Hope of finding the Titan five – the crew on board a missing sub on an expedition to the Titanic shipwreck – have grown after rescue groups reported ‘likely signs of life’ and ‘banging sounds.’

A Canadian Aircraft, part of the enormous search mission looking for the missing Titanic tourists, heard ‘banging’ at 30-minute intervals in the area the submarine disappeared.

The banging was noted in emails exchanged with the US Department of Homeland Security and seen by Rolling Stone.

Richard Garriot de Cayeux, President of The Explorers Club, confirmed in a Tuesday night social media post that ‘there is cause for hope.’ 

In a statement he said: ‘We have much greater confidence that 1) There is cause for hope, based on data from the field – we understand that likely signs of life have been detected at the site.’ 

It’s unclear when the banging sounds were heard, and officials have not confirmed the reports or said they have found the crew that has been stuck in the deep Atlantic Ocean since the submersible launched Sunday and quickly lost contact with the surface. 

Billionaire Hamish Harding, French explorer Paul-Henri Nargeolet, OceanGate CEO Stockton Rush and Shahzada Dawood, 48, a UK-based board member of the Prince’s Trust charity, and his son Sulaiman Dawood, 19, are reported to be the people stuck in the sub. 

The DHS memo on the banging sounds read: ‘RCC Halifax launched a P8, Poseidon, which has underwater detection capabilities from the air,’ the DHS memo read, ‘reported a contact in a position close to the distress position. 

‘The P8 heard banging sounds in the area every 30 minutes. Four hours later additional sonar was deployed and banging was still heard.’

The timing – or cause – of the banging is not revealed by the memo.

Garriot de Cayeux added The Explorers Club are confident the U.S. Coast Guard ‘precisely understand the experienced personnel and tech we can deeply’ and ‘believe they are doing everything possible with all resources they have’.

One of the five men on the ship, Harding, is a founding member of the Board of Trustees for the Explorers Club. 

The group said they have a direct lines to Congress, The Coast Guard, Air Force and Nave and the White House.  

A DHS announcement also stated that ‘the Joint Rescue Coordination Centre is working to find an underwater remote-operated vehicle through partner organizations to possibly assist.’ 

A massive search operation remains underway to find the missing OceanGate submersible, the Titan, after it lost contact with the mothership during its descent to the shipwreck on Sunday morning.  

Rear Admiral John Mauger, who is helping coordinate the search, said it could be stuck.

‘We don’t have equipment onsite that can do a survey of the bottom,’ Mauger said on Tuesday. 

‘There is a lot of debris, so locating it will be difficult. Right now, we’re focused on trying to locate it.’

Royal Navy Rear Admiral Chris Parry likened the bottom of the Atlantic to ‘being in space’, saying: ‘It’s utterly dark down there, and you have also got a lot of mud and other stuff getting swept up. You can only see about 20 feet in front of you with searchlights. There are very strong ocean currents which are pushing you along.’ 

If the mini-sub has lost power, with no working propellers, lights or heating, its five passengers will be in total darkness in temperatures of around 3C (37F) as the doomed craft rolls along the seabed.

Oceanographer and Titanic expert David Gallo said: ‘Where is it? Is it on the bottom, is it floating, is it mid-water? That is something that has not been determined yet. 

‘The water is very deep – two miles plus. It’s like a visit to another planet. It is a sunless, cold environment and high pressure.’

The basic problem is that the submersible, Titan, has stopped transmitting signals, making it almost impossible to locate. It is supposed to send a sonar ‘ping’ (radar and GPS not functioning underwater) to mothership Polar Prince every 15 minutes, but the last one was at 9.45am on Sunday – an hour and 45 minutes into the dive as it was floating right above the Titanic.

For some reason, OceanGate Expeditions, the company that runs the tours of the Titanic, took eight hours to call the coastguard on Sunday. It was reported to the US Coastguard at 5.40pm, and Canada’s Coastguard was alerted even later, at 9.13pm.

Among those taking part in the expedition is billionaire Hamish Harding, CEO of Action Aviation in Dubai, and Shahzada Dawood, 48, a UK-based board member of the Prince’s Trust charity, and his son Sulaiman Dawood, 19. 

The submarine’s oxygen supply was estimated at 96 hours, which gives rescue teams until Thursday morning to find the vessel.