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What happens if you don’t equalize your mask?

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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donmoore

New Member
Aug 19, 2002
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What happens if you don’t equalize your mask?
I just took my first freediving class and we had some discussion on mask equalizing. Unless I do it subconsciously, I’m not doing it. I used to do it scuba diving several years ago, but in freediving, I never even think of it. I have only been down to 40’ so far, but definitely have plans of going further once I get past ear equalization in the vertical position. I spearfish and am getting tired of the shooting the species in the 40’ and above level.

I asked my instructor if there were any negative effects besides pain from the mask contact, if I didn’t equalize. He said that at about 100’ if I didn’t equalize that I could suffer eye damage. Is that true? Why would there be more pressure on the eyes with an unequalized mask than one that is equalized and therefore has the same pressure as the water.

Unfortunately the diving part of the class was taught at a site that was only 22’ deep so the deep diving part was just theory and not practice.
Thanks
Don
 

immerlustig

BlueSkunk
Aug 17, 2002
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hi don

not equalising your mask gives you a mask squeeze on skin and eyes.

i´ve seen a diver (on a 10 meter dive) who, after returning to the surface, looked extremely ´evil´: all the white parts of the eyes was blood red.
she didn´t complain about any pain and i don´t have any photo to show but it looked absolutely evil. this condition stayed for a few days then she looked normal again.

so obviously bloodvessels in the eyes pop. same thing happens to the bloodvessels in the skin.

not equalising is not an option. i use a freediving mask now with a very soft skirt which alows me to equalise less often because the mask itself gives in to the waterpressure and moves closer to the face (i hope i describe that reasonably well).

i´m sure you equalise the mask but never really think about it.
when i equalise i pinch my nose with my fingers and exhale, and during this process a little bit of excess air goes into the mask without me making any conscious effort.

maybe you could do a very slow controlled descent and concentrate on that. that will surely help you to find out.

greetings

roland
:cool:
 

Erik

Well-Known Member
Jan 21, 2001
4,731
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Why would there be more pressure on the eyes with an unequalized mask than one that is equalized and therefore has the same pressure as the water.

[/B]


Don, as you descend with an unequalized mask, the pressure of the water will push the mask against your face with the growing pressure. At some point, the skirt of the mask will no longer flex, and the air pressure in the mask will remain constant (to a degree). As the growing pressure tries to compress the air in your mask, your eyes will be sucked into the mask towards the lenses, which is not a pleasant thing at all!
While instructing scuba a few years back, I saw the same thing that Roland saw: a student had done the whole first dive to 8 metres without equalising the mask at all! She looked like "Regan" from "The Exorcist"
:blackeye
Cheers,
Erik Y.
 

crazyfrenchmen

CW = Crazy'n Wet
Oct 17, 2001
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Re: Re: What happens if you don’t equalize your mask?

Originally posted by Erik

Don, as you descend with an unequalized mask, the pressure of the water will push the mask against your face with the growing pressure.

Almost that but not quite. Remember the formula P*V=P*V. That means pressure times volume equals pressure times volume. At surface, the pressure is 1 and the volume is 1 inside your mask. At 30' (10 meter) the pressure is 2, so to keep the equation 1*1=2*x, x equals 0.5 . That means the volume has to be reduce by 2. If the skirt can flex, it will, if not, your face will be sucked into the mask so that the inside volume of the mask is reduce. That applies to a closed environnement. Thus if you blow air into the mask, the volume will augment. The "sucking power" of the mask is the same from 0 to 10 meter as from 10 to 30 meter. That means that for an equalized mask at 10 meter (full of air, no squeeze), you will have the same squeeze at 30 meter that you would have if you did the same from 0 to 10 meter. That's the deeper you go the less you have to equalize you mask and ear.

To resume, the water DO NOT push on the mask, it's the air inside that pull the mask.
 

immerlustig

BlueSkunk
Aug 17, 2002
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crazyfrenchmen

well, let´s be even more specific here :

p*V = p*V is not quite correct either!

equation one : p*V = const

variation of equation one : p1*V1=p2*V2


i think we are all aware that a pressure change always goes along with a volume change.

we are also aware that we have to equalise the mask while descending.

we are aware that a softskirt mask will assist equalising.

we are also aware that having the ´Exorcist´-look won´t really get us any further when hitting on a hot babe.

since we are all so aware i propose to go diving.:D

see you all underwater (somewhere)

roland
;)
 

Erik

Well-Known Member
Jan 21, 2001
4,731
753
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I stand corrected mon ami! You are indeed correct, and I should have described it that way:head
Cheers,
Erik Y.
 

donmoore

New Member
Aug 19, 2002
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Erik & crazyfrenchmen,
Thanks, even though you might of felt like you were getting pity, I have gained a lot from your discussions. So crazyfrenchmen, if what you are saying is correct, “the water DO NOT push on the mask, it's the air inside that pull the mask.” then would it stand to reason that a scuba tank low on air pressure at depth, would have more air pressure at the surface. My scuba certification was 14 years ago. Seems like I remember hearing this, but then maybe it was just since the atmosphere pressure is less at the surface, the air pressure in the tank seems like more.

I guess this would explain why airplanes are pressurized instead of just sealed. I always thought submarines imploded (when the lost buoyancy and sank too deep), because of the water pressure on their outsides, but actually it’s the contraction of air in them?

One more thought. If you took a ProEar diving mask, that’s the one that has ear cups with one way values that lets pressure from the mask into the ear cups, seal off those values so the ear cups would not receive air from the mask, it would suck your ear drum outwards at depth, providing you could obtain a seal on them?
Thanks,
Don
 

immerlustig

BlueSkunk
Aug 17, 2002
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don

i hope i understood you correctly here (and what i write makes sense)...

about the tank and the submarine : both are non compressible (non flexible) containers therefore whatever the depth the inside airpressure will always be the same.

the implosion of submarines is caused because of the high outside pressure which the metal construction cannot withstand. since the pressure inside a submarine is 1 bar and diving depths of subs are around 200-400 meters (so i´ve read) there isn´t much inside pressure to hold against once the sub is going too deep.
piccard´s bathyscaph ´trieste2´(scientific submarine) which went down the mariana trench (approx 12000 m) had a meterthick steelcabin for a crew of 2 people.
everything is built for a purpose.


about airplanes : an airplane cabin is basically a flexible container for technical reasons (weight, flexibility..). therefore it is the intention to reduce pressure induced stress to the construction by reducing the cabin pressure somewhat (approx 0.8 bar at cruising altitude).
if you compare this to scubadiving : the airpressure in your lungs is the same as the waterpressure outside = equalising. you definitely have noticed that breathing resistance is noticably different from swimming on your belly and swimming on your back.
when swimming on your belly the airpressure that is given to you by the regulator is slightly greater than the waterpressure on your ribcage (because the regulators diaphragm beeing a bit lower then your chest) which means you need less muscle strength to inhale. when swimming on your back it´s the opposite.


about the proearmask : on a descent you equalise your mask and at the same time the outer ear (outside of the eardrum).
if you close that valve at depth and start your ascent outside pressure (on the eardrum) would be greater than inside pressure.
if you close the valve and continue the descent inside pressure would be greater than outside pressure.
rupture in both cases.
i´m not aware of a mask like that. never seen one, never heard of it before. do you have one yourself?

i rather keep things as simple as possible. regular mask and equalising works perfectly for me (fortunately). maybe i get to try one of those one day.


back to your first post : a mask is basically a flexible airspace. but only so far until it completely sits on your face and not even the flexible rubberskirt will give in. now since the skin tissue is soft and flexible it will get sucked outwards in an attempt to equalise the lower airpressure inside = squeeze (thanx erik for the ´exorcist´. very adequate indeed).


seems the problem of equalising will be with us for a while.


cheers

roland

:cool:
 

Pekka

neoprene dreamer
Aug 22, 2001
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What happens when you don't equalize..

When I dive, I don't tend to equalize my mask much... Even bit deeper dives..20m... Of course I do let "some" air in, but the mask is quite firmly against my face... I hope I haven't got any eye damage..
What I have noticed is that when diving deep my mask fills with tears.. so the pressure sucks tears to my mask..
Have any of you experienced anything like this? or am I just weird person crying when I dive:confused:

Safe diving!
Pekka
 
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donmoore

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Aug 19, 2002
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since the skin tissue is soft and flexible it will get sucked outwards in an attempt to equalise the lower airpressure inside

Roland,
Thanks for your explanation. I think this part here though is slightly contradictory to the rest of your explanation. The skin gets sucked toward the mask because of pressure decrease in the mask and not because of the increase water pressure from outside, is what the crazyfrenchman was saying. Well actually the pressure decrease (vacuum) in the mask is from the water pressure, but it is not the water pressure pushing the mask. I know it’s a slight difference, but to me it’s a major enlightment.

To me it seems the more a container is non-compressible, the more vacuum is going to be created when it is submerged. Hence the more rigid the mask, the more vacuum and the more sucking of your face (soft tissue) is going to happen.

I guess what I am saying is the quoted part above contradicts your non-compressible container explanation.

Do you see the difference? I used to believe exactly like the first ¾ of your post, until I read the crazyfrenchman’s posts. For instance try thinking of the submarine implosion as not water pressure on the outside of it pushing it in, but from the vacuum (decrease air pressure) on the inside that’s sucking it in.

The reason this is such a big change to my thinking is it makes the devilish unequalized mask face make sense. It is the vacuum created that is sucking all the exposed surface (eyes, skin, etc.) under the mask and creating the bloody look. Its similar to how your skin looks after its stuck to vacuum cleaner for a few minutes. If it were just water pressure, the only mark or irritation would be where the rim of the mask contacts the skin.
Thanks,
Don
 

donmoore

New Member
Aug 19, 2002
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cry baby

Pekka,
I think your just a weird person crying when u dive. Ha ha! Just kidding!

I don’t get any tears, but I do get a lot of snot, but then I get that even without a mask. I think its part of my mammalian dive reflex. When my body senses water, the snot starts pouring.

Hey, if you got tears coming out, maybe you are a candidate to learn the tear duct equalization technique.
Don
 

DeepThought

Freediving Sloth
Sep 8, 2002
2,334
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Tears & mask squize

Tears:
Pekka,
Sometimes I get a burn form the salt drying near my eyes, which makes me teary. :waterwork
Mask:
I have to state that another risk of not equelizing your mask is getting the lenses break or burst into your face.
I never saw it happen, but been told it's possible. :blackeye
I think that is the reason why manufacturers use Tempered glass for the lense, but still, a with low quality mask the frame of the lense might crack.

About that mask with the ear caps, I once saw someone usig it. He said that it's because he is not allowed to wet his ears. Probably a chronic infection or a chronic raptured eardrum problem, I don't remember.
 

crazyfrenchmen

CW = Crazy'n Wet
Oct 17, 2001
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Pressure

Originally posted by donmoore
One more thought. If you took a ProEar diving mask, that’s the one that has ear cups with one way values that lets pressure from the mask into the ear cups, seal off those values so the ear cups would not receive air from the mask, it would suck your ear drum outwards at depth, providing you could obtain a seal on them?
Thanks,
Don

And you would go def.

For the scuba thank, if you dont have any air left at 30 meter (90 feet), you have 4 bar at the surface. Actually, you still have 4 bar at 30 meter BUT, since the outside pressure is also 4 bar, you would have to "suck" the air out of the bottle. If you get an out of air situation, you can go up (slowly) and you will be able to breath again. The same apply to your lungs, if you take a breath at 30 meter and go back to the surface without breathing out, you my friend is going to explode.

When we freedive, blood goes into our lung when we go deeper and that's what prevent our ribcage from imploding.

Water is a wonderful element, it is the only one that can't be compress.
 

crazyfrenchmen

CW = Crazy'n Wet
Oct 17, 2001
185
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Re: Tears & mask squize

Originally posted by DeepThought
[BI have to state that another risk of not equelizing your mask is getting the lenses break or burst into your face.
I never saw it happen, but been told it's possible. :blackeye
I think that is the reason why manufacturers use Tempered glass for the lense, but still, a with low quality mask the frame of the lense might crack.

About that mask with the ear caps, I once saw someone usig it. He said that it's because he is not allowed to wet his ears. Probably a chronic infection or a chronic raptured eardrum problem, I don't remember. [/B]

Your face will be in a lot of trouble before a lens from a mask crack.

The eardrum mask is for very shallow dive, snorkling actually, it's not intend for diving.
 

donmoore

New Member
Aug 19, 2002
958
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Ok,
I don’t think anyone had the same paradigm change I did about the difference between the water pressure on the outside and the decrease in pressure on the inside, but try this one. If you want an equalization free mask, why not have a chamber of air in a soft collapsible container with an airway connected to the inside of the mask? As you descend the air would be sucked or pushed from collapsible container to the in side of the mask, thereby equalizing the pressure in the mask to water pressure on the outside.

It would all be a function of volume. To equalize it exactly at 30 feet, the volume of the collapsible container would have to equal the volume of the mask. To equalize at 60 feet it would need to be 150% of the volume of the mask. Since equalization does not have to occur as often, the deeper you go, and since you probably could get away with a little less inside pressure than outside water pressure, you may not have to have anymore volume in the container than 150% of the mask.

The size of the collapsible container would be dependant on the volume of the mask. To make it practical and not have much obstruction and water resistance, a low volume mask would probably be required.
Don
 

Pekka

neoprene dreamer
Aug 22, 2001
790
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Re: cry baby

Originally posted by donmoore
...Hey, if you got tears coming out, maybe you are a candidate to learn the tear duct equalization technique.
Don

Tear duct equalization....is there a thread on that somewhere? how can one train on that??:waterwork :waterwork :D
 

immerlustig

BlueSkunk
Aug 17, 2002
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cool idea don

i hope you post some pictures and a report on how they work uw.

good going!

roland

:cool:
 

Pekka

neoprene dreamer
Aug 22, 2001
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Thanks fellas...I read...I tried and I failed.. I guess I just have runny eyes:waterwork
 

DeepThought

Freediving Sloth
Sep 8, 2002
2,334
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collapsable containter:

Don, I actually thought of that idea some time ago, but I dismissed it since it sounded to me unefficient.
Carrying an air container underwater sounds to me like trouble cause:

1) it is actually a buoy.
2) if you will suck air from your mask while going up, like most people are used to do, you might casue yourself harm from surfacing with more air than you went down with.
3) and worse, if you will breath that air intentionally/accidentaly you are opening the possibility of DCS.
4) I feel freedive should be less complicated and equipment intensive.
5) for all those complications, I think fluid goggles should performe better while achieving the same resault. (yet, they are costy $$$)

Donmoore:
I think my 4th grader and I are going to try and make the self-equalizing mask I mentioned earlier, for her science project. She is certified scuba ranger and loves to freedive too.
:) good luck then, it sounds like it serves a higher cause now. :)
 
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