Pony Bottle setup

[Jorgy]

I have a 19 CF pony......

First a button gauge, too small and hard to read........

Small OMS gauge on 6" HP hose - worked well but made a "big" clump of stuff at the top of the tank, I sling my pony on my left side and I run my back gas gauge under my arm and clip it on my D-ring, so with my pony gauge it meant two gauges right next to each other........

So I settled on a 1" gauge - see picture below, large enough to read but small enough to not be in the way.........

I top off my pony every time I fill my tanks......I take a few breaths of the tank on each dive to check it works and practice deploying it.......so I loose a bit every dive......

My LDS tops them off for free, so it is no big deal........

Hope this helps...........M

 

[elan]

The OP has clearly mentioned that he is rigging a bailout bottle. Readability of the gauge is irrelevant under water. It's only used to check if you have enough gas or not to bailout while preparing for a dive. You do not include bailout bottle into the dive gas calculations so knowing the current pressure of the bailout bottle is useless. Once **** hits the fan you just start your bailout. There is no point of looking at the gauge

 

[bamamedic]

I understand your point, but at least for me, it would be kind of nice to have a pressure gauge that's readable underwater....particuarly on a deeper dive, when trying to decide if one has enough gas to stay for a safety stop.

 

[AndyNZ]

The OP has clearly mentioned that he is rigging a bailout bottle. Readability of the gauge is irrelevant under water. It's only used to check if you have enough gas or not to bailout. You do not include bailout bottle into the dive gas calculations so knowing the current pressure of the bailout bottle is useless. Once **** hits the fan you just start your bailout. There is no point of looking at the gauge

There are two school's of thought on that - my personal view is that there is every point in looking at the gauge.

For example, you may have forgotten to close the tank valve during the dive and a small freeflow has led to you having half a tank... so 6 cu ft of gas (the same size as my drysuit inflation bottle!). You are at 30m, is 6 cu ft enough to get you up? Do you end the dive, do you close the tank valve and go shallower to a depth where 6 cu ft is enough.... and so on.

Another example, you've bailed out and an ascent... a 13 cu ft is woefully small in my opinion. Is it better to be able to see the gauge and how fast it is dropping (so you can either vary your ascent rate or relax your breathing)or would you rather you just run out of gas half way up?

There is no definitive answer as to whether or not you should be able to see the gauge or not - you are correct, as am I. We make a choice to decide what to do - but simply telling someone what to isn't giving them the option of informed choice!

 

[idocsteve]

I understand your point, but at least for me, it would be kind of nice to have a pressure gauge that's readable underwater....particuarly on a deeper dive, when trying to decide if one has enough gas to stay for a safety stop.

The idea is to have enough gas remaining in your primary tank for the safety stop, which should be considered mandatory for dives greater than 60 feet.

 

[AndyNZ]

The idea is to have enough gas remaining in your primary tank for the safety stop, which should be considered mandatory for dives greater than 60 feet.

If you've had to bail out, thanks say to a catastrophic equipment failure (tank neck o-ring... rare but possible), you're relying on the pony.

Yes, you should size your pony so that it contains enough gas to do the ascent and a safety stop... but you can only size it on the basis of a best gas of what your stressed SAC rate is.

If you can see the gauge, you can choose to shorten or extend your safety stop depending on what led up to the bail out. If you can't see your gauge, you're just shooting blind.

 

[bamamedic]

The idea is to have enough gas remaining in your primary tank for the safety stop, which should be considered mandatory for dives greater than 60 feet.

I guess I just assumed that if I'm bailing to my bailout bottle, that something horrible has happened to my primary tank (massive freeflow, alien zombies stealing my gas, oh, I don't know) and I'm stuck having to ascend on my bailout bottle...thus, having to complete a safety stop on my bailout bottle.

 

[idocsteve]

If you've had to bail out, thanks say to a catastrophic equipment failure (tank neck o-ring... rare but possible), you're relying on the pony.

I guess I just assumed that if I'm bailing to my bailout bottle, that something horrible has happened to my primary tank (massive freeflow, alien zombies stealing my gas, oh, I don't know) and I'm stuck having to ascend on my bailout bottle...thus, having to complete a safety stop on my bailout bottle.

I see your points.

 

[elan]

I understand your point, but at least for me, it would be kind of nice to have a pressure gauge that's readable underwater....particuarly on a deeper dive, when trying to decide if one has enough gas to stay for a safety stop.

If you include your pony into the gas calculations for the dive it's a bad thing IMHO. You suppose to have enough gas in your main tank to be able to ascend from any point of your dive together with your buddy breathing harder than usual.

 

[idocsteve]

If you include your pony into the gas calculations for the dive it's a bad thing IMHO. You suppose to have enough gas in your main tank to be able to ascend from any point of your dive together with your buddy breathing harder than usual.

I made the same assumption you did when reading the post you and I both quoted.

That's true in a nonemergency routine dive situation, as opposed to an emergency that has depleted your primary much sooner than expected.

Read the three posts above yours, it's clarified rather well.