Back mount pony bottle

[Ross19966]

I'm considering setting one up. The only time I used one was when we were using surface supplied air, and thankfully never needed it. So here's my though process.

Worse case is I suck a tank dry. Not sure how someone could get to that point without realizing they are low in air, but it's worse case. If that happened, the octo on my main tank is not going do anyone any good. Me or a buddy. No air to breathe, inflate the wing or the drysuit. That's what's called a bad day.

More likely case is that I find myself low on air. At this point there is still enough to inflate the wing and drysuit but maybe not enough to get to the surface safely.

So considering the more likely scenario, I'm thinking a back mounted 19cu pony with it's own 1st and 2nd stage. Maintain the octo I currently have because I wont always need a pony bottle. That will give the breathing air I need while using what's left in the main tank for wing and drysuit inflation. The assumption is that if I ever needed to use alternate air, the dive is over. Maybe hang the pony 2nd stage on a necklace.

Does this idea hold water? I would also likely be in a FFM if that matters. I don't really dive solo anymore, but even on group dives there are many instances where I might venture away from the group. Far enough away that should something go wrong, I may not make it to a buddy's octo.

 

[tbone1004]

You will not get much love on this forum for pony bottles as most tend to believe that if you are concerned about such things you should be diving doubles which actually give you a properly redundant system. Marginal increase in weight but you don't have to have 3 tanks, only 2, don't have to worry about filling that 19cf bottle, and everything is working regularly so that is likely what you will see from everyone responding.

Edit: I will give the disclaimer that they are obviously used in the commercial/PSD world when diving with FFM's and make use of switch blocks and what not so the diver doesn't have to share air and remove the mask due to concerns with contaminated water and what not. This is outside the scope of recreational diving and while I think FFM's should also be outside of the scope of recreational diving people seem to like them. To me they are just a necessary evil when I have to talk to people either in-water or at the surface.

 

[Boarderguy]

Back mount upside down where you can manipulate the valve. Run hose under your right arm and clip to your harness. I dive mine charged and off (slightly on to make up for pressure change at depth). I do this so if it inadvertently free flows while I'm solo or on a scooter I won't lose my redundancy. This also keeps my chest clear for a camera rig.
Put a weight pouch opposite your pony on the lower cam band to help balance you out. I turned turtle a few times whole holding still for a shot before I got my weight right for it.

 

[wetb4igetinthewater]

Worse case is I suck a tank dry. Not sure how someone could get to that point without realizing they are low in air, but it's worse case. If that happened, the octo on my main tank is not going do anyone any good. Me or a buddy. No air to breathe, inflate the wing or the drysuit. That's what's called a bad day.

More likely case is that I find myself low on air. At this point there is still enough to inflate the wing and drysuit but maybe not enough to get to the surface safely.

You should always be neutrally buoyant (or slightly negative/positive as you descend/ascend in a controlled manner), so if you were to run out of gas, you don't need gas for your wing/dry suit as it will expand as you ascend. You learned how to orally inflate in your open water course.

So considering the more likely scenario, I'm thinking a back mounted 19cu pony with it's own 1st and 2nd stage. Maintain the octo I currently have because I wont always need a pony bottle. That will give the breathing air I need while using what's left in the main tank for wing and drysuit inflation. The assumption is that if I ever needed to use alternate air, the dive is over. Maybe hang the pony 2nd stage on a necklace.

That's one option. I had mine back mounted, but clipped onto my waist strap. The reason for this is, I preferred donating my primary and switching to my necklaced secondary. Diving min gas, and you always have enough to surface.

Does this idea hold water? I would also likely be in a FFM if that matters. I don't really dive solo anymore, but even on group dives there are many instances where I might venture away from the group. Far enough away that should something go wrong, I may not make it to a buddy's octo.

I don't have experiences with FFMs but as long as you are trained to switch to different regs and mask, I don't see the issue.

 

[Cthippo]

Back mount is not super common (most prefer front slung or side mount), but otherwise you are describing a fairly standard solo rig.

 

[Marie13]

Back mount pony? Bah! What’s wrong with side slinging it?

 

[GiraffeMarineSalvage]

There should absolutely never be the possibility of being surprised by an out of air situation, as in ever... Redundancy of air supply is not an excuse to ignore your tank pressure, it's important for a host of other reasons (such as 1st stage high pressure seat failure or any number of unlikely but potential gear issues...).
If there is a chance of your diving heading to more technical you'd get more longer term use with an aluminum 40 (or 30, but 40 most popular..)

 

[wetb4igetinthewater]

Back mount pony? Bah! What’s wrong with side slinging it?

I had it on my back/tank as I wanted my frontside as clear as possible.

 

[Ross19966]

I was thinking a mount like the Shark. Easy to add and remove. I'm coming from the commercial world 25 years ago to strictly rec diving now. We always weighted heavy so we could work on the bottom comfortably. We also never wore a wing. Tank on a backpack and a drysuit or helmet on surface air. I am aware that I can blow the wing by mouth and have done it in training.

 

[Ross19966]

I had it on my back/tank as I wanted my frontside as clear as possible.

My thoughts exactly.