How Deep Can You Do An "Out Of Air Emergency Ascent" From?

[Hawk]

Just a curious question here that may lead to something else. Some say that this should not be needed at all if your dive is planned correctly. If this is true should it even be taught at all? Just how deep is it possible to do this from and be ok when you surface?

This ought to start some interesting thoughts.




Later, Hawk.

 

[trymixdiver]

Assuming i had a total gas failure and my buddy was no where to be seen i would be comfortable doing it from 100'. Could i do it from deeper? hell yes but like i said i would be comfortable from 100'.

i could do it from 500' if living through it wasnt a requirement, im assuming it is is this case though

Sure hope this wasnt a deco dive, talk about a last resort option no one wants to do!

Andy

wonder how many people will exagerate the answer, lets just see whos gonna BS us all.

 

[VTWarrenG]

One can maintain consciousness for at least, say, 90 seconds with no air in the lungs at all. Assuming the diver has the wits about him to ditch his weights and ascend via buoyancy alone (i.e. not swimming), he could easily ascend from 130' with no air, pushing 100+ fpm.

Obviously the OOA weight-ditch ascent is the last tool in the bag.

- Warren

 

[jbd]

20 & 30 feet. Very easy in my opinion. So I agree with VTWarrenG and trimixdiver that it could done from 100' as long as the diver in question keeps his/her wits about them.

I think its a skill that should be practiced or reviewed with an instructor each year. That would help the diver keep their wits about them.

 

[trymixdiver]

just as a side note

My Dad was a diver when i was little, he told me that part of his cert dives was a 100' free ascent. he was certified in the early 60's in Auckland , NZ.

my my how things have changed

Andy

 

[TexasMike]

I caught something on the History or TLC channel about the Russion submarine Kurz(sp?) accident where they were showing how British sumbariners trained to do free ascents in a 100 foot tall tank. And each of the trainees appeard to be doing it just fine.

They also demonstrated with a small mylar balloon what would happen if you held your breath as you ascended. (by filling the balloon with a small amount of air at the bottom and letting it ascened until it popped.)

 

[SpyderTek]

Just watched a program on the History channel about Submarine's. A British navy submariner is required to check out doing a 100' free ascent on a single breath of compressed air.

My Open Water cert required us to perform this skill from 10 meters

Some of the best freedivers in the world do 1000 feet on a single breath of air. (Thats 500 down then 500 back up).

I think for the saftey factor probably lies less with how far you can go on the breath of air but rather what your nitorgen load is. You may be able to get to the urface that fast without running out of air but if your nitrogen load is high enough you're still looking at a heavy case of the bends and possible death anyway.

SpyderTek

 

[TwoBitTxn]

I remember being told and reading in an OOA situation not to ditch your scuba rig due to the possibility that as the air in the tank expands you may gain a breath or two. Also not to hold your breath.

Tom

 

[jbd]

Scenario--you are at 100' and are neutrally bouyant. Now you have the OOA situation. If you ditch your weight belt will you not become considerably positively bouyant and will not the air in the BC add significantly to that bouyancy as you ascend? Even if you can dump air fast enough won't you still be excessively bouyant?

Any thoughts.

 

[Hawk]

You are taught to keep your reg in your mouth and not hold your breath. Freedivers are holding their breath due to the fact that it was inhaled at the surface and therefore do not have to worry about expansion. When you are practicing the ascent "cheat" and slow the ascent rate, and take a few breaths on the way up. Does this make it easier? Of course it does! I have heard so many people say how bad the Spare Air is, but this in my opinion is exactly what it is for. To think that is a spare tank of air to casually go about your business when things for some unknown reason go wrong, is crazy! To help out your emergency ascent if things do go wrong is just what it is for.





Later, Hawk.