Sonar buoys have detected banging sounds at 30-minute intervals as the search for the missing OceanGate Expeditions submersible Titan is running out of time.
An internal email update sent by the US Department of Homeland Security's National Operations Center stated the "sounds" were detected by the US Coast Guard (USCG) early Wednesday (June 21), Rolling Stone reported, but it has not been confirmed whether they were coming from the Titan.
The USCG Northeast District tweeted they redeployed remotely operated vehicle (ROV) operations in areas where a Canadian P-3 Orion detected the "underwater noises" to explore where they were coming from. "Those ROV searches have yielded negative results but continue," the unit added.
The US DHS email added the underwater bangs were also detected by a Boeing P-8 Poseidon, a maritime patrol and reconnaissance aircraft that has underwater detection abilities from the air.
Banging Sounds May Come From Titan Crew, Expert Says
The five passengers onboard the missing vessel was earlier identified as OceanGate CEO Stockton Rush, retired French submariner Paul-Henri Nargeolet, British billionaire and adventurer Hamish Harding, and British-Pakistani businessman Shahzada Dawood and his 19-year-old son Sulaiman.
In an email to Live Science, the University of Portsmouth marine biologist Nicolai Roterman said the 30-minute intervals would "certainly be consistent" with the theory the trapped crew was still alive and trying to contact the outside world while conserving energy and oxygen.
"If this is the case, then it would indicate that the submersible is on the seafloor, and either the system for jettisoning weight has failed, or Titan is snagged or trapped somehow," he added.
In addition, Harding's friend and fellow explorer Chris Brown told the BBC the banging sounds at 30-minute intervals were unmistakably human. "I'm sure they're all conserving oxygen and energy because it's cold and dark down there," he said.
How Could the Sub Be Surfaced?
Roterman said there are no submersibles capable enough to rescue people from a trapped submersible at the depth of the Titanic (3,800m/12,500ft), but it could be possible for an ROV to help unsnag the Titan or tether it to the surface.
He added if the Titan has no power or auxiliary systems, the submersible would also be cold and dark, and the conditions inside would be cramped. "Given the situation, a big challenge for the occupants of Titan will be to maintain composure and not to panic so as to prolong their air supply," he added.
Running Out of Time and Oxygen
It was earlier reported the Titan went missing on Sunday (June 18), 1 hour and 45 minutes into its two-hour descent into the wreck of the Titanic in the North Atlantic Ocean. As of 05:00 Eastern Time Wednesday (09:00 UTC), the submersible has less than 30 hours of oxygen remaining.
The cause for the Titan losing communication with its mother ship Polar Prince remains unknown, but experts present possible scenarios like power loss, getting snagged on a piece of the Titanic, or an implosion.
The discovery of possible banging sounds underwater could mean the passengers might still be alive, making search efforts come to a fever pitch.
"Time is of the essence because once you...have an area where you know that the bangs are coming from...you need to get assets there...to investigate," American oceanographer David Gallo explained to CNN.
Ex-OceanGate Employee Says the Titan Needs More Testing
Earlier reports suggest the Titan was constructed out of conventional materials, steered by a gaming controller, and was not fit for sea voyage in the first place.
Supporting the latter claim was former OceanGate employee David Lochridge, who said the Titan needed more testing before they could accommodate paying passengers in an engineering report he wrote in 2018.
Lochridge, a former Royal Navy marine engineer, and ship's diver, was terminated from the company and subsequently sued by OceanGate for allegedly breaching a non-disclosure agreement. He sued the company back for wrongfully firing him, the Daily Mail reported.
In his counterclaim, Lochridge said OceanGate would 'subject passengers to potential extreme danger in an experimental submersible' despite it not being equipped to reach the depth of the Titanic's wreck. He added his concerns focused on the company's decision to rely on sensitive acoustic monitoring to detect flaws than a scan of the hull.
However, OceanGate argued that Lochridge was "not an engineer and was not hired or asked to perform engineering services on the Titan." The company fired him after refusing to accept assurances from its lead engineer that the acoustic monitoring was better suited to detect any flaws than a scan would be.
The case was settled on undisclosed terms several months after it was filed.
This is a developing story. Please check back on HNGN later for more updates.