.”

OceanGate, one of the few companies in the world that runs commercial voyages to see The Titanic, was founded by Mr Rush in 2009.

The Everett, Washington-based company had made two previous trips to the 1912 wreckage of the “unsinkable” ship.

frank.chung@news.com.au

— with The Sun and NY Post