The implosion of the Titan submarine (OceanGate) was so rapid that the pain wasn't even registered by the brain. They didn't feel anything at all. Utterly instantaneous.

[u/ThugLeeVoguee]

[u/Usual_Ask_7833]

It wasn't a test dive, the Titan actually made it to the Titanic 13 times prior.

The issue, as explained by James Cameron, was that each time a sub dives the material experiences fatigue damage and eventually fails. It's like a soda pop tab, it doesn't break the first or second time you bend it, but if you keep bending it then it will eventually break.

Rush didn't want to do the standard test to the hull after each dive because it was expensive and took a long time so he created his own acoustic monitoring system which obviously didn't work.

James Cameron says subs are normally retired after 6-8 dives, if Rush wasn't so cheap and replaced his sub more often he would probably still be doing dives today.

[u/FaudelCastro → u/Usual_Ask_7833]

The acoustic monitoring worked, he ignored it.

[u/Spear_n_Magic_Helmet → u/FaudelCastro]

Yep. Also ignored the “oops we let the untethered submersible bang dozens of times against another vessel in heavy ocean for several minutes” on the mission prior. And left it outside in winter. And and and

[u/flaming_burrito_ → u/Spear_n_Magic_Helmet]

This is why when you’re an inspector or safety supervisor in any serious position, they drill into you to never assume that people will follow a rule, no matter how obvious it is, or how many flashing lights you put in their face. Given enough opportunities, it is a near guarantee that eventually someone stupid will do the obviously stupid thing. Human creativity, and thus capacity for stupidity, is nearly infinite. People will find a way to bumble their way into situations you never even considered could be a possibility, because you are likely a reasonable person with a rational mind. They, however, are not.

[u/bigboyjak → u/FaudelCastro]

Even worse.. when you look at the data, even a layman like me can see that on dive 80 something OBVIOUSLY broke. The data from their own monitoring system shows obvious discrepancies from the dives before and dives after.

Mind you, this data is from how the hull is flexing and stressing under the dives.. Perhaps the most important data to a submersible.. and it was just ignored? Never looked at?

That's what I found most insane about the whole thing. Their own data showed something went wrong..

Here's an image I stole from another Reddit thread that shows the data I'm talking about. Blue is dive 80, orange is dive 81

[u/SpiritJuice → u/FaudelCastro]

Final report revealed that only five of the eight monitors were working at the final dive. Just more shit to add to the pile of things going wrong due to human error.

[u/AirconGuyUK → u/Usual_Ask_7833]

I'm still surprised it managed to make it down even once. It's such an unsuitable material to make a submarine out of on paper.

[u/blackhorse15A → u/Usual_Ask_7833]

each time a sub dives the material experiences fatigue damage and eventually fails

This is not true for all materials. Steal can be designed so that the load/deflection stays below a certain amount then there is not fatigue damage and you have infinite cycles. Design it or allow it to go past that load and then you will have a fatigue problem where repeated cycles add up until a failure happens. But it is possible to design steel for infinite cycles.

Aluminum however, does not have this property. No matter how small the load, how little the deflection, it will eventually fail due to the fatigue building up. That's why you can take a piece of aluminum and just bend it back and forth and back and forth until it eventually breaks. You can the part strong or the load on it smaller, that will increase the number of cycles, but there will always be a limited number of cycles and then it fail from fatigue.

Carbon fiber...well... cabon fiber in a resin polymer is not a metal. So technically it doesn't fail from fatigue the way metals do. But, that's actually kind of a bad thing because it's not as predictable. So under small loads carbon fiber is actually very good for fatigue- better than a lot of metals. However, they are many other factors that will degrade the resin or the fiber that metals would t be affected by. So a lot of other things are breaking it down even without any load at all, just sitting out in the sun or during storage. But when we start talking about very high loads (like deep ocean) that is very similar to metal fatigue in that it will start to create crack that propagate and then delamination occurs then failure. In metal that's a microscopic process at the grains of metal. In the carbon fiber it's a lot bigger and once it starts it can accelerate and then go catastrophic quick. So cyclic loading under high loads does cause carbon fiber to start to fail, and problem grows until it fails completely. Kind of like metal fatigue. But the process is different and the predictability isn't as good. Metal objects we could measure the deflection/load and just count the number of cycles then pull it out of service at a certain number (which is like 90% of expected life to account for variations and use different numbers based on how much safety margin you need.) But carbon fiber you'd really need to be inspecting it closely, like ultrasound the whole thing, regularly to keep an eye on it and detect the problem before catastrophic failure happens. Safety critical stuff might need that every time. Or, save a bunch of money and roll the dice and hope you don't die.

[u/IheartPickleSoda → u/Usual_Ask_7833]

They did pressure tests of smaller scale models and not a single one passed.

[u/Theyul1us → u/Usual_Ask_7833]

Dont forget that he fired and sued the engineer that said it wasnt safe