Spare air - or not?

[BDSC]

Can't say it breathes as nice as my B2.

It's probably not supposed to. Just as long as it gives you air when you need it that's all you're gonna care about.

 

[GrumpyOldGuy]

Oops... I missed a whole page of fun post and this was out of context - deleted.

 

[davetowz]

Question for anyone that can answer this.

What does it feel like to actually run out of air? Do you have a nice full breath and then the next there is nothing or can you began to feel like you are having to "suck harder" on the last few breaths thus letting you know you have a real problem?

Thanks.

Not sure what agency you did your OW with, but the one I work with has you experience this in the confined water dives. The instructor actually shuts off your gas and you breath it down until you feel the pull and the nothing.

 

[DevonDiver]

Dave, there is an issue that running out of air at depth provides a different sensation to when your instructor turns of your air in a pool. The sensation (and potential warning of increased resistance) also depends on the regulator used.

 

[RonFrank]

After diving for many years I've never ran out of air, never had to share air, never had a buddy run out of gas, and never had a buddy need to share air. I've had insta-buddies, and some have been poor buddies but they have at least kept an eye on their air. I have come to the conclusion that running out of air rarely occurs and the chance of both you and your buddy both running out of air is almost zero.

So why are we 70+ posts into one of these foolish threads...again as they come about more than they should. FYI for diving solo (rare) I use a 19CF pony. I also use one when I go deep if I have an insta-buddy.

 

[Warren_L]

Thanks to everyone for their opinions and info. What I got from this conversation is that Spare Air does
not cut the mustard as a pony tank. Good buddy skills and monitoring of gas is the way to go. I plan to dive
with Spare Air but understand its limitations. I will also continue to have 700lbs + of gas when re-boarding the boat.
Additionally, sometime in the near future I'll purchase a 19cf pony. As a pilot I know that
altitude is like money in the bank, I think having an additional air source is also like having money in the bank.

I tend to think it's not the additional source that is the money in the bank, but rather it is having sufficient reserves as per proper dive planning.

 

[GrumpyOldGuy]

After diving for many years I've never ran out of air, never had to share air, never had a buddy run out of gas, and never had a buddy need to share air. I've had insta-buddies, and some have been poor buddies but they have at least kept an eye on their air. I have come to the conclusion that running out of air rarely occurs and the chance of both you and your buddy both running out of air is almost zero.

So why are we 70+ posts into one of these foolish threads...again as they come about more than they should. FYI for diving solo (rare) I use a 19CF pony. I also use one when I go deep if I have an insta-buddy.

Simple because running low or out of gas remains one of the largest contributors to diver fatalities. Take away pre-existing medical conditions and its the tall pole in the tent for many. You personal experience (which mirrors mine) is not statistically relevant to the general population.

 

[Hatul]

It's good to have a SA thread now and then...


My pony flies anywhere I do. I keep everything clean, reassemble, and fill. It's for my bail out so as long as I am confident, I have it vized once a year.

You must be paying a steep charge for either excess weight or taking a scuba tank? If you pack it in a suitcase you'll easily exceed the wt limit with all the other gear.

 

[DandyDon]

You must be paying a steep charge for either excess weight or taking a scuba tank? If you pack it in a suitcase you'll easily exceed the wt limit with all the other gear.

Nope. I take 2-50# bags, 1-40# roll-on, and a personal bag. Yeah, I pay for one bag.

 

[Lobzilla]

Dave, there is an issue that running out of air at depth provides a different sensation to when your instructor turns of your air in a pool. The sensation (and potential warning of increased resistance) also depends on the regulator used.

Simple because running low or out of gas remains one of the largest contributors to diver fatalities. Take away pre-existing medical conditions and its the tall pole in the tent for many. You personal experience (which mirrors mine) is not statistically relevant to the general population.

My conclusion is that panic is the real killer, not the OOG situation. (I use the more generic term "Out Of Gas" instead of "Out of Air")

After a string of local OOG accidents at the beginning of this season I was curious how OOG really manifests itself. So, I closed the isolator valve on my AL80 doubles and breathed of the right tank like every recreational diver would breathe from a single AL80. I went down to 60' and swam around until I felt the breathing resistance increase. I dive Scubapro Mk17 first stages with G250V seconds, which are both balanced and give you less warning about low tank pressure than unbalanced regulators. When I felt the breathing resistance increase, I immediately started my ascent to 30' and stopped at 30' for 1 minute, slowly milking gas out of the regulator. Then I went up to 20', spent another minute there, then to 10' for another minute and finally, slowly to the surface. Since I deliberately took my time ascending I then needed to inflate the BCD/wing orally (which I survived too).

Please do not try this at home. Please understand that I had another gas source as a back up during this experiment (isolated left tank with its own regulator set). Do not use my story as a reason to skip proper gas planning or as an excuse for not monitoring your gas consumption during every dive. Running out of gas for real is stupid.

But if you ever run out of gas (unnecessary) without a buddy in sight (imprudent) do not panic. Get your rear end off the bottom FAST, spend as much time as possible in the shallows (above 50% of max depth) where you can suck more gas out of an "empty" tank, and don't hold your breath. Also, practice oral inflation of your BCD with surface air.

And PLEASE do not start another Spare Air thread.