very deep dives without mouthfil?

[sgnips]

which risks?

try losing your mouth fill during the descent: it's not that fun for your lungs, i've been through that once, unfortnately
also, Eric lists other risks in his document, including quick increase of personal depth limit, remember?

i disagree. i have taught probably 100+ people how to do a mouthfill in 3 days. very easy to include it in a course.

then i should have called you up when i began learning it: it took me 4 months to master the basics and still i find myself improving the skill on each dive

 

[efattah]

i disagree. i have taught probably 100+ people how to do a mouthfill in 3 days. very easy to include it in a course.
linda

Linda,

Although I appreciate that you teach the mouthfill in your courses, I have observed the technique of some of your students, and I would say that they have learned only a very basic version of the mouthfill. Neverthless, even teaching a basic or simplified version in 3 days is very good work. However it would be wrong to say that these students have 'mastered' the mouthfill in 3 days...

 

[x_yeti]

She didn't use the word 'mastered'?

 

[sgnips]

Linda,
Although I appreciate that you teach the mouthfill in your courses, I have observed the technique of some of your students, and I would say that they have learned only a very basic version of the mouthfill. Neverthless, even teaching a basic or simplified version in 3 days is very good work. However it would be wrong to say that these students have 'mastered' the mouthfill in 3 days...

different points of view...

 

[Mullins]

I've taught a handful of people - usually they get the concept fairly quickly but have a hell of a time keeping their mouths isolated from their lungs for the whole descent. So they might initially pick up a few metres on top of their Frenzel depth, but it's slow progress from there on.

 

[Mullins]

try losing your mouth fill during the descent: it's not that fun for your lungs

Do you mean losing the air out of your mouth?? Haven't heard of that happening before, except for a few bubbles when the overpressure is too high for the lips to hold. Normally people just lose it back into their lungs, which brings equalisation to a halt but otherwise isn't an issue.

 

[sgnips]

Normally people just lose it back into their lungs, which brings equalisation to a halt but otherwise isn't an issue.

that's it
but it's not a smooth transition from mouth to lungs: it often is a strong and sudden "gulp" and lungs can get squeezed

 

[Mullins]

Weigh that against the risks associated with doing Frenzel to the same depth though.... So if you've got students who want to do, say, 60m then i think it'd make sense to teach them the mouthfill. Of course you might not want them to go that deep in the first place, but that's another story.

 

[sgnips]

well, actually (fortunately?) we don't have students aiming for 60... so no real need to teach the mouthfill
will you be in Italy for the WC, Dave?

 

[Mullins]

No, but I might make it across to Greece for either the Med cup or depth WCs.

 

[sebastien murat]

Hi there you old sea-dogs!

A couple of personal notes:
Eric: "In my case diving on a 100% forceful exhale I must stop at 30.5m to avoid squeeze, even though the mouthfill could take me down another 10m". My experience suggests that the rate of blood-shift into the lungs/heart might have a hard time keeping up with the rate of compression
Mullins: ++ 100m FRC is doable (my experience) but conventional/specialized equalization techniques not recommended because breath-hold duration is markedly and adversely affected. Reason being (my opinion), lungs collapse much sooner, thereby preventing access to lung O2 stores. Once that happens, you better hope that the DR is strong enough to mitigate the rapid blood O2 desat. otherwise you're toast!

Best,
S

 

[aris ioannidis]

Dave, it would be nice to see u coming to Greece!! Too bad you are not going to Italy - but I guess it would give a beter chance to the rest of us !

great thread, by the way :chatup

 

[fnacinovich]

well, actually (fortunately?) we don't have students aiming for 60... so no real need to teach the mouthfill

That's true Sgnips, AA learning system is not aimed at coaching/training expert divers and anyway the maximum depth for all AA levels (standard courses) is 30m. So no mouthfill required, rather strong teaching on frentzel and hands-free techniques.

You may argue that 30m is really shallow nowadays and you are probably right. But that's AAs choice: teach people to freedive safely trough self-awareness and enjoy the related sensations.

For more skilled and demanding freedivers, there are plenty of AA and non AA stages out there, without any depth limit.

Regarding the mouthfills risks, I think Eric and Sgnips correctly pointed out them. (Please note: I am not saying it is dangerous and thus it should be avoided, just that it would not fit inside AA course)

Cheers

Francesco

 

[Mullins]

I'm a bit skeptical that inhaling a couple of hundred millilitres of air from your mouth at depth would present any kind of risk. Anybody actually been injured? I expect that for a given depth, mouthfill is somewhat safer than Frenzel.

 

[x_yeti]

I expect that for a given depth, mouthfill is somewhat safer than Frenzel.

I agree. In fact I find a continuous pressure mouthfill (keeping the tubes and sinuses open all the time) at shallower depths beneficial, especially on the first couple of warm up dives. Reason being I tend to suffer from dodgy sinuses and find that keeping them open all the time reduces the chances of blocking up and having to stop diving for the day.

 

[DivingDane]

Wow!

This thread has managed to attract the attention of Seb!!!! Welcome back.

Best thread I've read in a long time on this forum.

On a side note, I'm not sure how loosing a mouth fill back into the lungs would create a squeeze? If anything it would relieve some of the negative pressure being experienced in the lungs below residual, reducing the chance of squeeze. Only negative from loosing the mouth fill is that you can no longer equalize deeper and have to return to the surface. No big deal.
Posted via Mobile Device

 

[trullalla]

eric,
as john pointed out i didn't claim i teach to master a mouthfill in 3 days.
after 3 days the average student will be able to get to 20/30 meters with a mouthfill on the surface, and with a pile of info on how to make it better once they go home.
it can take months to get and use the mouthfill very efficiently, and unfortunately for me people can't pay for months of daily tuition...but once they get the basis they can definitely work on it on their own.

sgnips,
i really don't see how swallowing a mouthfill can present any danger for the lungs.
people do it all the time and they always survive. as long as you stop your descent and turn around when it happens and don't fight to bring it up again, which is the first thing i point out on day 1.
i can't remember reading anywhere eric saying about this being a risk according to him.

also, i'm not suggesting that AA should teach mouthfill or deep diving, i just disputed your statement that you can't teach mouthfill in a course.
and of course it goes without saying that no, we don't let students dive as deep as they want just because they now have the equalization potential!
every beginner know about the slow progression thingy.

linda

 

[fnacinovich]

On a side note, I'm not sure how loosing a mouth fill back into the lungs would create a squeeze?

I have never experienced that myself but indeed from the physical point of view I think that a squeeze might be theoretically possible in that circumstance. Here is my reasoning:

1. Inside the ribcage the volume lost due to air compression is replaced by blood (blood shift)
2. The air in the mouth is at a higher pressure than the air in the lungs (if you are head down). The difference is small but still not negligible and air will move always from higher pressure to lower pressure
3. If you loose the control of your glottis, some air will eventually translate from the mouth to the lungs possibly causing a squeeze.

Anyway, as pointed out by Dave, the quantity of air involved is probably still too small to cause any damage. Unless you are a trumpet player with 1.5l mouthfill, of course!

Cheers

Francesco

 

[trux]

If you loose the control of your glottis, some air will eventually translate from the mouth to the lungs possibly causing a squeeze.

No, there is no risk here. First of all, for a barotraumatic injury you need pressure either significantly bigger or smaller than the ambient pressure. You do not have any pressure meaningfully bigger than the ambient one in your mouth, so you can't hurt your lungs with it.

And then, at lungs already under the negative pressure, any increase of air volume is a good thing. Even if the volume of air was bigger than what the lungs currently contain, they can easily expand (both diaphragm and the chest are compressed at this moment close to the maximum, so have a lot of space for the expansion).

The real risk of the mouth-fill was already mentioned both by Eric and by Sebastien - it is that it can take you easily to much greater depth than you are ready for, and that it accelerates the pressure gradient. The later is because you remove air from your lungs and move it to the mouth-sinus cavity. So for example if you do a mouth-fill of 400ml at 30m you suddenly remove the equivalent of 1.6 liter of surface air from the lungs meaning that from now on they have to adjust for the continually increasing pressure with higher rate than if the air was still there. Still with gentle reverse-packing + Frenzel you can slow down a bit the gradient, but will reach the barrier quicker. And if instead of gentle mouth reverse packs, you try diaphragmatic pumping, you can injure yourself pretty fast.

PS: indeed great to see Sebastien Murat back on DB again!!! We already all wondered what you are doing these days. Do you plan coming back to active freediving, and to run some courses again?

 

[sebastien murat]

Hello Trux,

No, just had a curious look in to DB after what must be now several years I guess. Still diving, but dropped-out to do my own thing

Best to all
S