Full Face Masks

[FF / EMT]

It was kind of an unusual config for sure. Since they are a husband and wife buddy team that dives together all the time the next logical question was why not octos? Even in an emergency (sharing gas so doubling the massive hoovery) you would still think there would be more gas in one of their cylinders than a spare air, but I got the impression there was a lot of spearfishing, same ocean buddy diving and not being in the general vicinity of each other underwater that led to the spare air decision. The interesting thing was that in watching them underwater I kind of came to the conclusion that the underwater comms were actually part of the problem. That obviated their need to stay that close to each other since they could just press to talk and say "I'm over by the big rock" or whatever.

Their air consumption is their problem, not the ffm



also if you’re
Going the Pony bottle setup, you only need a
First stage, as you can use
Your octo from your other setup :nod:

 

[SlugLife]

Their air consumption is their problem, not the ffm



also if you’re
Going the Pony bottle setup, you only need a
First stage, as you can use
Your octo from your other setup :nod:

And a button-spg, which cost about $15. These are available from most dive-vendors for about the same price, but here's a link for the lazy.

Mini-SPG { 1 in | 2.5 cm } Face

Port plugs also come in handy. I like to have at least one more HP & LP port plug than I think I'll ever need, because I frequently discover I could use another one.

Regulator Port Plugs

You don't technically need this tool, but the XS Scuba Star Multitool this is by far my favorite scuba tool. It's amazing for doing field-swaps of hoses, first/2nd stages, port-plugs, etc.

xs scuba star | eBay

 

[flyboy08]

I bought one but have yet to use it yet. I plan to play in the pool to see if it’s a comfortable fit then try it recreational in the sea.....I’ll carry a backup mask.

 

[MikadoWu]

So it looks like my thread got hijacked....

Back to point... I am still trying to find out why gas switching is an issues with FFM. @kensuf Comments on commercial divers have more training. Ok, so if we out in the time and training, and practice is it viable, are there people doing or training FFM successfully.

Also, I noticed that several FFM are rated at 150 (my present max depth as well) or less. Presently I am not planning to dive deeper then 180, as I have no mission for one. Could that change, sure.

 

[O-ring]

Sorry about that..

 

[PfcAJ]

So it looks like my thread got hijacked....

Back to point... I am still trying to find out why gas switching is an issues with FFM. @kensuf Comments on commercial divers have more training. Ok, so if we out in the time and training, and practice is it viable, are there people doing or training FFM successfully.

Also, I noticed that several FFM are rated at 150 (my present max depth as well) or less. Presently I am not planning to dive deeper then 180, as I have no mission for one. Could that change, sure.

Switch blocks are an issue because of how they’re plumbed.

TYPICALLY they’re plumbed so you can just flip a lever to go from one gas to the next. The trouble is with the ease that the lever can be flipped. Normal OC tech dive gas switch procedures involve a personal and buddy verification of the gas you intend to switch to. Switch blocks make that process quite a bit more challenging and an inadvertent bump of the switch can put you on a hyper or hypoxic gas when you don’t intend to be on that gas. There ARE methods to utilize a switch block to stay on the mask and have only one gas plugged in at a time, but it’s not common. At least not that I’ve seen.

Breathing supply issues also require removal of the mask to get at another regulator. Blind and having gas problems is not ideal, and certainly worse than having only a gas problem without being blind.

Big volume, big drag, the issues with switching, convolutions with switch blocks, compounding problems in event of certain failure types, etc make a FFM far more of a liability than an asset in almost all recreational (as opposed to commercial) settings.

 

[Bigbella]

So it looks like my thread got hijacked....

Back to point... I am still trying to find out why gas switching is an issues with FFM. Comments on commercial divers have more training. Ok, so if we out in the time and training, and practice is it viable, are there people doing or training FFM successfully.

Also, I noticed that several FFM are rated at 150 (my present max depth as well) or less. Presently I am not planning to dive deeper then 180, as I have no mission for one. Could that change, sure.

Long story short, there are myriad horror stories out there -- some, not surprisingly, involving diving the Andrea Doria or other deep wrecks — about accidents, mostly bone-headed, where, say, a diver, using a gas block / manifold, inadvertently switched -- drained, out of sequence, either his primary gas; his bottom gas (trimix, whatever); his pony bottle; or, else, some other inappropriate, perhaps O2-rich deco gas, for his depth.

The Atmosphere masks, that I've used, are rated to 50 meters (about 164 feet); and the gas block that I have, cannot easily be switched by accident (requires some force) . . .

 

[Michael Perdue]

50m = 165ft
656ft = 200m

 

[Bigbella]

50m = 165ft
656ft = 200m

Yeah, thanks, I thought that it sounded way off -- couldn't be right. Cocktail hour.

I had quickly looked up the specs in the service manual . . .

Wow!

 

[kensuf]

So it looks like my thread got hijacked....

Back to point... I am still trying to find out why gas switching is an issues with FFM. @kensuf Comments on commercial divers have more training. Ok, so if we out in the time and training, and practice is it viable, are there people doing or training FFM successfully.

Also, I noticed that several FFM are rated at 150 (my present max depth as well) or less. Presently I am not planning to dive deeper then 180, as I have no mission for one. Could that change, sure.

Candidly and truthfully? Most people lack the self-discipline to really practice and hone skills appropriately. Example, when was the last time you and your buddies practiced air shares outside of a class? When the fit hits the shan, people will fail to the highest level of muscle memory, switch blocks and FFM's add a layer of complexity that most people will not likely be able to overcome.

Will some be able to succeed? Sure, maybe, if they're lucky. But keeping procedures as simple and streamlined as possible stacks the deck in their favor even more.

Let's turn the table - what problems is your buddy hoping to solve with a FFM? Someone mentioned CNS oxygen toxicity, but I view that as an easily manageable risk - analyze all of your gasses, label all of your bottles correctly, respect the MODs, test oxygen cells for linearity regularly on rebreathers and replace on a regular basis, keep working PO2s lower (~1.2/1.3 max).

In your first post in this thread you said:

My dive buddy wants to start diving his full face all the time, including technical dives. For me, I have never seen anyone on the boats diving a full face mask. I am sure it is done, just have not seen it.

There's a reason you won't see FFM's regularly on tech charters, it's because they introduce more problems then they solve. Personally, when engaging in high risk activities (deep technical diving is high risk, if you don't believe me, try getting life insurance that will cover you while doing it), I avoid going against the community standard unless I have an exceptionally good reason. There's zero, zero, zero reason that I can see where anything like a FFM and switch-block makes sense to me.