Also in the News - Part 2

[Trumpet]

2 minutes ago, The Doctor said:

 

https://www.bbc.co.uk/news/world-us-canada-65969476

 

Fortunately that is on hand *if* it's found: "Two Canadian Coast Guard ships and a Royal Canadian Navy ship equipped with a six-person mobile hyperbaric recompression chamber are also en route."

 

Less than 24 hours of oxygen left for 5 people, there's only one way to make the maths math for longer survival, and it involves a long pork dinner

I’d seriously consider putting myself forward if I was on board. It must be terrifying enough being cramped up in a small space like that at the bottom of the ocean, but to know you’re approaching a point where there’s no oxygen left and presumably a painful death, I think I’d chose to have control given that scenario.

[Zear0]

1 hour ago, yorkie1999 said:

Is that a problem with a submersible? 

Depends on the design but generally it isn't.  Unlike aircraft you don't have the luxury of air all around to run pressurisation systems.  For more advanced submersibles, you can carry gas bottles to overpressurise and then discharge during ascent to retain the same pressure.  These are generally for craft support systems exposed to the outside environment and not environmental systems. Being kind, the craft in question won't have any of these and will be running at a fixed pressure during submersion so they're not likely to suffer from the effects that divers suffer with.  I read a Royal Canadian Navy was bringing a craft with an on-board chamber as a mitigation just incase it's needed if the crew are pulled out at a more accommodating depth (won't happen let's be honest. Whilst the compression of the craft will slightly increase the internal pressure but it'll make, in technical term, a bee's dick of difference.  Noting the above, whilst balancing the internal pressure with the external pressure would be nice in reducing the hoop stresses on the pressure boundary, it's not going to be too agreeable to the crew.

Edited 21 June 2023 by Zear0

[leicsmac]

2 minutes ago, Zear0 said:

Depends on the design but generally it isn't.  Unlike aircraft you don't have the luxury of air all around to run pressurisation systems.  For more advanced submersibles, you can carry gas bottles to overpressurise and then discharge during ascent to retain the same pressure.  Being kind, the craft in question won't have any of these and will be running at a fixed pressure during submersion so they're not likely to suffer from the effects that divers suffer with.  I read a Royal Canadian Navy was bringing a craft with an on-board chamber as a mitigation just incase it's needed if the crew are pulled out at a more accommodating depth (won't happen let's be honest. Whilst the compression of the craft will slightly increase the internal pressure but it'll make, in technical term, a bee's dick of difference.  Noting the above, whilst balancing the internal pressure with the external pressure would be nice in reducing the hoop stresses on the pressure boundary, it's not going to be too agreeable to the crew.

I would think that fixed pressure is going to be pretty damn high though, so getting them out without exposure to that pressure gradient is going to be an issue.

 

(Unless we have reached the point where we can design submarines that can go to stupid depths while maintaining internal pressure close to surface. I mean, we may have, I don't know?)

Edited 21 June 2023 by leicsmac

[Zear0]

1 minute ago, leicsmac said:

I would think that fixed pressure is going to be pretty damn high though, so getting them out without exposure to that pressure gradient is going to be an issue.

0% chance!  Was more thinking if it was bobbing under the surface at 200ft.

[leicsmac]

1 minute ago, Zear0 said:

0% chance!  Was more thinking if it was bobbing under the surface at 200ft.

Ah, the penny drops, thank you. Yeah, getting them out at that depth would be much easier. Doing it from around 9000 feet or more, which is where they might be...

Edited 21 June 2023 by leicsmac

[leicsmac]

Though honestly, given the time frame, I do think unless they are pretty close to the surface then everyone is brown bread anyway. There's just not enough time.

 

I really hope I'm wrong there, though.

[The Doctor]

28 minutes ago, leicsmac said:

I can't laugh react to that because of the second half of the post, damn it.

 

Glad they have the gear in place, but they still need to find them and do everything in a very short time frame.

Look, you have these socialists talking about eating the rich but who's actually innovating and putting it into practice? Billionaires 

[Captain...]

In terms of depressurisation, could the craft surface safely without complete depressurisation? In which case can a new oxygen tank be fitted externally to give them more time to resolve the pressure issue.

 

If Oxygen tanks can be replaced externally without compromising the pressure there is a greater chance of success. Likewise getting food and water into the craft. They could even have had the foresight to allow for oxygen tanks to be replaced/added whilst the craft is at depth to buy time in case of such incidents. It is horrible to imagine yourself in this situation and any sort of positive outcome is highly unlikely.

[leicsmac]

Just now, Captain... said:

In terms of depressurisation, could the craft surface safely without complete depressurisation? In which case can a new oxygen tank be fitted externally to give them more time to resolve the pressure issue.

 

If Oxygen tanks can be replaced externally without compromising the pressure there is a greater chance of success. Likewise getting food and water into the craft. They could even have had the foresight to allow for oxygen tanks to be replaced/added whilst the craft is at depth to buy time in case of such incidents. It is horrible to imagine yourself in this situation and any sort of positive outcome is highly unlikely.

Yes, it can surface safely - you just wouldn't be able to open it up for a while to the surface air.

 

I'm sure it would be possible to get oxygen and other supplies to the passengers in that case (using a specially pressurised submersible, for instance, but that would have to be manned as well because of the need to unlock the door from outside, which would have its own attendant problems).

[stripeyfox]

4 minutes ago, Captain... said:

In terms of depressurisation, could the craft surface safely without complete depressurisation? In which case can a new oxygen tank be fitted externally to give them more time to resolve the pressure issue.

 

If Oxygen tanks can be replaced externally without compromising the pressure there is a greater chance of success. Likewise getting food and water into the craft. They could even have had the foresight to allow for oxygen tanks to be replaced/added whilst the craft is at depth to buy time in case of such incidents. It is horrible to imagine yourself in this situation and any sort of positive outcome is highly unlikely.

I don't think there is any way of accessing the craft  apart from unbolting the hatch (which is sealed from the outside).

 

And removing the hatch at depth will result in instant death for the occupants anyway, even if it were possible.

 

Food and water aren't the limiting factor here, it's oxygen. 

[leicsmac]

1 minute ago, stripeyfox said:

I don't think there is any way of accessing the craft  apart from unbolting the hatch (which is sealed from the outside).

 

And removing the hatch at depth will result in instant death for the occupants anyway, even if it were possible.

 

Food and water aren't the limiting factor here, it's oxygen. 

Removing the hatch even at the surface will result in instant death if the submarine hasn't had time to depressurise slowly (because doing it quickly would result in everyone getting the bends).

[ClaphamFox]

5 minutes ago, stripeyfox said:

I don't think there is any way of accessing the craft  apart from unbolting the hatch (which is sealed from the outside).

 

And removing the hatch at depth will result in instant death for the occupants anyway, even if it were possible.

 

Food and water aren't the limiting factor here, it's oxygen. 

If the hatch is sealed from the outside, does that mean the same issue with diminishing oxygen also applies if the sub is on the surface of the ocean? 

[leicsmac]

On ocean topics:

 

 

Gives an idea of the kind of depths we might be dealing with here.

[stripeyfox]

1 minute ago, ClaphamFox said:

If the hatch is sealed from the outside, does that mean the same issue with diminishing oxygen also applies if the sub is on the surface of the ocean? 

I'll defer to @leicsmac on that - he's the clever one!
 

[leicsmac]

3 minutes ago, ClaphamFox said:

If the hatch is sealed from the outside, does that mean the same issue with diminishing oxygen also applies if the sub is on the surface of the ocean? 

 

1 minute ago, stripeyfox said:

I'll defer to @leicsmac on that - he's the clever one!
 

Only in certain regards, mon ami!

 

Yes, the oxygen issue would still be a problem at surface, until another submersible capable of docking while maintaining pressure were to dock with additional oxygen. The good thing would be that you likely wouldn't need any further specialised equipment - once the rescue sub was docked, the oxygen it alone has would be more than enough for everybody until the pressure has changed enough to get everyone out and into a hyperbaric chamber.

[Zear0]

7 minutes ago, ClaphamFox said:

If the hatch is sealed from the outside, does that mean the same issue with diminishing oxygen also applies if the sub is on the surface of the ocean? 

Depends if there's a snorkel attached which there usually is on ocean submersibles.  Hoiking them out of the sea can be a challenge when things get choppy so they're fitted if they can't be removed swiftly.

[leicsmac]

Just now, Zear0 said:

Depends if there's a snorkel attached which there usually is on ocean submersibles.  Hoiking them out of the sea can be a challenge when things get choppy so they're fitted if they can't be removed swiftly.

Sorry to come back to this again, but would that work if the pressure inside the sub and at surface were drastically different?

 

Perhaps it might, but I honestly don't know.

[FoxesDeb]

Taken from The Independent today:

 

According to oceanologist Dr Simon Boxall of the University of Southampton, one common misconception is that people will get decompression sickness, commonly nicknamed “the bends”, if the boat moves up to the surface too quickly.

He told PA that those on board would not suffer “ill-effects” because the boat is at atmospheric pressure.

[Zear0]

6 minutes ago, leicsmac said:

Sorry to come back to this again, but would that work if the pressure inside the sub and at surface were drastically different?

 

Perhaps it might, but I honestly don't know.

Very easily.  At depth, the pressure is forcing water inwards so a diaphragm valve would increase the sealing capability the deeper you went.  It becomes more of a problem as you surface but that's easily designed out by fitting an isolating globe valve to give you a second barrier.

Edited 21 June 2023 by Zear0

[Zear0]

6 minutes ago, FoxesDeb said:

Taken from The Independent today:

 

According to oceanologist Dr Simon Boxall of the University of Southampton, one common misconception is that people will get decompression sickness, commonly nicknamed “the bends”, if the boat moves up to the surface too quickly.

He told PA that those on board would not suffer “ill-effects” because the boat is at atmospheric pressure.

Yeah I mentioned this earlier, I don't think this would be a problem in the slightest as the crew are within the pressure boundary and not seeing any meaningful change in pressure.

Edited 21 June 2023 by Zear0

[stripeyfox]

Just now, Zear0 said:

Yeah I mentioned this earlier, I don't think this would be a problem in the slightest as the crew are within the pressure boundary and not seeing any meaninful change in pressure.

I guess it would still take quite a long time to get to the surface (either by "floating") or being pulled up?

 

The wreck site is almost 2.5 miles down.

 

If the estimated life support is due to run out around 1000 GMT tomorrow (and I know that isn't a definite deadline) then any rescue needs to be happening very soon.

 

From BBC

 

[leicsmac]

33 minutes ago, FoxesDeb said:

Taken from The Independent today:

 

According to oceanologist Dr Simon Boxall of the University of Southampton, one common misconception is that people will get decompression sickness, commonly nicknamed “the bends”, if the boat moves up to the surface too quickly.

He told PA that those on board would not suffer “ill-effects” because the boat is at atmospheric pressure.

Yeah, getting up wouldn't cause ill-effects.

 

But is the sub really at atmospheric pressure inside and so the pressure differential wouldn't be a factor?

 

You know, having got home from work and looked for more information here. it turns out we have manufactured submarines that can work at that depth while maintaining atmospheric pressure inside, though I've no idea is this one is one of them (though Dr Boxall intimates that it is). So the pressure would in fact be a non-issue and my own thoughts - based on diving bell work - were horribly incorrect as I honestly figured DSV's would be pressurised in a similar way. Top bombing, Mac.

 

Guess they do indeed just have to find the thing and get it to the surface then, which simplifies matters somewhat.

 

Edit: You have to wonder in that case, what the point of bringing the ship with the hyperbaric chamber and why is the thing only designed to be opened from the outside?

 

32 minutes ago, Zear0 said:

Very easily.  At depth, the pressure is forcing water inwards so a diaphragm valve would increase the sealing capability the deeper you went.  It becomes more of a problem as you surface but that's easily designed out by fitting an isolating globe valve to give you a second barrier.

I can see how that would work, thank you!

Edited 21 June 2023 by leicsmac

[SpacedX]

24 minutes ago, ClaphamFox said:

If the hatch is sealed from the outside, does that mean the same issue with diminishing oxygen also applies if the sub is on the surface of the ocean? 

Yes. 

 

I think that there's a strong possibility that it has become entangled/snagged with something on the ocean floor - possibly within the debris field of the wreckage. Particularly since the knocking was detected at intervals which is thought to be the experienced Paul-Henry Nargeolet a former French naval captain and experienced diver. The contingency in the event of the loss of power is to release the drop weights and float back to the surface. It is also a possibility that the system for jettisoning weight has failed. I don't think that there has been any successful retrieval of a submersible at such a depth - particularly given the timescale. It would also need a very powerful winch and another remotely controlled submersible to be deployed very rapidly. There simply isn't the time. 

 

There is a small possibility that it has floated to the surface, but if communications are down, which has apparently repeatedly plagued the vessel - although during the dives themselves, no one would know unless they were spotted. The hatch on a submersible can usually be opened from the inside, but this appears not to be the case for the Titan which is apparently bolted down externally. If they are haplessly bobbing about on the surface of the Atlantic somewhere, which I doubt, then they are still at the mercy of their oxygen reserves. However, their chances of recovery are at least higher. 

[stripeyfox]

14 minutes ago, Line-X said:

Yes. 

 

I think that there's a strong possibility that it has become entangled/snagged with something on the ocean floor - possibly within the debris field of the wreckage. Particularly since the knocking was detected at intervals which is thought to be the experienced Paul-Henry Nargeolet a former French naval captain and experienced diver. The contingency in the event of the loss of power is to release the drop weights and float back to the surface. It is also a possibility that the system for jettisoning weight has failed. I don't think that there has been any successful retrieval of a submersible at such a depth - particularly given the timescale. It would also need a very powerful winch and another remotely controlled submersible to be deployed very rapidly. There simply isn't the time. 

 

There is a small possibility that it has floated to the surface, but if communications are down, which has apparently repeatedly plagued the vessel - although during the dives themselves, no one would know unless they were spotted. The hatch on a submersible can usually be opened from the inside, but this appears not to be the case for the Titan which is apparently bolted down externally. If they are haplessly bobbing about on the surface of the Atlantic somewhere, which I doubt, then they are still at the mercy of their oxygen reserves. However, their chances of recovery are at least higher. 

I agree with this hypothesis 

 

If it wasn't a hull breach (in which case it is game over anyway), then it's either become stuck on debris or as you say, the system for jettisoning ballast has failed.

 

 

 

 

[SpacedX]

1 minute ago, stripeyfox said:

I agree with this hypothesis 

 

If it wasn't a hull breach (in which case it is game over anyway), then it's either become stuck on debris or as you say, the system for jettisoning ballast has failed.

 

Their fate does appear to be sealed...

 

...I've just realised that was an unfortunate way of putting it but given that it was in all honesty completely unintentional, I've made the probably ill-judged decision to leave it in. Unfortunately, with the oxygen supply exhausted in little over 18 hours, there simply isn't time to stage a rescue or recovery. We can only hope that the often strong ocean floor currents free them from their plight and they are able to resurface and regain communication. 

 

If not, then let's hope that the Titan can be recovered and their bodies can be returned to the families. A grim and grisly thought and not really something one should entertain until their fate is confirmed, but it may be a substantially long time until the submersible is located and perhaps brought to the surface. The search for and recovery of Liberty Bell 7 was a long operation and it was was finally pulled to the surface by sea salvage specialists by Kevlar cord. The tether was attached to three clamps that had been hooked to the top of the spacecraft by a robotic recovery vessel. That was 4,000ft deeper than the wreck of the Titanic. 

 

I hope and pray that I am wrong.