A TOURIST submarine may be tangled in the wreckage of the RMS Titanic after it vanished, according to an expert.
Five people were on board the sub, including a British billionaire, when contact with it was lost in the North Atlantic.
The 22ft carbon fibre and titanium vessel is somewhere in the depths and the coastguard of both the US and Canada have undertaken a desperate search effort.
It is thought to have become entangled in the 20th Century shipwreck.
Former Rear Admiral Chris Parry told Sky News: "It's very worrying. It could have become entangled in the wreckage of Titanic, we don't know yet.
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"The wreck site is a long way from anywhere.
"The only hope one has is that the mothership will have a standby craft that can investigate immediately what is going on."
The sub is able to descend as deep as 4,000 metres (roughly 13,000ft).
It was designed by a team of NASA engineers in time for the expedition.
It weighs over 10,000kg and is powered by electric thrusters, generating a stop speed of three knots.
Unusually, it is reportedly steered by a reinforced Playstation controller, though there is no GPS system, with crew instead relying on texts from a team above the water.
As well as a window, which operators OceanGate claim to be the largest in the world, there is a high-res display showing the feed from the sub's Rayfin 4K camera.
What we know:
- Billionaire Hamish Harding is the first crew member to be confirmed to be on the trip
- Harding posted about poor weather conditions just hour before vanishing
- Paul-Henry Nargeolet was named as the second passenger after the French mariner offered a chilling warning
- Stockton Rush was also named as being on board the missing vessel
- The final ping from Titanic tourist sub revealed reveals more detail about the vessel's journey
- The Titanic submarine vanished for HOURS last year
- Timeline reveals missing Titanic sub’s movements before it vanished
It is launched by a platform which sinks to a depth of 9.1 meters, which it is supposed to land back on at the end of the dive to be brought back to the surface.
Dives can last for up to 10 hours, though it has been missing for considerably longer than that.
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OceanGate CEO Stockton Rush is believed to be among those on board.
He was reported to have taken the dive, along with experienced submersible pilot Paul-Henry Nargeolet.
The only passenger confirmed so far is UAE-based British businessman Hamish Harding.
His stepson Brian Szasz said on Facebook: "Thoughts and prayers for my stepfather Hamish Harding as his submarine has gone missing exploring Titanic.
"Search and rescue mission is underway.
"Thoughts and prayers for my mom and Hamish Harding."
A spokesman for OceanGate said: "We are exploring and mobilising all options to bring the crew back safely.
"Our entire focus is on the crewmembers in the submersible and their families.
"We are deeply thankful for the extensive assistance we have received from several government agencies and deep sea companies in our efforts to reestablish contact with the submersible.
"We are working toward the safe return of the crewmembers."
