Retrieving the missing Titan submersible and getting its crew to safety in time would be an extremely challenging task even if rescuers manage to locate the deep sea vessel, said observers on Thursday (Jun 22).
This comes as rescuers searching for the submersible near the wreck of the Titanic focus their efforts on a remote area of the North Atlantic, where underwater “banging” noises have been detected.
“It gives you some hope that they may still be alive,” said Professor Stefan Williams of the Australian Centre for Field Robotics at the University of Sydney.
However, it is still “an enormous challenge to get down and find this vessel”, Prof Williams told CNA938.
“I think the prognosis is not great and particularly, we're running up against that deadline of when their oxygen supplies are likely to run out.”
Estimates suggest the air supply on the Titan could run out on Thursday.
The vessel, deployed in international waters, went missing off the coast of southeastern Canada on Sunday while taking five people deep underwater to visit the Titanic wreck as part of a tourist expedition.
“The difficulty is, you still have to locate where that sound is,” said Dr Salvatore Mercogliano, associate professor of maritime history at Campbell University.
“There's a lot of sounds in the ocean. You get a lot of debris and noise sounds, especially around the Titanic wreck. You could have nets banging against the side of the ship.”
Most military submarines operate at a depth of about 300m, Dr Mercogliano told CNA’s Asia First, while the Titanic is at a depth of 3,800m.
“Sonar doesn't really operate very well down at that depth. And so even with the intermittent sounding, you're gonna need multiple sonars to basically triangulate where this is,” he said.
“Unfortunately, it sounds like the sounds are not being hit long enough or at a long enough duration to get a good fix on the position.”
Even after the Titan is located, experts stressed that rescue efforts would likely involve remote-controlled vehicles with a clear view of the obstacles around it and where to attach cables for lifting it up some 4,000m through the water.
Rescue efforts at this depth will take time, “whether it is attaching flotation bags to bring the submersible to the surface or trying to hoist it up with a winch”, but time is running out for the pilot and four passengers on board, said Dr Mercogliano, adding that the ocean is “a very unforgiving environment”.
Unlike ships and other vessels, submersibles are largely unregulated, especially when they operate in international waters, he noted.
As such, there was no second party to ensure that OceanGate Expeditions, which operates the Titan, got the submersible certified and was following the safety requirements needed, said Dr Mercogliano.
“Most classification agencies are there for purposes of insurance, to provide that double check, to make sure that companies are operating at the standards established usually by industry.”
Concerns were raised back in 2018 about the safety of the Titan submersible, but they were not addressed.
The 6.7m-long vessel has a hull made of carbon-fibre composite.
Carbon fibre is extremely strong, but it is largely untested for deep sea vessels compared to titanium or steel, said observers.
The Titan first made a voyage dive to 4,000m in December of 2018, and first dove to the site of the Titanic in 2021. It planned to make 18 such dives this year.
“One of the big challenges in building a pressure vessel with that kind of composite design is the fact that the different materials will compress and react in different ways under pressure, particularly as you cycle through multiple dives,” said Prof Williams.
“So it may work the first time and it may be able to withstand the pressure, but you can imagine the submarine going down to 4,000 metres or so and then coming back up, the pressure increases and decreases in that cycling.”
The Titan's viewport “may also not have been designed to withstand the sorts of pressures that it was experiencing”, said Prof Williams.
“Other potential points of failure are in the communication systems and the overall electronics that drive the vehicle.
“It does raise some concerns about the reliability of the overall system that they are using.”
Experts have since called for more regulations to ensure submersibles are built with safer designs and follow stringent standards.
Prof Williams said: “When you're putting people in a submersible like this, you want to be pretty sure that you've got the design right and you've gone and done all the testing.”