500 psi for two divers?

[flots am]

as for the no air, never should happen. bad regulator, what happen to your alternate? it's not just for your buddy!

It's definitly possible to have "no air" with a completely full tank if the dip tube or tank valve or regulator first stage inlet filter clogs. This typiclaly happens with poorly maintained tanks, when the diver goes head-down.

There's still no excuse for running out even with this type of failure, though, since you always need to be close enough to your buddy to share, or have your own fully-redundant air supply.

flots.

 

[tbone1004]

or any first stage failure if you don't have an H-valve or twin tanks

 

[decompression]

I think the key factor from tech diving is not the configuration itself but the relationship a diver has with it. Tech divers know their lives depend on it. If rec divers took the time to secure their octo in the right place, and ensure it's proper function, the triangle would work ok. Having said, that I use a longhose bungee'd B/U myself.

It's also really easy to tangle/trap a longhose. Just connect the drysuit whip over it. Of course, this would be caught with a proper pre dive check but so to would a trapped traditional octo.

Agreed, although I've seen countless times octos come loose during a dive regardless of the 8000 different octo holders and people fiddle with them to replace.
Also, if in proper trim the triangle isn't as visible as it is while firmly planted on your knees, in a pool, between cocktails......sorry, you just can't beat a bungee second.


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[ScubaSteve1962]

It's definitly possible to have "no air" with a completely full tank if the dip tube or tank valve or regulator first stage inlet filter clogs. This typiclaly happens with poorly maintained tanks, when the diver goes head-down.

There's still no excuse for running out even with this type of failure, though, since you always need to be close enough to your buddy to share, or have your own fully-redundant air supply.

flots.

I was going off the op's statement of no air left, and your buddy down to 500. which would mean someone wasn't watching their air consumption. and not following their dive plan.

 

[doctormike]

In the PADI OW class materials, it does describe the traditional octo setup, but it is not required for them to use that in the class. When I teach, I teach the traditional setup, because that is what my students are most likely to encounter, but I show and explain both the integrated alternate and the bungeed alternate so they can know there are other ways of doing it.

Assuming that your OW students are going to dive in the Caribbean or somewhere like that, and that they are going to rent a standard regulator with two second stages on standard length hoses, they can always take a few cents worth of bungee and make a necklace (or buy one, if necessary), and take it with them wherever they go. No need to use one of those problematic "golden triangle" hacks that are typically found on rental gear.

 

[DaleC]

...sorry, you just can't beat a bungee second.


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Hey, I ain't arguing. That's why I switched to a longhose myself.

 

[boulderjohn]

Also, if in proper trim the triangle isn't as visible as it is while firmly planted on your knees, in a pool, between cocktails......

This is a good point.

When I teach students, they are never on their knees. Even in CW #1, they are in horizontal trim, lightly touching the floor. When we do the OOA exercise, I have them apart, and the OOA diver swims toward the donor while signaling. the door's octo is pretty far away and out of reach, so they have to make an extra effort to make the donation. When we to it again later on, they are swimming in mid-water when we do it. We do it again on the last CW dive, with it happening unexpectedly while they are swimming as a buddy team.

Contrast that with what you see in a typical class taught on the knees. The two students are face to face, a couple of feet apart at most. It might only be a foot. The octo is right there for the taking. No physical movement beyond the arms is required. That is how it is also done in the later exercise. The third one I mentioned is an optional exercise in the final dive of the new standards. (I did it on my own for years, but it was just something I added.) I know instructors who did the OOA exchange kneeling in the sand in the OW dives as well.

I suspect a lot of divers have never practiced an OOA emergency in any way other than kneeling right next to each other, all prepped and ready to go.

 

[yellowfins]

Hi ,

the situation is ... two divers, max of 18 m, one diver has a problem with regulator or no air left, etc . They share one tank to surface. if the other has diver s tank is 500 psi, with slow , controlled breathing , is that enough to do safety stop and ascend for both of them?

i just cant figure out how long 500 psi would last and i think is useful to know in case i get to that situation.

thanks !

Better late than never, just found your post and felt compelled to answer. It seems your query is being approached as a mathematical puzzle as opposed to a real life practical possibility. You would not be planning your stated scenario, you would be living it and having to deal with it. The one functioning regulator has access to 500psi at about 60 feet. What do you do? The last thing is to start doing calculations in your head or assume you'll have the amount of gas left at 15 feet that you previously calculated beforehand. You're in a real life situation that requires calm action. You must get to the surface safely. As you were taught, maintain physical and eye contact with your buddy. The donor should frequently monitor his/her pressure gauge as you ascend at a rate that is commensurate with safety and getting to the surface. (You may have to quicken your assent or do an emergency controlled ascent as a last option. Remember to always exhale continuously when ascending in an out of air situation,) Once at 15 feet you have easy access to the surface and can breathe your remaining gas as long as it lasts or until you reach your safety stop time, whichever comes first. If you do drain your tank remember to orally inflate your bc at surface and have your buddy turn your tank valve off to keep sea water from entering.

 

[decompression]

Better late than never, just found your post and felt compelled to answer. It seems your query is being approached as a mathematical puzzle as opposed to a real life practical possibility. You would not be planning your stated scenario, you would be living it and having to deal with it. The one functioning regulator has access to 500psi at about 60 feet. What do you do? The last thing is to start doing calculations in your head or assume you'll have the amount of gas left at 15 feet that you previously calculated beforehand. You're in a real life situation that requires calm action. You must get to the surface safely. As you were taught, maintain physical and eye contact with your buddy. The donor should frequently monitor his/her pressure gauge as you ascend at a rate that is commensurate with safety and getting to the surface. (You may have to quicken your assent or do an emergency controlled ascent as a last option. Remember to always exhale continuously when ascending in an out of air situation,) Once at 15 feet you have easy access to the surface and can breathe your remaining gas as long as it lasts or until you reach your safety stop time, whichever comes first. If you do drain your tank remember to orally inflate your bc at surface and have your buddy turn your tank valve off to keep sea water from entering.

Or plan your dive so this scenario doesn't happen......


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[flots am]

Or plan your dive so this scenario doesn't happen......

I always thought running out of air was completely random and unavoidable, like buying a timeshare or getting pregnant.

Oh, wait.

Nevermind . . .

flots.