The Titanic submarine is 'locked from the outside' with no way to escape, according to a previous passenger.
A massive search and rescue operation is still under way in the mid Atlantic after a tourist submarine went missing during a dive to Titanic's wreck on Sunday.
David Pogue, a CBS reporter who travelled in the Titan submersible last year, told the BBC that passengers were sealed inside the vessel by bolts applied from the outside.
He said: "There's no way to escape, even if you rise to the surface by yourself. You cannot get out of the sub without a crew on the outside letting you out."
He added that there was currently "no way" to communicate with the vessel as neither GPS nor radio "work under water".
"When the support ship is directly over the sub, they can send short text messages back and forth. Clearly those are no longer getting a response," Mr Pogue said.
According to the Coast Guard, the craft submerged Sunday morning, and its support vessel, the Canadian research icebreaker Polar Prince, lost contact with it about an hour and 45 minutes later.
Unlike submarines that leave and return to port under their own power, submersibles require a ship to launch and recover them.
David Concannon, an adviser to OceanGate, said the submersible had a 96-hour oxygen supply starting at roughly 6 a.m. Sunday.
U.K. businessman Hamish Harding was one of the passengers, according to Action Aviation, a company for which Harding serves as chairman.
The initial group of tourists in 2021 paid $100,000 to $150,000 apiece to go on the trip.
Alistair Greig, a professor of marine engineering at University College London, said submersibles typically have a drop weight, which is “a mass they can release in the case of an emergency to bring them up to the surface using buoyancy.”
“If there was a power failure and/or communication failure, this might have happened, and the submersible would then be bobbing about on the surface waiting to be found,” Greig said.
Another scenario is a leak in the pressure hull, in which case the prognosis is not good, he said.
“If it has gone down to the seabed and can’t get back up under its own power, options are very limited," Greig said. “While the submersible might still be intact, if it is beyond the continental shelf, there are very few vessels that can get that deep, and certainly not divers.”
Even if they could go that deep, he doubts they could attach to the hatch of OceanGate's submersible.
