Low volume or high volume mask?

[Nirvanoje]

Hey guys!

I diving around 1.5 year, before i was using low volume mask, it was ok,i diving to 20 m normaly, now bought high volume mask and i realy like it.
Now starting to think about blackouts, maybe is better to use high volume masks, because when you coming back to surface, you can suck pretty much fresh air from mask, so its maybe helping lit bit, what you think? Maybe someone was testing? Last 10 meters are very dangerous, so if you get like half liter fresh o2 it can make big differrent (maybe) . I talking not about competitions, but just spearfishing or freediving to 30 meters ~ . Before dive i always take much air in mask, then start diving. So it will be nice to hear your opinions.
Sorry about my english.. :duh

 

[azapa]

I really think you are better off with a low volume mask, and save the air in the first place.

 

[sross]

Now starting to think about blackouts, maybe is better to use high volume masks, because when you coming back to surface, you can suck pretty much fresh air from mask, so its maybe helping lit bit, what you think? Maybe someone was testing? Last 10 meters are very dangerous, so if you get like half liter fresh o2 it can make big differrent (maybe) .

Nirvanoje, there's another factor you're forgetting about.

Equalization.

That's the reason everybody uses LV masks for freediving.

If you don't equalize your mask you're going to get a horrific face squeeze once you start to go deep, and HV masks take a large volume of air from your lungs to equalize. This means you have less air in your lungs during the deep part of your dive = less bottom time.

In fact, with a really large-volume SCUBA-style mask, you may find that you'll hit a depth where you can't equalize the mask at all.

 

[Nirvanoje]

Hi again !

Yes, i was thinking about it, but i talk about 30 meter diving, for example if i have no problem with equalization. Martin Stepanek did 120m with mask ( i think sphera mask ) , maybe there is some secret ? I know he is pro, but anyway..

 

[azapa]

for 30m there is not much diference indeed. I would pick the lowest volume mask, that fits well,. and has a wide enough angle of vision for what you plan to do. The micromask offers about the best mix of all those features, for my face anyway, its a perfect spearing mask. With practise equalizing always gets easier. If you have trouble equalizing wearing a small volume mask now, at your target depth, don't get a larger volume one, it will only make things worse. On the other hand, if EQ is very easy for you at your target depth, even with a big volume mask, don't bother changing if you like it's wide angle of vision.

 

[Nirvanoje]

Thanks for answers ! Yes i like wide angle vision, but mostly i was thinking about blackouts, can big mask make less chances to get blackout, when you coming back from depth? Because you can get much o2 from bigger volume mask, for example on last 10 meters.

 

[fabikp]

Nirvanoje, I think there is no advantage of HV mask: at first, you have always equalize the mask at least a little even in less depth than 30 m, so the air in it is not so fresh, and the second, the volume of the mask is not so big to play any significant role. And more, I doubt, it is possible to inhale from the mask more air than you exhaled into it before. Pavel

 

[trux]

At a mask, the volume is not as important as most freedivers believe. Of course it is always better having as low volume as possible, but the mask compressibility is much more important in fact. If you have a mask with high compression ratio, and which seals well regardless of the compression, then it does not matter the initial volume is high, since it actually auto-compensates without the need to blow any air into it.

For this exact reason masks with plastic lenses like the Sphera or Sommap Flow are so well suited for deep diving. The flexible plastic lens allows much higher compressibility than at masks with glass screen. The flexible design also helps keeping good seal at different levels of compression, which is usually not the case with scuba masks.

So a high volume mask with good compressibility and sealing well even highly compressed, would not be bad at all. The high compressibility also means the skirt has to be very soft, otherwise it does not compress proportionally to the ambience pressure, and a face, eyes, and/or sinus squeeze are quite likely (or you need to compensate it anyway).

Unfortunately I did not yet see a suitable high-volume scuba mask that would fulfill these requirements. In contrary, Sphera and Flow are very well compressible, so if you do not press them hard on your face on the surface, you can easily dive with them up to some 50m without compensating. I measured and tested the Flow. Surface volume is 200 ml, and it can easily compress down to 36ml, getting the compressibility ratio of 5.6

 

[Nirvanoje]

Very thanks! Very detailed answer, so i will use my sphera mask.