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In an interview with James Cameron, he mentions[1] that he and other submersible industry experts believe that the system worked and that they did in fact have

In an interview with James Cameron, he mentions[1] that he and other submersible industry experts believe that the system worked and that they did in fact have warning, as they had dropped the weights (which were found far away from the debris field) and were attempting to resurface before the implosion: [1]: "This Oceangate sub had sensors on the inside of the hull to give them a warning when it was starting to crack [...] they probably had warning that their hull was starting to delaminate. [...] It's our belief - as we understand from inside the community - that they had dropped their ascent weights and they were coming up trying to manage an emergency." https://youtu.be/rThZLhNF_xg?t=472 https://youtu.be/rThZLhNF_xg?t=472

carabiner 3y ago
Just fucking insane. In aerospace everyone knows that when a crack starts, IT'S OVER. Crack propagation is extremely rapid after that once nucleation has occurred. Your only hope is to prevent nucleation sites in the first place. Except it's extremely hard to characterize fatigue limits without tons of testing and even for metals there is wide variation for identical parts, not even getting into composites. Which of course we all know they did not do.
- elromulous 3y ago
  Tell that to Boeing[0] [0]https://leehamnews.com/2019/09/30/boeings-737-in-another-pickle/ https://leehamnews.com/2019/09/30/boeings-737-in-another-pic...
- lsh123 3y ago
  Not quite true. Stop drilling is commonly used on airplanes: http://o-si-sec.com/2018/10/11/5-facts-to-know-about-stop-drilling-to-treat-cracks-in-aircraft-structures/ http://o-si-sec.com/2018/10/11/5-facts-to-know-about-stop-dr...
  - kelthan 3y ago
    Air pressure decreases as you go up at a far lower rate than water pressure increases as you go down. Air pressure at 30K feet is ~0.3 Bar compared to 1.0 Bar at sea level. Water pressure increases by 1 Bar every 32ft (10m) of depth. To see the equivalent change in pressure in water (0.6 bar) as you see going up to 30K in the air, you only have to go down ~20ft (6m). The pressure on the submersible at 9000ft (2750m) is 276 Bar. F16s and other planes with composite body panels will sometimes lose a panel due to water buildup between layers of the composite. The water freezes between the layers popping the panel loose from the frame or retainers holding it in place. That is usually not a life-threatening problem (though not desirable). A crack in a submersible pressure vessel at more than a couple hundred feet is usually fatal. The description of the Byford Dolphin accident in ~300ft (~90m) of water or 9 Bar pressure, is illustrative: https://www.iflscience.com/byford-dolphin-accident-how-living-under-intense-pressure-led-to-one-of-the-most-gruesome-accidents-in-history-59230 https://www.iflscience.com/byford-dolphin-accident-how-livin... The pressure on the Titan would have been ~30 times greater than what occurred on the Dolphin.
  - maximilianburke 3y ago
    Stop drilling is only used in metallic structures, not in composites.
- colechristensen 3y ago
  > when a crack starts, IT'S OVER. Crack propagation is extremely rapid after that once nucleation has occurred This is an exaggeration, small cracks can develop and grow very slowly over the course of years. There’s lots of types and sizes of cracks.
  - watwut 3y ago
    It depends on the material and external conditions.
- kelthan 3y ago
  For those that may not understand the physics: There may have been monitors that detected structural issues in the hull (nucleation above), but at the pressures that the Titan was operating at, the amount of advanced warning is likely very, short--_maybe_ a second or two, if that. Probably not enough time to notice and reduce the pressure on the hull in any meaningful way. The slow-motion porthole cracking you see in movies like "The Abyss" is a fiction created by Hollywood for dramatic effect. The reality is far more likely to be like water freezing in a pipe: everything is fine until it isn't. The pressure the pipe exerts on the water inside of it keeps the water in liquid form until the temperature drops below the temperature/pressure equilibrium (~10F/-12C for residential copper pipe in the US). At that moment, the super-cooled water transitions from liquid to solid virtually instantaneously. <poof>. The pipe analogy is the opposite of what would happen in the submersible: the pipe explodes due to internal pressure, instead of implodes due to external pressure. But the pressure going from sustainable to unsustainable in very short order is the same.
deleted 3y ago
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seagullriffic 3y ago
This interview with Cameron has more information than most I've seen, thanks for the link.
js2 3y ago
> [Cameron] and other submersible industry experts believe that the system worked. Cameron did not say "the system worked" nor do I agree with summarizing what he did say as "the system worked." The claim in the blog post was this: > With this RTM system, we can determine if the hull is compromised well before situations become life-threatening, and safely return to the surface. It obviously did not do that. The system failed catastrophically. In the part you elided Cameron said: "I think if that's your idea of safety, then you're doing it wrong."
- xvector 3y ago
  Cameron implies that the system did detect a crack in the hull, giving them at least a few minutes of warning. Obviously, a few minutes isn't enough, but the point is that the occupants were likely aware something was wrong because of this system, as opposed to being vaporized without having enough time to comprehend their reality.
  - js2 3y ago
    I only take issue with saying that the system worked. It didn't work, since it was designed to detect failures well in advance which it did not do. Almost only counts in horse shoes and hand grenades. I wonder if they knew they were doomed or whether Rush was telling them not to worry to the very end. Personally, I think I would have rather been vaporized without the minutes of terror beforehand.

carabiner 3y ago

Just fucking insane. In aerospace everyone knows that when a crack starts, IT'S OVER. Crack propagation is extremely rapid after that once nucleation has occurred. Your only hope is to prevent nucleation sites in the first place. Except it's extremely hard to characterize fatigue limits without tons of testing and even for metals there is wide variation for identical parts, not even getting into composites. Which of course we all know they did not do.

elromulous 3y ago
Tell that to Boeing[0] [0]https://leehamnews.com/2019/09/30/boeings-737-in-another-pickle/ https://leehamnews.com/2019/09/30/boeings-737-in-another-pic...
lsh123 3y ago
Not quite true. Stop drilling is commonly used on airplanes: http://o-si-sec.com/2018/10/11/5-facts-to-know-about-stop-drilling-to-treat-cracks-in-aircraft-structures/ http://o-si-sec.com/2018/10/11/5-facts-to-know-about-stop-dr...
- kelthan 3y ago
  Air pressure decreases as you go up at a far lower rate than water pressure increases as you go down. Air pressure at 30K feet is ~0.3 Bar compared to 1.0 Bar at sea level. Water pressure increases by 1 Bar every 32ft (10m) of depth. To see the equivalent change in pressure in water (0.6 bar) as you see going up to 30K in the air, you only have to go down ~20ft (6m). The pressure on the submersible at 9000ft (2750m) is 276 Bar. F16s and other planes with composite body panels will sometimes lose a panel due to water buildup between layers of the composite. The water freezes between the layers popping the panel loose from the frame or retainers holding it in place. That is usually not a life-threatening problem (though not desirable). A crack in a submersible pressure vessel at more than a couple hundred feet is usually fatal. The description of the Byford Dolphin accident in ~300ft (~90m) of water or 9 Bar pressure, is illustrative: https://www.iflscience.com/byford-dolphin-accident-how-living-under-intense-pressure-led-to-one-of-the-most-gruesome-accidents-in-history-59230 https://www.iflscience.com/byford-dolphin-accident-how-livin... The pressure on the Titan would have been ~30 times greater than what occurred on the Dolphin.
- maximilianburke 3y ago
  Stop drilling is only used in metallic structures, not in composites.
colechristensen 3y ago
> when a crack starts, IT'S OVER. Crack propagation is extremely rapid after that once nucleation has occurred This is an exaggeration, small cracks can develop and grow very slowly over the course of years. There’s lots of types and sizes of cracks.
- watwut 3y ago
  It depends on the material and external conditions.
kelthan 3y ago
For those that may not understand the physics: There may have been monitors that detected structural issues in the hull (nucleation above), but at the pressures that the Titan was operating at, the amount of advanced warning is likely very, short--_maybe_ a second or two, if that. Probably not enough time to notice and reduce the pressure on the hull in any meaningful way. The slow-motion porthole cracking you see in movies like "The Abyss" is a fiction created by Hollywood for dramatic effect. The reality is far more likely to be like water freezing in a pipe: everything is fine until it isn't. The pressure the pipe exerts on the water inside of it keeps the water in liquid form until the temperature drops below the temperature/pressure equilibrium (~10F/-12C for residential copper pipe in the US). At that moment, the super-cooled water transitions from liquid to solid virtually instantaneously. <poof>. The pipe analogy is the opposite of what would happen in the submersible: the pipe explodes due to internal pressure, instead of implodes due to external pressure. But the pressure going from sustainable to unsustainable in very short order is the same.

deleted 3y ago

[deleted]

seagullriffic 3y ago

This interview with Cameron has more information than most I've seen, thanks for the link.

js2 3y ago

> [Cameron] and other submersible industry experts believe that the system worked. Cameron did not say "the system worked" nor do I agree with summarizing what he did say as "the system worked." The claim in the blog post was this: > With this RTM system, we can determine if the hull is compromised well before situations become life-threatening, and safely return to the surface. It obviously did not do that. The system failed catastrophically. In the part you elided Cameron said: "I think if that's your idea of safety, then you're doing it wrong."

xvector 3y ago
Cameron implies that the system did detect a crack in the hull, giving them at least a few minutes of warning. Obviously, a few minutes isn't enough, but the point is that the occupants were likely aware something was wrong because of this system, as opposed to being vaporized without having enough time to comprehend their reality.
- js2 3y ago
  I only take issue with saying that the system worked. It didn't work, since it was designed to detect failures well in advance which it did not do. Almost only counts in horse shoes and hand grenades. I wonder if they knew they were doomed or whether Rush was telling them not to worry to the very end. Personally, I think I would have rather been vaporized without the minutes of terror beforehand.