Safety stop deco bottle

[imasinker]

Ok just a quick question...

How many of you diving with a group or just buddied up leave a stage bottle at the recommended decompression safety stops during your dives for emergency? Do you feel a need for this or what circumstance would make you use, or not use one. I have been on a few deep dives with charters but have never seen these used.

 

[JeffG]

Only on my PADI AOW deep dive.

 

[jaybombs25]

its good practice to have a hang tank on most dives deeper than about 65 - 70 ft where your NDL may run out before your gas... however, you should manage your air so that you never need to use one.

 

[imasinker]

its good practice to have a hang tank on most dives deeper than about 65 - 70 ft where your NDL may run out before your gas... however, you should manage your air so that you never need to use one.

I very much agree with your reply. I read the post about a diver who had a free flow, was handed a pony bottle from another that ran out, and then had to breath from his buddy's alternate. I also know your supposed to plan your dive so you have enough return air for two to safetly ascend, or so it has been said. How many people actually make sure they have enough return air for two, plus the safety stops?

How much air do you return to the surface with?

 

[TSandM]

I've never seen a deco bottle hung from a boat, except on my AOW deep dive.

I plan my dives according to THIS kind of protocol, so it is not ever an issue for me or my buddies.

 

[rawls]

Where I dive, the charter captains have regs connected to air cylinders on the boat hanging at the safety stop...In any event I don't really see a need for hanging a bottle at a safety stop. On an NDL you can come straight to the surface. The stop is recommended but it is not an absolute requirement to do so to avoid DCS. I guess an exception would be if you went over your NDL and ran OOA. Hopefully you won't have that happen....

 

[sambolino44]

Where I dive, the charter captains have regs connected to air cylinders on the boat hanging at the safety stop...In any event I don't really see a need for hanging a bottle at a safety stop. On an NDL you can come straight to the surface. The stop is recommended but it is not an absolute requirement to do so to avoid DCS. I guess an exception would be if you went over your NDL and ran OOA. Hopefully you won't have that happen....

I've never heard of this. Can you even suck air out of a second stage at depth if the first stage is on the surface? That doesn't seem possible; don't both stages have to be close to the same ambient pressure for the system to work?

Back to the original post - I've never used hang bottles, not at 130' at the Blue Hole, not at 90' at my NAUI AOW class deep dives - never.

 

[seaducer]

I have never seen a hang bottle either, except in books. Not a bad idea, but I know a few too many people would rely on that gas and use more of their own on the bottom. That could lead to other issues.

 

[Blackwood]

I've never heard of this. Can you even suck air out of a second stage at depth if the first stage is on the surface? That doesn't seem possible; don't both stages have to be close to the same ambient pressure for the system to work?

Short answer: no.

Longer answer: nope.



The first stage doesn't care about the ambient pressure. It cares about the tank (internal) pressure.

 

[JBRES1]

I dove with a charter out of Savannah last year, and they hang a bottle at 20 ft. with 2 second stages attached. This was the first time I had seen it done.
I didn't need the extra gas, but it sure was nice to know it was there.
Jim Breslin