Submarine disappeared...

[RTB]

Pebbles167 said:

Hopefully they can be rescued quickly.

Out of interest, what sort of pressure would the body be under at that depth, if released into the water? Would a swim to the surface be safe enough to risk doing? I think people have escaped from submarines at lower depths, although many who attempt it die.

Not that I'm a diver, but speaking to a friend of mine who's an instructor it's feasible to survive from that depth (80m). World class free-divers swim down to similar depths (and back up again). Apparently it's not the absolute pressure but the change in pressure that is the issue, with the last few meters of the ascent being the critical ones (the longer you can pause a few meter under the surface the less chance there is of decompression related injuries).

It's possible to survive an ascent from 80m but not something I'd relish doing. You'd also have to be in pretty good physical shape to stand a chance.

I hope that the sailors are found safe - or they died immediately - the third option is unthinkable.

Edited by RTB on Wednesday 22 November 09:50

[John145]

RTB said:

Pebbles167 said:

Hopefully they can be rescued quickly.

Out of interest, what sort of pressure would the body be under at that depth, if released into the water? Would a swim to the surface be safe enough to risk doing? I think people have escaped from submarines at lower depths, although many who attempt it die.

Not that I'm a diver, but speaking to a friend of mine who's an instructor it's feasible to survive from that depth (80m). World class free-divers swim down to similar depths (and back up again). Apparently it's not the absolute pressure but the change in pressure that is the issue, with the last few meters of the ascent being the critical ones (the longer you can pause a few meter under the surface the less chance there is of decompression related injuries).

It's possible to survive an ascent from 80m but not something I'd relish doing. You'd also have to be in pretty good physical shape to stand a chance.

I hope that the sailors are found safe - or they died immediately - the third option is unthinkable.

Edited by RTB on Wednesday 22 November 09:50

Interesting question. For decompression sickness you need to go from a high pressure to a low pressure too quickly. However in this situation you will be going from a low pressure (atmospheric within the sub) to high pressure extremely quickly rising as quickly as possible to atmospheric.

So the bends won't be an issue as you aren't breathing at 9 bar (assuming 80m depth) as a scuba diver would be hence won't have the nitrogen in the bloodstream dependent upon that pressure.

Also worth noting that you will not float at that depth. I can't remember the exact figure (maybe 10m depth?) but any deeper as a free dive and you start to sink due to the compression.

I think survival would be down to 2 things:

- Fitness and being able to hold your breath to get yourself to the surface
- Cold shock from first contacting the water

[Ayahuasca]

Free dive ascent from 80 metres down? Not a chance.

[dirty boy]

Ayahuasca said:

Free dive ascent from 80 metres down? Not a chance.

I'm not sure.

I think the swim to the surface will be the most difficult, but not impossible, I can do 50m underwater, but I'd not welcome having to do it after exposing myself to freezing water....but life or death...an extra 30m? Who knows...i'd give it a shot with no other option i'm sure!

[98elise]

dirty boy said:

Ayahuasca said:

Free dive ascent from 80 metres down? Not a chance.

I'm not sure.

I think the swim to the surface will be the most difficult, but not impossible, I can do 50m underwater, but I'd not welcome having to do it after exposing myself to freezing water....but life or death...an extra 30m? Who knows...i'd give it a shot with no other option i'm sure!

The RN train to 30m free, and if they have escape suits I understand you can do 180m.

[red_slr]

I guess the big issue is conditions on the surface, you don't want to send someone up into massive waves. If it really is at 80m I think they would have tried something by now they will know their depth. At that depth they might even be able to try to surface the sub using other methods so its all really strange.

[E24man]

98elise said:

dirty boy said:

Ayahuasca said:

Free dive ascent from 80 metres down? Not a chance.

I'm not sure.

I think the swim to the surface will be the most difficult, but not impossible, I can do 50m underwater, but I'd not welcome having to do it after exposing myself to freezing water....but life or death...an extra 30m? Who knows...i'd give it a shot with no other option i'm sure!

The RN train to 30m free, and if they have escape suits I understand you can do 180m.

The RN did a training 601ft ascent/escape many, many years in a Norwegian Fjord iirc; all ascenders survived but one suffered the bends despite all being very highly trained and experienced SETT (Submarine Escape Training Tower) staff. They used the suits which allow free breathing to the surface.

The 10m, 20m and 30m escape training locks are mandatory training for any submarine staff in the UK, but even there accidents can/did happen with an occasional loss of life if you don't pay attention, screw it up and get it all wrong. Water pressure is very, very hostile to squidgy human bodies.

It is a tense set of exercises doing the training and whilst the first time you do it you are generally full of bravado, the second time you do it will be after you have served at sea and are a lot more aware of how easily things can go wrong and how severe the consequences could be.

[E24man]

red_slr said:

I guess the big issue is conditions on the surface, you don't want to send someone up into massive waves. If it really is at 80m I think they would have tried something by now they will know their depth. At that depth they might even be able to try to surface the sub using other methods so its all really strange.

If, after 6 days without power, at depth, with plummeting temperatures, reducing oxygen, increasing CO2, and in the dark, you had the choice of taking a risk with the waves in an escape suit I can guarantee most submariners would take the risk.

[Beati Dogu]

red_slr said:

US Navy have reported they may have found it, but only in 80m of water, which seems unlikely imho as they would be able to send emergency signals at that depth I would have thought.

It would be a regularly-timed acoustic signal from the sub, not a radio one. Rescue ships & aircraft will all be listening for this frequency as well as banging away on active sonar.

The sub may also have emergency buoys that will transmit a radio signal on the surface for a few hours. Doesn't sound like they had these though.

[red_slr]

Now turns out a possible underwater explosion was detected only a couple of hours after the last radio contact.. sounds pretty bad.

[MartG]

John145 said:

I think survival would be down to 2 things:

- Fitness and being able to hold your breath to get yourself to the surface
- Cold shock from first contacting the water

Holding your breath while ascending is the absolutely worst thing you can do - you need to exhale all the way up as the air in your lungs ( which you breathed in under pressure in the escape chamber ) expands massively as the pressure reduces. Hold your breath and your lungs will literally explode.

Anyway, all submarine crew will have done the escape training https://www.youtube.com/watch?v=rBDlZ7EHx4E

However with the surface weather conditions, leaving the sub would be the last option to try

[Ayahuasca]

MartG said:

John145 said:

I think survival would be down to 2 things:

- Fitness and being able to hold your breath to get yourself to the surface
- Cold shock from first contacting the water

Holding your breath while ascending is the absolutely worst thing you can do - you need to exhale all the way up as the air in your lungs ( which you breathed in under pressure in the escape chamber ) expands massively as the pressure reduces. Hold your breath and your lungs will literally explode.

Anyway, all submarine crew will have done the escape training https://www.youtube.com/watch?v=rBDlZ7EHx4E

However with the surface weather conditions, leaving the sub would be the last option to try

Yup. Basic Scuba training involves ascending from only 10 metres, exhaling all the way, it seems weird that you can exhale for ages without emptying your lungs as the remaining air expands within them.

[steveT350C]

We may have some news...
https://www.reuters.com/article/us-argentina-subma...

[Byker28i]

steveT350C said:

We may have some news...
https://www.reuters.com/article/us-argentina-subma...

Lets hope that it's real and not another false alarm.

[Last Visit]

Byker28i said:

Lets hope that it's real and not another false alarm.

As the link now confirms, it's not the missing sub sadly.

[CAPP0]

Byker28i said:

steveT350C said:

We may have some news...
https://www.reuters.com/article/us-argentina-subma...

Lets hope that it's real and not another false alarm.

Reuters article said:

Object detected by U.S. navy flight is not missing Argentine sub

[anonymous-user]

As a side issue to this. There is a channel on Freeview called Forces TV
Freeview Channel 96
Sky 264
Virgin 277
Freesat 165

http://www.forces.net/forces-tv

They in their news programmes have had some genuinely excellent sections about this missing submarine and the attempts to find it.
Really interesting news in general on their and excellent weather forecastings

[BlackLabel]

“Missing Argentine submarine: 'Explosion' heard”

http://www.bbc.co.uk/news/world-latin-america-4210...

[AndrewEH1]

Hopefully not another Kursk situation, still incredibly sad that the Russians delayed the rescue. Glad to hear that the UK stepped up despite the recent rhetoric from Argentina regarding the Falklands.

[Boosted LS1]

Do submarines have similar style escape hatches that allow rescue craft to dock with them?