2012-11-01

What's Different Diving with a Full Face Mask?

Perfect view in Blindsee («Lake Blind») in the Tirol Alps. (Blindsee, T/A)

So what really is different when SCUBA diving with a full face mask instead of the common half mask? Here is my highly subjective first-hand report.

Full Face Masks: Only Advantages ;)


Typically, you will hear more or less the following list of advantages. Depending on personal preference, some of these items may or really may not of importance to you.
  • a warm face and reduced thermal loss via your head,
  • breathe comfortably through your nose,
  • a comparable large view (but don't expect any miracles here),
  • no more unpleasant tensioning due to biting the reg mouth piece too hard,
  • full face masks simply don't flood so easy (to counter this dimwitted Hollywood myth),
  • and if you really have to: talk to your buddy under water.
But unofficially, we also have these advantages you won't find in any official advertising material:
  • interest for technology that traditionally is mainly used by professionals,
  • be able to look and sound like Darth Vader without having to come close to a Star Wars fan convention. (Okay, that's where the «Dive Vader» running gag comes from.)
Marketing, of course, only knows of these advantages; well, mostly the first block. But what marketing and specialty salesman tend to «forget» to mention is: diving with a full face mask is also different from diving with half masks with respect to other important aspects. And not everyone wants to accept these differences. For some people, it is easier when they knew in advance what really will be different.

Full Face Masks: Slightly Different


You may already have come across some marketing that tries to portrait diving with a full face mask as a beginner's piece of cake. It isn't.
ATTENTION! To make one thing crystal clear: compared to widely-known and thus widely trained handling of half masks, full face masks are much more intricate diving equipment. Full face masks do not only provide sight, they also provide you with your breathing gas! Thus, proper and safe handling of and experience with full face masks is crucial, as is their correct maintenance, to always ensure proper mask function. In turn, you need adequate training and you should take this warning seriously.

Mug Cover?


Be safe. And it's still so much fun:
diving with full face masks.
(In Lake Blindsee, T/A)
As a full face mask covers the, well, full face, in consequence your contact with and experience of the surrounding element «water» changes quite a lot. In cold water, this kind of seclusion typically is desired. But in slightly warmer water some divers may experience such a seclusion as unpleasant, sometimes even as menacing.

So, when you are swatting in your full face mask so that sweat is puring down into your mouth and you mask may fog then you cannot simply remove the mask. However, you can carefully lift a full face mask a little bit in order to clear or partially flood it to get relief. Don't be afraid: your full face mask won't flood; instead, you will need some practice in order to even get a small amount of water on your visor.

Depending on your type of full face mask you may have to fight mask fogging afterwards, but that's the lesser evil. Simply rinse and repeat, literally. However, exercising the drill in a snugly pool can help you to get acquainted with such situations so that they don't appear menacing to you anymore.

Mask Buoyancy and Weight


Due to the now additionally enclosed mouth area, full face masks usually have more buoyancy compared to half masks, where the 2nd stage is separated and you are holding it directly in your mouth. Fortunately, several clever constructive measures for full face masks keep the increased mask volume in tight check.

However, mask buoyancy shouldn't be compensated by integrating all kind of unnecessary accessories (read: needless mask gadgets): the associated additional weights will just tire your neck muscles because the full face mask then gets to heavy from all the gadgetry. Avoid useless mask weight!
From My Experience: If unclear, just test-dive a particular full face mask you are interested in. For instance, I was told by one diver that he could not bear the heavy lift of one so-called «integrated» full face mask which shall be left unnamed. In the end, he fell in love with an Interspiro Divator MK II full face mask and is happily diving it since ever then without any buoyancy problems. If there are any really professional full face masks, then the MK II is amongst them.
Even if the combined weight of a full face mask including a second stage may not be significantly larger than the weigth of a half mask together with a second stage the different mass distribution typically causes a different wearing comfort. Please be aware that different full face masks place the second stages in different places. One manufacturer puts the reg in a rather high position, most other manufacturers try to move the reg out of the way as much as possible.

In particular, if the second stage is comparable strongly protruding then one may need to get used to the different wearing comfort first. However, this should not take long so that you quickly can enjoy the wearing comfort of a full face mask.
From My Experience: Simply take some time at the beginning to get acquainted with your full face mask in a pool first. This way, you get used to the different mask weight (compared to your previous half mask) and this somehow different feeling that there seems to be «much more mask» now in front of your face. And that this «much more mask» safely stays in place even with rapid head movement.

The Full Face Mask Breathes


With a half mask you control the pressure inside the mask using your nose. If you have an ordinary nose reflex then breathing through your mouth normally won't influence this mask inner pressure – unless you want to do so. That's the way we SCUBA divers got trained.

Full face masks, however, now cover mouth, nose, and eyes in a single cavity (ignoring some special constructions). Even with a so-called oronasal inner mask covering mouth and nose the mask pressure is more or less the same in different places of the mask. Inner masks are used to better form and control breathing gas flow in order to keep respiratory dead space at minimum. Due to their construction, inner masks are never sealing perfectly and they don't need to.

Now, when inhaling the mask inner pressure slightly decreases, as it does in your mouth and lungs, and the second stage opens and delivers you breathing gas. In consequence, the full face mask also gets slightly closer to your face. Some divers don't seem to like this experience and find this unpleasant. But in the end, a full face mask does nothing different from the diaphragm in your regulator when you are breathing in and out. But you didn't noticed so far, as this happens inside the regulator, but now with the full face mask it becomes apparent.

When breathing out, the full face mask gets slightly away from your face, because a slight overpressure is required in order to make your regulator open its exhale valve. If the full face mask does not seal properly tight then in this situation you may experience the mask to start free flow during exhaling as it unintentionally acts as a large exhale valve. No, the mask won't blow off your head. Usually, this effect stops as soon as you stop exhaling. Normally, no water should enter your full face mask in such a situation, as in the same way no water enters your second stage when exhaling through it. Unless something is broken, but that's a different story. So this is not a dangerous situation, but in order to reduce any unnecessary stress, it is better to restore proper mask sealing.

Myth 1: Miserable Masks and Regs


Cycling under water with a full face mask:
always enough gas!
Several times, divers told me that they heard about bad regulator performance of full face masks. If asked for details, they could not give any details. Sigh, yet another boring myth.

In reality, today's common 2nd stages used with full face masks for SCUBA diving feature the same gas delivery performance as typical SCUBA reg. In fact, as in case of the Apeks/Dräger PND full face mask, they are exactly the same regs.

I actually stress-tested my Dräger full face mask to much delight during an  underwater cycling world record contest. Even under heavy breathing I got all the breathing gas I needed, while the Dräger was very pleasant to wear.

Maybe for this myth, manufacturers advice their customers to simply switch all adjustable knows to maximum or at least to a position where no free flow appears. This way, they avoid silly discussions and myths about performance problems.
From My Experience: I'm diving my own Dräger Panorama Nova Dive mask using the standard Apeks TX100 2nd  stages ... as they really can often be seen in standard SCUBA and tech diver configurations. Normally, I'm setting Venturi support to minimum and breathing threshold to mid. This way I'm getting a perfectly normal breathing experience, except that breathing through my nose is really relaxing.

Myth 2: High Gas Consumption


Another myth is that full face masks in general cause hight gas consumption. In fact, gas consumption does not considerably increase due to the additional mask volume caused by covering now nose and eyes. The pressure hysteresis times the difference volume caused by the slight sling in and out of the full face mask within one breathing cycle and thus kind of dead space is, well, dead low. Increased gas consumption results from other causes, more on this below.

Myth 3: Hollywood's Mask Drowning


To cut off the air supply of another dimwitted myth: full face masks normally don't flood easily. On the contrary, full face masks usually start free flow, thus expelling any water that may enter the mask. In addition, there is slight overpressure in the mask, caused by the cut-off pressure of your regulator.

On the other hand, if I'm running out of breathing gas, then this is not a problem of full face masks in general but instead it is my problem.

The root of this myth is most probably Hollywood in its desire to pimp up dramatic dive drowning scenes. Just think how boring such a scene looks like when the actors have to wear ugly half masks. With a full face mask, the drowning actor can grimace like hell and as the director desires, and the audience can watch the scene in awe. After all, there's a point for wearing cool glasses under water...

Now, the audience concludes that because when they see dead divers in the theaters, those wear full face masks, band masks, or helmets ... so these masks must really be dangerous. Yes, that's true. If ever Hollywood would tell us a lie, or two, ... never, ever!

Pressure Equalization


Equalization using
a nose block.
(OTS Guardian)
With full face masks, pressure equalization usually works different from what you are used to with ordinary half masks. As the front plate usually covers the nose area and is rigid, you cannot reach your nose anymore. Typical equalization helpers are thus a block directly below your nose or nose pads («sanitary nose pads»). These have to be adjusted to the particular mask wearer. For pressure equalization you need to adjourn your mask such that the block or pad temporarily blocks your nostrils.

Equalization using nose clips.
(Dräger PND)
Of course, there are better methods, without adjourning your carefully adjusted full face mask. Especially the Dräger full face masks (Panorama Nova Dive) feature easy-to-operate nose clips. These clips are basically your fingers' extensions. Depending on how you prefer, you operate the clips using either one hand or two hands using the levers on the front of the Dräger PND mask.

As far as I know, the Aquadyne DM5 and DMC7 had something along this way ... quite some time ago (but using a single lever mechanism only). Currently, in my view, no other full face mask available has a pressure equalization system that even comes close to the quality and ease of use of the Dräger full face masks. I don't like three-dimensional pins up my nose.
From My Experience: I started diving with a full face mask right with the Dräger Panorama Nova Dive. Instead of the commonly seen nose block or plug, this mask features the special Dräger nose clips.
Since then I rather feel uneasy when wearing other full face masks with the equalization blocks just below my nose. Equalization using these blocks is no problem for me, but I really dislike the nose blocks since I first met the Dräger.
Totally Dräger-spoiled ... (diagnosis: Wolfgang Friebe)

Hoods


What marketing doesn't like to tell you: diving full face masks is in many cases directly connected to cold water and thus also to hoods. That's because full face masks considerably reduce heat loss through the face, where hoods are of not much help. But in contrast to half masks, proper combination of hood and full face mask is even more important then ever. It is the basis for relaxed dives and can cause quite some stress in the opposite case.

Getting rid off of excess air.
I'm covering this important topic in a separate article about hoods. For this reason, here I'm only mentioning for the time being that you need to learn to deal with excess air coming from your mask and accumulating in your hood. If there is too much air in your hood, you are in danger of loosing buoyancy control. In addition, this hood air may influence your pressure equalization.

Another issue may be small and, at least in principle, undramatic leakages between full face mask and hood. The hood may unintentionally work as an amplifier so that even small leakages may sound like a big blow off. For a beginner, this background noise may cause considerable stress and thus may result in inappropriate reactions.
My View: Especially with such background stress in mind I'm suggesting that beginners to full face mask diving absolutely should train with hoods already during pool training. Only this way they will learn about the combination of hood and full face mask, all this in a confined, safe space. Personally, I'm strongly advising against complete dive beginners or trial divers immediately starting with diving full face masks and without proper command of SCUBA diving in general and stress handling.
Taking a closer look on the imagery of this blog you may notice here and there small telltale streams of bubbles. Oh well, seems that I'm too open...

Gas Consumption


Usually, gas consumption will be higher compared to diving with a half mask when you start diving with a full face mask for the first time. However, over time as you gain experience with this kind of equipment your gas consumption should return to normal. For some divers, gas consumption even get lower when diving with a full face mask compared to diving with a half mask. Reasons may be better relaxing or less breathing through the nose compared to breathing through your mouth.

However, if you use underwater communications, then usually your gas consumption will be higher again. This is caused by the speaking itself, as your breathing pattern then changes considerably.
From My Experience: Higher gas consumption may be caused in part by your subjective impression. To me, my gas consumption felt still higher after twenty or so dives. When I checked the facts using gas pressure data logged during my dives I was surprised: gas consumption was normal, in some cases even lower than when diving with a half mask. This is one of the few cases where I consider logging dive data on a second basis actually to be useful.


Related Posts


Have fun diving full face masks.
(Steinberger See, BY/D)
For those that managed to read up to this point and still want to enter the amazing world of SCUBA diving with a full face mask ... there is more to explore:
You will find even more blog posts on this topic following this tag: full face mask. Likewise, I've put some impressions from diving with full face masks online.
    And don't forget: the nose now stays dry!



    PS: Many thanks (again) to Axel Eisele and Peter von der Sitt for the nice shoots. They were taken in Blindsee (T/A) and Steinberger See (BY/D). The cycling photo was shot by Michaela Heinlein. Wolfgang Friebe contributed the photo depicting me doing the equalization maneuver with an OTS Guardian. Other imagery comes from my own stock of video stills.

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