Submersible missing while visiting Titanic wreck  - Page 1
Forum section: electronics / general

author: AlbertL
author_rank: Regular Contributor
timestamp: June 20, 2023, 12:11:44 am
content: https://www.bbc.com/news/world-us-canada-65953872

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 20, 2023, 02:26:18 am
content: I assume it should have a standalone ultrasonic beacon (similar to the ones on airplane data recorders) so that the ship always knows where it is, even if the primary means of communication isn't working.QuoteApollo 1 showed why that's a very bad idea. My take is that it should have some means of emergency flotation, after which the floats can be detached and used as lifeboats.

author: AlbertL
author_rank: Regular Contributor
timestamp: June 20, 2023, 03:02:03 am
content: The BBC story says ""When the support ship is directly over the sub, they can send short text messages back and forth. Clearly those are no longer getting a response," Mr Pogue said." I would assume the medium is some kind of low-bandwidth acoustical link.

author: floobydust
author_rank: Super Contributor
timestamp: June 20, 2023, 05:52:11 am
content: "... piloted by a video game controller; its lighting purchased from a camping shop, construction pipes making do as ballast." Big spendersAt 12,500 ft depth fluid pressure is 5,500 psi or 38.2MPa or 377 atm.If you have ever seen gear designed for that pressure, such as a cable gland connector to get a few wires out, it's a major piece of work. I did see that in offshore oil rigs for sensors at the ocean floor. Properly done it's very expensive. No wonder they lose comms and hopefully that's all that is missing.

author: Haenk
author_rank: Super Contributor
timestamp: June 20, 2023, 11:36:36 am
content: "the passengers were sealed inside the vessel by bolts applied from the outside" (and the bolts can not be opened from the inside)What's not to like about that...Honestly, that's a daredevil ride, and those happen to fail.

author: Psi
author_rank: Super Contributor
timestamp: June 20, 2023, 12:14:40 pm
content: Quote from: Haenk on June 20, 2023, 11:36:36 amI doubt there's many other options than a massive number of bolts all around the outside, given the depth and pressures involved.Even if you could move those bolts to the inside, i think that would probably make it less safe rather than more.

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 20, 2023, 01:12:14 pm
content: It could be designed so that it's primarily the pressure that holds it on, so that the retention mechanism only needs to work at shallow depths.

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: June 20, 2023, 01:40:13 pm
content: Prolly inappropriate me posting this. Anyway.https://en.wikipedia.org/wiki/Fantastic_Voyagehttps://archive.org/details/fantasticvoyage1966_202004

author: Messtechniker
author_rank: Frequent Contributor
timestamp: June 20, 2023, 01:44:33 pm
content: Its the old story: "Whatever can go wrong will eventually go wrong."Every lab door should carry this note.....

author: Smoky
author_rank: Frequent Contributor
timestamp: June 20, 2023, 02:09:19 pm
content: For the past 100 years or so the Titanic did rest peacefully.Future pictures will now show the wreckage but also with it having a white hotdog sitting on top of it.Can't we leave anything sacred alone? Like Mars too?

author: hans
author_rank: Super Contributor
timestamp: June 20, 2023, 02:50:34 pm
content: And the saga continues:https://www.bbc.com/news/live/world-us-canada-65953941QuoteQuoteOh gosh.https://www.washingtonexaminer.com/news/founder-titanic-oxygen-missing-submersibleQuoteWas thinking that. 96hr supply may be in the bottles, but its useless if CO2 isn't removed. It's a small interior volume, and it doesn't take that much CO2 contentration (couple percent pts) to be lethal. I suppose that limit would be reached in quite a brief time if anything was to go catastrophically wrong.Second question I have is, what they can realistically do if they even locate the vessel? If its at the bottom of the ocean, that's a damn long way down (almost 4km). The titanic ship is also there for a damn good reason, as its one of the most unreachable spots on earth.I don't think there is anything 'sacred' about these places. I'm not religious. But going down there with a DIY vehicle based on hope and luck doesn't sound like the best of ideas.

author: BrokenYugo
author_rank: Super Contributor
timestamp: June 20, 2023, 03:11:10 pm
content: TIL fly by night deathtrap deep sea tours are a thing.Looks to me like the one and only door on this thing is the whole front swings to the side on a hinge and is then bolted shut. That's sketchy even by my standards.Also, why carbon fiber beyond marketing BS?

author: iMo
author_rank: Super Contributor
timestamp: June 20, 2023, 05:10:47 pm
content: This cheapo submarines should be built like the bathyscaphe Trieste in 50ties.Basically a balloon filled with gasoline (thus not compressible), with steel balls like the ballast, hold by elmagnets.When the capsule with explorers bursts, or the electricity is lost or over, the magnets will release the ballast and the balloon will ascent automatically to the surface.

author: floobydust
author_rank: Super Contributor
timestamp: June 20, 2023, 05:15:50 pm
content: It's an “experimental submersible vessel that has not been approved or certified by any regulatory body and could result in physical injury, disability, emotional trauma or death.”Oceangate claims it's their technology - carbon fiber 5" thick and titanium bulkheads thatjustifiesthe vessel having no regulatory or classification, also to save years of red tape. "... the carbon-fibre main capsule had been co-designed with Nasa and the University of Washington and was "rock solid".I wonder if it even has a backup battery power system or all the money went into the cameras. One pic shows no manual controls, another does.The press is on about old 2022 CBS reporter David Pogue getting the creeps from the jerry rigged construction and CEO bragging about using cheap hardware- trip had loss of comms 3 times etc.https://deadline.com/2023/06/cbs-oceangate-titanic-submarine-viral-david-pogue-safety-concerns-1235420540/TeledyneBenthosacoustic modems were used for data acquisition during initial dive testing.Bit rates are sloooww, worst is 80bits/sec. I didn't know you could buy/rent a water acoustic modem.

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: June 20, 2023, 05:35:51 pm
content: Imagine paying $250,000 for a ride in a death trap. No thanks. Not for me.

author: iMo
author_rank: Super Contributor
timestamp: June 20, 2023, 05:42:10 pm
content: Deep sea exploration is important, as that is the future of the mankind..Not Mars but deep oceans, as Bob Ballard said..

author: TheSteve
author_rank: Unknown
timestamp: June 20, 2023, 07:36:49 pm
content: From what I've read it had no beacon of any kind, but they had discussed maybe adding one.

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: June 20, 2023, 07:53:21 pm
content: My guess? This thing, like MH370, will never be found.

author: MadTux
author_rank: Frequent Contributor
timestamp: June 20, 2023, 08:15:47 pm
content: Look at the 90deg winding direction here:https://youtu.be/4dka29FSZac?t=231Almost no longitudinal strength, if they really never put any lengthwise fibers in there, those fools.Unidirectional carbon fiber strength, along fiber: 3'430 MPaUnidirectional carbon fiber strength, 90deg to fiber direction: 96 MPahttps://www.luzi-2.ch/material/faser-kennwerteAccording to Barlow formula, you need 2x strength in radial direction and 1x strength in longitudinal directionhttps://en.wikipedia.org/wiki/Barlow%27s_formulaResult from that winding machine, 38x strength in radial direction, 1x strength in longitudinal direction.That thing folds like a coke can, looooong long before radial strenght has reached it limits.The only reason why it didn't fold at 3000m when he went solo is that they apparently used something like 5inches of carbon, i.e. totally over engineered, but without any brains.Right approach would have been using carbon fiber sheets with fibers in 2/1 ratio in radial/longitudinal direction.But using a stupid lathe and winding tons of carbon rowing @ 90deg is so much more simple and lazy.....My bets is that this deathtrap simply imploded, because of dumb engineering.

author: BILLPOD
author_rank: Frequent Contributor
timestamp: June 20, 2023, 08:17:25 pm
content: They will have to borrow James Cameron's 'Deepsea Challanger'https://en.wikipedia.org/wiki/Deepsea_Challenger

author: ataradov
author_rank: Super Contributor
timestamp: June 20, 2023, 08:47:15 pm
content: Rich people hate regulations and "red tape". The nature and physics do not care. They all signed waivers, so whatever. And there is no chance the company would be in business. You need to be incredibly stupid to get into one of those things.I don't really see the point of being there. Having good HD video is so much better.

author: .RC.
author_rank: Frequent Contributor
timestamp: June 20, 2023, 09:26:26 pm
content: I would rather be abducted by aliens and anally probed then get into that thing.

author: MadTux
author_rank: Frequent Contributor
timestamp: June 20, 2023, 09:33:47 pm
content: Quick and stupid calculation, from stuff I could find online:OceanGate sub inside diameter: 142cmWall thickness 5inches/12.7cmOutside diameter 167.4cmForce on 142cm disk @ 4000m => 6334'000kgFArea of the pressure hull frontside ring (area between inside and outside diameter)(83.4cm)²*pi)-(71cm)²*pi) => 6172cm²So pressure on that area 6172cm²/6334'000kgF => about 1000kg/cm²96 MPa (strength of unidirectional carbon in bad direction) => 960kg/cm²Somehow numbers add up surprisingly good.....Crush depth of that death trap really at 4000mif they just wound carbon rowings around??

author: mendip_discovery
author_rank: Super Contributor
timestamp: June 20, 2023, 09:40:37 pm
content: I do hope they are found safe and well but I don't think this is the case.The British explorer/billionaire sounds a lot like Gustav Graves to me. The way the BBC are fawning over him. Supposedly the two Pakistani people are also now British-Pakistani. I really don't care more about a story if there is a person from my country involved, I care becuae I am a human (your opinions may vary).Of the pictures I have seen of this vessel I wouldn't be happy with the price tag for the trip only to see out a very small viewing port. I know science is a b*!ch so it's not going to be like rovers we see in the movies. The chances are the $250k price tag and the experience is just for bragging rights nothing else.With regards to safety I will be interested to know what kinds of safety systems they have in place. I would have assumed some sort of sound beacon and flashing light would have been a basic. Though if I remember the visibility around there is terrible if the footage of the Titanic is anything to go by. I really dont like this idea you are bolted inside this thing with no way to get out, imagine getting to the surface only to die there because of too much CO².If they are dead, then I hope it was a quick death. I'd they are found alive I can see it becoming a movie.

author: Gyro
author_rank: Super Contributor
timestamp: June 20, 2023, 10:05:50 pm
content: The Titanium end rings are just glued to the ends of the carbon fibre tube - effectively just to the outer layer. I wonder what the differential of expansion (or rather contraction) is under extreme pressure. What are the chances of that causing delamination of the ends of the tube over several cycles?