Bonefish Blues
Banging donk
- Location
- 52 Festive Road
Or, thinking about it a little more, I guess they could have been ascending, since I understand that was the procedure to be followed if comms were lost, ie immediate surfacing.
This tiny submarine 2.4 miles under the sea, visiting the relics of RMS Titanic. Can it be found and the crew saved before the air runs out?
- Thread starter Accy cyclist
- Start date
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Ming the Merciless
There is no mercy
- Location
- Inside my skull
It’s not what they did last time they lost comms. But didn’t Harding post that it would likely be the only visit to Titanic this year?
Ming the Merciless
There is no mercy
- Location
- Inside my skull
Bonefish Blues
Banging donk
- Location
- 52 Festive Road
I agree that the more likely scenario was a failure whilst descending
DaveReading
Don't suffer fools gladly (must try harder!)
- Location
- Reading, obvs
The proximity of the debris to the Titanic is consistent with their not being that far above it when disaster struck.
lazybloke
Priest of the cult of Chris Rea
- Location
- Leafy Surrey
The truncated y-axis hides (at first glance) what amazing divers those whales are.
Seevio
Guru
- Location
- South Glos
I've just seen the BBC newsreader saying the sub suffered a "catastrophic loss of pressure." I hate to say it, but at 3km underwater, that is the one thing that definitely didn't happen.
Bonefish Blues
Banging donk
- Location
- 52 Festive Road
If the failure was contemporaneous with loss of comms they were 1.45 into a c2hr descent to the wreck
Beebo
Firm and Fruity
- Location
- Hexleybeef
They must have air in their lungs. So how do they not get crushed at that depth.
Drago
Legendary Member
- Location
- Suburban Poshshire
I'm no expert on whaleism but I believe their lungs do actually constrict with depth. Or not. I seem to recall something like that.
Bonefish Blues
Banging donk
- Location
- 52 Festive Road
Yes. Same for human free divers because the air volume decreases with depth and increasing pressure
https://gofreediving.co.uk/effects-of-pressure-and-depth-on-freedivers
https://gofreediving.co.uk/effects-of-pressure-and-depth-on-freedivers
Hover Fly
Lazy so and so
- Location
- Besides the lake, beneath the trees
The short answer is, they collapse their lungs, forcing all the gases into their blood and tissues. They have evolved rib cages can collapse in a controlled way to allow this.
Reynard
Guru
- Location
- Cambridgeshire, UK
Been following this with my materials engineer hat on with some degree of dismay.
There's a reason really deep sea diving vehicles are spherical and largely made of steel. And not a cigar-shaped CFRP-titanium hybrid. The basic maths, engineering design, manufacturing and material properties are pretty self-explanatory.
My best bet is that it's one of two things.
a) propagation of failure at a stress raiser - either the viewport or where the ends bolt on to the sub.
b) catastrophic failure of the carbon fibre layup due to an air bubble / manufacturing defect.
The first is pretty well much what it says on the tin. Especially since we now know that the viewport wasn't rated to the depths the sub was operating at.
The second is less obvious to the layman, which is where a manufacturing defect in the layup - an air bubble - causes cracking in the internal structure. On a one-off dive it may well hold, but repeated i.e. cyclic loading will mean that the bubble keeps expanding and contracting as the pressure changes, increasing the size of the damaged area and weakening the structure as microscopic cracks and delaminations propagate through the matrix. And since you can't see it, you won't know it's there until it fails. CFRP doesn't fail in the same way as metal, and when it does, it just shatters, more often than not without prior warning.
Am a bit out of practice on the maths these days, but after seven years in academia spent doing various things with composites including smashing them up, I can still visualise the failure processes in my head.
I know it's a bit heartless in the way, but purely from an engineering perspective, the sub was an omnishambles that should never have been allowed off dry land.
There's a reason really deep sea diving vehicles are spherical and largely made of steel. And not a cigar-shaped CFRP-titanium hybrid. The basic maths, engineering design, manufacturing and material properties are pretty self-explanatory.
My best bet is that it's one of two things.
a) propagation of failure at a stress raiser - either the viewport or where the ends bolt on to the sub.
b) catastrophic failure of the carbon fibre layup due to an air bubble / manufacturing defect.
The first is pretty well much what it says on the tin. Especially since we now know that the viewport wasn't rated to the depths the sub was operating at.
The second is less obvious to the layman, which is where a manufacturing defect in the layup - an air bubble - causes cracking in the internal structure. On a one-off dive it may well hold, but repeated i.e. cyclic loading will mean that the bubble keeps expanding and contracting as the pressure changes, increasing the size of the damaged area and weakening the structure as microscopic cracks and delaminations propagate through the matrix. And since you can't see it, you won't know it's there until it fails. CFRP doesn't fail in the same way as metal, and when it does, it just shatters, more often than not without prior warning.
Am a bit out of practice on the maths these days, but after seven years in academia spent doing various things with composites including smashing them up, I can still visualise the failure processes in my head.
I know it's a bit heartless in the way, but purely from an engineering perspective, the sub was an omnishambles that should never have been allowed off dry land.
HMS_Dave
Grand Old Lady
Been following this with my materials engineer hat on with some degree of dismay.
There's a reason really deep sea diving vehicles are spherical and largely made of steel. And not a cigar-shaped CFRP-titanium hybrid. The basic maths, engineering design, manufacturing and material properties are pretty self-explanatory.
My best bet is that it's one of two things.
a) propagation of failure at a stress raiser - either the viewport or where the ends bolt on to the sub.
b) catastrophic failure of the carbon fibre layup due to an air bubble / manufacturing defect.
The first is pretty well much what it says on the tin. Especially since we now know that the viewport wasn't rated to the depths the sub was operating at.
The second is less obvious to the layman, which is where a manufacturing defect in the layup - an air bubble - causes cracking in the internal structure. On a one-off dive it may well hold, but repeated i.e. cyclic loading will mean that the bubble keeps expanding and contracting as the pressure changes, increasing the size of the damaged area and weakening the structure as microscopic cracks and delaminations propagate through the matrix. And since you can't see it, you won't know it's there until it fails. CFRP doesn't fail in the same way as metal, and when it does, it just shatters, more often than not without prior warning.
Am a bit out of practice on the maths these days, but after seven years in academia spent doing various things with composites including smashing them up, I can still visualise the failure processes in my head.
I know it's a bit heartless in the way, but purely from an engineering perspective, the sub was an omnishambles that should never have been allowed off dry land.
If what is reported is accurate, it seems that the CEO knew they had cut corners to achieve this. The viewport itself which was made of plexiglass was allegedly only rated for less that half of the depth that the sub was heading for. There will be a thorough investigation for sure and I'm predicting a lot of dismaying facts will come out about the entire operation.
Reynard
Guru
- Location
- Cambridgeshire, UK
I don't doubt that any inquiry will dredge up some rather uncomfortable details regarding the design, build and sourcing of the sub's components.
Employing an expert to help with that, then firing him because he tells you things you don't want to hear about your pet project just about says it all, IMHO. Experts are experts for a reason.
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