Why fullface Mask for you? Which selection criteria?

schford

Noticed we have had a lot of chat around this lately and I just wondered what drove users of FFMs to use them and how did you pick the ones you use.

Obvious benefits I see are no worries with drowning as a result of Ox Tox and your warmer.

Down sides - harder to bail out to OC, risk of Co2 build up?

Looking forward to your views!

Stuart

caveseeker7

Not just OxTox, loosing your reg and drowning in general.
Need or want for UW comms is another reason you would use one.
The FFM's I used (M-48 and AGA) sit securely on your head, can't be accidentaly kicked off with the same ease as a normal mask.

Bailout depends on the type of mask. Scubapro, Dräger, Mantis etc. offer multiple ports, one main for the DSV, one on each side for additional OC 2nd stages and comms.

The Divematics and M-48 offer factory OC-integrated DSVs (the latter not available to the public, generally).

The M-48 also allows you to detach the pod with a single lever and either use a normal 2nd stage or attach an OC pod.

Only the AGA doesn't offer a separate factory bailout option, which is why aftermarket OC/DSV conversions like the Divematics are popular. On OC you have to switch masks and regs is you have a gas supply problem (they offer switchblocks for gas switching/bailout supply as an option, but only a single 2nd stage).

Any FFM requires some practise in regards to bailout procedures. For OC use there are formal training and certs available, too.

__________________
Cheers
Stefan



"Political Correctness is a doctrine, fostered by a delusional, illogical minority,
and rabidly promoted by an unscrupulous mainstream media,
which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"

ROB DAVIE

Quote: (Originally Posted by schford)

Noticed we have had a lot of chat around this lately and I just wondered what drove users of FFMs to use them and how did you pick the ones you use.

Stuart, et al,

As with everything, there are pro's and con's with full-face masks. I have used ffm's for a long time, but most of that use has been in Public Safety Diving work. As such, that has been on OC. The AGA, or Divator Mk II, is a great mask, and is used in the PSD role a lot. It is light, rugged, not hideously expensive as such items go, and, with the positive pressure lever, is much better than most if the water is mildly contaminated.

I took up using a ffm with my Rebreather because I wanted comm capability. When it comes to RB work, there are some unique considerations, though, that must be evaluated.

CO2 build-up in the large dead space offered by a ffm is probably the most critical concern. With quality masks like the AGA, the Widolf, and the EXO, this is taken care of by having a small oro-nasal cup which restricts the space in which a CO2 build-up can occur.

Other ffm's, such as the Oceanic JMC M48, the Scubapro, and the OMG unit (designator unknown), use the oral sex technique of having a tube and bit arrangement inside the mask that sticks into your mouth. This has the advantadge of definitely restricting the possibility of CO2 gas build-up. It has the disadvantadge of not permitting the use of comms, since it is hard to talk with your mouth full, as many women (and some men) have known for years.

Much has been made of the difficulty of doffing, or removing a ffm in a situation requiring such underwater. This "difficulty" is much exaggerated, and as a long-time user of the units, I would have to say that is a comment coming from those who do not use such units, or do not use them enough to be comfortable with them.

In practice, removal of the mask is accomplished one-handed by grasping the lower portion of the mask and pushing it forward away from your face and up at the same time. Nodding your head, i.e. chin toward chest, as you do it facilitates the removal. This would only be in the case where all else has failed. An example would be that your DSV has failed, and you can't switch to OC, or your gas supply is exhausted and you have to accept your buddy's regulator. It would behoove you to have a spare mask available, if this scenario is of concern to you.

As noted above by Stuart, if one gets into a hyperoxic event and experiences a convulsion, the mask will stay on your face and you will be able to breathe. This is, of course, why IWR rigs are configured with ffm's for the patient.


Full-face masks are also good protection in really cold water because your entire face is protected and warm.

One final note is the need for really good anti-fog treatment on the inside of the ffm lens when running one with an Rebreather. When these masks are used on OC, the properly designed ones cause the dry, fresh gas from the second stage to flow up onto the inner lens first, and then through flapper valves into the oro-nasal cup. This keeps the mask from fogging no matter how difficult the conditions are. Obviously, when running on RB you do not have that pressure feed of dry gas, and consequently, you will need a REALLY good anti-fog substance on the inside of the mask lens.

Just my PPO2's worth.

Rob Davie

__________________
[SIZE=2]"CC Rebreathers will become a viable part of tech diving [U]WHEN PIGS FLY[/U]!!"--GI3[/SIZE]

Crazyduck

Practice and fit are important issues.

Bonne Terre Nightmare-

A friend of mine named Alan was diving with an inexperienced diver in “Bonne Terre Mine” in Missouri. This is a public site and considered an open water environment. –Which I totally disagree with!

This individual was part of a group of four divers all friends. He was using a new FFM and was hoping that it would provide some level of comfort with breathing problems in cold water he was having (he should not have been diving but I am not a doctor.) Since the site is concerned that someone would swim off they removed all the lights from the divers. (To my understanding this has since changed and divers are allowed one small light to signal with.)

During the dive the diver felt a small trickle or leak and started to get worried. He turned to signal that he needed help. He could not signal because he did not have a light.

The diver feeling that he was in danger looked for open access to the surface and did not have it. They were swimming in a tunnel between two sites.

He approached the Divemaster in the rear and asked for help but he seemed not to understand how to help him adjust the mask and pointed him to catch back up to the group. Which the increased pace made the stress even worse.

The diver then tightened down the top straps thinking that it would help stop the leak. This actually made the leak worse by pulling up on the mask.

Eventually the dive came to an end and the afflicted diver exited the water. He was agitated, stressed out, and seemed to highly defensive. Once exited out of the water and warming up he told his buddies of his problems. They were scheduled for two more dives and he made none of them.

While often I have concerns with stories like this there is an interesting sidenote- my friend brought his doubles which the front office cleared. Upon arriving at the dive platform the Divemaster leading the dive pointed at my friend’s tanks and told him that they did not allow rebreathers. Yeah! Kind of paints an interesting picture.

Andrew

caveseeker7

The entire oral cavity of the M-48 is a bellows, allowing the diver to either use the bite piece or not. On the Rebreather pod there is an added ratchet that allows the bellows to be adjusted and in position with less strain on the jaw. So the diver has the choice of diving with minimum dead space or using the comms.

Add to that the availability of OC integration into the second stage, as well as the ability to remove (or switch) pods easily and the mask is my favorite. It's a shame Kirby-Morgan takes such a half-assed approach and sells the mask to recreational divers, but not the Rebreather pod.

The only two drawbacks of the mask are a very limited field of vision (it really sucks so bad you won't notice tunnel vision when you get it ) and less comfort from the 4 point harness than from the usual five point harness.

__________________
Cheers
Stefan



"Political Correctness is a doctrine, fostered by a delusional, illogical minority,
and rabidly promoted by an unscrupulous mainstream media,
which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"

ROB DAVIE

Let's see, this M48 that you like .....you CAN'T get the Rebreather pod (because it's SECRET WEASEL stuff), the field of vision SUCKS, and the harness is NOT as comfortable as the other ffm's.........and THIS is your favourite ffm?????

Stefan Stefanovich, my friend, this doesn't seem to make any sense....vas ist los??

Rob

__________________
[SIZE=2]"CC Rebreathers will become a viable part of tech diving [U]WHEN PIGS FLY[/U]!!"--GI3[/SIZE]

cbussel

I have been diving with the EXO on OC for about 5 years now and quite frankly hate standard mask now. I've been looking at the Divematics with integrated OC/DSV for my SCR. The years I've been diving with the EXO I would use a Sartek gas switching valve for bailout our deco and so for have never had to remove my mask in an emergency (knock on wood), but always dive with a spare standard mask and do practice ditch and dawns alot. I plan on using the same type system on the Divematics if I purchase it for OC bail out and emergency supply. I would be interested to here about more thoughts on the Divematics mask. I found the EXO a bit heavy at first. Thanks,

ROB DAVIE

cbussel,

I have attached a picture of the Widolf on display at DEMA Houston. The picture was taken by my friend Stefan Besier.

Like the EXO, this mask looks large. Unlike the EXO, the field of vision is better, and the mask is extremely comfortable because of the foam under the edge of the face seal. I've used AGA's, EXO's, and Ocean Reef's a lot, and have tried out other masks. The Widolf is by far the most comfortable mask I've had on, especially when worn for long periods.

If you get it with the Divematics DSV, you can specify which second stage you want, and right or left connection on the hose. It's a great set-up. There are more pictures on this site, and on Janwillem Bech's site. Also good pics on the Divematics site:

www.divenet.com/divematics

Cheers!

Rob Davie

Attached Images

WIDOLF ON TIGER Rebreather copy.jpg (18.2 KB, 216 views)

__________________
[SIZE=2]"CC Rebreathers will become a viable part of tech diving [U]WHEN PIGS FLY[/U]!!"--GI3[/SIZE]

TechBlue

Rob,Stefan,

We used to carry the "secret weasel pod" until KM decide the didn't want to deal with sporties or techies, from what I hear it had a lot to do with the idiot that sued Abysmal after he bolted to the surface while using a Poseidon/Superflow combo and got bent.

I still do use the mask, they did change the frame and lens to increase the field of vision to the point where I don't have any issues with it and I have never had a problem with fit or comfort. The removable pod is a definite plus and when the shit hits the fan anything that reduces the task loading like removing a mask, getting a shot of frigid North Atlantic water in the pus, breathing of a stage rig and then replacing you mask.......

It is my choice for FFM and it is a pity that KM won't release it to the public. However you can still use the mask with the accordion OC pod and simply substitute a DSV, I wouldn't recommend divimg as FFM with out having an OC/CC DSV though.

caveseeker7

Who says I can't get it?
I can think of half a dozen "civilians" I know that got them.

Not as good as the AGA, but it worked fine OC.

Not an issue as I dive with a hood, year round. Plenty of padding.

It was designed for Rebreather use from the start, allows easy and multiple bailout options and doesn't use plugs or clamps for equalizing. So yes, I like the mask.
As I said, I don't like the selective availability of the Rebreather pod.

__________________
Cheers
Stefan



"Political Correctness is a doctrine, fostered by a delusional, illogical minority,
and rabidly promoted by an unscrupulous mainstream media,
which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"