Yet ANOTHER pony tank question

[GrumpyOldGuy]

Remember to consider the buoyancy of a pony plus the extra regulators.

Bingo!

My AL ponies are all negative full with the regulators mounted and pretty close to neutral when empty. By the time I suck the pony empty, being a bit positive would be the least of my worries.

 

[scuba=dude]

I am not sure that I follow you - a larger pony requires more lead? Because of air consumption? If a pony is contingency air only to be used in emergency then you will (hopefully) not need it and there will be no swing in buoyancy from the pony.

OK It's like this (the way I see it) if you have gone and run out of air and you are at depth then you will start to use the air in that pony thank, now lets say that you REALY boned it good and you are deep........so you stayed to long , you must have your out of air, so you wil have to do some kind of Deco or safty stop for those that don't like the word deco. If you are not leaded down right you are going to flote to the top........now lets say that you don't run out of air but have some other porblem that has you bearthing from your pony, lets say that you have not been to deep depth and you are not under wieghted and you get to the top but you feel that you need more flowtion then you can inflate your BCD with the mouth pice on your inlfator or/and drop weights.....you don't have to drop all the lead if you don't need to just the amont you need to stay on the top. One way or the other you realy need to have your rig set-up in a maner that if you are at 15 to 20 feet underwater with neer NO Air you will NOT go right to the top. You carry a pony thank cuz you wish to be safe from some of the What Ifs then go the hole mile with it....what good would it do you to have the air but get bent cuz you didn't do the rest of the work to have a trully safe set-up?

 

[BEM]

I have an AL 19 and there is a steel 23 cuft high pressure that is approx the same size and weight (Faber) I'd go with the steel.

 

[pixelpixie]

I'm not planning on using the gas in the pony. It would be an emergency reserve for me or a buddy, but if I did need to use it, the Al80 will be empty and positive, so now I'd have two balloons. Factoring in xtra reg...good point.

 

[scuba=dude]

I have an AL 19 and there is a steel 23 cuft high pressure that is approx the same size and weight (Faber) I'd go with the steel.

For sure you would not have a "lift" if you used most all the air from it.....however you would allways be a good bit neg and unless you have your own air compressor you may have a hard time getting filled to "high pressure" as more then a few shop's will only go to 3000pis, But steel tanks do have some pluses that Al tanks do not. For one they don't go positve when you get to the bottom of the tank and you can get more air into one (for the same size) and they last longer then the AL tanks. But the biggy here is can you get them filled to the PSI they can handle? If you can cool, if not bummer... If not then you will have a tank that can hold more air then you can get pumped into it and be a good bit negative to boot.

 

[Crush]

OK It's like this (the way I see it) if you have gone and run out of air and you are at depth then you will start to use the air in that pony thank, now lets say that you REALY boned it good and you are deep........so you stayed to long , you must have your out of air, so you wil have to do some kind of Deco or safty stop for those that don't like the word deco. If you are not leaded down right you are going to flote to the top........now lets say that you don't run out of air but have some other porblem that has you bearthing from your pony, lets say that you have not been to deep depth and you are not under wieghted and you get to the top but you feel that you need more flowtion then you can inflate your BCD with the mouth pice on your inlfator or/and drop weights.....you don't have to drop all the lead if you don't need to just the amont you need to stay on the top. One way or the other you realy need to have your rig set-up in a maner that if you are at 15 to 20 feet underwater with neer NO Air you will NOT go right to the top. You carry a pony thank cuz you wish to be safe from some of the What Ifs then go the hole mile with it....what good would it do you to have the air but get bent cuz you didn't do the rest of the work to have a trully safe set-up?

IMHO it is better to be bent on the surface than drowned at depth. My pony is an emergency reserve that does not factor into my planned dive. I don't weight for an empty pony for several reasons:

1. I don't plan to use the air since I don't plan to run out of air;
2. I don't plan to go into Deco, therefore I can afford to blow my safety stop at 15 ft. Now, I always DO my safety stop, but it is not required;
3. I do not plan to be far away from my buddy on challenging dives; and
4. I do not plan to combine items 1, 2, or 3 (above) in any manner.

I am not saying that my logic is perfect, but it is how I have decided to dive.

 

[GrumpyOldGuy]

Scuba Dude,

You trying to make an issue over an insignificant value. The buoyancy swing in a typical AL19 pony is 1.3 pounds from full to empty.

If this affects someones ability to do their stops, then they should not be using a pony....or scuba in general.

 

[Hatul]

I'd go with aluminum for pony based on a theoretical reason. You don't normally use and replenish the air in the pony, and there have been reports of steel tanks sitting for a long time with oxygen consumed from the tank in the process of corrosion inside.

Adam

 

[MC]

I'd go with aluminum for pony based on a theoretical reason. You don't normally use and replenish the air in the pony, and there have been reports of steel tanks sitting for a long time with oxygen consumed from the tank in the process of corrosion inside.

Adam

I was hoping this thread would not get into a "pony safety argument" but it kind of went that way.

long story short. I can and will be buyign 13cf ponys. my choice either aluminum or steel. Your thought makes sense, but I'm kind of differernt. We "empty" our ponys very often.

so back to the topic-
If you were to chose, steel or aluminum? Any benefit for hydro dates?

 

[GrumpyOldGuy]

I was hoping this thread would not get into a "pony safety argument" but it kind of went that way.

long story short. I can and will be buyign 13cf ponys. my choice either aluminum or steel. Your thought makes sense, but I'm kind of differernt. We "empty" our ponys very often.

so back to the topic-
If you were to chose, steel or aluminum? Any benefit for hydro dates?

I go for AL pony tanks...
1) They are much more cost effective than steel.
2) The amount of oxidation seems to be less than steel
3) They are close enough to neutral so you don't need to readjust ballast if you change your config or hand off the pony to a buddy.

Hydro dates should be the same for steel or AL.

For a primary tank in cold water the added cost of a steel tank is a good investment. I don't believe this is true for a pony. My 2 cents.