I’m mostly putting this up as a way to keep a record of my own own speculation on the sequence of events that happened with the Titan Submersible when it imploded. I expect the final report is going to be months, or even years away.
To be absolutely clear, I have no special knowledge, or even qualifications here, everything I have to say is purely speculative based on the bits and pieces that have come to be known in the public domain through news media.
At some 4000-5000 psi, there’s a ton of pressure on the hull of the Titan. While the pressure is evenly distributed, it only takes a very small flaw in any one part of the hull to allow ingress. The points we know of where that’s most likely on the Titan were:
The interfaces between the carbon fibre tube and the titanium rings that the end caps connect to.
Any points where power and control wiring harnesses enter the hull
Additionally, any flaw in the carbon fibre matrix resulting from repeated compression / decompression sequences could become a point of ingress for water into the craft.
First, I am going to go to the obvious conclusion that the ultimate point of failure was the carbon fibre tube. I don’t think this is particularly controversial.
I will assert that a flaw in the glue binding the titanium ring to the carbon fibre tube allowed one or more small streams of high pressure water to enter the carbon fibre matrix of the hull. This likely started several dives before the failure, and small amounts of water had already begun to disrupt the polymer structures that hold together the carbon fibre tube.
Over the course of the dive, the submersible began to take on more water, and by the time they realized they were in trouble, the effective mass of the craft had increased substantially with the addition of water which was weakening the carbon fibre matrix. Once that reached a critical point, probably when the “acoustic monitoring” of the hull started issuing alarms, it was too late. Any actions taken were “too little, too late”, as water had taken hold of the craft and was introducing the inevitable flaws that would result in the implosion.
All of the other criticisms of the design and implementation of Titan aside, once water started to make ingress into the hull, it was doomed. How could this have been mitigated? Some kind of scan of the hull after each dive might have helped identify the emerging failure. Are monitoring systems like the acoustic monitor that they dreamed up adequate? Clearly not. Current technologies on that front are clearly inadequate in terms of detecting problems early enough to be able to take corrective action.
Please remember, this isn’t definitive, and the final report could come along and prove my speculation here completely wrong. I’m writing this so I don’t lose track of my current thoughts, and so that we can see what the analysis shows when the professionals doing the analysis are finished with it.
[PS - July 14]: A couple of additional thoughts regarding the Titan submersible.
The more we see about the way this thing was constructed, and the risks and shortcuts taken in so many areas, the development of the Titan strikes me as a failure of fundamental engineering principles that stem from the Tacoma Narrows bridge collapse.
It was well known that carbon fibre vessels do not do well under compressive load, yet the developers of Titan chose to use that material without doing any kind of prototyping and destructive testing. (Yeah - costs money - I know - too bad)
Mixing different materials in a design intended for a high compression load environment has enormous risks associated with it. Again, destructive testing would have been more than justified - and feels like basic materials science stuff that should have been done.
"Acoustic Monitoring System" - sounds like a good idea, but I suspect it was nowhere near sensitive enough to provide anything more than a "you're fucked" alarm. Again, a lot of prototyping would be necessary to make this viable. I would also think that sensors embedded throughout the carbon fibre matrix to detect water ingress would be absolutely necessary. I'm not sure how feasible such a design is - I know the technology around the sensors, but I lack the knowledge of carbon fibre materials to know if such a sensor network would compromise the carbon fibre.
So many aspects of this craft feel like "quick and dirty" solutions to problems that ultimately are somewhere between inept and professional negligence. Yeah - sure you can buy a bunch of hardware off Amazon or Ali, but that doesn't make it fit for purpose ... and buying "time expired" carbon fibre from Boeing? Seriously? What the heck are you thinking?
