Why don't technical divers use full face masks?

[supercritical]

Just curious. I was thinking that a full face mask would have saved Dave Shaw or many other people from drowning. Is it because the mask makes regulator switching troublesome?

 

[kaerius]

It wouldn't have(his death was due to his body needing more oxygen than his breathing could provide, due to exhaustive workload at 270m depth), and yes it makes regulator switching a bit trickier.

Your premise is flawed however as there are indeed technical divers who do use full face masks. Indeed they are almost exclusively used by professional(commercial) and technical divers.

 

[Centrals]

CO2 poisoning or O2 deprivation?

 

[rongoodman]

There's been quite a bit of discussion in the rebreather community about impaired ventilation due to increased gas density, and the CO2 hit that killed Dave Shaw has been mentioned often. More discussion here. It's hard to see how a full face mask would have helped him.

 

[PfcAJ]

Makes gas switching a bit convoluted which introduces a whole host of problems, and if you do happen to run out of gas somehow, you're compounding the issue with a full face mask flooding. No bueno. Also makes donation from the mouth difficult.

KISS.

 

[rameus]

Makes gas switching a bit convoluted which introduces a whole host of problems, and if you do happen to run out of gas somehow, you're compounding the issue with a full face mask flooding. No bueno. Also makes donation from the mouth difficult.
KISS.

That pretty much sums it it up. Since I just did my tec/trimix and also the Closed Circuit Rebreather (CCR) training on the Poseidon MK VI a few months ago we asked the same questions. Fact is: There are theoretical possibilities to use a full face mask but as mentioned by PfcAJ you already have a lot of things to think about startin with the whole setup before you jump then the descent checks and once you are on the way back up the gas switches. At one point you should also deploy a surface marker buoy... all these things add to taskloading and a full face mask certainly would not help to lower that one.

thom

 

[Jared0425]

We use a transfer block on the BC. But that is for PSD set up between main tank and pony. Now theoretically you can use back gas as main and then switch gases by block by interlocking hoses. Tried and old tested works the best overall though in my opinion.

 

[kaerius]

The one situation where a full face mask can save your life, that I can think of, is when you suffer a CNS hit or otherwise lose consciousness, and you have a buddy. That said, you shouldn't dive so you risk CNS hits(or rather, you should stay within conservative safety limits to minimize chances, I have heard of one US navy diver who had a hit when diving 1.4 PPO2, prompting them to lower their standard to 1.3).

 

[rongoodman]

There was a young woman cave diver who seized and died a couple of years ago at 1.4 too.

 

[JohnN]

The one situation where a full face mask can save your life, that I can think of, is when you suffer a CNS hit or otherwise lose consciousness, and you have a buddy. That said, you shouldn't dive so you risk CNS hits(or rather, you should stay within conservative safety limits to minimize chances, I have heard of one US navy diver who had a hit when diving 1.4 PPO2, prompting them to lower their standard to 1.3).

Sorry for the thread hijack, do you have a link for that USN diver taking a hit at 1.4?


Thanks