Nitrox to an OOA Diver?

[Gilldiver]

Having twice been around when an OOA diver went looking for air, it is not “Pardon me, but I seem to be a bit short of gas to breath, would you mind if I had some of yours?”

It’s a lot more like an underwater mugging, they take what they want and you will only see it coming if they happen to be in the direction you are looking. If they are above, below, to the side, or behind you the first you might know of them is as your regulator is torn from your mouth. Hopefully without taking some teeth with it.

As for gas, any gas is better then water and bent on the surface is infinitely better then dead on the bottom.

I run my deco gas so that its MOD is at least about ½ my depth. So if I’m at 140 feet I’ll run 50% etc. O2 tox is not instant and takes at least a few minutes. If I have to, or they have to, go on to a mix with a PO2 of 2, 3 4 etc. so be it, but once on that gas we will be doing an accent to the MOD as fast as we can, 60-100 FPM at least. Once at the MOD, stop, take stock of the situation and then act as you need to.

If you are in an overhead where you can’t do such an accent and only a little pony, we need to have another talk.

 

[peterbj7]

Any gas that I'm carrying is turned off until it becomes breathable. Anyone who just grabs a (the wrong) reg won't get anything out of it.

 

[Sas]

Respectfully, since your posts outnumber your reported dives at a ratio of more than 10 to 1, here is my response:

Why are you using a pony with 40% nitrox?

What difference does it really make unless it's your deco gas (and, if it is, I'll be REALLY amazed)?

Just curious?

Not sure how post number is relevant on the topic?

I didn't get the impression the OP was doing this type of thing given it was posted in Basic Scuba but was just curious about a scenario they'd thought of.

 

[Jax]

I'll go stand in the corner

I figure what will happen is as you say -- you aren't going to fight it out with an OOA victim. Although it hasn't happened yet, I figure it is only a matter of time before it does.

 

[Heavy water]

I give, I give, then we go. In over twenty some years of diving its happend to me twice. Both times from someone other than a member of my party. Mugging is a soft term, You will be groped,pinched,poked . Then your mask will probably be ripped off.(mine was both times) I started using my back up gas, give them what thay want. then catch the first large bubble up

 

[D_B]

Gilldiver is right ... O2 tox is not a worry, your not staying at depth long enough for it to be a factor, your going up as soon as things are squared away

 

[Puffer Fish]

You newbie's

People sometime confuse really low on air (the nice, could I have some of your air please?), with actually Out. I've had a few more than couple, and they were all ugly. Oddly also never from my buddy. My worst was someone that grabbed the reg from behind, and then first choked me, which quickly went to a surface bolt, where they knee -ed in the head, all the way to the surface.

I use a back mounted pony, and while I can easily open and close the valve, leave it on (but I have a wireless pressure transmitter on it)and the second stage is on my chest.

One thing I will never understand, is running out of air. Rule number one is "Don't ever run out of air underwater". Rule number two is "If you cannot do rule number one, then don't dive".

I have had and been with divers where equipment broke, but those don't seem to lead to the same sort of behavior.

I give, I give, then we go. In over twenty some years of diving its happend to me twice. Both times from someone other than a member of my party. Mugging is a soft term, You will be groped,pinched,poked . Then your mask will probably be ripped off.(mine was both times) I started using my back up gas, give them what thay want. then catch the first large bubble up

 

[kanonfodr]

When I carry a pony, it is generally the same gas I am using as backgas. I have issues with carrying a pony (which is a redundant air source to possibly be breathed on the bottom in an emergency) that I can't use on the bottom safely. Also, just because it may be safe for me to use on the bottom does not mean my buddy can use it (they may be more susceptible to OxTox), another good argument for ensuring your pony gas will be below a pO2 of 1.2 on the bottom.

Also, your pony bottle is YOURS. If a diver is in a real OOG, they are going for the regulator that they have the easiest access to: the one in your mouth (an argument for the long-hose setup that I dive). At that point you should be switching to your backup regulator, then possibly opening your pony bottle up and begin breathing from it (especially if you are near rock bottom, play it safe and let them have your backgas). I'm in the "carry your pony charged, but closed" group, so if a real f**kup occurs you have a breath in your hose while you manipulate the valve to get full access to your gas.

The key is to reduce the risk, especially with an OOG diver who is potentially in a panic/near-panic state. One of those risks is switching regulators: that is a dangerous time so you want to do it as little as possible. One time I was shooting an SMB and got a little water in my mouth when I replaced my regulator after inflating the bag. I managed to keep cool, but ended up going through my primary reg, my secondary, and then my buddy's donated primary before I quit choking on water. Not fun, but it just goes to show that even the little things can mess up your game.

Peace,
Greg

 

[Hammerhead]

Respectfully, since your posts outnumber your reported dives at a ratio of more than 10 to 1, here is my response:

Why are you using a pony with 40% nitrox?

Respectfully, since your reported dives outnumber your SB posts at a ratio of more than 3 to 1, here is my response:

Why are you on Scubaboard and not out diving?
:mooner:

 

[joe8mofo]

I'd like to hear experienced thoughts on a scenario:

I'm diving with a pony that has 40% Nitrox. My primary tank will have anything from 30% - 36% Nitrox.

I'm approached by an OOG Diver. S/he grabs my pony reg and sucks desparately.

Do I leave him or her on it, grab the victim's BC and head for the surface?

or​

Do I grab the BC, start up, and try to get him or her on my primary reg with the (probably) lower NIitrox %? After all, that is *my* emergency air s/he is consuming!

I'm figuring that since we're ascending immediately, that it really doesn't matter what percentage the individual is on, they'll be above the MOD of 40% because *I* wouldn't be near the MOD of 40%.

Jax,

I agree with your logic on this one, as I would also carry 40% in a pony and not simply air. Emergency's do not happen often so you basically carry a pony bottle just to carry a pony so you might as well give it a second purpose; the basic nitrox cert allows for up to 40% and at least some of the courses touch on using higher % mixes in order to accelerate decompression, which I am assuming you are doing. So you are getting 2 uses out of your pony bottle.

Even at the recreational limit of 130 you (or your out of air diver) will not be exposed to a high enough PPO for a long enough duration to lead to OXTOX. A PPO of 1.4 is extremely conservative as it is, and you will definitely be at or below a PPO of 1.4 within 1-2 minutes as you will be heading to the surface. OXTOX is cumulative and not instant at recreational depths on recreational mixes (<40%). I disagree with the flaming going on around you using 40%, a minute's exposure to a PPO of 2.0 will not likely kill you, but drowning definitely will.