Chef’s kiss.
Nobody expects a sudden hull implosion.
Except for the people at Oceangate who did !
Four! Four things are pressure, water, hubris, and death. 
Seriously, that was great work by @DesertDog
Yes. Thanks!
Thank you, thank you. Like XKCD there’s a Pythonism for any occasion. The whole thing popped into my mind about the time I was typing ‘polar opposite.’
I worry sometimes about where my mind goes but it’s so damn fun to watch where it winds up.
It was 2 years ago today.
IMPLOSION
Q & A —
Q: What did Stockton Rush say to Wendy before he walked out the door?
A: You feed the dogs. I’ll feed the fish.
I find it sorta interesting that all of the fallout from this in some sense validates the use of carbon fiber. Consider that the Titan was:
Incompetently designed
Incompetently built
Incompetently qualified
Incompetently operated
Incompetently maintained
And a few others…
And yet the sub still made several successful dives before failing! Imagine that they had just spent a little more time on the design, a little more money on the construction, had actually paid attention to what their sensors were telling them, and so on. They could have operated it indefinitely without incident. The hull itself would probably still have to be a wear item and be replaced every so often, but it would have completed more dives had it just been made well. The titanium parts and the parts that don’t serve as a pressure vessel could be used indefinitely.
Whether true or not, carbon fiber, at least the sort available now, will stand for “do not get into any submersible made from it” for the foreseeable future.
Simply rebranding it as Super Strong Miracle Krazy Fiber won’t do. Certifying that you tested the hell out of it and retested it after every dive won’t do.
What any future commercial deep-dive operation will need to promote is Extra-Heavy Triple-Thick Expensive Sherman Tank Steel, and charge customers what that is worth.
Yeah, and that sucks. Already I’ve seen a couple examples of people concerned about airplanes using carbon fiber because of the Titan. It’s dumb, because obviously there’s no connection between how airplanes are developed vs. Titan, but nevertheless lots of people are incapable of thinking beyond a vague “carbon fiber bad” (or, in general, “X is bad” when presented with “thing A uses X and failed”).
Nothing to be done, I suppose. But it does mean that a very useful technology will have a shadow cast on it because of one idiot.
Maybe, maybe not. My only knowledge of the engineering issues comes from reading the news stories and recently watching the Netflix documentary. But what strongly sticks in my mind is the sounds recorded on some of the dives that I heard for the first time in that documentary. These were not the “creaking” sounds I was expecting to hear, as of a strong material under pressure. These were actual “bangs”, like a hammer hitting the hull, and were the sounds of carbon fibers literally breaking.
What motivated these idiots to continue developing this thing after a huge crack was found in the first hull seems to me totally inexplicable and irresponsible. It was like Stockton Rush was fixated on the carbon fiber idea, and nothing could dissuade him.
I’ve been thinking somewhat along these lines too, a bit. Think of an aluminum soda can, and how one typically holds it while drinking from it. It’s super easy to squeeze in the sides of the can. That’s essentially the failure mode of the Titan’s hull at depth — a very simplistic view of it anyway. But if the Titan hull was reinforced with internal titanium rings (say, 3 or 4 rings) such that the hull’s walls could not flex appreciably under 6,000 psi, the resultant hull would weigh much less than one made entirely of titanium or steel or whatever the proven, typically certified deep submersibles’ hulls are made of. It would weigh more that Titan’s hull, but still significantly less than an all-metal hull.
Rush might have been on to something new that can eventually work in some form, but he was too hurried and under too much financial strain to build it right.
A carbon fiber hull, reinforced, just might end up working.
The hull started with voids and poor layer adhesion. And it wasn’t a good design, having little redundancy in the wrap directions, among other issues.
But that’s good in terms of the basic resilience of the design. It’s a bad thing if the design fails after the first tiny creak, because it means you have no margin whatsoever. It’s good if the hull has a few dives left even after the carbon fiber starts failing. Which seems to be the case here.
Of course, in actual passenger operation you don’t want to come anywhere close to that point, ideally retiring the hull before there are any signs of failure. It’s nevertheless good to know that if there are signs of failure, due to unforeseen circumstances, there is nevertheless still enough excess margin to safely return to the surface.
I don’t have access to the two new videos but 60 minutes Australia just did a segment that appears to contain some of the footage. Of course they lean heavily on the personal interest factor centering their story on the wife/mother of the paying clients but a few things stood out. First, the engineer who is still insisting that the design could work despite being fired after voicing his concerns. Second, Stockton’s wife who was monitoring the Titan, heard the sounds of it imploding and appeared to laugh it off.
Bolding mine. That’s not an accurate description of it. She asked, What was that sound? And then after a second or two when she received the message from Titan that they dropped two weights, she appeared perhaps relieved. Definitely not laughing it off.
I guess I was shocked by her apparent nonchalance and smiling. I take back my prior comment. Is there a way to see the BBC documentary? YouTube only has one from 2024.
If you can access BBC iplayer, it’s available here.
Cool, thanks for that link. It is also available on Max ➜ Watch Implosion: The Titanic Sub Disaster | Max ■
Unfortunately the BBC link says I have to be in UK to watch it.
There were signs of failure from the first dive! Every bang sound was one little bit of failure. This wasn’t “seasoning”, this wasn’t work-hardening. It was small structural failures.And it was progressing. It was never going to get better.
And it was clear it did NOT have excess margin. It failed spectacularly, probably as the warnings were going off. I bet the hull was popping like popcorn when Rush reported he was coming up. Too late!
To get any demonstrated margin of safety you should consider replacing the hull every 5 dives (If I remember, there were only 13 dives below 3000M, so margin of safety of ~2.) That’s all the data that exists. It was completely undertested. Rush needed to test several hulls to failure (unmanned, natch’) and watch the sonic data before he even considered sending it with people.
Carbon fiber is not good in compression, but that wasn’t the main problem. A cylinder is not the best shape. The connection to the sphere ends was a poor design. The viewing window wasn’t rated to that depth. The lifting rings put the wrong loads on the hull. The failed launch where the hull banged against the launching boat, for hours, was bad, and may have contributed to the failure. The hull was poorly made. During wrapping, it developed wrinkles. So what did they do? They machined them off. They machined carbon fiber! They cut the fibers. That’s criminal ignorance!
But the worst thing was they left it outside during the winter. It’s a virtual certainty that water got in, froze, expanded, and did serious damage. Possibly fatal damage.
Can carbon fiber make a successful submersible? Maybe. Was this a fair test of the material in a design? Not at all.