Excitement over 'banging' noise detected in the missing sub search is just 'grasping at straws,' expert says

• "Banging" noises heard in the search for the missing submersible raised hopes of a rescue.
• But it's very unlikely the noise would be coming from the sub, a former Royal Navy officer said.

"Underwater noises" detected in effort to find the submersible lost near the wreck of the Titanic raised hopes that the crew might still be alive.

But one expert said tracing the noises back to the sub is a "fool's errand."

"Trying to differentiate it from tapping noises as it were, I'm afraid is a fool's errand," Former Rear Admiral Chris Parry, a retired officer in Britain's Royal Navy, told Talk TV.

"I'm afraid people are grasping at straws here and I'm really concerned that we don't divert attention away from trying to find the submersible where it really is," Parry said in his interview.

A rescue operation is underway to recover the Titan, a submersible carrying five people that lost communication with its mother ship on Sunday as it set off for the wreckage of the Titanic 12,500 feet underwater.

The vessel carried enough oxygen to last until Thursday, officials coordinating the rescue efforts said.

The US Coast Guard tweeted that it had picked up "underwater noises" in the Titan's search area.

This came after Rolling Stone reported on Tuesday that searchers on a Canadian aircraft detected "banging" in 30-minute intervals coming from the area where the submersible went missing, according to a leaked Department of Homeland Security email.

A 'dull thud' rather than a bang

Parry said the sounds likely would not have come from the sub.

"You get a lot of mechanical noise in the ocean," he said.

"Titanic herself is making a lot of noise under the water because she's made of metal," he said.

The hull of the submersible is said to be made of carbon fiber, which Parry said would more likely make an undetectable "dull thud" than a tapping noise.

Stefan B. Williams, a professor of marine robotics at the University of Sydney whose lab works with uncrewed submersibles, told Insider it was possible the noise could have come from the crew, but that it would be difficult to confirm that without further analysis.

"There have been reports when there have been issues with submarines where the sailors will bang on the hull and that acoustic noise will travel," he said.

"Still, you can't rule out that that's coming from a ship or some other source," said Williams.

Oceanographer David Gallo, senior adviser for strategic initiatives for RMS Titanic Inc. told "CNN This Morning," the situation reminded him of the search for Malaysia Airlines flight MH370 that disappeared from radar in 2014.

"When I first heard about the banging, I said: 'Oh no, here we go again.' In [the search for] Malaysia Airlines we heard banging quite often, and it always turned out to be something different," he said.

Friends say passengers would know to make noise in that situation

Gallo said however that banging on the hull to get attention is "something PH Nargeolet would certainly do." Paul-Henri Nargeolet is one of those on the sub, a Titanic expert who has worked with RMS Titanic Inc.

Chris Brown, a friend of another passenger, billionaire Hamish Harding, also told the BBC this also sounds like something Harding would do.

The noises have "got them written all over it" and "just the sort of thing I would have expected Hamish to come up with," he told the BBC.