Titanic tourist sub goes missing in Atlantic Ocean, June 2023 #4

[somequestions]

Oceangate as a private company is not the same as NASA so maybe that is not the best example, but I think in all the cases the decision making was wrong. I can understand how people might have trusted Stockton Rush and Oceangate if you do not understand engineering. The father and son who died probably trusted that Stockton Rush knew what he was doing. Having the CEO along on the submersible would only confirm that belief. Following safety precautions is never a waste, but I think Oceangate, because of its CEO, was not a very safety-first company. The management probably followed the CEO. I wonder how many others at Oceangate besides David Lockridge voiced their safety concerns?

 

[LinasK]

Ok, but the space shuttle had been flown a few times before with erosion of the O-ring seals and it did not blow up like space shuttle Challenger. Engineers knew about the erosion of the O-ring seals and simply approved it instead of redesigning the joints. The space shuttle had shed foam before but never caused major damage to a wing. They had photographic evidence of a foam strike that may have caused damage to the left wing of space shuttle Columbia. About the Challenger, the NASA director said in the video, "We made a grievous error."

The other founder of Oceangate reminded everyone in the 60 Minutes Australia piece that the carbon fiber frame had been replaced on the Titan submersible and was not the same one as the one that was making noises on previous dives. Maybe there was something different about this particular dive that caused the Titan submersible to implode?

My point was only to look at it from the perspective of the people making the decisions, not that I agree with their decisions (or CEO Stockton Rush's decision to dive the Titan submersible).

No, carbom fiber was designed to expand for air pressure. That's why it's used for airplanes. It wasn't designed to withstand the forces of water pressure (compression). That's the best I can explain it. I'm not an engineer.

 

[panini]

Apologies if this has been mentioned already, but the Channel 5 (UK) documentary titled The Titan Sub Disaster: Minute by Minute is available on YouTube.

 

[somequestions]

I wonder if it being a colder than usual winter had any effect on the Titan submersible when it dove. According to Stockton Rush, this dive was the earliest in the year the Titan submersible had ever dived. The following is another video talking about the company Oceangate and their submersible Titan. It brings up some of the concerns the Chief Pilot David Lockridge had about the Titan submersible.

 

[ch_13]

I wonder if it being a colder than usual winter had any effect on the Titan submersible when it dove. According to Stockton Rush, this dive was the earliest in the year the Titan submersible had ever dived. The following is another video talking about the company Oceangate and their submersible Titan. It brings up some of the concerns the Chief Pilot David Lockridge had about the Titan submersible.

It’s pretty consistent temperature-wise once you get a few hundred feet underwater.

Regardless of the time-of-year it will be just above freezing in the waters near the Titanic.

 

[LinasK]

It’s pretty consistent temperature-wise once you get a few hundred feet underwater.

Regardless of the time-of-year it will be just above freezing in the waters near the Titanic.

True. although I have heard about a "storm window" for when you can dive. Some trips have been postponed for this reason.

 

[somequestions]

If what James Cameron said is true, that the Titan had dropped its ballast weights and was trying to ascend, then whatever problem the Titan had came on slowly. Whatever the problem was aboard the Titan submersible, it seems like it had to be something they could see or hear, like the acrylic port window starting to crack or the hull itself cracking so much that warnings were going off in the acoustic warning system.

I can understand why submersible operator, Karl Stanley, said what he did about Stockton Rush on the
60 Minutes Australia program. Why would you design a safety system that does not give you enough time to deal with an emergency if you have one? I think the fact that the Titan submersible had dived to the Titanic safely before really affected Stockton Rush's decision making. Maybe he thought the submersible or one of its parts could not fail in some way over a period of time?

I wonder if there will be an investigation inquiry board like there was for the Challenger space shuttle explosion? It would be interesting to know what Oceangate's management was thinking when they designed and made the decision to dive the Titan submersible.

 

[LinasK]

If what James Cameron said is true, that the Titan had dropped its ballast weights and was trying to ascend, then whatever problem the Titan had came on slowly. Whatever the problem was aboard the Titan submersible, it seems like it had to be something they could see or hear, like the acrylic port window starting to crack or the hull itself cracking so much that warnings were going off in the acoustic warning system.

I can understand why submersible operator, Karl Stanley, said what he did about Stockton Rush on the
60 Minutes Australia program. Why would you design a safety system that does not give you enough time to deal with an emergency if you have one? I think the fact that the Titan submersible had dived to the Titanic safely before really affected Stockton Rush's decision making. Maybe he thought the submersible or one of its parts could not fail in some way over a period of time?

I wonder if there will be an investigation inquiry board like there was for the Challenger space shuttle explosion? It would be interesting to know what Oceangate's management was thinking when they designed and made the decision to dive the Titan submersible.

i disagree that the problem came on slowly. From everything I've learned about this tragedy from the experts and my husband who was a mechanical engineer and has done diving, this problem happened very quickly, long before they had time to ascend. They may have heard the cracking, but no way could they rise quickly enough to relieve the pressure. Also if you rise quickly, divers risk getting the bends from the change in water pressure. They were close to the depth of the Titanic where the pressure was the greatest.
Rush had what's called Chutzpah to believe that you could apply the principles of air pressure to water pressure. The safety of past dives in no way was an indicator of the safety of future dives. It's just a shame that he took along paying customers.

 

[Odeto BJ]

i disagree that the problem came on slowly. From everything I've learned about this tragedy from the experts and my husband who was a mechanical engineer and has done diving, this problem happened very quickly, long before they had time to ascend. They may have heard the cracking, but no way could they rise quickly enough to relieve the pressure. Also if you rise quickly, divers risk getting the bends from the change in water pressure. They were close to the depth of the Titanic where the pressure was the greatest.

The interior of Titan's shell was at or near atmospheric pressure and there would be negligible effect on the passengers from rising either quickly or slowly, providing the expulsion and introduction of "fresh" air could be controlled throughout. Limitations of the control system maintaining that oxygen content and internal pressure would be determinant of the rate of rise the passengers could tolerate.
The shell of the vessel would be effected by the rate of rise and the effect is cumulative over a count of dives. In simplest terms, the shell would shrink marginally as Titan descended, then expand as Titan ascended. For an elastic material formed in a simple sphere, the shape and material integrity would be the same after the descend-ascend cycle as it was prior to being submerged.

Dating back to the late 1960's and known to be conservative: NASA SP-8007 was the guiding light for composite structural analysis until manufacturing methods improved and inherent discontinuities and imperfections were minimized. The great incentive for aerospace to minimize weight meant the too safe approach could not be sustained; much of the subsequent studies were done between 2002 and 2014. Abstract of one example is below: its list of references indicative of the progress in this area and the dates as investigations evolved in this area. https://www.sciencedirect.com/science/article/abs/pii/S0263823108000438
Notable for fiber composites: a specific manufacturing technique has an identifiable range of imperfection size; and that the ratio of imperfection size to vessel size is not as great a determinant as is the proximity of imperfections of a given size. For lack of a better explanation: high stresses would cause the material to crack in the span between adjacent imperfections. Cracks would propagate faster if adjacent discontinuities were close together.

Almost exclusive to the Titan: a void in the original material that contained air and a few volatiles could shrink considerably as Titan descended if the confines of the bubble had any elasticity; and subsequently expand as Titan ascended. The resultant would be very high forces applied to the localized confining material and the described cracking between voids. This is one mechanism that would cause the shell to weaken overall with successive trips. This also represents one contrast between commercial airliner construction where the pressure changes are relatively small, and submersibles where the pressure cycle is very large.

A simple way to think of this: Blow up a balloon to a known pressure lower than its burst pressure, let it deflate, repeat 4 to 5 times. With each cycle, the balloon gets larger before the known pressure is reached. And inevitably at some count of cycles the balloon is going to burst before the control pressure is reached because with each cycle the balloon's skin got thinner as its overall contained size grew. Service progressive failure mechanism.

So the question becomes, for a specific pressure and initial size/ thickness of balloon, how many cycles? If the control pressure is close to burst pressure, not many. And if you sampled 100 balloons, quality definitely becomes a topic: the best might tolerate 1000 cycles, the worst 10. Balloon manufacturing is probably not a highly quality-controlled process, the outcome of poor quality being largely insignificant. Unless its your birthday...

Sorry about the length

 

[I am not Sherlock H.]

I am not a civil structural engineer but my late father was. Wish he was around to ask these questions: weren’t there also some opinions or concerns about the asymmetrical shape of portions of this submersible? At least that odd shape on the one end almost like a genie’s slipper or teardrop? And weren’t there also concerns about the attachment mechanism and materials to fit the end ring to the cylindrical tube? And inherently dissimilar materials? MOO

 

[PrairieWind]

I am not a civil structural engineer but my late father was. Wish he was around to ask these questions: weren’t there also some opinions or concerns about the asymmetrical shape of portions of this submersible? At least that odd shape on the one end almost like a genie’s slipper or teardrop? And weren’t there also concerns about the attachment mechanism and materials to fit the end ring to the cylindrical tube? And inherently dissimilar materials? MOO

The exterior shape you are seeing, in regard to the sort of pointed end is all just outside non-pressurized cowling. The pressure hull was cylindrical with half spherical caps. I believe the caps were titanium and cylinder was composite material. There has been a lot of talk about the fitting of the caps to the cylinder hull and of course the shape, cylinder vs sphere is largely cited. The porthole that was not rated for that depth. I think there were a lot of potential failure points. I don't know they will be able to pinpoint the failure point. It seems like they may have recovered enough to figure that out, but I don't know.

 

[PrairieWind]

If what James Cameron said is true, that the Titan had dropped its ballast weights and was trying to ascend, then whatever problem the Titan had came on slowly. Whatever the problem was aboard the Titan submersible, it seems like it had to be something they could see or hear, like the acrylic port window starting to crack or the hull itself cracking so much that warnings were going off in the acoustic warning system.

I can understand why submersible operator, Karl Stanley, said what he did about Stockton Rush on the
60 Minutes Australia program. Why would you design a safety system that does not give you enough time to deal with an emergency if you have one? I think the fact that the Titan submersible had dived to the Titanic safely before really affected Stockton Rush's decision making. Maybe he thought the submersible or one of its parts could not fail in some way over a period of time?

I wonder if there will be an investigation inquiry board like there was for the Challenger space shuttle explosion? It would be interesting to know what Oceangate's management was thinking when they designed and made the decision to dive the Titan submersible.

I have not had a chance to watch a lot of the video/documentaries on this. What was the basis of knowledge for Cameron's statement that Titan had dropped its ballast and was trying to ascend?

 

[LinasK]

I have not had a chance to watch a lot of the video/documentaries on this. What was the basis of knowledge for Cameron's statement that Titan had dropped its ballast and was trying to ascend?

That may well be true, but there's no way that they could have ascended rapidly enough to relieve the pressure once the cracking started.

 

[Odeto BJ]

I am not a civil structural engineer but my late father was. Wish he was around to ask these questions: weren’t there also some opinions or concerns about the asymmetrical shape of portions of this submersible? At least that odd shape on the one end almost like a genie’s slipper or teardrop? And weren’t there also concerns about the attachment mechanism and materials to fit the end ring to the cylindrical tube? And inherently dissimilar materials? MOO

The teardrop shape is not pressure containing or defining. It is basically a shield over some of the mechanical equipment and tanks, hoses, etc. and acts somewhat as a rudder. The shape of concern is the overall cylinder and its junction to the end bells. Because they are dissimilar materials there was always going to be some relative motion at the flanges as external pressures rose. Of course one pair of flanges were bolted and that introduces another quality issue: How did they control the assembly procedure such that the bolt landings and torque were sufficient and the same around the entire bolt circle? One bolt that was over tight would introduce a high local stress to both materials, which the titanium would likely tolerate but the carbon fiber? Of course, the external pressure is pushing the flange faces together so the bolts are less stressed at depth than they are on the ocean surface.

I drafted my post above as explanation of the progressive nature of the failure mechanism, or to put it another way: why did the Titan survive multiple dives to the depths of the Titanic and then fail on this trip? If it had been made entirely of a homogeneous isentropic material (like titanium plate...) at stress levels where fatigue would not play a role: it would have performed the same way on the first dive as it would on the hundredth dive.

It will be interesting in the near term to see how Boeing and others approach the life cycle of carbon fiber components of aircraft. For planes, the localized high stresses are the result of events: hard landings, severe turbulence, quick manoeuvres. Maybe even bird strikes. Aircraft maintenance inspections will involve precision high tech equipment which means a whole new round of training. All this will have been long since been developed: and those manufacturers have the great benefit of a large population of equipment that have encountered virtually all those events by now.

 

[BeachSky]

If what James Cameron said is true, that the Titan had dropped its ballast weights and was trying to ascend, then whatever problem the Titan had came on slowly. Whatever the problem was aboard the Titan submersible, it seems like it had to be something they could see or hear, like the acrylic port window starting to crack or the hull itself cracking so much that warnings were going off in the acoustic warning system.

I can understand why submersible operator, Karl Stanley, said what he did about Stockton Rush on the
60 Minutes Australia program. Why would you design a safety system that does not give you enough time to deal with an emergency if you have one? I think the fact that the Titan submersible had dived to the Titanic safely before really affected Stockton Rush's decision making. Maybe he thought the submersible or one of its parts could not fail in some way over a period of time?

I wonder if there will be an investigation inquiry board like there was for the Challenger space shuttle explosion? It would be interesting to know what Oceangate's management was thinking when they designed and made the decision to dive the Titan submersible.

IDK if you watched the CNN special on the Columbia explosion last Sunday. But IMO that final fatal decision (or the buck)stopped at one person. That one person had the final say. Even though others were deeply concerned, begged (with proof) re entry would be fatal.

MOO

 

[Odeto BJ]

Why would you design a safety system that does not give you enough time to deal with an emergency if you have one? I think the fact that the Titan submersible had dived to the Titanic safely before really affected Stockton Rush's decision making. Maybe he thought the submersible or one of its parts could not fail in some way over a period of time?

BBM: some readings from between the lines...
The Titan's alarm system was monitoring the vibration of cracks as they occurred and developed over time, for the entire service history of the vessel. I believe it was not just counting but also ranking the intensity of vibration such that it would record the "product" of how often and how hard. A single anomalous sound was not sufficient to trigger the warning. The warning would not be an audible alarm: some passengers would have gone into panic or immediate cardiac arrest if such a signal of pending disaster was issued.
That leads to the premise that the designers were aware of the decay mechanisms and were using the "acoustic" system to anticipate when the accumulation and propogation of defects left the shell "unsuited for purpose". They were expecting that on the early trips the count would be fairly low and of decreased intensity but as the trips accumulated both the rate at which cracks developed and their extent would increase: So more cracks per minute after 10 trips than there were on the first trip; and should the intensity also increase, that would represent a greater cumulative decay. The records may also have a orientation component, that is the area of the shell from which the vibration was initiated could be established and retained as a zone of progressing decay.
This demonstrates awareness of the shortcomings of CF matrix and an attempt to identify when failure was forthcoming; the accumulated data would be reviewed after each dive as the frequency and intensity of vibration events. Presumably the designers had established emperically what rate and intensity and concentration or "focus" represented unacceptable hazard and that would be cause to stop diving to depth and renew (or possibly downrate...) the shell. From afar, I believe that tolerable loss of integrity is what they got wrong. JMO because I do not know the details of the system; but this approach makes at least some sense over waiting for a single big event.
I would also anticipate that this cumulative, integrated measure was being monitored full time from the surface vessel.
Of course, there is the possibility that something happened in the depths that applied forces totally beyond the static and dynamic forces anticipated, though in this service a designer would anticipate that the static would far exceed any anticipated dynamic.

 

[somequestions]

IDK if you watched the CNN special on the Columbia explosion last Sunday. But IMO that final fatal decision (or the buck)stopped at one person. That one person had the final say. Even though others were deeply concerned, begged (with proof) re entry would be fatal.

MOO

I posted a clip of a Retro report about both the Challenger and Columbia disasters in post 534. It is a great 20 minute clip. Columbia story starts at the 13 minute mark. The head of the management team for Columbia did not participate in the program.

The Challenger disaster was more surprising for me because I did not know all the decision making that went into the decision to launch. The project director for Challenger did participate in the program.

Oceangate CEO Stockton Rush said he worked with NASA when building the Titan submersible even though that turned out not to be true. Because the main component that failed on the Challenger was O-ring seals and David Lockridge wrote up the "O-Ring Seal" as part of his concerns about the Titan submersible when he worked at Oceangate, it made me wonder about how the acrylic viewport or the O-ring seals could be affected by cold water temperatures.

 

[Odeto BJ]

Because the main component that failed on the Challenger was O-ring seals and David Lockridge wrote up the "O-Ring Seal" as part of his concerns about the Titan submersible when he worked at Oceangate, it made me wonder about how the acrylic viewport or the O-ring seals could be affected by cold water temperatures.

Clipped by me...

Morton Thiokol and others designed the flange joint to a set of requirements that included ambient temperature at launch. A whole team and a lot of testing was applied to ensure that it meant the coincident requirements: and when the weather did not cooperate and NASA wanted MT to advise on suitability at the lower temperature: MT balked and obfuscated; but eventually yielded. One of the times when senior managers overrode the engineering team. Point being, the envelope of application had been established and limits set; then they wanted to work outside that envelope.
The difference largely is: the explosion took place in mid air, with lots of media and NASA themselves recording, with the craft at a pretty high speed. Highly visible mishap.

For Titan: The conditions of high pressures and low temperatures were anticipated and understood. Actually in temperature terms the variance from ambient is not all that great; not even a third of what would be encountered by a commercial air liner. The pressure is well past what most containments are designed for, even high force hydraulics operate at less than half of the submersion pressures here.

 

[Charlot123]

I posted a clip of a Retro report about both the Challenger and Columbia disasters in post 534. It is a great 20 minute clip. Columbia story starts at the 13 minute mark. The head of the management team for Columbia did not participate in the program.

The Challenger disaster was more surprising for me because I did not know all the decision making that went into the decision to launch. The project director for Challenger did participate in the program.

Oceangate CEO Stockton Rush said he worked with NASA when building the Titan submersible even though that turned out not to be true. Because the main component that failed on the Challenger was O-ring seals and David Lockridge wrote up the "O-Ring Seal" as part of his concerns about the Titan submersible when he worked at Oceangate, it made me wonder about how the acrylic viewport or the O-ring seals could be affected by cold water temperatures.

Thank you very much for linking this movie. It is interesting to compare all three situations from the leadership angle. 1. The Challenger. At that time, the critical decision was left with the wrong team (the managers). However, NASA is still a team structure. A spacecraft consists of many parts; at any point, things can go wrong. When the spaceship disintegrated, it wasn’t “oh, darn, these O-rings”. It took Rogers commission over 5 months to arrive at their conclusion. Given how many times the launch had been postponed, I suspect that post-accident, different scenarios were entertained. Ultimately, Lawrence Mulloy, a manager, took the most flak. His attitude was, “we have been postponing it for too long, and we don’t have any data about O-rings performance at low temperatures. They have held so far. So let us make the decision to go ahead, and if we are wrong, it will be my head on the table.” A wrong decision, sadly, but in Mulloy’s stance, I can still see that old generation of leaders who are unafraid of responsibility. On the screen, he is humanely grieving. Also, you can see how everyone still feels about the Challenger and the crew. No engineer says, “me, me, me was right”. Everyone blames himself for not having done more. The only problem with that old leadership is perhaps excessive response to pressure from above in the context of financial constraints, but it is not the worst thing that can happen.

2. The Columbia leadership is a huge step down. Communication is bureaucratized, rigid and fractioned. Everything is politics (“improper lines of communication”), but the chief enforcer is a poor politician. I don’t know by what parameters Linda Ham was chosen to lead, but is a mismatch for the role. Being blunt and unapproachable, Linda, sadly, serves to dehumanize the outcome. Did she personally contribute to the disaster? I don’t think so. Perhaps the astronauts were doomed either way. But at least the management ought to have publicly acknowledged the risk and considered trying to save the crew instead of denialism. Why didn’t Linda participate in this movie? I think being interviewed about the disaster is hard for a person who feels the empathy but can’t project it onscreen. Another explanation - a new generation of leaders shies away from responsibility.

3. In comparison to NASA, the Titan is a tiny one-man show with a glitzy, conceited leader. Instead of teams, Rush leads students from a local community college, the only person with experience being fired and sued. The whole story revolts around Stockton Rush’s own inflated, vindictive ego. Responsibility? Nada, zero - the submersion “is safer than crossing a street”, he says. A private grandiose entrepreneur, Rush feels absolutely no empathy for the passengers because he’d die too.

I would describe the Challenger and the Columbia catastrophes as “we don’t know, but we haven’t had a problem with it before, so let us take the risk,” situations. With Rush, it was “I absolutely do know” one.

Interestingly, i can see some superficial parallels between Rush and Richard Feynman, both being extremely self-conceited, but first, Feynman was a Nobel prize winner, and second, he accused NASA of showmanship in bringing Christa McAuliffe to that flight.

 

[ch_13]

Interestingly, i can see some superficial parallels between Rush and Richard Feynman, both being extremely self-conceited, but first, Feynman was a Nobel prize winner, and second, he accused NASA of showmanship in bringing Christa McAuliffe to that flight.

Feynman may have had an extremely high opinion of himself, but as you note it was deserved and based on his long, long list of achievements. Not because his ancestors came over on the Mayflower and he inherited a lot of money.

And Feynman would have never confused facts with what he wanted to be true. As a practicing scientist, Feynman understood the difference between theorizing something and running experiments and tests to actually prove the theory correct. Rush just assumed if he thought something was true ("carbon fiber would make a good pressure hull"), then reality would bend to his will.

This reminds me of the clip from a young Feynman's physics lecture at Cornell: "It doesn't make a difference how beautiful your guess is. It doesn't make a difference how smart you are; who made the guess, or what his name is. If it disagrees with experiment, it's wrong."

Free: Richard Feynman’s Physics Course from Cornell (1964)

We're beaming you back to 1964. Richard Feynman, our favorite Bongo-playing, Nobel Prize-winning physicist, reduces science to the barest essentials, to its most fundamental truth. If a theory doesn't square with experiment, it's wrong.

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