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Yeah,
I don't know much about the missing submersible that's been on the news. Just what they say on the TV.
Bruno van Dooren wrote: In a properly designed machine, safety would not hinge on a single point of failure
Indeed. There is a reason everyone is adopting triple redundancy. But it also triples the cost. Including three control computers to read and vote on which sensor is correct.
Bruno van Dooren wrote: The controller isn't even close to the top 10 list of major problems with their situation.
Sounds really bad based on your description. Do you have a link to anything I can read?
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OceanGate boss Stockton Rush revealed he's 'broken some rules to make' lost Titan sub | Daily Mail Online[^]
Idk if it mentions everything but from what I gathered so far from different sources:
The hull structure has a max rating of 1300 m depth. Not 4000.
It's controlled with a laptop and logitech game controller knockoff. Via bluetooth.
There didn't seem to be simple electromechanical failsafes.
Control cabling runs on the ourside of the hull where it can snag, which means it can get stuck, as well as lose control that way.
The thing is made from a carbonfiber titanium composite which engineering studies told him he should not use, because tthose 2 materials have very dissimilar thermal expansion coefficients.
In a previous mission a current stuck it to the hull of the titanic and they had to literally wiggle themselves loose.
It is bolted shut from the outside. Even if they surface: if they are not found, they will suffocate in hell like conditions, 1 foot removed from fresh ocean air.
Which brings me to the next point: if it should surface, it will be invisible because it would float just under the surface, and is white without visible markings. Because the CEO hated the original bright yellow hi-visibility coating.
What about communications to find it, should it surface? Well it seems there aren't any. No GPS tracking, no satellite receiver or radio. Because all of that is unnecessary.
It did communicate via sonar (soundwaves) using basic protocols, but that stopped suddenly, shortly into the mission. This was not unexpected because communication loss was a regular occurrence in previous missions.
There are no emergency protocols for when primary systems fail.
And I am probably forgetting a couple more things. Such as the fact that he fired the guy who expressed safety concerns, and he is on record saying he refused to hire people with actual engineering or sub backgrounds because they were not 'inspiring' and say no to everything he wanted to do.
This sub is a literal death trap with several near misses, and several people have probably died a gruesome death in a cold dark metal coffin where they didn't have access to a toilet for days.
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Yet, I prefer to read news articles with some critical sense.
"the 7inch thick acrylic window on lost Titan sub will get 'squeezed in' under the water pressure".
It will? It did under earlier expeditions? "In a previous mission a current stuck it to the hull of the titanic and they had to literally wiggle themselves loose." So it has been down at those depths earlier. Why didn't it collapse then, if it can be said without any reservation that "the window will get 'squeezed in'"?
It seems quite clear that the safety margins were on the negative side. Yet, when someone makes an unconditional statement that something will happen under given conditions, and it has been shown cases under such conditions where it did not happen, then I am not willing to take other statements from the same source as Absolute Truth.
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That is actually a very safe thing to say. The properties of plexiglass under pressure are well understood and the pressure is a simple function of depth. that a plexiglass cupola will deform under pressure is a given and the amount of deformation can be calculated. 25 years ago I knew how (I'm an engineer).
that the cupola will be squeezed in is a given. I can guarantee you that as an absolute given. And it did on those earlier voyages. That doesn't mean it will implode. Those are 2 different things.
That's were safety margins, repetitive stress fatigue and many other factors come into play. Like the carbon fiber / titanium pressure hull, it went down before. But there are definite reasons not to use that combination. Just because it can handle those pressures several times doesn't mean it will continue to do so, which is why it isn't used for that.
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OK, so your understanding of 'will get squeezed in' is in the range of "might be slightly bent".
I certainly recognize your professional interpretation of this wording. However, I do not believe that this is the interpretation the 'common man' reads into it, and I do not believe that it was the interpretation that MailOnline tried to convey to its readers.
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Here in the UK, The Mail is taken with a large pinch of salt.
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Yep, based on everything I've read I really hope they find this sub. Then the CEO will be on the hook for criminal negligence at the minimum and some level of murder at the maximum. He may still be on the hook for criminal negligence in any case.
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The CEO is dead, along with the passengers.
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Bruno van Dooren wrote: It also has no GPS locator or communication electronics.
GPS wouldn't make much sense. Radio waves at 1.5 GHz don't make it more than a cm or two below the surface. If you have seen a GPS unit reporting a position at greater depth (or a kilometer into a long tunnel with a few hundred meters of rock above your head), it is provided by an accelerometer/gyro, tracking the relative movements from the last known position. I am impressed by the precision of these mechanisms, but they do drift over time, and they are not GPS. Of course they might have a GPS, but it would be of any use only when the Titan is surfacing.
For communication electronics: I guess that very long wave radio signals, maybe as low as 80-100 kHz (a wavelength of roughly 3 km) could break through 3800 m of water, given sufficient transmitter power. That power might be available at a support ship, signaling to Titan. I question whether it would be available in Titan for signaling to the surface. At these wavelengths, very little bandwidth is available; you might easily disturb other essential communications. Long wave radio signals go a long way! Of course they might have communication electronics for 'normal' communication frequencies, but this would be of any use only when the Titan is surfacing.
Neither GPS nor communication electronics (with a possible exception for extremely long wave) would be of any help a few thousand meters below the surface, where we may assume that they are located now.
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That thing would float just under the surface. It's white. It will be a needle in a haystack. At that point electronic comms would literally be a lifesaver.
We also don't know whether it is still submerged. There were supposedly systems which would allow it to float up if something happens. For all we know, those could have worked and those people have been bobbing just below the surface, 1 foot away from fresh air, because noone knows where they are and they have no way of signaling.
Of course it would not matter, 4000m below. The point is that there are so many scenarios where those people are f***ed because every possible 'what if' was ignored.
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One might suppose as well that if the controller failed completely, even blew up, that it would not stop the communications from working.
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In the worst-case scenario, (which I sincerely pray does not happen), if the vehicle gets crushed under the extremely high water pressure down there, likely that it will become something of the size of a couple of footballs, making the detection and recovery extremely difficult, isn't it?
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No. Neither the titanium bow nor the carbon fiber hull will be pancaked to that extend.
Advertise here – minimum three posts per day are guaranteed.
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Thanks.
Meanwhile here is a nice video of the depths of the various seas all over the world, including the depth of the Titanic wreck. Interesting to note that Titanic is not the deepest ship wreck.
Ocean DEPTH Comparison 🌊 (3D Animation) - YouTube
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Fascinating animation!
But some of us are spoiled ... If I jump into a boat here in Trondheim, Norway, and steer out towards the open sea, I will floating on almost 600 meters of water before I am out of the Trondheim Fjord. Norway's longest fjord, the Sognefjord, is also the deepest, slightly more than 1300 m.
So I am more surprised by how shallow many seas are. I sort of expect 3-400 m to be the "normal" 
Then a question to anyone who might know:
The animation shows "SAPEI (Deepest Submarine cable) ≈ 1600 m". To me, it looks difficult to find a path for a trans-Atlantic cable (and no simpler for a trans-Pacific one!) that won't cross any depth exceeding 1600 m. So, are all those trans-ocean cables simply floating in free water at some depth? At which depths? How do they keep it stable? For how long stretches can a cable be free-floating like this? Unless the cable has a specific weight (i.e. density) very close to the surrounding water, there must be a tremendous drag in the cable on both sides! How is this handled? And what happens if a giant hungry shark takes a healthy bite of the cable, is it possible to pick up the pieces from both sides and tape them together again, or would it be just as simple to lay an all new cable? (Well, I do assume that the cable is reinforced to handle attacks from small sharks )
Feel free to provide a link to a web site that answers this kind of questions!
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They're probably running out of oxygen today.
Really sounds like one of the worst ways to go, waiting to suffocate in a tin can on the bottom of the ocean 
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It had more to do the fact he wanted to hire inexperienced people to man the vessel. That's the price of making a political statement rather than a genuine one. That dude still could've marketed to a younger crowd if he wanted to sell his soul to propaganda, while still having experienced people run the thing.
Jeremy Falcon
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BillWoodruff wrote: Frightening. One can only hope for a miracle ?
Also, not to be a downer. But, I come from a family of scuba divers. I'm not a nautical engineer, but I can testify that if something went wrong structurally to the vessel, they're dead. Zero chance of survival at that depth. There are a thousand reasons why, not the least of which is the pressure. That's over 363 atmospheres, something the human body cannot withstand.
To give context, an aquatic atmosphere is measured by the difference in air pressure at sea level when compared to space. Underwater however, that same delta only takes 33 feet. So in essence, that depth is over 363 times the amount of pressure you feel at sea level. If the vessel was poorly constructed and was damaged, they or a piece of crappy equipment would've been instantly crushed by the pressure. They would not have time to ascend. They would be crushed instantly.
Jeremy Falcon
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An open water diver is typically allowed to only go down 100-120 feet tops. And that's for experienced divers. Beginners should not ever start with that depth. The human body can withstand more pressure (not the depth of the Titanic though) and in fact you be nitrox certified to go down to 200 feet. That's for very experienced divers. If you don't know what you're doing and ascend too fast, your lungs will explode for instance - no biggy. You fly the next day, you have problems, etc.
Point being, at 200 feet you need to be trained to handle that amount of pressure. And that's only like 6 atmospheres. There's no way a human could survive at 363 atmospheres.
Jeremy Falcon
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Why is that frightening? It's just a device that converts hand or finger movements into digital signals, and a well developed reliable one too. Inside the sub it will be operating in an environment not unlike your home, in terms of temperature, humidity, pressure etc. And no dogs to trample on it.
It's what those digital signals control that is important.
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Wordle 733 X/6
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![Elephant | [mastadon]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/elephant.gif) Another one of those!
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Wordle 733 5/6
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Wordle 733 6/6
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Don'cha hate it when it takes a few to get the last letter
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