THE family of a crew member trapped on the missing Titanic sub have blasted the delay in a rescue mission being launched.
Authorities weren't alerted to Titan's disappearance until eight hours after it vanished on Sunday - and high-tech underwater robots only hit the seabed today after the vessel's oxygen supply likely ran out.
Search crews have been frantically looking for the vessel in the Atlantic in a tense race against the clock after it lost communication on Sunday with just 96 hours of life support.
But the US Coastguard warned the oxygen supply was due to reach empty at 12.08pm BST (7.08am ET) today - meaning it is probable the crew on board Titan are now without breathable air.
Experts say humans can only survive a few minutes without oxygen, but rescue crews are hoping for a miracle as underwater robots were deployed today to scour for the stricken sub.
Questions have been raised over why it took so long for the Coast Guard to the alerted to the vessel's disappearance.
More on the missing sub
OceanGate's sub, Titan, vanished less than two hours into its descent 12,500ft down to the Titanic wreckage on Sunday.
It failed to resurface that afternoon, with its final "ping" to mothership Polar Prince placing the sub directly above the ruins.
But operators failed to notify the Coast Guard until 12.40pm BST (5.40 ET) - eight hours after contact was lost.
Kathleen Cosnett, a cousin of British billionaire Hamish Harding, slammed OceanGate for taking "too long" to alert authorities.
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The 69-year-old told the Telegraph: "It’s very frightening.
"[It] took so long for them to get going to rescue [them], it’s far too long.
"I would have thought three hours would be the bare minimum."
Mr Harding paid £200,000 for the trip along with businessman Shahzada Dawood, 48, and his son Suleman, 19, a .
It was led by OceanGate CEO Stockton Rush, 61, and veteran French explorer Paul-Henri Nargeolet, 77.
The US Coast Guard has also been criticised for being slow to authorise private groups with state-of-the-art equipment to aid the rescue effort.
It's understood teams applied as early as Monday to help, but were not contacted until last night, reports the .
But US Coast Guard's Rear Admiral John Mauger, who is heading the search operation, today insisted rescuers remain focused on finding the five-member crew alive.
Mr Harding's friend Professor Mark Hannaford, the founder of World Extreme Medicine, also urged people to "not give up hope".
He told the : "We should not conclude the opportunity to rescue them. All efforts should continue until the point of impossibility. "
And Guillermo Sohnlein, who founded OceanGate with Mr Rush in 2009, believes if all five men have stayed calm and laid still, there is a chance their oxygen supply could’ve lasted longer.
He said: “Today will be a critical day in this search and rescue mission, as the sub's life support supplies are starting to run low.”
A doctor also echoed Mr Sohnlein's hopes as he revealed the crew could survive for 10 to 20 hours by moving as little as possible and staying calm, therefore depleting the oxygen supply at a slower rate.
Dr. Richard Moon, a professor of anesthesiology at Duke University, told ABC: "The actual amount of time that they have is unpredictable, but it's probably less than 24 hours after the final oxygen in the tank is depleted."
Sounds of banging detected underwater on Wednesday had raised hopes of a last-gasp miracle as extra rescue ships rushed to join a final bid to find lost craft Titan in the Atlantic.
The late arrivals - carrying the world’s most advanced undersea search technology - provided the best hope of an incredible last-minute rescue.
The US Coastguard said today that Canadian vessel Horizon Arctic has deployed a robot that has reached the sea floor and started its search for the missing sub.
And RAF and USAF cargo planes are today flying a specialist ultra-deep submersible to St John's Canada to assist what sources are now calling the "recovery mission".
The remotely operated vehicle, nick-named Juliet, has already surveyed the Titanic wreck.
It is flying with a 10-strong crew of expert operators and 6km of armoured steel cable to power and control it underwater.
US Coast Guard captain Jamie Frederick confirmed deep-sea noises had been heard which were being analysed by sonar experts to establish if they came from the 22ft craft.
French ship L’Atalante - carrying the robot Victor 6000, which is capable of reaching depths of 20,000ft - arrived at the scene today, as did US crane ship Horizon Atlantic.
Crews on board L'Atalante submerged Victor 6000 to comb the seabed at about 12.30pm BST (7.30am ET)
The robot can dive deeper than other equipment at the site.
Operated by a 25-strong crew, it has arms that can be operated to cut cables or perform other manoeuvres to release a stuck vessel.
While the vehicle could not lift Titan to the surface on its own, it could help to hook it to a ship.
The US Coast Guard confirmed shortly before midday BST (7am ET) that Canadian vessel Horizon Arctic has also deployed its own ROV "that has reached the sea floor and began its search for the missing sub".
It's understood a Canadian Navy ship carrying a medical team specialising in dive medicine was sent to the area today.
According to the Joint Rescue Coordination Centre Halifax of Canadian Armed Forces, it has a hyperbaric recompression chamber that can hold up to six people.
Experts warned that even if the sub is located, it would take hours to winch it to the surface.
Deep-sea explorer Dr David Gallo told Good Morning Britain, he said: "We have to, at this point, assume that that's the submarine [banging] and move quickly to that spot, locate it and get robots down there to verify that is where the submarine is.
"They've got to go fully ready as if that was the sub because it takes a while to locate it and get it up to the surface, it takes hours."
No10 confirmed Lieutenant Commander Richard Kantharia would be part of the Titan rescue efforts "as long as is required".
The experienced submariner is understood to have joined the US Coastguard mission on Tuesday evening in the US.
A Downing Street spokesman said: “At the request of the US Coast Guard the UK has embedded a Royal Navy Submariner to assist the search and rescue efforts for the missing submarine.”
Two of the trapped men’s wives were on ships at the surface on Wednesday monitoring the operation.
The Titanic sank on its maiden voyage to New York in April 1912 after hitting an iceberg.
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More than 1,500 of the 2,200 passengers and crew onboard were killed, and many died within minutes of being thrown into the -2C waters.
The decaying wreck of the 822ft liner was first discovered in 1985.
Titanic OceanGate Submarine News
Everything you need to know about the missing submarine, which vanished near the Titanic on June 18, 2023.
- What happened to the OceanGate Submarine?
- When did it go missing?
- Who was Hamish Harding?
- How deep is the Titanic in the ocean?
- Do submarines like this disappear often and has this happened before?
- Who was Paul-Henry Nargeolet and what is he known for?
- Who was Shahzada Dawood?
- Who was Shahzada Dawood's son Suleman?
- When did the Titanic sink and have people explored the wreckage before?
- Was the submarine safe to take part in this mission?
- Who was OceanGate CEO Stockton Rush?
- What has been found from the submarine?
- What caused the submarine to implode?