Back mount pony bottle

[johndiver999]

That is why you dive with it charged and turned off. Feather the valve as you descend to keep the hose pressurized OR charged and turned ever so slightly on so that it will keep the line charged but you won't lose more than a breath or two over the dive if it does get hit. Back mount should be upside down so you can reach the valve IMO.

Maybe, but only if you mount it upside down and want to screw with it during the dive and risk flooding and messing up your reg if you forget. This solution adds task loading and may reduce the reliability of your gear if you get a flood and don't know it or address it and it starts a corrosion problem.

Upside down adds task loading and the potential that it will be off when you think it is on.

I'm not saying there are no benefits to this upside down configuration, but every method has advantages and drawbacks. I honestly think it would be easier to just run an additional spg hose from the pony, if you are that worried about it and leave it on, but I have never done either of those solutions myself.

 

[Boarderguy]

Lefty loosey is the same either normal or inverted. You won't flood your reg unless you purge all air from the line. Keeping it slightly on gives you the ability to not feather it and still maintain a no/minimal loss situation. It's not really task loading to reach back once every 30-40 ft and twist on/off if not keeping it on. Dive your rig and learn it. No other way around it. If you (not you specifically) can't do that then you have no business diving.

 

[SlugLife]

As far as losing a little air each dive, I usually highly recommend getting some sort of transfill setup. It lets you skip the "fill/VIP/hydro tax" while still being able to take practice breaths and not worry about losing a little each dive. I was able to make one for about $40 using 2 parts meant for transfilling paintball tanks.

 

[Boarderguy]

 

[DAJ]

Another reason I carry a 40 are the local conditions that can occur while swimming out or trying to get back in. Having a small bailout may work for getting me to the surface but if I need to navigate about 100 yards or more of a heavy surf zone, it won’t be the best option to stay on the surface. I prefer to stay down until I’m through the zone and then stand up in 4-5 feet of water over getting rolled and pounded in the surf getting back in. While I have never needed a bailout in all my years of diving, it’s always there if needed. The worst experience I have had with surf and surge was at Bird Rock off of the San Diego coast. If you hit that on a bad day, you better pack a lunch because that is going to be a workout. My buddies wife gave up diving off San Diego that day.

 

[GiraffeMarineSalvage]

Another reason I carry a 40 are the local conditions that can occur while swimming out or trying to get back in. Having a small bailout may work for getting me to the surface but if I need to navigate about 100 yards or more of a heavy surf zone, it won’t be the best option to stay on the surface. I prefer to stay down until I’m through the zone and then stand up in 4-5 feet of water over getting rolled and pounded in the surf getting back in. While I have never needed a bailout in all my years of diving, it’s always there if needed. The worst experience I have had with surf and surge was at Bird Rock off of the San Diego coast. If you hit that on a bad day, you better pack a lunch because that is going to be a workout. My buddies wife gave up diving off San Diego that day.

Exactly, bailout requirements need to be thought out to address worst case scenarios...
Sluglife's link to his pony capacity summary is a good overview of the various tank sizes but what I had been trying to get at (and fully admit I don't think I effectively communicated..) was more along the lines of: Were you lucky or were you good?
Roughly 10 to 15% more gas in a pony bottle is viable redundancy for some dives and not for others, and it takes consciously considering all variables to make an informed decision on the volume of ones redundant air supply...

 

[SlugLife]

Exactly, bailout requirements need to be thought out to address worst case scenarios...
Sluglife's link to his pony capacity summary is a good overview of the various tank sizes but what I had been trying to get at (and fully admit I don't think I effectively communicated..) was more along the lines of: Were you lucky or were you good?
Roughly 10 to 15% more gas in a pony bottle is viable redundancy for some dives and not for others, and it takes consciously considering all variables to make an informed decision on the volume of ones redundant air supply...

I think we're on the same page!

A relatively minor incident was enough to motivate me to spend money I might not normally spend. Which includes those 2x spare airs I have listed for-sale, and a brand new 19cu I bought. I already had extra regs, which are easy enough to come by at a big discount if you watch used markets.

Something I'm still trying to figure out is why I can't get my buddies (who solo-dive) to carry a pony bottle at all. Over time, I've collected more regs and more pony-bottles, including another 1x 19cu and 2x 6cu loaner bottles with regs and rigging. They're welcome to borrow those bottles at any time at no cost, but never take me up on the offer. Most of these buddies own their own 30 to 40cu bottles and extra regs, but I've never seen them use them.

I do like being a little on the over-prepared side, which is why I switch to dual 80s past 100ft, because....

My buddies wife gave up diving off San Diego that day.

...even in that minor incident I talked about, had it happened at 60 to 90ft, I probably would have survived, but might have gotten a sort of PTSD and given up on diving.

 

[GiraffeMarineSalvage]

I think we're on the same page!

A relatively minor incident was enough to motivate me to spend money I might not normally spend. Which includes those 2x spare airs I have listed for-sale, and a brand new 19cu I bought. I already had extra regs, which are easy enough to come by at a big discount if you watch used markets.

Something I'm still trying to figure out is why I can't get my buddies (who solo-dive) to carry a pony bottle at all. Over time, I've collected more regs and more pony-bottles, including another 1x 19cu and 2x 6cu loaner bottles with regs and rigging. They're welcome to borrow those bottles at any time at no cost, but never take me up on the offer. Most of these buddies own their own 30 to 40cu bottles and extra regs, but I've never seen them use them.

I do like being a little on the over-prepared side, which is why I switch to dual 80s past 100ft, because....


...even in that minor incident I talked about, had it happened at 60 to 90ft, I probably would have survived, but might have gotten a sort of PTSD and given up on diving.

Definitely on the same page
As to why a people choose to solo-dive without a pony bottle while having a 30 or 40 tank at home it's likely two other pesky aspects of human psychology: biases based upon a relatively narrow personal sample size and a tendency to drift / normalize deviance after numerous dives in which there was not any adverse outcomes..
While it's not at all a substitute for a pony bottle or other truly redundant source of air maybe you could at least convince single tank solo divers to at least go for a double valve? Like Speleo-Tech Valve - 200 bar - Fathom Dive Systems as "risk-reduction" relative to counting on a single first stage/all hoses and regs attached to it for a solo dive...

 

[NYCrecdiver]

There is an aspect of this which I think is worth emphasizing. If you have a back mounted pony and no ability to monitor the pressure during a dive, then it is very advantageous to wear the second stage where you can FEEL a free flow or leak. If you wear it as a normal octopus, it can blow bubbles especially on a rigorous descent down an anchor line in a current. It is easy to not notice a freeflow , for example when wearing a thick suit, hood etc. and swimming hard against a current and fighting waves etc.,

If the second stage is around your neck then you should be able to detect a freeflow.

If your normal octopus freeflows, you always have the ability to notice this when you check your air pressure.

True. Which is why I have a transmitter on my pony regulator. Plan to add a button SPG so I can check pressure w/o DC.

 

[ChrisMBC]

I get it..... but twin LP50's is still only 100cf. My 120hp primary with a 19 Pony is a total of approx 140CF and a much easier transition in an emergency to simply swap to my chest mounted Pony 2nd and head for the surface... But like i said I get it...... Best to dive whats best and most familiar and trusted for you.

I mean...assuming that you're rigorously following the "LP" part. Filled to the norm for HP tanks, you've got ~130CF. I'm also not in total agreement that it's a more foolproof transition - with doubles I'd guess there's less chance of switching to a non-working reg (pony bottle turned off/drained by freeflow), although I will agree that at bare minimum you need to close the isolator in order to preserve your gas in the case of something failing.

I totally get the benefits of a stage-rigged pony sitting on your front - valves accessible, right there to view, totally separate system. The part that I find odd, I guess, is back-mounting a pony, which basically seems to be independent doubles, but with mismatched tank sizes.