THE DAY:   Like many of you, I spent a good part of the day following the submersible story.  The ending was not surprising.  I thought the television news organizations did a solid and restrained job of covering the tragedy.  I rarely get a chance to praise them, but praise is due. 

The tragedy will be followed by a major investigation, or several of them.  As I understand it, there is really no precedent for an investigation into the loss of a tourist submersible, no automatic assignment of a probe to a particular agency.  That will all have to be worked out.   The BBC ran an excellent summary of what investigators will be looking for.

After the grim discovery of debris from the Titan submersible on the ocean floor, the focus of the rescue efforts will now be turned towards understanding what caused the accident.
According to Rear Admiral John Mauger, what they found was consistent with a "catastrophic implosion".

This is because they found two patches of debris, one containing Titan's tail cone and the other its landing frame, suggesting that the vessel blew apart.

To answer the question of why this happened and what could have been done to prevent it, the authorities will be gathering every piece of the debris they can find, according to Ryan Ramsey, former submarine captain in Britain's Royal Navy.

"There is no black box, so you are not going to be able to track the last movements of the vessel itself," he says, but otherwise the process of investigation is not dissimilar to that of an airplane crash.

Once investigators bring the pieces back up to the surface, they will look for the break structure in the carbon fibre structure, which is key to helping them understand what happened in those last moments, he says.

Each piece will be closely examined under a microscope to examine the direction of the carbon fibre filaments, looking for tears which suggest the exact place where the rupture happened.

The big question investigators will be trying to answer is whether the cause was a structural failure.

If it was, then the submersible would have been subjected to incredibly high pressures, equivalent to the weight of the Eiffel Tower, says Professor Blair Thornton from the University of Southampton.

"We're talking about a very powerful implosion of the main housing," he says.
If this is what happened, the critical question is whether it was because of a lack of proper testing, as some experts have suggested.

"Carbon fibre fails from internal defects in its construction," says Professor Roderick A Smith of Imperial Imperial College London. The joints between the carbon fibre and the titanium need very careful inspection, he says.

The violence of the implosion means that it may be very difficult to determine the sequence of events, he adds. "Hence the need for retrieval and painstaking examination if possible."
It is unclear at this stage which agency will lead the investigation as there is no protocol for such incidents with a submersible.

Admiral Mauger said that it was particularly complex because the incident took place in a remote part of the ocean involving people of many different nationalities.

But since the US Coast Guard has played a leading role in the operation so far, it is likely to continue to play an important part.

COMMENT:  This will be a continuing story, with possible ramifications for other types of vehicles and transportation systems that are running around out there.  I am not a lawyer, but I wonder if any criminal liability is involved in the Titan tragedy, concerning the construction of the submersible and its operation.  We understand from news reports that Titan was never certified by any capable certification agency.

June 22, 2023