Titanic submersible confirmed destroyed with loss of all five souls onboard.

beeb interview with billionaires wife just aired r4today - son had taken her place partly with prospect of being first to solve a rubik cube at -4K

glue used on hull - if you watch mrk's video of Cameron's ship - they were criticized for just a few small titanium bolts holding two sides of sphere together,
but as they said, water pressure keeps it together - bolts only really needed when its above water ! so similarly glue on titans parts may have been cosmetic at -4k
 
Chaos said:
Stumbled across this today quite interesting.


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Watching Cameron's mir-1/mir-2 submersibles from that film (2005) and specifications from the c11:30 point really does put into perspective.

Capable of operating at a depth of 6000m and their quote was being well within the working limits at the Titanic depth. Also dive as a pair.

9 inch thick nickel alloy for the 7 foot diameter cockpit sphere with 7 inch thick plexiglass.
 
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Jokester said:
Refusing to do NDE on something critical to passengers life like that is criminal.
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It really depends on the material. Things like carbon fibre are notoriously difficult to NDE because they are of laminated contruction. Likewise it may not have been appropriate for radiography. The nuances with non destructive testing are so particular it's unfair to jump to conclusions without knowing the specifics.
 
PlacidCasual said:
It really depends on the material. Things like carbon fibre are notoriously difficult to NDE because they are of laminated contruction. Likewise it may not have been appropriate for radiography. The nuances with non destructive testing are so particular it's unfair to jump to conclusions without knowing the specifics.
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If you can’t demonstrate something has been manufactured correctly, probably best not to use in safety critical functions.
 
Demon said:
I think everything about the pressure vessel construction is under suspicion due to its unorthodox design, including all interfaces.

However the CF (composite) was not just bonded on the inside of the Titanium ring. the ring has a pocket in it, with all surfaces of that pocket glue’d and slid over the CF (composite) cylinder which had recesses machined or similar so it’s all flush when seated.
This means both inner/outer and end face of the CF (composite) tube are bonded.

The video of the end ring being bonded shows it clearly.
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Yes this is true, I stand corrected, but I think this is what happened:

IMG-0601.png


The pressure is from one side of course, but I still think that titanium lip digging into the CF is where it failed, yes its a cross section of a ring but that lip and CF in that area would still flex - either the CF failed, or it was teased apart enough that water was able to leak in - which at 6000 PSI would act like a laser cutter and immediately cut open the sub.
 
This is another good watch:

It allowed the guy to get the bottom of all 5 oceans, but look at the teething issues and it all seemed touch and go at the end.. better design, but the issues it had and the last minute nature of getting things just working was a bit concerning..
 
Jokester said:
If you can’t demonstrate something has been manufactured correctly, probably best not to use in safety critical functions.
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That tends to be where destructive testing of test articles and high degrees of quality assurance come in. For instance bullet proof jackets and armour plates you proof test the design and different stages of the manufacturing process then apply QA processes that ensure the methodology is being replicated correctly and you also design in such a way that the types of defect that you can miss are non critical. Large pressure vessel forgings often follow similar design methodologies you design them such that the largest defect you can't reliably detect is non critical in size.
 
Don't know how this popped up on my YouTube feed but I think this shows just how something like this happened. Problem after problem, this would have sent alarm bells ringing. Even asked for help fix the problems!

youtu.be

Titanic Sub Tourism Expedition - Exclusive Footage (My Personal Experience)

In this video I share my personal experience with OceanGate Expeditions during Mission III, 2023My condolences goes out to the people who passed away and the...
youtu.be youtu.be
 
PlacidCasual said:
That tends to be where destructive testing of test articles and high degrees of quality assurance come in. For instance bullet proof jackets and armour plates you proof test the design and different stages of the manufacturing process then apply QA processes that ensure the methodology is being replicated correctly and you also design in such a way that the types of defect that you can miss are non critical. Large pressure vessel forgings often follow similar design methodologies you design them such that the largest defect you can't reliably detect is non critical in size.
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I don’t think any of this was done in this case though? Indeed, he was keen to not even do hydro tests (if they were carried out at all?) due to the knowledge that the carbon fibre wasn’t designed to cope with the pressure in a permanent manner.
 
Although he didn't go down in the end, having watched that Youtuber's experience of the OceanGate trip, it looked very ragtag for such a serious and dangerous escapade...
 
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PlacidCasual said:
That tends to be where destructive testing of test articles and high degrees of quality assurance come in. For instance bullet proof jackets and armour plates you proof test the design and different stages of the manufacturing process then apply QA processes that ensure the methodology is being replicated correctly and you also design in such a way that the types of defect that you can miss are non critical. Large pressure vessel forgings often follow similar design methodologies you design them such that the largest defect you can't reliably detect is non critical in size.
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In other words you overengineer it and don't use pringles tubes held together with string
Jokester said:
I don’t think any of this was done in this case though? Indeed, he was keen to not even do hydro tests (if they were carried out at all?) due to the knowledge that the carbon fibre wasn’t designed to cope with the pressure in a permanent manner.
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Apparently only rated for one dive and not for multiple due to the nature of the material and the risk of water ingress and subsequent delamination of the fibres. Totally reckless and completely dismissive of engineering common sense it appears
 
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