Your big fat pony Bottle

[hypertech]

My definitions:

Pony bottle - Seems to be most commonly used by divers who don't practice good buddy skills and want the security of a separate gas supply.

I'll suggest that at least a good portion of the time, it is a diver with good buddy skills who doesn't trust his instabuddy to have the same. In essence they prepare for the dive as if it were a solo dive and if they get a competent buddy, then great.

At least, that's why I got the pony bottle.

 

[Cave Diver]

I'll suggest that at least a good portion of the time, it is a diver with good buddy skills who doesn't trust his instabuddy to have the same. In essence they prepare for the dive as if it were a solo dive and if they get a competent buddy, then great.

I tend to think those two go hand in hand. If I'm paired with an insta-buddy that's lacking in skills, I'm going to call the dive or monitor my gas closely and stay at a depth where I could safely make an ascent in the event of an emergency. YMMV

 

[rob1967]

OK, here is my 2¢ worth:

Bailout bottle: emergency gas to breathe in case of primary reg failure, catastrophic gas loss, re-breather failure, surface supply failure, etc

Stage bottle: a bottle you stage somewhere (i.e.., you leave it at the bottom of the descent line, entrance to cave, etc., for planned use at some point in the dive.

Deco bottle: bottle reserved for decompression stops, usually with a higher percentage of oxygen to reduce deco time.

So these definitions generally agree with what others have said.

I think a pony bottle is a more general term, which could include all of the above.

Therefore, to me a pony bottle is any auxillary bottle, generally smaller than your main cylinder.

Keep in mind that there will also be geographic variations in use of terminology also.


I carry a 40 cu ft pony bottle, but I load it with 50% oxygen. I like to switch to it when ascending from any deep dive, say deeper than 60 ft. Having had an "undeserved" DCS hit, I have to be more conservative. Any diver has the potential to get DCS on any dive. Just staying within recreational limits does not guarantee no DCS. So to me, every dive is a decompression dive. So I guess my pony is a really a deco bottle. I switch to it at around 40-50 ft (don't want to push the O2 too much), and make at least a 5 min safety stop, even longer whenever possible. For example, this past weekend, I did 2 dives to about 110 ft, with 20-30 min safety stops using the 50%, and felt great after, absolutely no post-dive fatigue, but rather that burst of "Nitrox energy".

Sure, some will argue that 50% is not useful in case of OOA emergency at depth, but, hey, everything is a compromise. I don't do overhead environments, so in case of OOA at depth, I am going straight up to 70 ft anyways, so 1-2 minutes of high p02 is far less serious than nothing to breathe.

Sure, the 40 cu ft is a bit big to lug around for a shore dive, and if I am planning a shallow shore dive, a 19 cu ft bottle would be better, but hey, I can't buy every piece of scuba gear I want today.

cheers and happy diving!

 

[Cave Diver]

OK, here is my 2¢ worth:

Bailout bottle: emergency gas to breathe in case of primary reg failure, catastrophic gas loss, re-breather failure, surface supply failure, etc

Stage bottle: a bottle you stage somewhere (i.e.., you leave it at the bottom of the descent line, entrance to cave, etc., for planned use at some point in the dive.

Deco bottle: bottle reserved for decompression stops, usually with a higher percentage of oxygen to reduce deco time.

So these definitions generally agree with what others have said.

I think a pony bottle is a more general term, which could include all of the above.

Therefore, to me a pony bottle is any auxillary bottle, generally smaller than your main cylinder.

You're entitled to your opinion, but I have to disagree with the bolded statement.

Keep in mind that there will also be geographic variations in use of terminology also.


I carry a 40 cu ft pony bottle, but I load it with 50% oxygen. I like to switch to it when ascending from any deep dive, say deeper than 60 ft. Having had an "undeserved" DCS hit, I have to be more conservative. Any diver has the potential to get DCS on any dive. Just staying within recreational limits does not guarantee no DCS. So to me, every dive is a decompression dive. So I guess my pony is a really a deco bottle. I switch to it at around 40-50 ft (don't want to push the O2 too much), and make at least a 5 min safety stop, even longer whenever possible. For example, this past weekend, I did 2 dives to about 110 ft, with 20-30 min safety stops using the 50%, and felt great after, absolutely no post-dive fatigue, but rather that burst of "Nitrox energy".

Sure, some will argue that 50% is not useful in case of OOA emergency at depth, but, hey, everything is a compromise. I don't do overhead environments, so in case of OOA at depth, I am going straight up to 70 ft anyways, so 1-2 minutes of high p02 is far less serious than nothing to breathe.

Sure, the 40 cu ft is a bit big to lug around for a shore dive, and if I am planning a shallow shore dive, a 19 cu ft bottle would be better, but hey, I can't buy every piece of scuba gear I want today.

cheers and happy diving!

Totally agree with the above two bolded sentences.

 

[Trimix2dive]

Heiser 140 - fill with whats needed. OK OK so I use it as a drop bottle for 4 people - it could be a bail out. LOL

 

[NC Wreck Diver]

Generally, that's a generalization.



Round here it's not uncommon to carry a stage bottle for a shallower portion of a multilevel wreck dive in order to extend the dive by switching to a richer mix when coming shallower. Often this offers the opportunity to significantly extend bottom time while avoiding/limiting deco obligation as well:

Here's a dive on the Stolt or Algol here off NJ with EANx 28 back gas...

Dec to 130ft (2) Nitrox 28 50ft/min descent.
Level 130ft 17:24 (20) Nitrox 28 1.35 ppO2, 115ft ead
Asc to 80ft (21) Nitrox 28 -30ft/min ascent.
Level 80ft 30:00 (51) Nitrox 28 0.94 ppO2, 70ft ead
Asc to 20ft (53) Nitrox 28 -30ft/min ascent.
Stop at 20ft 21:20 (75) Nitrox 28 0.45 ppO2, 15ft ead
Surface (75) Nitrox 28 -30ft/min ascent.

Here's the same dive with a staged bottle of EANx 40...

Dec to 130ft (2) Nitrox 28 50ft/min descent.
Level 130ft 17:24 (20) Nitrox 28 1.35 ppO2, 115ft ead
Asc to 80ft (21) Nitrox 28 -30ft/min ascent.
Level 80ft 30:00 (51) Nitrox 40 1.34 ppO2, 53ft ead
Asc to 20ft (53) Nitrox 40 -30ft/min ascent.
Stop at 20ft 3:20 (57) Nitrox 40 0.64 ppO2, 7ft ead
Surface (57) Nitrox 40 -30ft/min ascent.

Certainly worth staging a tank of 40% in order to shave 18min of deco off your hang, especially if the water is cold and/or choppy - which it usually is here.

In fact, staging and switching to 40% at 80ft lets you out of the water faster than if you carried 02 for deco...

Dec to 130ft (2) Nitrox 28 50ft/min descent.
Level 130ft 17:24 (20) Nitrox 28 1.35 ppO2, 115ft ead
Asc to 80ft (21) Nitrox 28 -30ft/min ascent.
Level 80ft 30:00 (51) Nitrox 28 0.94 ppO2, 70ft ead
Asc to 20ft (53) Nitrox 28 -30ft/min ascent.
Stop at 20ft 7:20 (61) Oxygen 1.59 ppO2, 0ft ead
Surface (61) Oxygen -30ft/min ascent.

I agree with this plan that RJP describes. Cutting off your deco obligation makes a lot of sense. Hanging on the line off Jersey can be taxing.

I carry a good amount of gas on each dive. I use doubles for my back gas, and sling a 30 in most cases. This 30 is for emergencies. It's a bailout bottle, or a pony, if that's want you want to call it. I use the same O2 mix in my 30 as my back gas.

If we go deeper or stay longer, we may carry one or two 40's. These are stage bottles, to have plenty of gas for our deco. One may have the same O2 mix, the other is a higher mix (40% max), to shorten our deco.

I can agree that a bottle used by a diver with a rebreather is a 'bailout bottle' too. My buddy uses closed circuit on some of his dives, and it's standard procedure for him to carry his slung 30.

 

[Kern]

Just staying within recreational limits does not guarantee no DCS. So to me, every dive is a decompression dive. So I guess my pony is a really a deco bottle. I switch to it at around 40-50 ft (don't want to push the O2 too much), and make at least a 5 min safety stop, even longer whenever possible. For example, this past weekend, I did 2 dives to about 110 ft, with 20-30 min safety stops using the 50%, and felt great after, absolutely no post-dive fatigue, but rather that burst of "Nitrox energy".

Yep, all dives are deco dives. Some however are no stop dives, & some are staged decompression stop dives. If I do a no stop dive to the limits, I do what some might call minimum deco, but I do that on back gas, & I almost never get out of the water with any fatigue.

On a no stop (MDL) dive I have no need for a deco stage.

 

[hypertech]

I tend to think those two go hand in hand. If I'm paired with an insta-buddy that's lacking in skills, I'm going to call the dive or monitor my gas closely and stay at a depth where I could safely make an ascent in the event of an emergency. YMMV

We'll just have to disagree then. My choice is stay home or be self-reliant. I choose to be self-reliant. Monitoring your gas isn't going to do you any good if your first stage somehow fails closed. It shouldn't happen, but if it does I've got the pony.

 

[Cave Diver]

We'll just have to disagree then.

I'm good with that.

My choice is stay home or be self-reliant. I choose to be self-reliant. Monitoring your gas isn't going to do you any good if your first stage somehow fails closed. It shouldn't happen, but if it does I've got the pony.

Just to be clear, I'm not disagreeing that some people could find a pony bottle useful. I just disagree about the circumstances *I* would put myself in for that to become a reality.