At those extremes anything less than 100% is fatal. The closest comparison in aerospace would be the point of Max Q in a rocket launch, and that's a very limited time to endure unlike underwater.
this post was submitted on 23 Jun 2023
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What I'm getting at is that designing a pressure vessel to go down to a specific depth, even repeatedly, seems like a solved problem. The fact that it imploded seems more like negligent homicide/suicide than an accident.
There were definite corners cut, he even admitted as much. Some things you simply can't fudge numbers and substitute off the shelf parts. It seems like it was a little bit ego, a little bit ignorance, and a lot of greed to shave more profit by not doing as you suggest, standard practices and materials.
There's a 2019 Smithsonian article that describes the founder as a "daredevil inventor," and quotes him saying that regulations "needlessly prioritized passenger safety over commercial innovation." Maybe not the right attitude for someone leading a safety-critical endeavor, eh?
Are those the same regulations that are said to be written in blood because people died before such rules were formed? We also have a saying at work - don't create the need for a new rule with your name on it.
I think it largely is a solved problem. They just didn't use one of the known, well tested solutions. Instead they used a shape (cylinder with spherical end caps) known to have force concentration problems as well as a composite material known to be weaker under compression than in tension.
Then they bonded the titanium rings to the CF tube in a flippin' warehouse. Not a dust free, temperature controlled clean room. Not under vacuum to ensure no trapped air in the epoxy weakened the seal. Nope, in a regular ass warehouse, by hand. And while the titanium rings would be pressed into place by the enormous amount of pressure from the water column, any leak no matter how tiny, would be catastrophic.
Not to mention the other corners they cut. What about all the other hazards for submersibles? Was there any way to protect the passengers if there was a fire, or smoke from the off the shelf electrical gear? What about restraints for the passengers should they surface under heavy seas or if the submersible were to become unstable? Would the ballasts be deployable if power is lost?
It's a shock to me that it survived the first dive, let alone multiple. It's negligent arrogance, plain and simple.