D1V3R
Contributor
i use a stage bottle to breath off when i scrub the crap off the bottom of my pool, and i dont even bother to put a guage on it becauseits only like 10 feet deep, that is the only instances when i've run out of air
Have you ever sucked the bottom out of your air tank?
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Our rescue instructor brought a pony to one of our sessions, and had us run our main down to zero, then switch to the pony to surface.
Interesting to note the change (for me) in breathing effort, and a reason I stick with my old fashioned mk2.
Interesting to note the change (for me) in breathing effort, and a reason I stick with my old fashioned mk2.
divengolf
Contributor
TexasMike:
Mike,
That's one of the best tips that I've picked up on this board.
Thanks much.
Harry
scubapro50
Contributor
with all the fancy computers and guages no one should ever "SUCK A TANK DRY" these days ..... back in the 60s' when I stated diving it was common ...... J valves let you know you were at 300 lbs. and sometimes that wasn't enough to make it back to the boat ...... that's why we always wore snorkels so we could come directly up and swim back on the surface ..... GOD .... it's a wonder we survived at all using those double hose regulators and CO2 vests ..... Yes .... I have sucked many a tank dry but not in the last 30 years ......
Somethin-Fishey
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D1V3R:
Almost every "Work" diver uses this same method. You get used to running out and just pop up. Diving for real, never, I know too much what it feels like :disappoin
jumbo
Guest
Working divers (kinda)
When I was golf ball diving I used to run out of air a few times a day, I would use a forty foot hose that ran to my cylinder that was held up by a bag. The greatest thing about golf ball diving is you could use a gauge but you would not be able to see it underwater the vis is that great. It took a while but eventually I could figure out how long I would have left under water by the gradually increasing breathing resistance, sort of an advantage of an unbalanced first stage.
Jumbo
When I was golf ball diving I used to run out of air a few times a day, I would use a forty foot hose that ran to my cylinder that was held up by a bag. The greatest thing about golf ball diving is you could use a gauge but you would not be able to see it underwater the vis is that great. It took a while but eventually I could figure out how long I would have left under water by the gradually increasing breathing resistance, sort of an advantage of an unbalanced first stage.
Jumbo
socaldiver
Contributor
One time too many for myself. Fortunately (I guess) was while I was completing my "deep dive" for my AOW, so I was with my instructor.
I had notified him I was getting low on air while completing my exercise at 100 fsw, once I completed it we headed back towards the boat and of course the safety stop. I knew I didn't have enough to complete the stop on my own air so when we got to the anchor chain we shared air and for 5 minutes just hung out degassing.
On a lighter note, sort of got excited when I first started reading this thread (not paying any attention to when it started naturally) and seeing some names from the past - joewr, iguana don, keraluca, texas mike, scubabunny ( all of whom have not posted in well over a year on here, but people I still miss discussing things with). Hope all of them are well in what they are doing now.
I had notified him I was getting low on air while completing my exercise at 100 fsw, once I completed it we headed back towards the boat and of course the safety stop. I knew I didn't have enough to complete the stop on my own air so when we got to the anchor chain we shared air and for 5 minutes just hung out degassing.
On a lighter note, sort of got excited when I first started reading this thread (not paying any attention to when it started naturally) and seeing some names from the past - joewr, iguana don, keraluca, texas mike, scubabunny ( all of whom have not posted in well over a year on here, but people I still miss discussing things with). Hope all of them are well in what they are doing now.
SStrecker
Guest
Around 25 years ago, when I was using a J-valve tank, I would occasionally drain the tank completely, on a NDL shore dive, during the return segment, in 10 to 20 FSW, in calm water, to extend a dive, in the Pacific Northwest. I could definitely feel the steady increase in effort required to breath the last 200 PSI. This always went without incident. Nevertheless, this was the foolishness of youth acting. I certainly do not do this any longer and I would definitely not recommend it to others. Age and experience make you a safer diver.
I hate to admit it, but I did drain a tank during one of my OW check out dives. I started with a tank that was only at 2000psi, we were told to let our instructor know when we hit half our supply and to let him know if we were surfacing. I was first to hit half supply, so we turned and headed back toward shore, when I hit 500 I began watching to let him know I was low and needed to surface, but he didn't turn back again to check on us for quite a while, when I hit 100psi it started getting difficult to breathe, I wasn't overly concerned because by that point we were only in 10 ft of water, so I signalled my buddy and we went up - I drew the last breath off of it after hitting the surface.
I also ran low on one of my AOW dives. I hit my safety stop with 800psi, and was to shoot a lift bag. I ended up tangling the line on the reel badly and spent some time attempting to untangle it - I did keep an eye on my gauge, and let the DM know I was getting low, but he motioned that he would untangle it and I should try again, by the time he had reset the reel and I'd deployed the bag again I was at 200 psi, and by the time I hit the surface it had dipped to 100and my regulator was starting to "shudder" from the low pressure. I later learned that the DM supervising me was at 200psi when we surfaced.
Between those two events I learned to take responsibility for my own safety, regardless of who I'm with - even if my buddy happens to be an instructor or DM telling me it's ok to continue the dive... if they don't like this, then we don't need to dive together any longer...
Aloha, Tim
p.s. - it may be an old thread, but it's still quite relevant...
I also ran low on one of my AOW dives. I hit my safety stop with 800psi, and was to shoot a lift bag. I ended up tangling the line on the reel badly and spent some time attempting to untangle it - I did keep an eye on my gauge, and let the DM know I was getting low, but he motioned that he would untangle it and I should try again, by the time he had reset the reel and I'd deployed the bag again I was at 200 psi, and by the time I hit the surface it had dipped to 100and my regulator was starting to "shudder" from the low pressure. I later learned that the DM supervising me was at 200psi when we surfaced.
Between those two events I learned to take responsibility for my own safety, regardless of who I'm with - even if my buddy happens to be an instructor or DM telling me it's ok to continue the dive... if they don't like this, then we don't need to dive together any longer...
Aloha, Tim
p.s. - it may be an old thread, but it's still quite relevant...
I would argue that everyone should beathe their tank dry - at least once in a few feet of water so they can see what it is like with their particular regulator and SPG.
If you have an unbalanced piston reg like the Scubapro Mk 2, you get a fair amount of warning as the inhalation resistance begins to noticeably increase below about 300 psi. and you have to be really clueless to miss the hint the reg is giving you and actually run out of air. (I use unbalanced first stages on my deco bottles for this reason) With a very high performance first and second stage however, your last breath can be entirely normal and your next breath may only be half there or even not there at all. Fully exhaling and then getting nothing from your reg always gets your attention.
The other issue is that most SPG's are calibrated for accuracy about mid-range and can be 200-300 psi off at the upper and lower ends of the gauge. Now practically speaking, a gauge that reads 200 psi on an empty tank does not make it out of the factory and is easily noticed if it does. But it is very common for an SPG to read "0" when there is still 100-300 psi left in the tank. So it is interesting to know if you can in fact breathe for 3 to 5 more minutes at a 10 ft safety stop after the needle does reach "0".
At some point that knowledge may enable you to confidently complete a safety stop when low on air. I am one of those people who sees absolutley no value in blowing off a safety stop if you have air in the tank and I see "back on the boat with 500 psi" as a nice guideline, not a reason to shorten or skip a safety stop - it's what your reserve is for and if you aren't going to ever use it to complete a safety stop after you have used more air than planned, why have it?
In the real world, I had an incident once where the SPG stuck on the same reading. If I had not noticed:
1. the unchanged reading after a few more minutes at 120' and/or,
2. that the gauge said I had more air than I should have had at that point in the dive,
this could have led to an OOA situation in short order. So checking your SPG regularly, realizing when it is telling you something it should not, and being aware of any signals your reg may be sending about low gas pressure all play parts in never running out of gas.
If you have an unbalanced piston reg like the Scubapro Mk 2, you get a fair amount of warning as the inhalation resistance begins to noticeably increase below about 300 psi. and you have to be really clueless to miss the hint the reg is giving you and actually run out of air. (I use unbalanced first stages on my deco bottles for this reason) With a very high performance first and second stage however, your last breath can be entirely normal and your next breath may only be half there or even not there at all. Fully exhaling and then getting nothing from your reg always gets your attention.
The other issue is that most SPG's are calibrated for accuracy about mid-range and can be 200-300 psi off at the upper and lower ends of the gauge. Now practically speaking, a gauge that reads 200 psi on an empty tank does not make it out of the factory and is easily noticed if it does. But it is very common for an SPG to read "0" when there is still 100-300 psi left in the tank. So it is interesting to know if you can in fact breathe for 3 to 5 more minutes at a 10 ft safety stop after the needle does reach "0".
At some point that knowledge may enable you to confidently complete a safety stop when low on air. I am one of those people who sees absolutley no value in blowing off a safety stop if you have air in the tank and I see "back on the boat with 500 psi" as a nice guideline, not a reason to shorten or skip a safety stop - it's what your reserve is for and if you aren't going to ever use it to complete a safety stop after you have used more air than planned, why have it?
In the real world, I had an incident once where the SPG stuck on the same reading. If I had not noticed:
1. the unchanged reading after a few more minutes at 120' and/or,
2. that the gauge said I had more air than I should have had at that point in the dive,
this could have led to an OOA situation in short order. So checking your SPG regularly, realizing when it is telling you something it should not, and being aware of any signals your reg may be sending about low gas pressure all play parts in never running out of gas.
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