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Post by fish on Jun 20, 2023 9:04:20 GMT 12
This is tragic and hilarious at the same time. A tourist sub, carrying 5 passengers has gone 'missing' whilst diving to the Titanic. Tickets cost $1/4mil US. The story has lots of details about how complicated the rescue mission is going to be etc, and then this little gem: The 5-person submersible, named Titan, is capable of diving 4000m “with a comfortable safety margin,” OceanGate said in its filing with the court. It weighs 9072kg in the air, but is ballasted to be neutrally buoyant once it reaches the seafloor, the company said. The Titan is made of “titanium and filament wound carbon fibre” and has proven to “withstand the enormous pressures of the deep ocean,” OceanGate stated. Now, I'm no metalurgist, but I wonder if these guys understand cyclic loading and just how brittle carbon fibre is? I'm sure there is a proper technical term for it, elastic modulus or something. Basically the reason we aren't allowed to have carbon fibre staunchions. This companies marketing team must be top shelf. You couldn't pay me $1/4mil to hop in a carbon fibre can and drop to 400 atmospheres of pressure. And on the marketing, the spin is to go and see how much the wreck has deteriorated each year. i.e. the wreck is a shit hole that is falling apart, how do we spin that to get people to pay to go and look at it? And if it hasn't suffered a catastrophic structural failure, i.e. has 'just' blown a fuse and is sitting on the bottom, it has 96 hrs of air. Isn't there a really bad movie on Netflix called 'last breath'? about a commercial diver stuck in a diving bell and running out of air? What a silly thing for the wealthy to spend their money on. www.stuff.co.nz/world/us-canada/300909402/submarine-that-takes-people-to-see-the-titanic-goes-missing
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Post by eri on Jun 20, 2023 11:54:49 GMT 12
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Post by eri on Jun 20, 2023 12:07:40 GMT 12
"They have SEVEN different ways to rise to the surface—multiple redundant ballast and air-bladder systems," David Pogue tweeted today.
not a good sign that they haven't come up
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Post by sabre on Jun 20, 2023 14:34:55 GMT 12
Of all the ways to go this would be one of my least favourite...
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Post by em on Jun 20, 2023 16:29:47 GMT 12
Fuck that
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Post by fish on Jun 21, 2023 10:16:06 GMT 12
"They have SEVEN different ways to rise to the surface—multiple redundant ballast and air-bladder systems," David Pogue tweeted today. not a good sign that they haven't come up At 4,000m deep (400 atmospheres) I doubt seven different ways to blow ballast would help. The rate of ascent would become so fast the sub would rip apart. Or the air would expand so rapidly in the ballast tank it would blow the tank apart and the sub would sink again. You would think this is the basic physics problem of diving to those depths, so they must have come up with a solution for it, I just don't know what it is. I wouldn't be relying on a pressure relief valve on the ballast tank, that's for sure. I'm fairly sure air is compressed 100% at 100m (10 atmospheres). The nutbar free-divers that go to 100m, their lungs are compressed solid at those depths. So if you are loads deeper, if you can get air to displace water in the ballast tank, its going to have an eye popping rate of expansion once you start rising. The other basic physics problem. If the water in the ballast tank has a pressure of 400 atmospheres on it, you are going to need a gas with equal or greater pressure to displace it out of the ballast tank. That is A LOT of pressure to hold in a compressed air bottle. That, and if air is 100% compressed at 100m, how do you get it to expand into a gas at 4,000m to displace the ballast tank water? Oh, I've given myself a head ache. Might go and google how deep sea subs work. Maybe they rely on a differential pressure between the compressed air tank and the ballast tank. This is why I am not a submariner, despite thinking Hunt for Red October is the best movie of all time.
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Post by GO30 on Jun 21, 2023 10:41:09 GMT 12
Have to agree withy ya on that. Good actors with a great script certainly helped.
We were just talking on how to get back from that depth. The water pressure will be pushing you deeper or trying hard to hold you down there so you have to over come that to start with. As you noted blowing out ballast is both tricky and could easily lead to an uncontrolled assent. While you try super hard not to do that when down there it is a pressurised sub so the contents should be OK from pressure point of view i.e. the bends etc. It would be a hell ride though so you'd be a bit like the pea in a whistle. But then a live slightly broken pea is better then a dead pea, assuming you're the pea.
The biggest issue they have is the construction of the sub makes it a little stealthy, due to the materials not intentional subterfuge, which is a bugger. I'm a little surprised they reckon it is very hard to see considering all the metal that'll be in and around it. But then that's only from news reports so it's accuracy could be total shit. But then it is 4km deep under thermal/s layers etc and military uses those to help hide so the news reports maybe right.
No matter what happened, is happening, is about to happen, I'm glad it's not me. I'd love to go have a suss of the Titanic but not that much I want to climb into a tiny can to get there.
In another report on who is in the thing it shows there is a shot load of money so no doubt a lot of thet will be thrown at it in an effort to find them in time. About 6pm Thursday our time is the suggested end of the O2.
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Post by fish on Jun 21, 2023 12:07:05 GMT 12
There is some great irony that these passengers have all the money in the world, and it is fuck all use while you are sitting in a carbon fibre can at the bottom of the ocean.
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Post by eri on Jun 21, 2023 12:15:30 GMT 12
if it was on the surface nothing can be opened from the inside anyway, it can only be unbolted from outside...
so as well as search the surface looking for debris they are looking for it bobbing about...but if it were bobbing about they'd be using their radio, unless they had no power....are the surfacing systems reliant of power?
undersea contact was by sonar pulsing, they stopped pulsing 1hr45min into the dive at about 3,500mt
even if they were tangled in the wreck, they should still be able to pulse
the dive was called off several times due to bad weather, then they got a break in the weather and decided to nip down for a 6 hour trip, 2 hrs down, 2hrs around the wreck, 2 hours up
even if they did find them unharmed with no power sitting on the bottom, they'd need a 4km cable to bring them up....i don't think they have one on the surface ship
or another submersible to hold them with an arm and bring them up.....none are within range and it's never been done before
but first they have to find them. hopefully banging on the hull or once they get their power back on line
does it have lithium batteries?
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Post by eri on Jun 21, 2023 12:37:12 GMT 12
When the Titan is submerged, communications with the support ship on the surface are conducted over an acoustic link. Crewed submersibles sometimes have two separate systems with independent power supplies: one an acoustic beacon that regularly pings the ship to reveal its location, and another that can carry short text-like messages. This ensures that if the main power supply fails, the beacon keeps working, allowing the surface ship to track the vessel. According to some reports, the Titan did not have an acoustic beacon and had become lost before.In the event of a major power failure, the Titan should have dropped its weights, resurfaced, and made immediate radio contact with the support vessel – provided the radio communications had a separate power supply. If an incident onboard the vessel knocked out all the electrics, the submersible could be adrift on the surface and awaiting rescue.www.theguardian.com/uk-news/2023/jun/20/missing-titanic-submarine-best-and-worst-case-scenarios
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Post by Fogg on Jun 21, 2023 12:38:40 GMT 12
I'd love to be optimistic but realistically I see zero chance of a happy outcome here.
Even the CEO of OceanGate (who is apparently aboard the stranded sub) has previously said that if anything goes wrong down there it will be a recovery mission not a rescue mission.
One thing that isn't clear to me is the agencies involved in the S&R efforts - is it just the US & Canadian Coastguards and Canadian Navy? Or is the US Navy involved? I'd have thought they would have the most appropriate submarine rescue technology if anyone is going to stand a chance of pulling this off. But I've not them mentioned.
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Post by fish on Jun 21, 2023 14:18:46 GMT 12
if it was on the surface nothing can be opened from the inside anyway, it can only be unbolted from outside... so as well as search the surface looking for debris they are looking for it bobbing about...but if it were bobbing about they'd be using their radio, unless they had no power....are the surfacing systems reliant of power? undersea contact was by sonar pulsing, they stopped pulsing 1hr45min into the dive at about 3,500mt even if they were tangled in the wreck, they should still be able to pulse the dive was called off several times due to bad weather, then they got a break in the weather and decided to nip down for a 6 hour trip, 2 hrs down, 2hrs around the wreck, 2 hours upeven if they did find them unharmed with no power sitting on the bottom, they'd need a 4km cable to bring them up....i don't think they have one on the surface ship or another submersible to hold them with an arm and bring them up.....none are within range and it's never been done before but first they have to find them. hopefully banging on the hull or once they get their power back on line does it have lithium batteries? Maybe the 2,500 odd ghosts on the Titanic got sick of the racket & constant pinging disturbing their peace and decided to sort out the rude tourists? Lets not forget there are a lot of bodies on that ship. Are you allowed to do commercial tourist trips to wrecked warships that are covered by, what's it called? wartime graves rules?
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Post by em on Jun 21, 2023 14:57:35 GMT 12
I'd love to be optimistic but realistically I see zero chance of a happy outcome here. Even the CEO of OceanGate (who is apparently aboard the stranded sub) has previously said that if anything goes wrong down there it will be a recovery mission not a rescue mission. One thing that isn't clear to me is the agencies involved in the S&R efforts - is it just the US & Canadian Coastguards and Canadian Navy? Or is the US Navy involved? I'd have thought they would have the most appropriate submarine rescue technology if anyone is going to stand a chance of pulling this off. But I've not them mentioned. USN is en route with some whizz bangery ship but its of no use unless they locate the thing
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Post by Fogg on Jun 21, 2023 15:17:11 GMT 12
Bloody hell, apparently they’ve detected banging sounds coming from the drop zone…
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Post by GO30 on Jun 21, 2023 15:40:54 GMT 12
Bloody hell, apparently they’ve detected banging sounds coming from the drop zone… There is a women aboard? Oh hang on, I may have read that wrong....
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