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Engineering assessment of the OceanGate Titan failure

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Re: Engineering assessment of the OceanGate Titan failure

#41

Post by onlyrealcuzzo »

SV_BubbleTime wrote: post #18
ramesh31 wrote: post #14

Earlier quoted context omitted.

My question is just... why? It's not like carbon fiber was any cheaper than just making the thing out of steel or titanium like literally every other submersible. It just doesn't make any sense. You have none of the weight penalties that exist in aviation, so the heavier and the thicker the better.

As I understood it, you do have a weight penalty for a sub. You need to get back up by powered movement, or down by it. You are limiting your dive time either way. They can’t use foam for flotation at that depth. There is a concrete like “synthetic foam” if you want unpowered rise to surface but it’s expensive. I read early on they wanted carbon to be light enough to get back up by releasing weights on powerloss. Fro…

> Nothing they did showed that they ever chose the more expensive option.

It's so absurd. Deep sea tourism is going to be something only for the .1% for a while.

They can afford a vessel that's 1000x more expensive. Your market is about 50 people. They've got unlimited money, basically.

Why cheap out and die? I just don't get it.

Re: Engineering assessment of the OceanGate Titan failure

#42

Post by parl_match »

AdamH12113 wrote: post #25

> It was previously stated by the CEO that each time he descended to that depth, the viewport deformed several inches inward. Is that normal for a submersible viewport? I feel like that's probably not normal.

At those pressures, it's not particularly unreasonable for their to be flex and shift in materials. That would be baked into design, maintenance, and monitoring. However, the lack of safety culture, testing, or modeling is more red flags than a communist rally.

More succinctly: It's probably "normal", but OceanGate didn't know if it was "normal".

Re: Engineering assessment of the OceanGate Titan failure

#43

Post by Arrath »

pugworthy wrote: post #23

> It was previously stated by the CEO that each time he descended to that depth, the viewport deformed several inches inward. Dear lord even if it is/was supposed to do that, this would be disturbing to look at.

I can't imagine a shorter path to making my lizard brain scream "SURFACE NOW"

Re: Engineering assessment of the OceanGate Titan failure

#44

Post by ghostpepper »

> Consider the fact that most engineers can explain the cause of the Hyatt Regency walkway collapse (if you can’t, you shouldn’t be an engineer), the Tacoma Narrows bridge failure, the Union Carbide Bhopal disaster, and the space shuttle Challenger disaster

Does anyone know of a good documentary about famous engineering failures? Bonus points if they actually go into detail about the scientific explanation, as opposed to focusing on the human failures

Re: Engineering assessment of the OceanGate Titan failure

#45

Post by Arrath »

throwway120385 wrote: post #31
JKCalhoun wrote: post #16

Earlier quoted context omitted.

And perhaps like the Tacoma Narrows bridge it will end up being a cautionary tale for future engineers.

The kinds of people who make these stupid decisions are never the same people who actually learn lessons the easy way like you're proposing.

This case was kind of the exception that proves the rule, beyond the 4 others caught in it.

Re: Engineering assessment of the OceanGate Titan failure

#46

Post by DiggyJohnson »

hef19898 wrote: post #8

After an initial reluctance to follow this story, mostly due to the hysterical media coverage of a pointless rescue operation, my engineering half of my brain got interested. I am by no means a materials engineer nor a naval architect, but I was involved in some Design FMEAs and wrote thesis about the manufacturing of structural, pressurized aerospace carbon fiber parts. Some things I came across, which are in line w…

Off topic: do you not use a spell-checker?

Re: Engineering assessment of the OceanGate Titan failure

#47

Post by hef19898 »

DiggyJohnson wrote: post #46
hef19898 wrote: post #8

After an initial reluctance to follow this story, mostly due to the hysterical media coverage of a pointless rescue operation, my engineering half of my brain got interested. I am by no means a materials engineer nor a naval architect, but I was involved in some Design FMEAs and wrote thesis about the manufacturing of structural, pressurized aerospace carbon fiber parts. Some things I came across, which are in line w…

Off topic: do you not use a spell-checker?

On mobile, regularly typing in three languages? No. Usually I don't write texts as long as that neither.

Edit: My Pixel 2 trained muscle memory is just so slightly off at the new Pixel 7, you should see initial versions of my posts lately...

Re: Engineering assessment of the OceanGate Titan failure

#48

Post by philjohn »

ghostpepper wrote: post #44

> Consider the fact that most engineers can explain the cause of the Hyatt Regency walkway collapse (if you can’t, you shouldn’t be an engineer), the Tacoma Narrows bridge failure, the Union Carbide Bhopal disaster, and the space shuttle Challenger disaster Does anyone know of a good documentary about famous engineering failures? Bonus points if they actually go into detail about the scientific explanation, as oppose…

Fascinating Horror and Plainly Difficult are OK - Plainy Difficult tends to go more into the mechanics of disasters, but both are operating under the constraints of a 10-15 minute YouTube video.

Re: Engineering assessment of the OceanGate Titan failure

#50

Post by buildsjets »

SV_BubbleTime wrote: post #36
hef19898 wrote: post #32

Earlier quoted context omitted.

Especially if you buy your material because it is past shelf lofe, don't use an autoclav and forgoe curing. Fun experiment: Take a roll from some toilet paper, squeeze it somewhat evenly at the ends. It is kond of stable. Then peel the layers apart, ans squeeze again. The same would happen if the composite tube delaminated at one of the end cap rings. This whole thing is beyond infuriating.

> don't use an autoclav and forgoe curing. I haven’t read that. But, that’s not an option. Carbon won’t just cure on its own, ever. It will be a shitty sticky mess forever. It had to be cured somehow. As to the carbon expiration. I don’t know what that was. I suspect it could be epoxy like in prepreg, but I doubt prepreg here. And it could be shelf life of the carbon itself as it can be hydrophilic in some cases.

Allegedly, they bought expired (out of freezer time) prepreg from Boeing Surplus. Boeing has released a statement that they have no records of this, so it likely passed through a third party before he acquired it.
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