Tourists on missing Titanic submersible had to sign waiver before boarding

The missing submersible which takes tourists down to the wreckage of the Titanic gets passengers to sign a waiver about the potential risks of diving deep under the sea.

A rescue mission is underway for an OceanGate submarine, which is supposed to take people down to the wreckage of the infamous ship that sunk on her maiden voyage across the Atlantic.

Their Titan submersible has become lost beneath the sea with five people on board and there's a finite amount of time before they run out of oxygen.

US and Canadian teams are out searching for the submersible that vanished 1,448km from Cape Cod, Massachusetts, at a depth of 4km on Monday (19 June).

Contact was lost with the submersible about an hour and 45 minutes into the dive, with experts warning that it's possible the vessel had suffered from a 'catastrophic failure' or become entangled in the wreckage of the Titanic itself.

The five people inside the sub are thought to have enough oxygen to last until around 6am BST on 22 June, but they will need outside assistance to survive according to a previous passenger.

Someone who's been on board the OceanGate submersible before is CBS journalist David Pogue, who recounted his own experience on board the sub after being invited aboard.

He reported that among the paperwork shown to potential passengers was a waiver which said: "This experimental vessel has not been approved or certified by any regulatory body, and could result in physical injury, emotional trauma, or death."

And on CBS's Sunday Morning, he is seen reading the waiver out loud.

Pogue also said there were 'some elements of MacGyver jerry-riggedness' with the submersible.

He recently told the BBC that the sub had seven different ways to get back to the surface and it was 'really concerning' that none of these appeared to have worked as of yet.

Pogue said he was initially hesitant going aboard the submersible because some of the components seemed 'off the shelf, sort of improvised'.

He added: "You steer this sub with an Xbox game controller, some of the ballast is abandoned construction pipes."

Pogue also said there was no way of escaping for the people inside without help as 'there's no backup, there's no escape pod' and that it was a matter of 'get to the surface or die'.

In a statement, OceanGate said they were 'exploring and mobilizing all options to bring the crew back safely' and this was the subject of their 'entire focus'.

They also thanked the multiple government agencies helping them attempt to recover the submersible and were working for 'the safe return of the crewmembers'.

Among the passengers on the missing sub is British billionaire Hamish Harding, while the family of Pakistani businessman Shahzada Dawood said he and his son Suleman were also on board.

Facebook posts from Harding suggest that French explorer Paul-Henry Nargeolet could also be on board along with OceanGate founder Stockton Rush.