Advice on slinging an AL40

[doctormike]

With the valve closed, the only mechanism for a run-away IP would be to blow a hole in the hose

Oh, with the shutoff valve. Sorry, didn't see that.

 

[Marie13]

@Cowfish Aesthetic

Is the LDS renting you a pony reg, too? When you get it, take a small loop of thin bungee and put it over the valve. Once the reg is on on the cylinder and hose stuff in the hose retainer (elastic or rubber band around cylinder), stick the second stage in that loop of bungee, so it is held against the valve. I've seen way too many people with ponies and the second stage just flopping around with nothing more to hold it than the hose retainer. This way, it's not flopping around and you can easily pull second stage out if you need to use it.

 

[Cowfish Aesthetic]

@Cowfish Aesthetic

Is the LDS renting you a pony reg, too? When you get it, take a small loop of thin bungee and put it over the valve. Once the reg is on on the cylinder and hose stuff in the hose retainer (elastic or rubber band around cylinder), stick the second stage in that loop of bungee, so it is held against the valve. I've seen way too many people with ponies and the second stage just flopping around with nothing more to hold it than the hose retainer. This way, it's not flopping around and you can easily pull second stage out if you need to use it.

Yes, they are. And will do.

 

[markmud]

I dive a Shrimp (a BOV) as well as an additional BO on CC. CC is an entirely different animal than what we're discussing here.

@Cowfish Aesthetic Dive and let dive: do what seems best FOR YOU. None of us are doing your dive for you so you get to choose. Yay you! Consistency is a great asset. Deco, stage and OMG! bottles are all handled under the same protocol by me. I don't want to put a reg in my mouth and have to consider what I did with this one as compared to another one. As @RyanT pointed out, it only takes a 1/4 turn and you are breathing

A couple of additional thoughts. For me, bail out implies being on a CCR. On OC, it's either redundant gas if it's the same mix or an OMG! bottle if it's air. It's my opinion that solo divers should probably be carrying air in their OMG! bottle. Why? It's always breathable. You won't have to drain the 36 and put in 28 to match your mix on a deep dive. I actually had the same fill on one OMG! bottle for six years and it was an AL19. I breathed it once every dive and never ran out of gas. I never did a vis or hydro as it had never been emptied. I sold it when I moved to AL40s.

Caveat: just because you can carry a bottle, doesn't mean you have the knowledge and/or training to use it safely. It amazes me how quickly people spend money on gear and yet are reticent to pay for training that will enable them to use it safely and get the most out of it.

Hi OP,

I am with Pete on multiple issues.

1. I dive my pony and/or sling bottle with the regulator charged and valve off.
   1. If your situational awareness is such that you need your redundant gas supply RIGHT NOW or you drown, you need to rethink your skillset and resolve those issues.
2. Pete's caveat: I dived with a pony before getting solo training. I practiced with and was competent with that one action (switching to my redundant system). My solo instructor taught me about different issues that can occur while being self-reliant. I now practice resolving multiple issues in a parallel fashion, not serially. The training was good for me and it will be good for you.
3. 21% nitrox is best for an OMG or OC bailout bottle. Who cares if it screws up your NDL on your computer if you are diving EANx. Get to the big SCUBA tank in the sky and worry about the other stuff later. However, if you do have EANx in your pony and it is at 1.7 ata when you need it, go for it. Ascend safely but quickly and you won't suffer a CNS hit. A CNS hit won't manifest itself in one or two breaths while you ascend to 1.6 ata and continue up to lower partial pressures of O2.
4. Dive and Let dive-- I am now an advertiser for Pete's newest advocacy group--click on the URL below (signature box).

I am happy that you are interested in self reliance. I FEEL that it is the only way to dive.

markm

 

[doctormike]

If your situational awareness is such that you need your redundant gas supply RIGHT NOW or you drown, you need to rethink your skillset and resolve those issues.

Excellent point. Practicing switching to a backup gas source is important for any diver using one. This is - as mentioned upthread - very different from CCR bailout, where a CO2 hit may make all of the best training and practice go out of the window, and you want whatever gear solution you can have to optimize things (like a BOV). Theoretically, you could rig up a BOV for OC diving as well, but it just isn't necessary.

21% nitrox is best for an OMG or OC bailout bottle. Who cares if it screws up your NDL on your computer if you are diving EANx. Get to the big SCUBA tank in the sky and worry about the other stuff later. However, if you do have EANx in your pony and it is at 1.7 ata when you need it, go for it. Ascend safely but quickly and you won't suffer a CNS hit. A CNS hit won't manifest itself in one or two breaths while you ascend to 1.6 ata and continue up to lower partial pressures of O2.

This is also correct, although I hesitate to stress it in a basic diving forum without a lot of context. Yes, you should NEVER exceed the MOD for any breathing gas, but Ox Tox is really dose over time. There wouldn't be many situations where you would need to breathe a hot gas, but in my OC tech training, it was stressed that if you were at depth and really lost all of your back gas (manifold issue or something), and all you had was a deco bottle with EAN 50, just take a sanity breath and head for the roof.

 

[Cowfish Aesthetic]

Thanks everyone. Visibility was poor, the water was freezing, and I had an awesome day of diving.

I learned several things from my first go at slinging the 40: 1) the advice about the difficulty of reaching the hip D rings on the AL Dimension was spot on. Struggled to get the thing off me after the dive with cold hands. 2) when I do my own setup, I'm definitely putting a swivel on the reg. Breathing off a right hand reg from a left-slung pony is a pain. 3) I recognized myself getting very task loaded just playing with the pony (turn on, switch regs, switch back, stow hose, etc.). I definitely need some time with this before it feels comfortable.

 

[KenGordon]

You ought to check that regulator on the bottom now and again.

There are pos and cons to the “charged and off” advice. One possible problem is a flooded first stage. Undetected that can lead to a somewhat trashed regulator which seems to work but doesn’t when you actually want to take proper breaths. This will happen if you completely forget to charge it or if the regulator loses the charge. That will happen in the same circumstances as a freeflow plus if the regulator is knocked or otherwise discharged, such as when you jump off a boat.

 

[Cowfish Aesthetic]

You ought to check that regulator on the bottom now and again.

There are pos and cons to the “charged and off” advice. One possible problem is a flooded first stage. Undetected that can lead to a somewhat trashed regulator which seems to work but doesn’t when you actually want to take proper breaths. This will happen if you completely forget to charge it or if the regulator loses the charge. That will happen in the same circumstances as a freeflow plus if the regulator is knocked or otherwise discharged, such as when you jump off a boat.

Do you need to check the reg itself, or is periodically checking the pressure gauge sufficient? That is, if the gauge is still showing 3k psi, no problem, right?

 

[doctormike]

That will happen in the same circumstances as a freeflow plus if the regulator is knocked or otherwise discharged, such as when you jump off a boat.

Exactly. And unlike a freeflow, you likely won't notice it when it happens. Checking the SPG from time to time will also help you watch for that.

 

[KenGordon]

So since you are carrying a 40, why not just dispense with your back gas octopus? Why do you need it, even if you are diving in a team? If someone needs gas, you have it for them in the form of a completely redundant scuba unit that you can donate completely or just donate the reg. Far preferable to the "standard" single tank configuration of donating half of your only gas source with an octopus.

In an OOA situation the gas will have to be turned on.