A wreck hunter has said 'tapping' has been heard during the search for a missing Titanic submersible amid fears the chance of rescue is just one per cent.
David Mearns is a friend of billionaire Brit Hamish Harding - one of the five people onboard the vessel - and says he had seen reports of “tapping” being heard in the water.
Among the five people inside the 22ft long single windowed sub were three Britons; Harding, 58, British-based Pakistani businessman Shahzada Dawood, 48, and his son Sulaiman Dawood, 19.
Stockton Rush, who is the CEO of OceanGate Expeditions - the company which owns and operates the vessel, was also onboard alongside French submersible pilot Paul-Henry Nargeolet as they made the trip to the wreckage site of the Titanic.
The expedition, which is thought to cost £195,000 per head, launched at 4am on Sunday, but communications were lost to the mothership MV Polar Prince around one hour and 45 minutes into the two-hour descent to the Titanic wreck site - which sits about 3,800m (12,500ft) below sea level at the bottom of the ocean around 370 miles off the coast of Newfoundland but in US waters.
The sub is believed to have just 40 to 41 hours before their oxygen runs out, the US Coast Guard has heartbreakingly revealed.
At a press conference on the traumatising case that has captivated the world, held at 6pm BST on Tuesday, Coast Guard chiefs gave the deadline, which would fall around 11am BST on Thursday.
But Mr Mearns is remaining optimistic about their survival rate, despite the diminishing oxygen levels.
He told Channel 4 News: "They’ve got sonobuoys out there; there may be some other hydrophones that the mothership, the Polar Prince, had in the water."
Experts meanwhile warned there was a “1 per cent” possibility of finding the vessel in the Atlantic.
A former submarine commander has explained to the Mirror what the submersible crew could do to buy themselves time and help the search teams find them.
Captain David Marquet, who served in the US submarine force for 28 years, said: "The laws of nature are really quite unforgiving. If you don’t do something right…
"We would always say: 'Nature doesn’t care if you went to church that day'. You do the wrong thing, you're going to sink. You’re going to die."
He suggested they could also try and take steps to alert rescue crews to their whereabouts.
Captain Marquet said: "They might have one person banging on the hull to make noise and have the other four people on board sleeping. Then taking turns doing that."
The missing Titanic submarine "wasn't signed off by a regulatory body" according to a chilling waiver passengers have to sign before entering the vessel.
Passengers previously on board the OceanGate submersible have revealed how they were asked to sign a waiver which admits the vessel has not been verified by a professional regulatory body.
CBS journalist David Pogue, who boarded craft to visit the wreckage of the Titanic last year, said that among the paperwork shown to potential passengers was a waiver which stated: "This experimental vessel has not been approved or certified by any regulatory body, and could result in physical injury, emotional trauma, or death."
