- #176
Vanadium 50
Staff Emeritus
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1960's tech put a man on the moon.pinball1970 said:1960 tech was ok?
1960's tech put a man on the moon.pinball1970 said:1960 tech was ok?
9 years was a long time in the 1960s.Vanadium 50 said:1960's tech put a man on the moon.
Dunno.pinball1970 said:That's real?
1960 You not amazed by that? 5 miles down, I had to use one of those conversion things to get the PSI.Vanadium 50 said:1960's tech put a man on the moon.
I'm sorry for the kid to be honest. Did he look into all this, risk, design, protocol tests? Of course not. He was with his dad right?DaveC426913 said:Dunno.
But the crewmember
View attachment 328423
- is sitting on a flat floor with no equipment nearby, and
- has a mission patch that seems to check out.
Yes, the descent was made in the Trieste bathyscaphe.pinball1970 said:The depths, PSI are crazy there.
1960 tech was ok?
https://en.wikipedia.org/wiki/Trieste_(bathyscaphe)Trieste is a Swiss-designed, Italian-built deep-diving research bathyscaphe which reached a record depth of about 10,911 metres (35,797 ft) in the Challenger Deep of the Mariana Trench near Guam in the Pacific. On 23 January 1960, Jacques Piccard (son of the boat's designer Auguste Piccard) and US Navy Lieutenant Don Walsh achieved the goal of Project Nekton. It was the first crewed vessel to reach the bottom of the Challenger Deep.
The passage of time does not prevent poor design choices. The Trieste was a steel sphere, the Titan a composite cylinder. You seem to have concluded that the designers of the Trieste were ahead of their time; an alternative conclusion is that the designer of the Titan was negligent. There seems to be a lot of evidence confirming the latter.pinball1970 said:1960 fit for purpose but fast forward to 2023 at half the depth and this.
In April 2019, Karl Stanley, who runs his own deep-sea exploration company in Honduras, took a 12,000-foot plunge inside the Titan off the coast of the Bahamas and said he heard a large cracking sound during the two-hour dive.
Victor Vescovo is a Dallas businessman and submersible pilot. He was friends with two of the victims, British adventurer Hamish Harding and French Titanic expert Paul-Henri Nargeolet.
Investigators from the United States, UK, France and Canada are working together to try and figure out what caused a submersible to implode eight days ago.
The U.S. Coast Guard's Marine Board of Investigation will work with authorities from Canada, the U.K. and France.
The dive was supposed to happen during July 2022Last summer, for a CBS News Sunday Morning story, I joined OceanGate for a dive on its Titan submersible. I never saw the Titanic. We were only 37 feet below the waves when mission control aborted our dive.
He [Paul-Henri Nargeolet] observed the testing and construction of the Titan and is completely satisfied with its design. “I will say, in the world of the submarine, there was a rule: no carbon fiber,” he says in his French accent, laughing. “But he was working with Boeing, with big company. And when you see the way they were doing the cylinder — it’s not in a garage, you know, with glue and stuff like that. It’s very well done.”
So, if Pogue's dive had been successful to the Titanic, the recent failure probably would have happened earlier during a previous successful dive.Rush says that the Titan has already made 20 uneventful dives to Titanic depths, which also calms me. And above all, Rush himself pilots most of them. Why would he drive the Titan if he has any concerns about its integrity?
Red flag.I also know stuff goes wrong in the North Atlantic. In 2021, Mexican YouTuber Alan Estrada filmed the return of the Titan dive before his own. When the sub rose to the surface, the OceanGate crew couldn’t get it back onto the ship. Its occupants spent 27 hours inside before they could be rescued.
I’m slowly realizing the Titan doesn’t actually make it to the Titanic very often. On each of the nine OceanGate expeditions so far, Titan reached the shipwreck twice, once, or not at all. Indeed, Rush explains, that’s why only six paying customers are onboard, enough for two dives; he has learned he can get only two or three good dive days a week. Tomorrow, day one, will be our CBS dive. After that, the selection of “mission specialists” for each dive depends exclusively on Rush’s mysterious internal logic.
We'll once the debris field map is published, which would show the pieces of hull (and end caps) and where they landed.Thursday, June 22, 2023
They’ve just found the debris of the Titan.
Everyone’s suddenly a carbon-fiber expert. But if you really want to know what happened, I think Alfred McLaren, a retired Navy sub captain who has spent a cumulative 5.75 years of his life underwater, has the most plausible explanation.
It wasn’t the carbon fiber itself. It was the three dissimilar materials: carbon fiber, titanium, and plexiglass. “They have different coefficients of expansion and compression,” he tells me in another CBS interview. “You make repeated cycles in depth, of course you’re gonna work that seal loose.”
Um why?Astronuc said:Red flag.
Looks like not great planning.Vanadium 50 said:Um why?
The moon landing amazes me. The amount of technology that had to be invented from scratch and massive complexity of the craft with so much that can go wrong is mind boggling. Many of the astronauts started their careers flying prop planes, because jets hadn't even been invented yet.pinball1970 said:1960 You not amazed by that? 5 miles down, I had to use one of those conversion things to get the PSI.
Thick or thin walled pressure vessel.russ_watters said:But a deep see submersible is just a spherical metal ball (well....most of them). There's exactly one major engineering problem to solve. And yes it's big, but its straightforward and its always exactly the same. And the problem itself is probably something you can find in a sophomore Statics book. It's that simple from a conceptual standpoint. My suspicion is the main problems were in metallurgy and manufacturing (how to make your spherical metal ball as uniform as possible). Also how to cut holes in it without weakening it too much.
So far what I've seen is the nose cone (looks intact, but it's without the window part?) and the two ring-like pieces attaching the front- and back cones to the tube.russ_watters said:I haven't seen anything yet might look like the remains of the pressure hull.
I think the difference between the old and new tech would be nothing dramatic. New tech allows more homogenous and strong material, better quality check and more precise manufacturing => a bit thinner hull, based on less conservative over-design. But the very basis of withstanding high pressure is the very same: solid metal, and lot of it.pinball1970 said:1960 tech was ok?
You had one job! One job!russ_watters said:But a deep see submersible is just a spherical metal ball (well....most of them). There's exactly one major engineering problem to solve.
I thought the Titan didn't have an umbilical?Vanadium 50 said:I'm not sure I agree with this. Think about the umbilical.
https://www.yahoo.com/gma/debris-titan-submersible-brought-ashore-161416927.htmlFormer National Transportation Safety Board investigator Tom Haueter called the probe "uncharted territory" that could take "months" to analyze the failures.
"This is the first fatality on a passenger carriage submarine I can think of and certainly the first one going into Titanic at this depth," Haueter told ABC News.
Haueter said a big part of the investigation will involve metallurgy specialists looking at the materials the submersible was made of to see what could have failed. The pressure vessel area -- the compartment where the passengers were -- may also reveal what failed, he said.
Investigators will also look at its design, diving history and maintenance, he said. What is learned could improve what he called a very small industry.
"I think there are things they'll be able to learn to say, OK, if we're going to do this again and allow people to descend to these incredible depths and amazingly high pressures, that here's things that should be considered when developing these types of vehicles," Haueter said.
On Wednesday evening, the TSB of Canada, which is assisting in the investigation, said in a statement that they had completed “collecting relevant documents and completed the preliminary interviews with those on board the support vessel Polar Prince.”
The outer wall of the hull experiences a pressure of about ~5500 psi (~375 atm, 37.9 MPa), or a slightly greater (I'm finding different numbers).256bits said:Radial stress is 0 ( 14.7 on the inner wall and the outer wall follows the pressure from the sea water at depth.
Or shear, or axial splitting.256bits said:But as for most things, other considerations follow.
A slender rod can take the compression, and not fail from the compression stress alone - they fail by buckling.
Is the crushed tanker under elastic stress?256bits said:See the pictures of the tanker implosions. Once the failure starts there is no negative feedback to counteract. the process continues to final completion equalizing the pressure differential between inner and outer.
https://www.yahoo.com/news/stockton-rushs-oceangate-had-college-043106609.html
- OceanGate hired teenage interns to design the Titan's electrical systems, The New Yorker reported.
- "The whole electrical system — that was our design," the former intern Mark Walsh said in 2018.
- A community college that sent interns to OceanGate stopped offering internships with it in 2019.
OceanGate's former finance director said she quit when Stockton Rush asked her to be the Titanic submersible's chief pilot after firing the original one for raising safety issues: reportThe ambitious seafaring company previously touted its partnerships with NASA, Boeing, and the University of Washington on the Titan's design. These claims were later denied by Boeing and the University of Washington, who said they did not work on the Titan submersible.
Washington State University said in a statement to the local daily newspaper the Everett Herald on June 22 that they did not "have an alliance with OceanGate."
https://www.yahoo.com/news/titan-investigators-try-why-sub-181658100.htmlThe MBI will look into any accountability aspects and can make recommendations for civil or criminal sanctions if necessary. The investigation can determine "whether an act of misconduct, incompetence, negligence, unskillfulness, or willful violation of law" contributed to the accident.
Any subsequent enforcement will be pursued under a separate investigation, Neubauer said.
The Marine Board of Investigation will produce a report with its findings, which will be sent to the Coast Guard Commandant and international maritime partners in an effort to improve safety measures for submersibles worldwide, according to Neubauer.
I'm not sure if galvanic corrosion has been mentioned in the thread before, butIvan Seeking said:I was trying to find a source to confirm this and haven't spotted one yet. However an engineer from the submarine community stated in an interview that carbon fiber has already been ruled out as unsafe for salt water submarines [at least]. The claim was that where you have a joint between carbon fiber and titanium, as at the end caps, because carbon is a metal, you get current flow between the dissimilar metals. This in turn starts to break down the epoxy used in the carbon fiber, which eventually begins to delaminate.
The claim was that this was clearly established some years ago. Additionally, carbon fiber is appropriate for tension, not compression. And lastly, cycle testing was refused. And that is where the problems occur. It isn't just the pressure. It is the number of pressure cycles that causes problems.
jedishrfu said:Another video related to sub implosions and sub rescue operations:
Thinking same. I can get the note part, Bigger the vessel the deeper the note, longer the wavelength.snorkack said:Stupid question: how can a submarine implosion have a bubble pulse frequency or it be usable to determine the depth?
Well, I have the issue with "bigger"/"known volume" here.pinball1970 said:Thinking same. I can get the note part, Bigger the vessel the deeper the note, longer the wavelength.
(quick google) Translate to depth, deeper it it is, the higher the pressure, higher energy so higher amplitude? Louder? Mind you deeper it is the fainter the signal.
Need a physics/acoustics guy.
Ok. The physics is beyond me here.snorkack said:Well, I have the issue with "bigger"/"known volume" here.
For explosion, the pulse frequency is easy. Underwater explosion in homogenous, spherically symmetric water would create a spherically symmetric bubble, apart from the pressure gradient, and that would still leave the axial symmetry intact. One bubble pulsing at one frequency that depends only on explosion power and depth.
But a submarine? Cylindrical vessel full of contents?
If the cylinder fails first at one end, the water hammer would then travel along the cylinder, break the waterproof bulkheads in succession and leave the bubble at the other end. But if the cylinder fails somewhere near the middle but not exactly in the middle then the water hammers travel from the middle towards both ends, creating two bubbles of different sizes and periods. Plus the large internal structures which have further potential to alter the bubble behaviour and split them. Bubbles with similar but different periods, close enough to each other to modify each other significantly...
Pun intended?pinball1970 said:I'm out of my depth here.
Possibly yes. That's bad. Apologies to the people who are human beings on the site.Vanadium 50 said:Pun intended?
Hey, waitaminute. What about the rest of us?pinball1970 said:Possibly yes. That's bad. Apologies to the people who are human beings on the site.
When the structure fails, I would expect it to fail everywhere pretty much at the same time.snorkack said:If the cylinder fails first at one end, the water hammer would then travel along the cylinder, break the waterproof bulkheads in succession and leave the bubble at the other end. But if the cylinder fails somewhere near the middle but not exactly in the middle then the water hammers travel from the middle towards both ends, creating two bubbles of different sizes and periods.
I disagree. The composite probably failed at the largest flaw resulting in asymmetric failure.jack action said:When the structure fails, I would expect it to fail everywhere pretty much at the same time.