75 ft out of air, What do YOU do?

[Charlie99]

Dr Paul Thomas once bubbled...
The SETT instructor descended to 30 metres in the bell, took a breath of air at ambient pressure, exited the bell in swimming trunks alone, and then performed a perfectly controlled buoyant ascent at no more [1 meter/5 sec ?? ], breathing out gently all the way, without moving a muscle!

It took him well over five minutes to ascend, and he controlled his rate of ascent perfectly through adjusting his buoyancy by means of exhaling sufficient air to keep his lung volume constant against the ever reducing ambient pressure in the water column. He made no swimming actions at all. When he reached the surface, he was not even short of breath and was entirely composed.

The SETT instructor is doing what should really be taught for an emergency swimming ascent --- just leaving the airway open.

During my initial OW training the instructor wanted me to hum or go aaaaaaaah during the ascent. I would always run out of breath.

If I just left my airway open and made no attempt to exhale while keeping my lungs at the midpoint of a breathing cycle everything just happened naturally --- air bubbled out as needed; I didn't feel a need to breathe; and you arrive at the surface with the same amount of air in your lungs as what you started with.

Ok,now that I've vented on one of my pet peeves about OW training Ill step off of the :box:

 

[Grajan]

There isn't time to teach this both safely and properly in the current course schedules.

When I trained (CMAS Deuxieme Echelon) we started practicing this from 40m to 30m then 40 - 20 then 40 -10 then 40 - surface.
this allowed practice with small volume changes.

This process took about as long as the OW course....

 

[The Iceni]

Big-t-2538 once bubbled...
Do you mean 5 seconds per meter????

Well spotted!

I have corrected my post to read what I meant to say, which was a free ascent rate of 5 metres per minute. Hence it took him over five minutes to ascent from 30 metres - and all on one breath!

 

[Popeye]

J.P. once bubbled...
I was asked this by my boss and the answer I gave he said was wrong...although it was out of the book. I need to know by professional people. Please give real serious answers so I may show him.
You are at 75 feet and OUT OF AIR. Your buddy is out of site, and neither of you have any comm gear on. What do you do

I practice ESAs from 70 ft regularly, and have done them from 90.

Not too hard when you practice, and it's not a total surprise...

But practicing is better than planning on it not happening.

You've recieved several good answers, I'll give you some food for thought.

I also practice breathing my BC (wing).

It has the same gas in it you were breathing moments ago.

You'll only need a breath or two to make it 75 ft. up.

You might want to get a little out to slow your final ascent.

If you keep your lungs from trying to spasm, it frees up mental resources to deal with other problems.

 

[zeN||]

Thanx for that post, it is so nice to actually see a really tantalizing post, lawyers and disclaimers be dammed, that little technique sounds like it could def save your bacon, and I appreciate the tip, which I will definitely research zeN

 

[Rick Murchison]

Two & a half years ago I posted the following:

Rick Murchison once bubbled...
Assuming that you've run out because you've breathed the tank "dry" rather than because of an equipment failure, and that you don't have a redundant air supply:
You should do an emergency swimming ascent. Look up, reach up, swim up. Keep your regulator in your mouth, exhale slowly but continuously (if you have air in your lungs when you begin the ascent). If you run out of breath, go ahead and attempt to inhale - on a standard 80, which has an interior volume of about .4 CF, an ascent from 75' will free up about .9 CF (measured at STP), which will provide several (high variability here, heavily dependent on equipment and the depth at which the breaths are taken) normal breaths during the ascent. An ascent rate of 60 fpm can be safely maintained - the ascent takes 90 seconds, and with the air coming available from your tank during ascent, you should make it without difficulty.
----------------
If you are out of air because of an equipment malfunction (ruptured hose, freeflow, catastrophic first stage failure) then an emergency buoyant ascent is in order.
Rick

It was "what to do" then, and remains what to do now... a couple of points others have suggested to consider...
(1) Just keeping your airway open - that's the general idea of the "exhale slowly" drill. The key point here is that our bodies aren't plumbed to sense lung overexpansion through pain and an overexpansion injury can be fatal. Miscalculatiing on the "exhale" side will simply cause one to run out of breath, which, while uncomfortable, ain't gonna kill you (especially since as I and several other posters have mentioned, by the time you run out of breath you'll be able to get another one from the tank) while miscalculation in the other direction can be disastrous. For those who practice the CESA on a regular basis - and everyone should - the transition from "slowly exhale" to "just keeping the airway open" procedure can be fine-tuned and perfected, but if you haven't practiced it, "slowly exhale" on ascent - that's the safe thing to do.
(2) BC breathing. There are two reasons we don't teach BC breathing. First of all, we don't want to teach something we don't practice. The reason we don't practice BC breathing is because things grow inside BC's. Nasty things. Things that can give you bronchitis - or worse - pneumonia. (Yes, there are ways to sterilize the inside of the BC, but who does? And would you want to breathe what was used to sterilize it?) Also there is a pretty good chance that sooner or later you'll aspirate some water from the BC hose - not good either.
Second, down here in the warm water diving world, having no air at all in the BC is common, especially for the properly weighted diver just wearing a skin. Indeed, the properly weighted diver just wearing a skin who has run a tank dry will already be positively buoyant by about a pound even after completely evacuating the BC. Having to figure out whether to switch from regulator to BC inflator or not based on whether there's any air in the BC adds unnecessary complexity to an already stressful situation - and it is unneeded.
Rick

 

[Popeye]

Rick Murchison once bubbled...
(2) BC breathing. There are two reasons we don't teach BC breathing. First of all, we don't want to teach something we don't practice. The reason we don't practice BC breathing is because things grow inside BC's. Nasty things. Things that can give you bronchitis - or worse - pneumonia. (Yes, there are ways to sterilize the inside of the BC, but who does? And would you want to breathe what was used to sterilize it?)

Never ceases to amaze me when people offer the argument that they'd rather drown than get a chest cold (you're not the first).

I breath my Wing on each and every dive, each and every, and never get sick.

Proper gear maintenance is all you need, with a common household product.

Also there is a pretty good chance that sooner or later you'll aspirate some water from the BC hose - not good either.

Something else I train for. Next time you're in the shower, snort a bit of water in your sinuses. Not only does it clean them out grandly, it gets you used to, or past, the sneeze reflex. Sure, it sux at first, but you get used to it quickly.

There again, I'd rather aspirate a little water from my BC than 100% water from the surrounding environment.

Second, down here in the warm water diving world, having no air at all in the BC is common, especially for the properly weighted diver just wearing a skin. Indeed, the properly weighted diver just wearing a skin who has run a tank dry will already be positively buoyant by about a pound even after completely evacuating the BC. Having to figure out whether to switch from regulator to BC inflator or not based on whether there's any air in the BC adds unnecessary complexity to an already stressful situation - and it is unneeded.
Rick

It's an option. Simply, one that I have, and you don't. The only reason you can say it's unneeded is because you're one of those people that believe any given mishap will occur -exactly- as you plan it. I find that very scary.

I sure hope you don't get hung up on something and/or loose your reg, because your contingency plan will be out the door, whereas mine will give you several minutes to work things out.

Not having any air in your BC isn't an issue- you can exhale what you've got into your LPI, and re-aspirate it.

It allows you to exersize your lungs.

Of course, to have this potentially life saving option, you have to practice it.

Better to have it and not need it than....

 

[sheck33]

Rick Murchison once bubbled...
Two & a half years ago I posted the following:.....

I have seen this posted before, how do you figure an ascent from 75' frees up .9 CF if an 80 has an interior volume of .4 CF?
you cant apply Boyle's law to a rigid container that way.
the volume of a -flexible- container would go from .4 to 1.3 CF, increasing by .9
The volume of the tank is not affected by depth.

 

[Genesis]

consider your regulator.

You cannot draw a breath (even sucking REALLY HARD) if the tank pressure is at or below ambient pressure. Your diaphram cannot produce more than one psi or so of negative pressure at maximum exertion.

As you ascend, the ambient pressure goes down. The tank pressure, however, is constant (the walls are rigid.) Therefore, as you ascend from 66' to 33', you remove one atmosphere of pressure from ambient.

If the tank is at 45psia (absolute) at 66', it is "empty" at that depth and the gauge reads zero. However, at 33' it contains 15psig (gauge) of pressure, which probably gives you a breath (or possibly two) - not an EASY breath, but a breath nonetheless.

 

[MikeFerrara]

sheck33 once bubbled...


I have seen this posted before, how do you figure an ascent from 75' frees up .9 CF if an 80 has an interior volume of .4 CF?
you cant apply Boyle's law to a rigid container that way.
the volume of a -flexible- container would go from .4 to 1.3 CF, increasing by .9
The volume of the tank is not affected by depth.

The amount of gas "freed up" would be determined by the volume change required to drop the tank back to ambient. So it would depend on the tank size and the distance ascended (ambient presure drop).