Pros & Cons of Using a Full Face Mask

[DA Aquamaster]

Here is an example of where a FFM can be a liability. Me and my buddy (a PSD who likes his AGA) are at about 140' and he has the AGA along as the bottom temp is in the 35-37 degree range. His first stages freezes up resulting in a violent freeflow. He looks like an airstone at the bottom of an aquarium. We are almost but not quite in a deco situation but more importantly I am not real thrilled with surfacing where we are at (boat traffic) and would like to abort the dive by swimming out of the channel first.

Normally this is no big deal - put him either on my long hose or his backup and shut down the post with the frozen reg for a few minutes until it thaws to conserve the gas and retain as much redundancy as possible. Then surface more or less normally.

However, he is less than thrilled with removing his FFM, and in any event as I discovered later did not bring a back up mask, apparently not a PSD procedure, so gas sharing was not an option any way (and this is partially my fault for not discussing the possibilities and options prior to the dive). The situation now requires a direct abort to the surface to ensure he has enough gas to get there (and forget a deep stop or safety stop). Plus I have to go with him in case he runs dry.

In addition, the positive pressure FFM combined with a less than perfect seal and related higher gas consumption probably aggravated the heat transfer and may have been a factor in his first stage freezing up in the first place.

 

[MBH]

I think the FFM question does belong here in this forum, as I recall GI3 mentioning that JJ often used a FFM during deco. The OP might want to ask about FFM's on the Quest List.

I doubt that I could ever Equalize in a FFM. I just don't see that happening. I have to pinch both nostrils closed and give a little puff. Right ear equalizes and a split second later the left one does.

How EXACTLY does a FFM diver equalize? I would really like to know from someone who does it.
Thanks

 

[amascuba]

How EXACTLY does a FFM diver equalize? I would really like to know from someone who does it.
Thanks

The Ocean Reef mask has nose plugs built into it. So when you want to equalize you press the mask so that it plugs the nostril and equalize as if you had pinched your nose. I didn't find it very comfortable to do it like that actually.

With the Scubapro mask you can actually pinch your nose through the mask. The mask is made of the same silicone material as mask skirts.

 

[MBH]

Ok , I could deal with that. Thanks amascuba.

Clearing dosen't look like a problem, it just might take a little more air than a regular mask, but that's not a big thing.

 

[rjack321]

How EXACTLY does a FFM diver equalize? I would really like to know from someone who does it.
Thanks

The AGA has a rubber block which is adjustable in height (3 positions). Its slightly V shaped. Some people can just flex their jaw and push their nose against it to pinch it closed. I have to take my hand and push up and in on the mask to get the noseblock to seal and clear.

 

[DA Aquamaster]

The M48 is similar to the Scubapro FFM in that it also has a conventional nose pocket that allows more or less normal equalization.

 

[rjack321]

Clearing dosen't look like a problem, it just might take a little more air than a regular mask, but that's not a big thing.

Most FFM regs are tuned for a slight positive pressure flow to minimize CO2 buildup. I haven't been able to tell the significance of this cause when I use a FFM I'm breathing off a big set of bank cylinders and my buddy is breathing off the same. So I don't know how much the positive flow will impact your SAC.

On a more positive note, I do find a FFM slightly warmer than a regular mask + reg. Not having cheeks exposed etc.

 

[amascuba]

On a more positive note, I do find a FFM slightly warmer than a regular mask + reg. Not having cheeks exposed etc.

It's my lips that get cold in colder water for me. I was in 42 degree water earlier last week and my lips were numb toward the end of the dive.

 

[MikeFerrara]

It's my lips that get cold in colder water for me. I was in 42 degree water earlier last week and my lips were numb toward the end of the dive.

I know what you mean. I have more trouble in the beginning of the dive after a few minutes in the water my face gets used to it and all is well. At times my lips have been so numb that I almost have to hold the reg in.

 

[k-valve]

Since this is the "technical forum" I think the pros and cons should be framed in that context. As far as I'm concerned one of the most critical tasks on a technical dive is gas swithing and some dives can require LOTS of gas switching...say you're using 2 or 3 decompression gasses, a stage bottle or two and rack up a significant amount of decompression. Between stages, decompression gasses and taking back gas breaks during decompression, you might end up doing 15 or 20 gas switches. If you're diving in a "team situation" you could be called on to donate whatever gas that you might be on at the time. Getting the wrong gas at the wrong depth could bring your dive and your life to an abrupt halt. Gas switch procedures nned to be pretty much fool proof and I haven't seen a FFM setup that I really think provides that.

Voice communications is sometimes touted as a big advantage but is it? We already have clear enough means to communicate the important stuff to our buddy. I doubt that there is much anyone on the surface can do to help you if you have a problem on a technical dive. Additionally, I think that most UW comms are ultrasonic and, due to obstructions, turbidity or even thermoclines, you may not be able to talk to the surface (or your buddy for that matter). I don't think I'd want to go changing my gas switch procedures for the ability to chat.

I don't see FFM's as being very well suited for most technical diving.

Excellent points...thanks! I was looking into the gas switching possibilities yesterday and didn't find a solution I felt good about.

John save your monies!

Yeah, I think I'm gonna do just that. I think I've read and heard enough to see that I don't have a need for an FFM.