mouthfill tips?

[JimGlynn]

I am now at the point where I have reached RV and am working on the mouthfill to go deeper. I can fill my mouth at 80 feet, hold it in to 125' and then invariably as soon as I start going deeper I lose concentration and the mouthfill goes back into the lungs and the suction pulls the mask in and its time to go up. Does any one have any tips to hold the air in more securely? I feel like if I can master this technique it will be a milestone.
Thanks,
Jim

 

[efattah]

Fill your mouth at the surface, close your throat, and descend. You should be able to get to 10-20m, and then you will run out of air in your mouth, and be unable to equalize. If you can still equalize after 10-20m, then you are cheating and using air from your lungs.

Using this method you can practice 50 times in a row, as opposed to the rare attempt on a deep dive when you have other things to worry about.


Eric Fattah
BC, Canada

 

[JimGlynn]

Excellent, thanks Eric. When the technique is mastered, does it become second nature or is it always a lesson in concentration?
Jim

 

[efattah]

To get a huge mouthfill at a deep depth always require effort and thinking, but once the mouth is full, the rest becomes second nature, and there is no danger of 'losing' the air...


Eric Fattah
BC, Canada

 

[Alun]

i've experienced this problem on occasion too. personally i find that it happens when i apply too much pressure with my cheeks and tongue. the increased pressure in my mouth results in air leaking up into my lungs. i realised this after doing lots and lots of the dives that Eric has just mentioned (but on empty lungs). on these shallow dives i could focus more carefully on my equalisation. the plus side is that you can't possibly 'cheat', but on the minus side, the dives are more stressful because they're done on empty lungs.

once the tubes are open it's best not to apply too much pressure, *just* enough to keep them open. you can minimized the amount of pressure you need to apply by pushing your jaw forward. when you're doing it right, it will seem like you're not doing anything. i can do it reasonably well now, but i'm still learning. it can take a long while to master properly...

 

[JimGlynn]

Should I be exerting constant pressure into the tubes ie. a continuous eq when I am past RV and using the air in the mouth? Also, how often does one need to eq. a mask ( I am using the sphera) past 40 meters?
thanks,
Jim

 

[efattah]

With a nose clip it is nice to exert constant pressure against the ears, once the mouth has been filled.

However, with a mask, it takes too much energy to pinch the nose constantly. For that reason, I only pinch the nose occasionally and equalize occasionally. However, when learning the technique, it is easier to trap the air and keep it when using constant pressure. The intermittent pressure is much harder to master and will more likely result in losing the air back into your lungs.

Remember also that as you run out of air in your mouth, touch your chin to your chest and collapse the back of your throat; this allows less dead space in the throat and allows an extra few equalizations with whatever air is left. Finally, after touching your chin to your chest, you still start to run out of air to equalize with, and as that happens the pressure you can apply against your ears decreases below the threshold at which they will pop. At that point you can still get yet another equalization by moving your jaw to slightly loosen your tubes (as if doing hands free equalization), which will allow one last pop with the small pressure remaining.

Eric Fattah
BC, Canada

 

[Alun]

you can work out how far you can go with the sphera. i hope i've done my maths right....
d_1 is the maximum depth you can reach from the surface without equalising the mask... 15-20m?
d_2 is the depth where you make the final equalisation....40m?
d is the maximum depth you can reach before you have to equalise again

d = ( (d_1 + 10)(d_2 + 10) ) - 10
( --------------------------- )
( 10 )

i think you'll find that with a full equalisation at 40, you should be fine from then on... unless you're going past 100!

oh dear, the spacing has gone all wrong, i hope you can interpret all that gibberish.

 

[JimGlynn]

So it would seem that one's max depth is not limited by their lung capacity but rather by their cheek capacity? After that would come wet eq. which I am not in any hurry to try. I am looking forward to really making this work at shallower, much more manageable depths. Thanks for the detailed explanation, Eric.
Jim

 

[Alun]

you're limited by both.
the later you can fill your mouth, the deeper you can go.
the bigger your mouth is (!) the deeper you can go.

 

[JimGlynn]

Alun- thanks for the formula. Going by that if I do a mask eq. at 30 meters, a very comfortable depth, then I should be in good shape to reach the bottom of our quarry at 46 meters. It has been very frustrating having only 7.5 meters to go but I want the dive to be very clean, easily replicated and serve as a stepping stone to more depth.
Thanks,
Jim

 

[efattah]

While the mouthfill works well for inhale dives, it doesn't work well enough for passive breath dives which are my latest interest. Sebastien Murat is forced to flood his sinuses on the passive breath dives. I don't want to flood my sinuses, so I've been working on a new method of equalizing.

The mouthfill is limited by the size of your cheeks and mouth. The bigger your mouth and cheeks, the deeper you can go. Since you can't significantly increase the size of your mouth and cheeks, you need an extra, artificial place to store the 'mouthfill' air.

The method is to use a large volume mask. In theory it would work with a non-modified mask, but it would be more difficult. Ideally you have a thin tube connected to the TOP of the mask, which then bends around and goes into your mouth.

At the mouthfill depth, you fill your mouth & cheeks and mask as well. Then, as you use up the air in your mouth, you pack through your nose, sucking air from the mask, keeping the epiglottis closed. Your 'empty' mouth now fills up by draining the mask. Soon you get mask squeeze, so you release the tube from your mouth. Now, as you descend, water slowly enters the mask from the top (away from your nose), and as it does you keep sucking with your nose, getting the last drops of air from your mask before it is entirely filled. Once filled, you pinch your nose to prevent water in the sinuses. You mount a fluid goggle like lens in front of one eye only, so when the mask is dry you can see with your left eye, and when the mask is wet you can see with your right eye.

This way, you can dive on a passive breath, fill the mouth at 10m and still reach the abyss without flooding the sinuses. It would work for no-limits as well.

Of course, there are variations. You don't need a mask at all, but could use a small plastic 'bag' like device with a tube to the mouth.


Eric Fattah
BC, Canada

 

[JimGlynn]

Do you feel that you have reached your personal depth limit using mouthfill or do you think passive exhales are safer for really deep dives?
Jim

 

[efattah]

I have never reached a depth on an inhale dive where I couldn't equalize. The deepest I have reached on a single mouthfill from the surface is 22m, and I can completely fill my mouth at 37-38m if head down, and much deeper if I do a somersault and fill up while feet first.

However, the passive breath dives appeal to me because they reduce the narcosis, and they make the descent much more enjoyable. Further, the descent with a monofin is extremely complicated from a technique/technical standpoint, and on passive breath dives you sink the whole way down, which means that you have the perfect technique.

 

[efattah]

I have never reached a depth on an inhale dive where I couldn't equalize. The deepest I have reached on a single mouthfill from the surface is 22m, and I can completely fill my mouth at 37-38m if head down, and much deeper if I do a somersault and fill up while feet first.

However, the passive breath dives appeal to me because they reduce the narcosis, and they make the descent much more enjoyable. Further, the descent with a monofin is extremely complicated from a technique/technical standpoint, and on passive breath dives you sink the whole way down, which means that you have the perfect technique.

 

[efattah]

I have never reached a depth on an inhale dive where I couldn't equalize. The deepest I have reached on a single mouthfill from the surface is 22m, and I can completely fill my mouth at 37-38m if head down, and much deeper if I do a somersault and fill up while feet first.

However, the passive breath dives appeal to me because they reduce the narcosis, and they make the descent much more enjoyable. Further, the descent with a monofin is extremely complicated from a technique/technical standpoint, and on passive breath dives you sink the whole way down, which means that you have the perfect technique.

 

[Bernt]

Could someone explain what a passive breath dive is?

 

[Alun]

passive exhalation, as opposed to forced exhalation.
this leaves you with your functional residual capacity on land
but in water... if you have very flexible chest and diaphragm, then you are left with approximately your residual volume in your lungs. this happens to me when i do FRC dives. after a passive exhalation i cannot exhale any more air.
so a passive breath dive can sometimes effectively be an empty lung dive...

 

[JimGlynn]

Does the need to equalize become less and less the deeper you go or is it contingent on each individual's eardrum flexibility? Is there any formula for amount of eq.'s vs depth?
Jim

 

[Erik]

Jim, because of the incompressibility (for all intents) of water, the increase in pressure remains constant as we descend. If you've done a scuba course, they'll have taught you this.
Surface= 1 atmosphere of pressure.
-10 metres= 2 Atm
-20 metres= 3 Atm
-30 metres= 4 Atm
etc, etc, so lets assume the airspace in your mask is "10" at the surface. At -10 metres, if you do not equalise, it will be "5". Then at -20 metres it will be "2.5", and -30 metres it will be "1.25". The volume is reduced by half at every 10 metre increment. Of course you must equalise your mask, so at -30 metres, the molecular count of air in your mask (since you've equalised it all the way down)is 4 times the amount that it would be at the surface, because you are at 4 ATM's of pressure.
Since the volume drops by half every 10 metres as you descend, the amount of air necessary to equalise all your air spaces becomes less and less the deeper you go.
Forgive me if I have over-explained or under-explained. I am not a good spatial thinker (not an Engineer by any stretch).
Cheers,
Erik Y.