quote:

It also doesn’t work

It took many manned dives, so I would argue that it does indeed work.

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Except for the carbon fiber because nobody else actually is doing this with people at that depth. They won’t try it anytime soon either.

Are those building these submersibles out of carbon fiber, but without people on board experiencing catastrophic failures? I suppose that's more evidence that "it works".

The question is what are the limitations, and how can the technology be improved.

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Nobody has a deep diving submersible made of carbon fiber. Nobody

Again, that's simply not true. And even if it was true, that doesn't mean it's not viable.

In 1800 NOBODY had an aluminum airplane capable of flying at 30,000 feet at several hundred miles and hour. NOBODY! Yet here we are today with tens of thousands of people getting on them daily, having learned from many successes, failures, and loss of life. Progress.

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completely avoidable deaths.

My opinion is that people don't really need to be on any of these things at all. The technology available with high resolution video and remote control capabilities means that people can stay safely on the mothership or even land while operating them. Doesn't matter what they are made of.

The people getting inside these things are doing so for bragging rights. Look at me! I've been the deepest! That's not a material problem, that's a human problem. But as long as they are doing so with free will, then who am I to tell them what they can and can't do?

quote:

Originally posted by pedropcola:
Nobody. Nobody has a deep diving submersible made of carbon fiber. Nobody. You literally referenced 2 failed designs that aren’t going anywhere. Carbon fiber is attractive because compared to the alternatives (that work) it is cheap and light. It also doesn’t work. Nobody is building a deep diving manned submersible in this manner. That is just the fact.

When somebody does something that is so stupid that basically everybody told them it would fail and then it fails in exactly the way they were told it would fail there are no real lessons learned. The Wright Brothers flew 10 feet off the sand. They risked broken bones. They didn’t take their untried, untested device and launch off the side of a cliff. Because they weren’t idiots.

Of course humankind can learn from mistakes. Mistakes of this magnitude though don’t actually have great value.

What is the huge lesson here? Don’t use a viewing port that isn’t rated for the depths you are going to? Don’t use carbon fiber as a pressure vessel? Redundancy is good? Reliable comms also good? The lessons learned from this have mostly already been learned and incorporated. Except for the carbon fiber because nobody else actually is doing this with people at that depth. They won’t try it anytime soon either.

It seems like you are determined to add some meaning to these senseless, pointless, and completely avoidable deaths. There isn’t any. They died predictably and to no value. A waste of 5 human lives for nothing.

Well said.

quote:

Originally posted by pedropcola:
He used carbon fiber because it was cheaper. That’s it.

In its essence, yes. I read a couple of days ago that OceanGate's annual company revenues were 9 million dollars. As a comparison, the Alvin, the Navy owned submersible with an excellent track record for over 50 years, had a recent upgrade overhaul done, costing approx. $40 million. Cameron's single man sub that went down to the Challenger Deep cost $10 million to build a dozen years ago.

quote:

Originally posted by a1abdj:

quote:

It also doesn’t work

It took many manned dives, so I would argue that it does indeed work.

quote:

Except for the carbon fiber because nobody else actually is doing this with people at that depth. They won’t try it anytime soon either.

Are those building these submersibles out of carbon fiber, but without people on board experiencing catastrophic failures? I suppose that's more evidence that "it works".

The question is what are the limitations, and how can the technology be improved.

quote:

Nobody has a deep diving submersible made of carbon fiber. Nobody

Again, that's simply not true. And even if it was true, that doesn't mean it's not viable.

In 1800 NOBODY had an aluminum airplane capable of flying at 30,000 feet at several hundred miles and hour. NOBODY! Yet here we are today with tens of thousands of people getting on them daily, having learned from many successes, failures, and loss of life. Progress.

quote:

completely avoidable deaths.

My opinion is that people don't really need to be on any of these things at all. The technology available with high resolution video and remote control capabilities means that people can stay safely on the mothership or even land while operating them. Doesn't matter what they are made of.

The people getting inside these things are doing so for bragging rights. Look at me! I've been the deepest! That's not a material problem, that's a human problem. But as long as they are doing so with free will, then who am I to tell them what they can and can't do?

You're missing the point. Read my comment about prototype testing. The number of aircraft prototypes built and tested to failure, and the gradual approach to flight testing, from mild up to the aircraft's limits over many flights is how you ENGINEER things to work. Yes, test pilots died, and lessons were learned. But you DON'T make an educated guess (all designs are educated guesses until tested), build a prototype, do minimal testing (and no testing to failure) and use it up to the design intent in a commercial setting with high paying passengers.

Sure before the Wright brothers various backyard inventors tried to make flying machines that failed. That was before there was any real knowledge about aeronautical engineering, not after 60 years of established knowledge.

Modern commercial jet aircraft are all remarkably similar in design. After the Boeing 707 60 years ago established the general design, most planes look similar, because it is the most efficient design. The past 60 years has been refinement of the design with improved materials, fewer engines, bigger cabins, better controls, etc. Notice there are no 3 or 4 engine planes made anymore - one engine per wing for a large plane or two on the tail for a small plane.

If some yahooo says he's going to build a jet airliner that breaks all the current conventions because of INNOVATION and OLD WHITE GUYS AT THE FAA TOO CONCERNED ABOUT SAFETY MAKING THINGS CHANGE TOO SLOWLY, he would be laughed out of business. How about an entirely new way to make a jet engine? Ignore the base of knowledge at your own peril.

And this asshole ignored 60 years of knowledge about deep sea sub design.

a1bcdj, although I haven't stated it every single time, I have stated it enough for you to acknowledge I am speaking of MANNED carbon fiber submersibles, and I think you know that.

Nobody else runs CF manned submersibles to these depths. Yes, every so often someone explores the possibility because of the immense cost and weight savings. Then they realize, fuck, this won't work. Or at a minimum they realize it won't work very many times.

Once again, please point us to the accurate number of dives to depth that the TITAN had actually taken. OceanGate blurs that distinction because they had multiple submersibles and not all dives were to great depths.

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The primary issue doesn't seem to be carbon fiber's ability to work.

Let's back up a bit. As others have plainly stated, carbon fiber works well in tension. That fact seems to be proven. Apparently, it does not work well in compression; something not well-proven. Think of a rubber band. Up to a point, it works well in tension to hold things together. In compression...not so much.

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I have stated it enough for you to acknowledge I am speaking of MANNED carbon fiber submersibles, and I think you know that.

Does having humans on board play a role in the success or failure of the construction materials? I know what you're saying, and I say it doesn't matter. The material either works, doesn't work, or can be made to work through innovation.

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Then they realize, fuck, this won't work. Or at a minimum they realize it won't work very many times.

Make up your mind. Does it not work at all? Work sometimes? Maybe will work if proper adjustments are made?

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Once again, please point us to the accurate number of dives to depth that the TITAN had actually taken.

I wasn't there to personally verify anything, so the best I can do is point you towards some reporting. Here is reporting on the testing dives made to depth in 2018. We know it did one with the owner on board, and then a "series" of unmanned dives to depth. Let's call that 2, for a total of 3. We are already out of your original claim of only a few dives to depth, and it hasn't even been put into service yet.

https://sea-technology.com/man...eter-validation-dive

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The 4,000-meter validation dive took place on Monday, December 10, 2018 approximately 12 miles east of Little Harbour on Great Abaco Island, Bahamas......

Testing of Titan began in Puget Sound with 20 shallow manned dives, followed by a series of unmanned dives in the Bahamas to proof test the pressure hull to 4,000 meters in June 2018......

Then fast forward to 2021, we know that it made at least 10 dives to Titanic itself.

https://dan.org/alert-diver/ar...titan-meets-titanic/

quote:

By the end of 2021, the team had accomplished 10 successful dives to the Titanic: four at depth along the debris field and six surveys of the wreck. Titan’s large viewport allowed three people to simultaneously view and document the Titanic as the pilot and copilot attended to the controls.

This article mentions that Rush himself was on board 6 times in 2021, and 7 in 2022, so let's add another 7:

https://www.geekwire.com/2022/...-deep-sea-frontiers/

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Now Rush has 13 Titanic dives under his belt: six in 2021, and seven in 2022.

So just based on the reporting, and being conservative, it looks like around 20 reported dives to Titanic depths. This thing was also apparently be used in other dive locations as well. Perhaps they kept a log book that would indicate the number of dives, depths, and other information?

You've got your work cut out for you, don'tcha?

And it wasn't the dead woke guy who decided to use carbon fiber, 'cause someone else thought of it first. Meaning, of course, that he had no choice but to use it. That is to say, he didn't really choose it...uhh, it was chosen for him. Yeah, that's it.

Anyway, never mind me. You're busier than a one-legged man at a butt-kicking contest. Go get 'em, tiger!

quote:

Originally posted by a1abdj:
So just based on the reporting, and being conservative, it looks like around 20 reported dives to Titanic depths. This thing was also apparently be used in other dive locations as well. Perhaps they kept a log book that would indicate the number of dives, depths, and other information?

Logic would indicate, AT LEAST one dive too many...

quote:

Originally posted by oddball:

That is one hell of a way to be proven wrong. When a lot of experts tell you the path you're on will get you or others killed, you ignore them at your own peril, and likely at others if you do it as a commercial venture.

If you can't build it to the recognized standards because you think it costs too much, then go find something else to build.

I hope this gives anyone else starting down or on a similar path serious pause.

quote:

Logic would indicate, AT LEAST one dive too many...

There in lies the key. You have to know when enough is enough.

quote:

Picture of parabellum
posted June 24, 2023 02:39 PM Hide Post
You've got your work cut out for you, don'tcha? Big Grin

And it wasn't the dead woke guy who decided to use carbon fiber, 'cause someone else thought of it first. Meaning, of course, that he had no choice but to use it. That is to say, he didn't really choose it...uhh, it was chosen for him. Yeah, that's it. Big Grin

Anyway, never mind me. You're busier than a one-legged man at a butt-kicking contest. Go get 'em, tiger!

The more I look around the more people I find using or looking into using these materials for underwater craft. I bet our government has already spent some time and effort there as well.

I suppose if some of the naysayers spent some more time looking into things they'd find that it's not rare as they believe it to be.

Yeah, you're the only one around here with a bead on it. That's it. If only you could share your vision with them!

You ought to test it as well...It seems they went straight from the design concept, to production, to 'sea trials', and ultimately to the sea floor!

Thanks for those links. It seems to have up to 20ish dives. I sure would love to find a source, like a logbook, that would indicate how many dives exactly, how long, and how deep. That would be interesting.

I disagree with nearly every thought you have in your head on this subject. I won't convince you of anything. You seem to think with "proper adjustments" this design is potentially safe. I think you are capital N nuts for thinking this design is anywhere near safe regardless of what they do short of starting over from scratch and not using CF.

It was cheap. That was the appeal. In some arenas cheap is a great idea. Diving into the harshest environment on the planet doesn't suffer fools or cheapskates who think they can cut corners. Maybe I will be proven wrong and the next generation of deep diving submersibles will be all carbon fiber. I am very comfortable taking the under on that bet though.

That text thread makes that one dude sound like Nostradamus. Either way, interesting topic and gonna be a great movie.

I guess he won't be tired of people telling him he is going to kill someone anymore. If a bunch of people tell you that, maybe just maybe, you should reassess.

quote:

Originally posted by a1abdj:
The more I look around the more people I find using or looking into using these materials for underwater craft. I bet our government has already spent some time and effort there as well.

It might help your argument if you were a lot more specific with examples. Who + Pictures + Sources?

I think mermaids or aliens or some other absurdity at the bottom of the sea would be more fun to debate than the construction details of a squished sub. Even if folks here build carbon fiber subs as a job or even hobby the level of commitment to the carbon fiber is good or carbon fiber is bad argument seems a bit much. I also just don’t feel like this entire issue was worth more than a passing mention and a few minutes in the news cycle but it seems to have been the top news item for 3 days.

I had not intended to post more in the thread, but Para asked for a clarification.

quote:

Originally posted by P220 Smudge:

quote:

Originally posted by a1abdj:
The primary issue doesn't seem to be carbon fiber's ability to work. It's been designed, tested, and actually used successfully. The problem seems to be the potential for damage caused by repetitive diving cycles, which if unaddressed could lead to failure.

Ok, let's bring it all back to this. Since you like researching, take a look into how the aviation industry deals with damage to carbon fiber sections of airframes and it will tell you everything you need to know about how suitable is is for a high pressure submarine hull.

Since he's taking all challengers and ignoring this, I'll go head and post the punchline. The way damage is addressed in carbon fiber airframes is to cut the damaged carbon fiber and honeycomb core sections (you know, the thing that provides structural strength in the direction the carbon fiber weave doesn't travel which this sub hull didn't feature) out and replace them with either wet layup or prepreg sections matching the weave directions. This is fine in aircraft. You can take FOD damage that punches a hole right through the airframe and land safely, the hole can generally be repaired and the plane can live for many more flight hours. Compressing such a repair to thousands of pounds per square inch? "Wholly inappropriate" doesn't even apply, it's fucking nuts. You wouldn't do it.

Wrapping carbon fiber around a tube mandrel to the point where it's five inches thick and calling it good strikes me as stupid and lazy. A completely round shape with weaves running in all conceivable directions with and underframe of honeycomb core would have made a lot more sense - it would have provided structure in all directions, but they didn't do that or anything even remotely close to it.

Now, I'm not an expert. I took a class from a dude who deals with such things for Boeing, I have family and friends who work with carbon fiber airframes in both commercial and non-commercial capacities. I have slightly more experience and time logged talking with people who do this for multi-million dollar contract money than your average person, though. There may be people building deep sea subs out of carbon fiber. I highly doubt there's anyone else building what amounts to a glorified fishing reel for a hull shape and running people down to the bottom in it.

This explains another reason why Carbon Fiber tubes are not good for this application.
Plastic deformation is basically a material stretching under a load and not completely returning to its original dimension. A spring overstretched but not breaking is an example.
Elastic deformation is bending but returning to its original dimension, like a spring does in normal use.
Submarines actually compress or shrink in size somewhat in deep depths but return to normal at the surface.
Much like tempered glass, that's strong right up until it isn't.

Start on page 2, more than you wanted to know on the subject.
https://www.osti.gov/servlets/purl/1504745

quote:

Originally posted by Stlhead:
I also just don’t feel like this entire issue was worth more than a passing mention and a few minutes in the news cycle but it seems to have been the top news item for 3 days.

Well, important enough to compel you to post a couple of times in this thread.

Speaking for myself, as the days went by with new details about the company and the CEO, this became a compelling story, it has many elements to the tale; a ticking time clock of life and death, wealth and money, science, high and low end technology to satisfy the nerds, greed, lies, and deceit, a little bit of identity politics, etc. Not exactly your run-of-the-mill blond-teenage-coed-gone-missing-from-her-dorm story.

Members here thought so as well; this thread generated 25 pages in less than a week.