Pony bottle

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Pony bottle threads have got to be one one the most frustrating threads on SB with the possible exception of deep stop threads. I do not understand why people that don't dive or even believe in pony bottles insist on giving advice in a how to thread.

To the OP. You are correct. You will need some form of redundancy for solo class. The vast majority of divers choose to use a pony. H values do not give full redundancy and doubles or sidemount is just plan nonsense for most recreational divers, even solo ones. I won't even say the phrase Spare Air.

I don't know your diving environment where you plan to solo and this may affect your choice on pony tank but on the boats I dive the vast majority of divers with ponies dive a 19 cf. This size will give most divers plenty of air for a safe ascent, easy to maneuver and stow on a boat and is less likely to be left home because its just too much trouble.

Rig in in the dir style linked earlier. I modify mine slightly and put tube webbing around the hose clamp and a small section of plastic hose to cover the screw


23.8

Required Equipment

Basic open water scuba equipment as described in section three of this manual with exception of a safe second, or octopus, is not allowed as a redundant air source.

One of the following must be used to provide an additional independent regulator attached to an air source: pony cylinder, twin cylinders with isolation, H-valve, independent doubles, or SpareAirTM
 
Onc you go sidemount you will never go back.And a 19cf not a chance,get a 40cf attach a 40" hose to it ,no worries just dive.
 
Onc you go sidemount you will never go back.And a 19cf not a chance,get a 40cf attach a 40" hose to it ,no worries just dive.
I've done SM for Intro cave. I dive a 13 or 19 solo boat. I can get 2 normal ascents from a 19.

Can you just imagine the chaos on the average recreational dive boats if all divers with ponies switched to doubles/SM?

Again, this will all depend on the OP's planned diving environment.
 
Whether one believes in pony bottles or unicorns or not, for the SDI Solo certification you will need one. That is a pony bottle, unicorns, not so much.

N

The OP might not realize that SDI Solo requires 100 or more dives beyond AOW before you can even take the class.
 
I've done SM for Intro cave. I dive a 13 or 19 solo boat. I can get 2 normal ascents from a 19.

Can you just imagine the chaos on the average recreational dive boats if all divers with ponies switched to doubles/SM?

Again, this will all depend on the OP's planned diving environment.

there'd be one less bottle per diver on the boat though....
 
I really should keep my mouth shut, but maybe someone can show me where I am wrong. I respect tbone's experience and comments, but this one seems to be written out of emotion or bias.

basically what they said above. I sit firmly in the camp of "rely on your buddy because that is what you trained and planned for", if you don't want to/can't rely on your buddy, dive doubles, sidemount, etc. Yes they're bigger/heavier, but it's the same amount of equipment to carry around total, and you don't have to swap tanks out, nor do you have a finite amount of time.

These must be magical tanks and i would have used these as my primary rather than my backup since they have unlimited air.:D


My biggest issue with pony's is most people that I have been around use pony's that are way too small. I would not dive a pony smaller than an al30, ideally an AL40 because of the buoyancy characteristics, but 30 is the bare minimum for me to be comfortable with a completely normal ascent. "oops, my first stage exploded, oh well, I'll switch to pony and just call my dive from here and if I see something cool on the ascent, I can stop for a minute and look at it without worrying". If I'm going through the hassle of doing that, I would rather dive doubles where I don't have something clanging around on my left side etc.

Also, if you are using the other tank as a backup, (and I am assuming here) that that tank is not used in you dive calculations since it is a backup, why would you "stop for a minute and look". I'm making a big stretch here so don't read too much into it, but I am now on my backup, called my dive, I'm on my way up. Do not pass go, do not collect $200.

I have a 19 cf pony that I sling for one reason only: "if something goes pear shape I have a completely redundant air source to get me or my buddy up from 100'. MAX"

A couple points here (so correct me if I am wrong)
- I don't use the pony in my dive planning calculations
- at my RMV and if max planned is 100 ft (typically less than 80 ft) my 19 will give me 15 minutes of air and that is using a conservative factor to allow for higher RMV/SAC (choose your poison) for a nice controlled safe accent with a safety stop.
- buoyancy characteristics aside, I don't find the 19 to be intrusive or affect my diving.
 
The AL30s and AL40s are definitely the way to go, but I wouldn't dump on AL19s too hastily. They make great travel ponies and the cost of the bottle is just one part of it. You can always buy extra bottles for one set of regs and rigging.

There's a thread in the accidents forum here on SB (Bonaire Close Call) where a diver had a 2nd stage flood. Buddy was 20ft away but both were fighting a current. Diver panicked, did a 60 ft CESA, and got bent despite only 10 min bottom time. User error - didn't reach for own octo. But what if it were a first stage failure and the octo was also flooded? Then the CESA was the correct decision.

A pony is simply entry-level redundant air. Buy a good reg and that can be used for sidemount down the road. Buy a good bottle and that can be used for deco down the road. Don't get a "pony kit" because it'll just be a one-trick... pony.
 
@jzipfel it depends on how much reserve you have. I believe in Rock Bottom calculations mostly and if I do the calculation at 100ft with a sac of 1, I get 20cf needed. I always reserve at least 500psi in my tank for regulator performance. Where I disagree is 1 minute to assess, I prefer at least 3 mins so you can get to the other end of the wreck, or calm a buddy down, or whatever you choose to do. If I were to dive with a pony bottle, I would use that as my source of air, i.e. no octo on my back gas regulator which means I need that to have enough time at the bottom for me to stabilize everything. AL40 is the minimum I would go with for a pony bottle because even following the Dive Nerd calculator, you need 34cf to get up. No problem, an AL40 will suffice and cut it close. That said, if my regulator explodes and I'm on my pony and I have an AL40, but only diving to 100ft where that calculator says I need 20cf, if I'm on that bottle and everything is going fine except my regulator blew up, then I'll do my ascent as normal because my pony bottle will have at least as much gas in it as my backgas tank would have if it didn't blow up so why change your ascent plan? Only time I have a "do not pass go, do not collect $200" moment is if someone thumbs the dive *we always use the turn around sign to start an ascent unless in an emergency*. A failed primary regulator to me is something that immediately causes the dive to end, but if you have ample gas and you go up from 100ft to 60ft and there is something cool at the top of the wreck, I have no issue stopping for a minute or two. That said, I'd be diving doubles on that dive and not have to worry about it, but I have buddies that use pony bottles and that is something you have to discuss and weigh against your personal risk aversion.
 

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