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Post by eri on Jun 21, 2023 17:23:51 GMT 12
looks like a canadian air force anti-sub plane has picked up some thumping noises from a dropped sonar buoy
the race is on!
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Post by jim on Jun 21, 2023 19:11:44 GMT 12
a bit of rough maths puts the pressure down there at a bit over 5000 psi. 340 tons on each square foot... i hope they are rescued, but sadly I think they're toast.
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Post by fish on Jun 21, 2023 21:40:27 GMT 12
The sentiments of this song are probably appropriate for the occupants of the sub. New York Mining Disaster, by the Beegees:
I keep straining my ears to hear a sound
Maybe someone is digging underground
Or have they given up and all gone home to bed
Thinking those who once existed must be dead
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Post by fish on Jun 21, 2023 23:13:15 GMT 12
While we are glued to the news about 5 mostly wealthy tourists lost on a submarine on their way to seek the wreckage of a sunken ship, today is World Refugee Day, and only last week a boat holding hundreds of refugees sank off the coast of Greece. Many (including children) lost their lives on that sinking ship while on their way to seek a safer existence. While what is unfolding beneath the waves in the middle of the Atlantic is a tragedy, and an extremely anxious time for their families, it’s hard to not be cynical about the state of society that this story has gripped us in the midst of a constantly rising refugee crisis with more and more people dying on the daily, and not getting nearly as much attention.
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Post by armchairadmiral on Jun 22, 2023 8:22:44 GMT 12
You're right. Choose how you die. A car crash is far less spectacular than a plane crash for example. Jumping off into the Grand Canyon gets the news but killed on your way there gets nil news value. Sensation is the key. Very sad that's where the (in)human species is at
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Post by GO30 on Jun 22, 2023 9:33:58 GMT 12
The problem refugees and most who died on things like this is they do it in a manner that's been done before to the point it's now boring. The 5 in the sub are most likely going to clock out in an unusual far more interesting manner.
That's life in the 21st century.
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Post by eri on Jun 22, 2023 9:44:49 GMT 12
their air runs out tonight
they still don't know where they are
but they still hear thumping....
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Post by harrytom on Jun 22, 2023 11:47:32 GMT 12
their air runs out tonight they still don't know where they are but they still hear thumping.... And they heard thumping where MH370? went down too. My understanding is,going down to titanic you actually look out a window interesting article about how safety concerns were raised by the builders www.kcra.com/article/what-we-know-missing-titanic-submersible/44264641
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Post by fish on Jun 22, 2023 15:16:30 GMT 12
their air runs out tonight they still don't know where they are but they still hear thumping.... And they heard thumping where MH370? went down too. My understanding is,going down to titanic you actually look out a window interesting article about how safety concerns were raised by the builders www.kcra.com/article/what-we-know-missing-titanic-submersible/44264641yeah, apparently the previous CEO got sacked for questioning safety. Think he was the CEO, was a senior employee anyway. Told he wasn't an engineer. Went to Court, which is why there is so much publicly available information about the design form 2018. One of the points of concern was that while the sub was designed for 4,000m, the viewing hatch was only designed to 1,300m. The sub company couldn't be bothered getting the hatch company to certify the hatch to 4,000m. That, and a really random way of monitoring for cracks in the carbon fibre. They wanted to listen for 'pinging' noises in the structure to determine its structural integrity. For some reason they completely refused to use ultrasound, like everyone else.
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Post by eri on Jun 22, 2023 15:27:17 GMT 12
another report from a passenger last year was that one of the control fins? fell off before launch
so they cable-tied it back on and carried on....
the makers keep stressing that it's a prototype under-development and the passengers aren't passengers but science techs who have signed multiple disclaimers
apparently the first page says "death" 3? times
another previous trip went down, had comm problems, didn't get steering commands from the mother-ship, got lost and couldn't find the the wreck in its 2hrs? tooling around the bottom
because these comm failures have been common they didn't put out the international distress call for 8? hours after losing contact...
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Post by GO30 on Jun 22, 2023 18:33:41 GMT 12
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Post by em on Jun 22, 2023 19:03:44 GMT 12
Shame you don’t have a shop in New foundland , they need 12KM of dyneema
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Post by eri on Jun 23, 2023 8:14:50 GMT 12
sadly it looks like it failed on or soon after they lost contact 1.45hrs into the dive
the pressure bulkheads seem to have been found intact suggesting the tube between them failed
i think this was the first diving bell that wasn't spherical....so they could fit paying passengers in without having to make a MASSIVE sphere
as fish mentioned earlier if the carbon sheath cracked the titanium tube wouldn't hold by itself
or the apparently lower pressure rated porthole blew
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Post by sabre on Jun 23, 2023 9:26:47 GMT 12
At least they would have been dead before they knew it. Would far prefer that to slowly running out of air 4km down.
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Post by fish on Jun 23, 2023 10:21:32 GMT 12
sadly it looks like it failed on or soon after they lost contact 1.45hrs into the dive the pressure bulkheads seem to have been found intact suggesting the tube between them failed i think this was the first diving bell that wasn't spherical.... so they could fit paying passengers in without having to make a MASSIVE sphere
as fish mentioned earlier if the carbon sheath cracked the titanium tube wouldn't hold by itself or the apparently lower pressure rated porthole blew Crickey, that's like the 3rd time if been right about something this week. I'm on a role. The sad thing about this is the failure is totally predictable and in short comes down to money / profit. You simply can't put repeated pressure cycles on a product / compound like that and expect it to withstand the same pressure every time. You have to de-rate the pressure rating with every repeated cycle. This is Bachelor level engineering stuff. The short story is they should have replaced the carbon tube after ever dive or couple of dives. Of course that costs money... Additionally, they were already arguing over how to measure their cyclic fatigue. This is exactly what the former CEO got sacked for, told he was not an engineer. He recommended using ultrasound to assess the carbon, where as the company wanted to listen for 'pings' as the carbon filaments failed. Bat-shit-crazy idea. To put this in context, I have investigated pumped pipeline failures around NZ that have been failing (bursting) repeatedly after 18 yrs of operation, when the design life is 100 yrs. The pipeline material is always a modified m-PVC that came out about 20-25yrs ago. Supposed to be the latest, greatest material. Only it is brittle as fuck. Just like carbon. Carbon is strong, but it has bugger all elastic modulus. Think of wiggling a wire until it breaks. Bendy wires take ages to break. Stiff wires break straight away. For pipelines we now use a polyethylene. It is kind of soft and pliable. But we still have to de-rate it to get it to last 100 yrs. Typically, for a 16 bar pipe we would de-rate it to 8 or 10 bar maximum operating pressure. The thing here is that a 16 bar pipe can handle 20 bar or 24 bar easily. But only once or twice. If you want it to do 50 million pressure cycles (pumping your poos and wees miles away to the treatment plant) then the pipe can only handle 8 bar. In the context of this sub, you could take a carbon tube rated for 16 bar, and you could safely descend to 24 bar (245m in this example) BUT ONLY ONCE. You might get away with it a second or a third time. But come the fifth or sixth time, you are playing Russian Rullet. The issue here is just because a pipe / tube is rated to a certain pressure, doesn't mean it can handle that pressure. And that the people on this sub or operating this sub wouldn't be aware of this really basic engineering phenomena beggars belief. With completely un-educated people you could so, "oh, this sub has done it loads of times before, so it is safe". But with anyone with the slightest bit of technical understanding, if you said "oh this sub has done it loads of times before" that would ring alarm bells bigly. Given the wealth and resources of half the punters onboard, I wouldn't have described them as un-educated.
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