Pony bottle questions

[Freewillow]

Thanks guys, I got it

 

[Roman_66]

Tank Buoyancy - Full Buoyancy (500 psi) Weight Empty Outside Diameter Cylinder Length

AL19 -1.9 lbs -0.7 lbs 7.85 lbs 4.38 in 17.25 in

AL30 -2.0 lbs -0.1 lbs 12.3 lbs 5.25 in 19.48 in

From my point of view, the real different is only 4.5 lb outside of the water.
19cu should be enough to go to surface from recreation deep for ONE diver, so it more personal choice I think.

 

[NAM001]

LowDrag
You are going to need a 3rd regulator. The pony is not a substitute for the 2nd reg on your primary tank. Think of it this way if you pass your pony to your buddy. you no longer have a backup reg with you. The pony is not part of your gas planning. I look at it as "the pony is my replacement for my buddy" I am sure many would argue that point, however it is a good buddy replacement for an OOA event. dont get a small pony get a 30 or 40. They are not that big and they sling nice. I find the 13 or 19 is a tough thing to sling. You only have about 75% of the contents that you can use, so using one below 500 psi could be a real risk. Grossly saying,,,, you need 200 psi to make your reg work normal, and a gage error of 10% on the extreem of the gage is not uncommon. Next any issues at depth will triple gas consumption till all calms down. So .5 sac at 100 ft is now 2 and tripple that and you are sucking 6 cu ft. NOt much more than 1 minute on a 13 cu ft pony, 2 min on a 19 4 on a 30 and 6 on a 40. (worst case. ) So now what does that insta buddy use. And where is he when you need him? Go for the 30 or 40.

 

[redacted]

I found that an Al13 will safely get me back to the surface from any recreational depth, but there may be little to spare. The big advantage to that smaller pony is it can be pack in your luggage for air travel without blowing your weight allowance. My Al19 is more than enough air with a nice cushion. I have seen some folks take them on air travel but that starts to push it. An Al30 makes sense if you are not going to fly. I have seen some live-a-boards that do not allow anything bigger than a 30.

Tank mount is a PITA if you have to change tanks and may not fit in some tank racks. Slung is easier to manage.

I have never understood why a good diver with an adequate redundant gas supply is expected to double his consumption just because he uses his pony or why you can't breath it dry if needed. I have breathed all my regs down to below IP where breathing gets noticably difficult just to know how my regs and gauges work. But I guess you need to have a good idea of how you will respond when the fit hits the shan.

 

[DENLASCUBA]

I use a back mount 4 ltr steel bail-out which puts me about 1.5-1.75 kg over weight but I only use 1 kg anyways so it puts me just slightly over. I like the back mount more for terms of getting out of the water, but the tank wants to pull me on my back once I am bouyant on the surface. Also some boats may require you to switch tanks in between dives and generally where I am the boat crews will do that, but if you have a back mount most likely they will not want to be the one to take the bail-out off and reattach it once the tank is changed over.

If you go with back mount then you will also need to decide what type of mount you want. I liked my previous pin and plate mount but this was a permanent mount as I never had my tanks changed out since I was on the boat everyday working. This type uses stainless steel bands to hold one piece to the primary tank and another to the bail out, then you have a locking pin to hold the two together. This felt a bit more stable.

I then switched to a similar mount but instead of mounting the plate to the main cylinder with stainless steel bands it used a cam band. For both mounts I found the pins starting to corrode and also the bands even with constant cleaning with fresh water.

I switched to a mount that has one solid AL plate that acts as the mount for both tanks and is held to the primary by cam band and then to the pony with a smaller cam band. Since I am not on one bost permanently this worked out best but sometimes if you try to move be it while on the boat it does not feel as secure as the other options and it also has a slightly higher profile.

 

[BugHunterNY]

I found that an Al13 will safely get me back to the surface from any recreational depth, but there may be little to spare.

Where do you dive that you can make this statement? "Recreational" depth could be 130ft. So if you're around 100-120 ft, maybe a 5 minute swim from the anchor line, well, this 13cuft is just NOT going to cut it...

Maybe if you're in a warm water, shallower than 100ft, this will get you to the surface - but quite honestly, the 13cuft tank is an illusion of safety, and in a true emergency, in many situations it is not enough. 19 is barely enough. 30 is a much, much better choice. There is actually no choice - for OP - I don't know your diving patterns, but get the 30 or 40. You'll end up buying one eventually anyway!

I have never understood why a good diver with an adequate redundant gas supply is expected to double his consumption just because he uses his pony or why you can't breath it dry if needed. I have breathed all my regs down to below IP where breathing gets noticably difficult just to know how my regs and gauges work. But I guess you need to have a good idea of how you will respond when the fit hits the shan.

Have you breathed these regs down at depth? They will breath down to empty at the surface much differently than underwater. You may be able to drain a tank at the surface, but on the bottom, they will stop breathing much sooner...



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[dumpsterDiver]

Where do you dive that you can make this statement? "Recreational" depth could be 130ft. So if you're around 100-120 ft, maybe a 5 minute swim from the anchor line, well, this 13cuft is just NOT going to cut it...

Maybe if you're in a warm water, shallower than 100ft, this will get you to the surface - but quite honestly, the 13cuft tank is an illusion of safety, and in a true emergency, in many situations it is not enough. 19 is barely enough. 30 is a much, much better choice. There is actually no choice - for OP - I don't know your diving patterns, but get the 30 or 40. You'll end up buying one eventually anyway!



Have you breathed these regs down at depth? They will breath down to empty at the surface much differently than underwater. You may be able to drain a tank at the surface, but on the bottom, they will stop breathing much sooner...



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I agree that if you have to swim for 5 minutes on the bottom before you can begin your ascent from 120 feet a 13 cu-ft bottle is not going to cut it. I'm not even sure if a 30 will work, i will let you do whatever calculations you think you need to determine that.

HOWEVER, why swim for 5 minutes to an anchor line - when you have a true emergency? If you are diving recreational profile, no deco, why would you not begin the ascent immediately? Is it so dangerous to just come up? What are the consequences of that decision? Is it so bad that you would rather swim for 5 minutes at 120 and load yourself up with nitrogen and CO2 and then have to ascend with no redundancy.. since presumably your primary has failed?

I think it is important for everyone to determine what procedure they will follow when a bail out occurs. My general response is going to be go UP.. right away.

 

[redacted]

Where do you dive that you can make this statement? "Recreational" depth could be 130ft. So if you're around 100-120 ft, maybe a 5 minute swim from the anchor line, well, this 13cuft is just NOT going to cut it...

Maybe if you're in a warm water, shallower than 100ft, this will get you to the surface - but quite honestly, the 13cuft tank is an illusion of safety, and in a true emergency, in many situations it is not enough. 19 is barely enough. 30 is a much, much better choice. There is actually no choice - for OP - I don't know your diving patterns, but get the 30 or 40. You'll end up buying one eventually anyway!



Have you breathed these regs down at depth? They will breath down to empty at the surface much differently than underwater. You may be able to drain a tank at the surface, but on the bottom, they will stop breathing much sooner...



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Mostly warm water in TX and south. I have run my 13 from about 90 ft, made a very slow ascent, did a 5 minute rest stop, and back onto the boat. No, I would not be looking for a line with the 13 - it would be a direct ascent. An AL13 is the same as 500 psi in an Al80. Most divers can do a lot with that. An AL19 is the same as about 750 psi in an AL 80. If it is not too far, I would take that to an anchor line.

I think a tank is going to stop breathing completely (at depth) whenever the pressures inside and outside are the same. And If the inside pressure is about 150 psi gauge (regardless of depth) it will breath pretty much normal with balanced regs. My unbalanced 1sts (on my pony) give a bit more warning as gauge pressure falls below 500 psi. While consumption rate will increase with depth, performance is not effected very much within recreational depths. But I am diving an original Scubapro Pilot so that is what should be expected. Although my Balanced Adjustables are little different.

Why do you say they will breath down differently at depth, or are you simply referring to the usage rate? I really have no use for a 30 or 40. If I just want more gas, I can sling a 63 or an 80.

 

[BugHunterNY]

I agree that if you have to swim for 5 minutes on the bottom before you can begin your ascent from 120 feet a 13 cu-ft bottle is not going to cut it. I'm not even sure if a 30 will work, i will let you do whatever calculations you think you need to determine that.

HOWEVER, why swim for 5 minutes to an anchor line - when you have a true emergency? If you are diving recreational profile, no deco, why would you not begin the ascent immediately? Is it so dangerous to just come up? What are the consequences of that decision? Is it so bad that you would rather swim for 5 minutes at 120 and load yourself up with nitrogen and CO2 and then have to ascend with no redundancy.. since presumably your primary has failed?

I think it is important for everyone to determine what procedure they will follow when a bail out occurs. My general response is going to be go UP.. right away.

As I said, not sure of Op diving conditions, but in NorthEast where I dive - a free ascent could be just as bad as no gas (floating away into the Atlantic...)

I think it's a fair assumption, for a diver who is just starting to use a pony, shooting a bag and tying it off to the bottom as an emergency up line is not a skill they're proficient with.

I may be taking some liberties here, but there are many places a free ascent is not possible. Personally, I'd take the bottom swim back to the anchor and empty whatever gas I have to do that and breath as long as possible on the anchor, rather than risking a free ascent where i might end up a mile+ from the boat, in potentially seas and weather where they can't see me!

Mostly warm water in TX and south. I have run my 13 from about 90 ft, made a very slow ascent, did a 5 minute rest stop, and back onto the boat. No, I would not be looking for a line with the 13 - it would be a direct ascent. An AL13 is the same as 500 psi in an Al80. Most divers can do a lot with that. An AL19 is the same as about 750 psi in an AL 80. If it is not too far, I would take that to an anchor line.

I think a tank is going to stop breathing completely (at depth) whenever the pressures inside and outside are the same. And If the inside pressure is about 150 psi gauge (regardless of depth) it will breath pretty much normal with balanced regs. My unbalanced 1sts (on my pony) give a bit more warning as gauge pressure falls below 500 psi. While consumption rate will increase with depth, performance is not effected very much within recreational depths. But I am diving an original Scubapro Pilot so that is what should be expected. Although my Balanced Adjustables are little different.

Why do you say they will breath down differently at depth, or are you simply referring to the usage rate? I really have no use for a 30 or 40. If I just want more gas, I can sling a 63 or an 80.

They breath differently because of ambient water pressure. You cannot just assume that if you can breath down to 150 psi at surface, you'll be able to get that same amount at depth. Besides the fact that those margins are way too close to "count on". There really shouldn't be any circumstance where you drain tanks that low - that is the point of planning a dive / diving a plan - the point of contingency planning is to manage gas and dive so that even in worst case scenarios - you are not approaching an empty tank..ever.


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[DENLASCUBA]

To add on to dumpster diver sorry don't want to fill the thread with quote after quote.

What if you run into a current on your way back to the anchor line, if your on your bail-out you should be heading up to the surface, if your worried about not being seen by the boat crew you should have an smb and or audible device.