My suspicion as to what caused the Titan disaster

[jmowreader]

Well...apart from the insanity of getting in such a thing and diving two miles below the surface of the ocean.

This vessel made something like 50 dives, many of them to the Titanic. The water pressure at Titanic depth is 5625 psi. By comparison, water will compress by one percent of its volume at the relatively low pressure of 3000 psi. Hence, this thing was at a depth high enough to compress something normally considered absolutely incompressible.

Titan's pressure hull was made of 660 layers of filament-wound carbon fiber. What that means is they got a big pipe or something that was the outside diameter of the inside of the pressure hull, coated it with something epoxy won't stick to, and put it in a machine that will rotate it at a certain number of revolutions per minute. This pipe would be called a mandrel. They then got a roll of carbon fiber, and wound the filament onto the mandrel through a machine that coated the filament in epoxy until the winding was as long as they needed it to be. Epoxy is used because it's the only thing that'll stick to carbon fiber. Once they get to the end of the winding they put a new roll of CF onto the machine and wind it back the other direction. Do this over and over until you have 660 layers of CF on the mandrel. After doing all this they stick the mandrel and its layer of CF into an autoclave to cure it. At the end of the curing cycle they pull out the mandrel and have a pressure hull.

This is a video of them making a Boeing 787 fuselage section the same way.

Filament-wound carbon fiber is used for many things like making bicycle forks. It is a proven and reliable technology.

Now for the problem: Epoxy is not flexible. At the depths this boat operated, it was going to compress at least slightly. US Navy submarines compress at their operating depth, which is far shallower than Titan worked at. Repeated compression and expansion is going to abuse the epoxy, and at some point the abuse is going to get severe enough that the epoxy in the CF matrix will fail. Unfortunately for five rich people, this failure happened at the worst possible time - when the boat was two miles below the surface.

[ellisonz]

1. Excessive Wealth Disorder

It's a thing!

[Alexander Of Assyria]

2. Too many woke passengers in third class!?

[ellisonz]

3. No lifeboat for you.

Yes, clearly all problems are simply a matter of engineering.

[ellisonz]

4. Next up: Introduction to the Physics of Icebergs

Don't hit em!

[jmowreader]

18. The third-class passengers were required to ride on the roof

[Alexander Of Assyria]

19. It's a joke! Aware of their plight..the Rich have a long history of suppression and cruelty.

All the gawking over the artifacts of the rich…ignoring the masses … again.

[demosincebirth]

15. They are still human beings

[ellisonz]

20. So sad.

[Sky Jewels]

23. I especially feel for the 19-year-old son of the Pakistani businessman.

It was reported that he didn't want to do the excursion, but went ahead with it because it was Father's Day.

On the other hand, as far as I'm concerned, Stockton Rush, the safety-and-regulations-eschewing CEO, can burn in Hell for killing four people (five, if you count him) with his hubris. ... I wish I actually believed in Hell.

[Kennah]

30. So were the hundreds on a migrant boat off the coast of Greece

[Boomerproud]

31. A correct and empathetic response.

NT

[Kennah]

32. I have to be careful

If I think too much about, I descend.

Imagine if the money sunk, no pun intended, into OceanGate had been applied to safely transiting migrants to their destinations.

[wnylib]

34. Well, they were. Past tense seems appropriate here.

But, I agree. Dehumanizing others also dehumanizes us.

What I don't understand is what could be so great about looking at the debris of an old wrecked ship? They were not able to actually explore the ruins. They would only see the shipwreck on a TV screen. Couldn't they just as well view it on a screen from above the water by sending down unmanned cameras?

It's not like they would have seen the beautiful staterooms, dining room with tablecloths and place settings, or chandeliers glittering from the ceiling. They would only see debris.

[ellisonz]

35. Why does anyone need to view the Titanic at all?

It's a gravesite. Lots of people died there, it shouldn't be a tourist destination.

If you want to see the Titanic, watch the movie!

[demosincebirth]

36. Curiosity? We do stupid things

[LiberalFighter]

37. What they need to do is manufacture a couple hundred of them.

And then find enough suckers to make the trip all on the same day.

[Ptah]

5. Epoxy can be flexible:

https://www.dic-global.com/en/products/epoxy/flexible/

[WarGamer]

6. well said...

A carbon fiber wing assembly is NOT rated to perform a trillion cycles...

Carbon fiber weakens slightly with time as you noted, BECAUSE of the resin.

So... the sub may have been okey dokey and a-ok fine on the first 50 dives and the slightest weak spot would have caused the failure.

This is why... in the complex world of Gov't and Gov't contracted work, parts and pieces are examined closely after every use.

In fact... if the Gov't had a carbon fiber chamber, maybe they'd require destruction after 25 uses.

[NutmegYankee]

11. The Navy would not have certified the material without extensive testing beforehand. nt

[sarisataka]

7. That is similar to the concern

Expressed by the safety manager. Repeated dives could be weakening the hull. There wouldn't necessarily be any external sign of the accumulated wear and tear.

He wanted to have it tested, they fired him instead.

[tinrobot]

8. Carbon fiber tends to fail catastrophically.

Just look at what bike frames do when crashed. Steel and titanium will deform/bend to a large degree, but carbon mostly shatters.

At those depths and pressures, it was only a matter of time before that carbon fiber failed.

Interestingly, the titanium end cap survived.

[doc03]

16. I had a carbon fiber fishing rod I used for years I bent it nearly double and dropped it

a hundred times. One day I leaned it on my boat seat to tie on a lure and it slid maybe 6 inches and it just tapped the edge of the aluminum boat and lt literally exploded. I just got a carbon fiber bicycle this spring, it cost almost $3000, I hope I don't drop it. Metals also get brittle over time from heating and cooling sometimes that is why a boiler, bridge or building fails.

[LiberalFighter]

38. Sell your bike soon?

[doc03]

42. I will take my chances. I just got it a couple months ago, have about 800 miles on it.

It weighs about half of what my old aluminum one does. I know several people that have CF bikes one did have
his break but he is younger and he rides mountain trails. I am 75, I stick to rail trails that are paved or crushed limestone.

[jmowreader]

17. Why do you think I refuse to ride a carbon fiber bicycle?

I suspect if I was an Ironman Pro and I HAD to ride a CF bike I'd change my frame halfway through the season, and I DEFINITELY would have a new frame for Kona! Truth be told, I don't trust the stuff.

[obamanut2012]

24. Which is why I don't buy carbon-framed bikes

I know me, and it would shatter within three months. Luckily, Trek has plenty of steel/aluminum frames!

[NutmegYankee]

9. And when carbon Fiber fails, it's violently.

It doesn't crack and arrest like a metal.

[PCIntern]

10. Hey! Don't bother me with scientific facts!

You know, it’s people like you what cause unrest…

I am old enough to remember when they built the space shuttle, and they said if any of those tiles failed the space shuttle would disintegrate due to the great heat upon reentry. Most of assumed that at least one of those tiles had to have some faults to it, but miraculously for years, until the end, all went well. Until it didn’t.

[Blue Owl]

13. That's right -- it was either the work of THE LORD or SATAN

[Chainfire]

27. For heaven's sakes at least leave open the possibility of aliens.

Or perhaps there is an intelligent lifeform living at those depths that don't want people poking around.

[anciano]

12. It was a "vanity" excursion plain and simple.....

you can view the Titanic wreckage on YouTube for free.

[Easterncedar]

14. On second thought. I'm deleting.

[sdfernando]

21. Its really just a one word answer...

Hubris.

Now I appreciate your explanation and the mechanics certainly make sense...but for me the simple answer is hubris.

[Sneederbunk]

22. Murphy's Law is immovable.

[mike_c]

25. five souls lost at sea

Hindsight is always 20-20. I hope they died quickly and mercifully. That sounds likely. Their wealth is not the point. Following their passions, five souls were lost at sea.

[Chainfire]

26. If I was a betting man, I would be betting on a hull fitting blowing in rather than a hull collapse;

window, cable penetration or something similar. But, no matter what caused the vehicle to rupture, it would have probably been over long before the crew and passengers knew there was a problem. It would be like a 200 pound bomb going off under the seat you are sitting in. Here on second, gone the next. Which would be far, far better than slowly suffocating after several days.

[Chainfire]

28. So what happens to a human body if suddenly exposed to those types or pressures.

Not trying to be morbid, but I am curious.

[sarisataka]

29. As I understand

Within milliseconds of the moment of failure all that pressure would be applied and the term bodies essentially becomes meaningless.

Anything in the body which can be compressed such as air in the lungs, Soft tissue, bones etc. Ra would be squeezed to the smallest possible space much like squeezing down a sponge.

Since fluids are essentially incompressible they would have been left behind when all those other parts were squeezed.

With pressure coming from all directions the passengers would be squeezed into one organic lump surrounded by human fluids and sea water.

[LiberalFighter]

39. There should be a video of it.

[Chainfire]

41. That sounds like it would make your ears pop.

[ZonkerHarris]

40. the effect is like stepping on a bug.

[BootinUp]

33. I found a composites world article on the OceanGate design and fabrication

Published 5/10/2017
Composite submersibles: Under pressure in deep, deep waters
Manned deepsea exploration calls for a highly engineered composites solution that saves weight and preserves life — at 6,500-psi service pressure.
#autoclave #focusondesign

In 2014, submersibles manufacturer OceanGate Inc. (Seattle, WA, US) was coming off the successful launch of Cyclops 1, its steel-hulled, five-person craft, rated for underwater exploration to a depth of 500m. The company was set to embark on development of Cyclops 2, a five-person research-class submersible, designed for a maximum depth of 4,000m.

OceanGate CEO Stockton Rush says the company had been evaluating the potential of using a carbon fiber composite hull since 2010, primarily because it permits creation of a pressure vessel that is naturally buoyant and, therefore, would enable OceanGate to forgo the use — and the significant expense — of syntactic foam on its exterior. So, for Cyclops 2 OceanGate decided to avoid the metallic hull altogether and began a search for a manufacturer that could help it develop a composite hull.

It is believed that the first time carbon fiber composites were applied to the hull of a deep-diving, manned submersible was for the one-person DeepFlight Challenger, commissioned by adventurist Steve Fossett in 2000 for a dive to the bottom of Challenger Deep (see Deepsea submersible incorporates composite pressure capsule). Designed and built by famed marine engineer and submersible designer Graham Hawkes, a principal at the time of Hawkes Ocean Technologies (Point Richmond, CA, US), it featured a cylindrical carbon fiber/epoxy composite hull with 6-inch-thick walls. It was nearing completion in 2007 when Fossett was killed in a light-aircraft crash. The Challenger was subsequently sold, and has yet to be fully tested or deployed in a deepsea dive. Spencer Composites Inc. (Sacramento, CA, US), a designer/manufacturer of composite parts and structures for a variety of end-markets, had designed and fabricated the DeepFlight Challenger’s hull.

“I knew of the submersible Graham Hawkes designed for Steve Fossett,” says OceanGate’s Rush. “And I knew Spencer Composites manufactured that cylinder.”

https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters