How deep can you do a CESA and survive?

[victor]

???????????? Mix of gases ? Don't you just get out with a 1 atm lungfull of air and go up like a rocket ? Or have I missed the point ?

The preasure difference between the inside and outside of the sub at 600 ft is about 272 lbs per square inch.

So to open the door and not kill the submariner you need to equalise the preasure in the escape chamber.

If you did not then the water entering the chamber as the door started to open would cut the person inside into little pieces. :no

If you pumped air into the chamber then you will increase the partial presure of O2 well its toxity level. An O2 hit at this depth would not be a pleasent experience.

To overcome this you would need to pump in a mix of Helium, Nitrogen and Oxygen.

Since this would be non-swiming ascent you could take the O2 up to 1.6 or higher, a bit of a gamble but you won't be spending long or working very hard at this depth.

I will let people much more skilled at this work out the optimum mix of gasses and how long it would take to get the escape chamber down to 600 ft.

 

[Karibelle]

cudachaser,

I believe he was saying to let air out as the pressure builds up. Much like a burp, you feel the pressure building up then eventually you let it out. Same way, when you are ascending, the pressure in your lungs will build, as you feel that pressure building (maybe it'd be better before that feeling), slowly exhale and it will release the pressure.

(Does that make sense? )

Michael

I don't think so. The point is to keep your airway open, not to have it be closed, and then open it when you feel pressure. I don't believe we are astute enough - especially while doing an emergency ascent - to feel the pressure building in our lungs.

If your airway is open the entire time but you're not actively exhaling, the expanding air would just come out on its own rather than being forced out through the "ahhhhhh" sound. In this case, pressure would not "build up" as the air would be continually escaping as it was expanding...

Never, ever hold your breath. Even when you think you have none to hold.

kari

 

[mwhities]

Karibelle,

Essentially that's what I meant, just didn't type it correctly. I know one should never hold their breath under water while diving. I was just trying to give an analogy to get the point across, I just didn't say it right. Thanks for the clarification.

Michael

 

[Charlie99]

Though I use the humming technique for CESA, please explain your airway method, more specifically how would you effectively teach it?

It is probably easier for people whose languages have a velar fricative or velar stop.

Cough a couple times. Did you notice that you close your airway by moving something at the back of your throat? When you are in that state just before you "release" the cough, if you shoved hard into your gut no air would have come out. Take a deep breath, then start to cough or clear your throat, but stop with the airway closed. Notice that you can now relax your chest muscles and still be holding your breath. This is a closed airway situation. Bad, bad, bad. While diving, you should never ever be using this method of pausing your breathing, even for an instant. That's a bad habit -- don't EVER do it.

Now take a full breath and hold it by using your chest muscles while leaving your airway open. While keeping your lungs nearly full, you should be able to exhale and inhale tiny bits of air, or just pause while still keeping the airway open. Pushing hard onto your abdomen in this state should cause a puff of air to come out, even if you don't relax your chest muscles. Were you to take a deep breath at depth and then start ascending while staying in this "full lungs, airway open" state, the excess air from Boyle's Law expansion would just flow out of your lungs without injury.

Some divers have trouble figuring out how to equalize. Some equalize but don't know how they do it. Some divers manage to get voluntary control of their eustachion tube and can do voluntary equalization.

It's kind of the same with control of the airway closure / epiglottis. Once you get the feel of what you are doing, it only takes a little bit of practice to get full voluntary control.

Charlie Allen

 

[cudachaser]

Also hyper extending the neck would help. Maybe we ought extend this thread to what exactly causes over expansion injuries, hyper neck extension and not allowing any resistance in the mouth area should work...but are there other areas in the breathing system that could cause blockage? What iis the exact mechanism?

 

[Karibelle]

It is probably easier for people whose languages have a velar fricative or velar stop.

That's easy for YOU to say. :blinking: Velar who? (getting out my dictionary...)

kari

 

[SteveAD]

The preasure difference between the inside and outside of the sub at 600 ft is about 272 lbs per square inch.

So to open the door and not kill the submariner you need to equalise the preasure in the escape chamber.

If you did not then the water entering the chamber as the door started to open would cut the person inside into little pieces. :no

If you pumped air into the chamber then you will increase the partial presure of O2 well its toxity level. An O2 hit at this depth would not be a pleasent experience.

To overcome this you would need to pump in a mix of Helium, Nitrogen and Oxygen.

Since this would be non-swiming ascent you could take the O2 up to 1.6 or higher, a bit of a gamble but you won't be spending long or working very hard at this depth.

I will let people much more skilled at this work out the optimum mix of gasses and how long it would take to get the escape chamber down to 600 ft.

In a sub escape in one of those suits an oxtox hit would be of little or no importance. Oxtox all by itself poses very little danger to a person. Too much ppo2 and the body starts convulsing, reduce the ppo2 and the symptoms will subside. The reason divers (rightly) fear oxtox so much is that with a standard regulator in our mouth and swimming untethered the initial hit will likely cause us to lose the reg and drown and/or sink to the bottom unconcious. If a submariner were to tox in one of those escape suits, he is completely enclosed in a bouyant bubble of air, he has no risk of drowning and the ppo2 to which he is exposed is rapidly dropping. Assuming he does tox (which is likely) the tox should resolve before he reaches the surface. As far as the time to pressurize the escape trunk, this would be a life or death escape situation a few ruptured eardrums would be a small price to pay to get any men off a sub having a catastrophe at 600feet. the chamber could probably be equalized in under 1 minute.

I am not a submariner, the above is merely my theorization based on my knowledge of physics and physiology. I would be glad to hear from someone with more practical knowledge provided it doesn't breach security concerns.

 

[Gilldiver]

I thought I'd get a few comments on the sub escape. What happends is that the man puts on the suit and enters the escape chamber, in a real escape you may have 5 or 6 men at a time.

The chamber is pressurized with air in about 30 seconds - never mind the ears, this is life or death time. As the chamber pressurises, narcosos will make you pass out.

When the chamber reaches outside pressure, the chamber opperator opens the escape hatch and the men are blown to the surface (The chamber opperator is on the inside of the boat and not in the pressurized area - now who runs the chamber for him? I guess he gets the Victoria Cross). They ride in the air bubble and just about all they know is that they wake up on the surface with ears that hurt and most likely a bloody nose. Accent time from the bottom will be less then 2 minutes. Total time at pressure, less then 3 minutes.

Having the men pass out make it all work better as a passed out man will not hold his breath.

Last thing to note, in the Brit boats the hatch opens on top of the chamber so you float out, in US boats it is on the side. So, if you are in a US boat, well too bad you better not pass out.

 

[pickens_46929]

UK and Russian Submariner's train together... (video) ... from 30m

More about the training here

Good YouTube video of a recreation dive in the SETT tank

 

[jimdiverman]

I thought I'd get a few comments on the sub escape. What happends is that the man puts on the suit and enters the escape chamber, in a real escape you may have 5 or 6 men at a time.

The chamber is pressurized with air in about 30 seconds - never mind the ears, this is life or death time. As the chamber pressurises, narcosos will make you pass out.

When the chamber reaches outside pressure, the chamber opperator opens the escape hatch and the men are blown to the surface (The chamber opperator is on the inside of the boat and not in the pressurized area - now who runs the chamber for him? I guess he gets the Victoria Cross). They ride in the air bubble and just about all they know is that they wake up on the surface with ears that hurt and most likely a bloody nose. Accent time from the bottom will be less then 2 minutes. Total time at pressure, less then 3 minutes.

Having the men pass out make it all work better as a passed out man will not hold his breath.

Last thing to note, in the Brit boats the hatch opens on top of the chamber so you float out, in US boats it is on the side. So, if you are in a US boat, well too bad you better not pass out.

So if the suit rips on the way out the chamber or on some obstruction on ascent, the suit fills with water and Davy Jones fills his locker once more. There is no one awake to go after them. Perhaps if they were all tethered together somehow, that may prevent losing a guy?

Just a thought...