I had no idea that "tourists" visited Titanic. Is this the new thing after Everest became crowded?
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I know this is a left wing leaning site but this takes the cake for tasteless comment of the day.
Titanic tourist submersible goes missing with search under way
341–350 of 649 posts
Re: Titanic tourist submersible goes missing with search under way
#342Earlier quoted context omitted.
The hatch is bolted shut from the outside. When you make it back to the surface, there is no way to get out without external support. If the mother ship can not find the sub the occupants could be trapped bobbing just below the surface until their air runs out.
Could they just have some drills with diamond-tipped bits stored inside for emergency use? If needed, drill through the whole shell, stick an arm out and unbolt from the outside. Or maybe a jackhammer to just hammer through whatever glass is there for observation purposes.
why would a sub be carrying a jackhammer? that makes no sense
Re: Titanic tourist submersible goes missing with search under way
#343Earlier quoted context omitted.
> Composite properties can be fairly accurately measured and tested, just like any other material including plate steel or aluminium Metals are uniform and broadly predictable. Composites vary cure to cure. We simply don’t have the deep engineering tables that let you know how a material will behave without destructive testing.
Then there’s also the issue of minor failures cascading. I’m by no means a structural engineer, but with bike parts — in steel or aluminum, if you get a tiny 1mm chip in the material, you can more-or-less just treat it as if the steel is 1mm thinner. With engineering tolerances it is irrelevant. But in a carbon fiber, that 1mm chip could be totally unnoticed for months, while slowly causing an invisible hairline crac…
NB: Aluminium is rather notorious for its tendency to develop invisible hairline fractures which fail suddenly. Particularly around high-stress regions.
The BOAC Comet failures (cracks propagating from squared-off window corners) is a notorious example, with multiple total hull losses in flight.
I've experienced somewhat less significant failures of bicycle components (though they could easily have proved far worse). It's a good idea to replace components after a wreck or even hard-cornering of a crankset.
Re: Titanic tourist submersible goes missing with search under way
#344Few more details from The Seattle Times: >David Concannon, an adviser to the company, said Oceangate lost contact with the sub Sunday morning. It had a 96-hour oxygen supply, he said in an email to The Associated Press on Monday afternoon. “Now 32 hours since sub left surface,” said Concannon, who said he was supposed to be on the dive but could not go due to another client matter. He said officials are working to ge…
He got lucky
Just like this persian who was given a lot of money to go on the Titanic's maiden voyage, but gave the money to charity instead. He came to the USA in 1912 and spoke out against the racism here
https://www.huffpost.com/entry/abdul-baha_b_1419099
> Throughout his U.S. visit he swept aside the social protocol of segregation by insisting that everywhere he spoke be open to people of all races. Not the biggest crowd pleaser at the time. At the Great Northern Hotel on 57th Street (now the Parker Meridien), the manager vehemently refused to allow any blacks on the property.
> "If the people see that one colored person has entered my hotel, no respectable person will ever set foot in it," he said. So Abdu'l-Baha instead organized a multi-racial feast at the home of one of his followers, with many whites serving blacks -- a subversive, even dangerous notion at the time.
Re: Titanic tourist submersible goes missing with search under way
#345I'm hesitant to speculate but just sharing -- an earlier version of this submersible was scrapped: "OceanGate will take advantage of lessons learned during the construction of its carbon-hulled Titan submersible, which was originally built for Titanic journeys. Rush said tests that were conducted at the Deep Ocean Test Facility in Annapolis, Md., revealed that the Titan’s hull “showed signs of cyclic fatigue.” As a r…
The hatch is bolted shut from the outside. When you make it back to the surface, there is no way to get out without external support. If the mother ship can not find the sub the occupants could be trapped bobbing just below the surface until their air runs out.
According to David Pogue (journo who did a dive on this vessel last year), at least as of last year there was no beacon to transmit location. One would hope radio would be working, in that case.
Source: https://twitter.com/Pogue/status/1670826522138091521?s=20
Re: Titanic tourist submersible goes missing with search under way
#346Earlier quoted context omitted.
David Pogue, who traveled to the Titanic with OceanGate last summer, has said that he was on the control ship when a previous sub was "lost for about 5 hours". Source: https://twitter.com/Pogue/status/1670835763536183297
> and they shut off the ship’s internet to prevent us from tweeting. Some how that makes it even worse.
I try to have a generous read of everyone's intentions, but that anecdote is alarming.
Re: Titanic tourist submersible goes missing with search under way
#347Earlier quoted context omitted.
If your design breaks at less than the target then you really have to question the logic of continuing with that design. Making it slightly bigger won't fix the inherent issue with the materials. They're potentially opening themselves up to charges for killing these people. They knowingly or recklessly put them on a boat when it isn't capable of reaching the depth safely and now they are dead.
No, that's how a lot of aerospace testing works. You break it, see where it broke, and make that point bigger (thicker).
Yeah, destructive testing is still a must for process checking. Though non destructive methods for even composites keep getting better! Composites are very very hard to test though, and I think it's one of the biggest bottleneck to their usage.
(I work in NDT(non destructive testing) but on the software stack not the probes/scanners. So I'm not sure if my last point is still true these days! )
Re: Titanic tourist submersible goes missing with search under way
#348I get the flex this affords, but I can't think of anything less appealing than spending 8 days underwater in a tiny capsule. I hope they're found and nothing happened.
Re: Titanic tourist submersible goes missing with search under way
#349Earlier quoted context omitted.
Carbon seems to be the go-to material these days. It often seems to fail catastrophically in ways that, for example, steel does not. I wonder if future engineers will look back at these carbon decades and shake their heads.
I'm no expert, but I do know there's anything fundamentally flawed about polymer composites (including carbon fibre composites) in place of metals. Composite properties can be fairly accurately measured and tested, just like any other material including plate steel or aluminium. If a structural failure has occurred, it's related to a design, manufacture or maintenance issue. For example, not enough layers, or a weakn…
Composites can be tested. Not as easily as metals can be, and it involves a lot more software analysis and even AI, but it's still possible. I work on flaw detection/segmentation with ultrasounds -and I have not directly worked with metal scans so I can't exactly compare- but we can already get some pretty good results with the right probes and scanners. The other major issue is that NDT on composites needs more care and time from the inspectors on the ground, and might need a lot more organizational resources to track and make sense of the data.
But now that i think about it, I have no clue about performance or even feasibility of testing carbon composites. I'll have to ask around, but I'm pretty sure we have clients that use our hardware for Carbon! :)
Re: Titanic tourist submersible goes missing with search under way
#350let me be naive : carbon fiber composite is about tensile stength, not compression strength ? what happens in the ocean ? compression...