What if you need to use some of that 500 psi contigency reserve?

[captain]

I don't have to. Re-read the posts with greater care.

I say "when they're empty", Pete from Belize talks of the issue with extreme low pressure. Low pressure results in "empty". Here's why....

Here's the fact: Tank valves that are in resort-use, they all leak. It may be barely noticeable, you might need bat's ears or soapy water to notice- but they all leak. Tanks that are filled 3200 psi on Friday Night and racked as the dive staff goes home (for the resort changeover days) are often down to 2200 psi on Sunday morning for the first divers of the new week.

Do a little math. If you rack a tank at, say, 100 psi, the air will leak out within minutes allowing the ambient salty humid air to insidiously enter and affect the threads and further mutz-up the valve. Mutzing is a technical term.

It's easy to have an empty tank begin to assume ambient air, even if you know you racked it with 500 psi. They all leak.

This factor also gives rise to another Diver Myth. That 2200 psi tank that I mentioned... the one that new divers often find all racked up for the first dive of the new dive week? You will see this comment often in trip reports and resort/op comment cards: "The tanks were low on the first day so we complained and they kept them filled after that". No, you just pulled tanks that were very recently rotated and filled. They hadn't been sitting, leaking slowly for a weekend.

I've seen my share of dive op and resort operations in tropical environments. If I had a nickel for every tank valve I pulled and worked on, I'd have gotten a real job on an island. In a large-op, quite often at least one guy pulls and changes out valves, one day a week. All day, 8 hours.

Rental tanks at resorts are not my concern and if they are not properly maintained that is another issue, fact is a tank with even 0 pounds and a good valve will not get water in it. If the valve can keep 3000 psi in it can keep anything else out. Even with a regulator attached and the valve open nothing is going in unless the purge is held depressed and the tank is submerged to a greater pressure than tank pressure.

 

[Web Monkey]

All the air in my tank is mine! Period and if I let someone have it I will choose and control it! If you have been taught that get better training! You are not a baby sitter it is your life support not your buddies! If you are diving as a buddy team you turned on the less air tank and you are at 15ft with 500psi of your air! He can suck his tank dry in go up!

So exactly what's complicated about choosing to save some gas so you and your buddy can do a nice slow ascent?

I realize that you probably have four million dives and haven't had any damage that you know of, but standards change and sometimes the change makes things safer.

At 15' it's not big deal. At 115', if I blow and o-ring or have a cold-water freeflow on a single tank, I really like knowing that it's no big deal because my buddy has enough gas left to safely get us both to the surface.

Terry

 

[dumpsterDiver]

Someone else mentioned the value of experiencing what it is like to breath a tank down to nothing. I agree. I helped teach some classes with an instructor who was very good about this sort of thing. He manifolded a pony bottle with an 80 tank. He would bleed a few hundred pounds into the pony and then shut the manifold off and let the student breath the pony down to zero in the pool. Each OW student learned exactly what it will feel like to run out of air. Of course the process is much quicker with a pony than with a large volume tank, but they got the idea.

Another thing I learned was that you can breath a tank down to zero with very little stress if you press the purge button in and gently accept the slowly delivered air rather than sucking on the reg when the tank pressure is low. Sucking on it makes you feel air starved. Sipping the air that is freeflowed at you is, for some reason, much less stressful.

I used to golf ball dive with an old reg and would typically breath the tank down to zero (of course I was diving in 10-12 ft or less usually) The reg would get a little hard to breath at a few hundred pounds, but I could milk it for a couple of minutes. I'm not recommending that anyone plan on not reserving enough air, but everyone should understand what it feels like to milk the last 5-6 breaths from a tank. It could be the difference between being a little stressed or totally panic if they feel resistance from their reg at 80 feet.

As for Papa Bear.... well classifying him as the anti-george sounds pretty good to me. Has he told us yet that exercising and swimming is a total waste and diving is so simple that any out of shape, HFS should be doing it ?.

 

[Gombessa]

As for Papa Bear.... well classifying him as the anti-george sounds pretty good to me.

I don't know what the opposite of a blue banana hammock is, but the more we have that is not George, the better.

 

[Doc]

Rental tanks at resorts are not my concern .

Unfortunately, that was the basis for this thread.

If you're working within an environment where you are bringing your own tanks, I don't think anybody's going to be looking at your SPG.

 

[Teamcasa]

Water in tank see new thread Water in tank – low pressure or air fill?

 

[Ice Mike]

Just trying to clear something up.

1.
When you talk about not sharing air with an out of air diver, do you mean you will not buddy breath with him?
(Just for clarity: Buddy breathing I see as passing one second stage regulator between two divers. Air sharing I see as two divers breathing from the same tank but each with their own second stage regulator.)

2.
When you talked about accidents investigations where deaths were related/part of/due to/xxxx sharing air. Was this with divers having to do buddy breathing?

 

[TheWetRookie]

DanyDon, Thanks for an entertaining thread and I think it is a worthwhile discussion especially for new divers. When I was new I had the same concern, gotta come up with 500PSI. Then an experienced diver explained and showed me how long 500PSI lasts in the shallows and to not let it worry me so much. Since then I have not worried about 1 bit, plus with proper gas management I don't have to now either.

Thanks

 

[Thalassamania]

Well let me tell you I have been on the California Dive accident investigation board in the 70's and investigated drownings of single and buddy teams and I will tell you you are advocating the most dangerous behavior in diving! Tell me the agency that teaches what you advocating and I will contact them, because they need to be educated! I will with my experience encourage every diver hold precious their air! Anything else is criminal! Look this isn't playing games this is life or death and at the end of the day I go home! Better one dead diver than two. I have been a public safety diver for a number of years and have done things you can't even imagine! But I will post where I see fit, I notice you have no problem posting as you feel necessary! So maybe you should get an eduction in basic diving before you promote "Give your life to your buddy" type diving! And yes all my potential buddies know my attitude because I discus it before we get wet! If they have a problem go kill yourself and someone else!

That's rather interesting since in the 1970s I was working at the NOAA/NIOSH/OSHA/U.S. Coast Guard funded National Underwater Accident Data Center and I have no memory of any "California Dive accident investigation board." I remember the individual Coroners out there from whom we got reports, and the left coast divers who were our sources much of the time ... but no such boards. And perhaps I'm getting old and befuddled but I do not remember any multiple fatalities on the California coast that stemmed from a screwed up rescue. But then I did work on over 2,000 cases and I might have forgotten one.

 

[PfcAJ]

...Everything!...!...!.....

You can't be serious. There's just no way this can be legit, its just WAY too far out there. Comical? Definetly. Good advice? Hardly.

And where on earth did you get your lifeguard training? A crackerjack box? NO WHERE in my lifeguard training were we told to hold someone down until they submit. Is this UFC all of a sudden? Horrible, horrible idea that will get you sued at a minimum an sent to prison at the worst.

...!