What size pony?

[Buccaneer]

well, I am thinking about doing some solo diving, and want to get set up w/ a pony bottle. my question is, what size is best for solo diving? personally, i am leaning towards the 13CF, but it seems like everyone uses a 19 or even 30CF bottle. Personally I prefer the smaller size, and don't plan on using it as a "dive extender" it's sole purpose will be a bailout bottle in case of primary failure. I think I will not even bother with a bracket. just simply sling it on my side attached top and bottom to d-rings on my bc. I am just not sure if it is enough air. i know depth/breathing rate has a big effect- any reasons I should consider the larger bottles??

 

[jagfish]

Hey Buc
Well, since I am probably one of the few people who is awake right, now, I'll say hi. I think your thread might attract some negative posts from those against solo diving and those against pony bottles. I am against neither.

There are some excellent threads in the past that outlined pony bottle size as compared to anticipated dive depth. I am sorry that I do not have the link handy, but it was calculated using hypothetical ascents plus safety stop from various depths. Without running the numbers, I'd say the 13 cf would likely be adequate air for 60 ft or less depending on your SAC, but you should check on that yourself. Find or estimate your SAC, from a desired depth, calculate the time to safety stop at 30 or 60 ft/mon, then air to be used at safety stop, then ascend the rest of the way up. Depending on your conservatism, you might want to build in a cusion as well. The deeper you would want to go, the larger bottle you would need for a safe return.

Dive safe
JAG

 

[wedivebc]

well, I am thinking about doing some solo diving, and want to get set up w/ a pony bottle. my question is, what size is best for solo diving? personally, i am leaning towards the 13CF, but it seems like everyone uses a 19 or even 30CF bottle. Personally I prefer the smaller size, and don't plan on using it as a "dive extender" it's sole purpose will be a bailout bottle in case of primary failure. I think I will not even bother with a bracket. just simply sling it on my side attached top and bottom to d-rings on my bc. I am just not sure if it is enough air. i know depth/breathing rate has a big effect- any reasons I should consider the larger bottles??

Hey Buccaneer,
There is a lot of very good reasons for solo diving which is why SDI developed a training program to teach you how to do it safely.
It isn't as simple as just strapping on another tank and go. There is a lot more to it such as navigation skills, bouyancy, complete self sufficiency and most important, filing a 'flight plan' with someone.
This is one of the most popular courses I teach and there are a huge number of solo divers who won't admit it publicly for whatever reason.
The other advantage of solo certification is the less hassle you would have with the insurance company in the event of an accident because you would be diving within your training level.
Now to your question. The course would answer that for you because it is based on several variables such as planned depth and RMV (breathing rate). Chech out http://sditdi.com/ for more information.

cheers,

 

[saintsfan]

I agree with jagfish about the negative responses about solo diving,you will get some.I have done a few solo dives and I do feel more safe with a pony,13cuft,worse case I wont have to shoot to the surface,best case i can do my deco stops.I have a pony bag or case that straps to the right side of my main tank valve down,you will have to shift aprox 1lb of weight from the right to left do to the ponys weight,for example i had 4lbs in each rear pouch now i use 3 in right and 5 on left.at first I didnt care for the pony but now on deep or solo dives I dont leave home without it.

 

[mjh]

Hey I have no problem saying it: I solo dive and I like it! Been many threads on this so I will just say I dive with a 30cf pony. I dive almost all open water some limited structrue or wreck. In case of some problem I want a backup that will give me time to resolve the problem, not just enough air to get to the surface.

 

[NEWreckDiver]

well, I am thinking about doing some solo diving, and want to get set up w/ a pony bottle. my question is, what size is best for solo diving? personally, i am leaning towards the 13CF, but it seems like everyone uses a 19 or even 30CF bottle. Personally I prefer the smaller size, and don't plan on using it as a "dive extender" it's sole purpose will be a bailout bottle in case of primary failure. I think I will not even bother with a bracket. just simply sling it on my side attached top and bottom to d-rings on my bc. I am just not sure if it is enough air. i know depth/breathing rate has a big effect- any reasons I should consider the larger bottles??

If you think you might be in a situation where a pony bottle makes since to have, Then go with a 30cf. You want to make sure that it has enough volume to get you out of a tight spot should you need it.

Good luck to you.

 

[MXGratefulDiver]

If you think you might be in a situation where a pony bottle makes since to have, Then go with a 30cf. You want to make sure that it has enough volume to get you out of a tight spot should you need it.

Good luck to you.

This is something few consider ... you might find yourself in a situation where you have to do something other than simply ascend. Especially as a solo diver, you might have a problem that requires some action on your part prior to beginning the ascent.

There are some rules of thumb you can use to calculate the size pony you'd want to have.

First, you've got to know your SAC rate. Then, based on the deepest depth you plan to dive ...

- Allow gas for one minute at depth to take care of any problem that might cause you to begin an unplanned ascent. In this case, you're probably better off calculating this at twice your normal SAC, since it'll probably be something that catches you off-guard and will induce some amount of stress.
- If you're doing a deep dive, you might want to allow gas for a one-minute stop at half your deepest depth.
- Allow gas for an ascent rate of no more than 30 fpm.
- Allow gas for a standard safety stop.

Add up those four figures, and purchase a cylinder that'll provide you with at least that much gas volume.

And, of course, all of this assumes no overhead or required deco ...

... Bob (Grateful Diver)

 

[hogsniper]

I solo dive often to 130' depths while spearfishing and lobstering. Suunto computer and Nitrox always- to minimize my DCS risks. The most important reading on my computer is my O2 saturation and ascent warning. I do not approach deco requirements but do use 98cf steel tanks with stamped operating pressures of 3400. I do not rely on my pony to get me home. Plenty of air will not help in an equipment failure, but a 19cf pony will get you to the surface. If you are deco diving and are trained to do so, you wouldn't be asking what size tank to use, so don't get yourself in a deco situation where you can't ascend if you need to. My suggestion is to be confident in your skills, buy the best equipment you can afford, dive solo if you are ready and enjoy not having to babysit a partner. I use a 19cf pony and have never needed it, but my partners have grabbed for it over the years because they do not rig their gear for solo diving, they depend on a partner. Don't worry, you can easily get up from 100', do a 4 minute stop at 20' and arrive alive. Rig your gear like you are the only diver for miles. If you partner up or not, your gear is ready to bring you both back. When you rely on a partner to save you, they are usually swimming the other direction chasing fish as has happened to me. They always say the same thing back on the boat, man I was swimming along and you just dissapeared! I will dive solo anyday of the week before relying on a ill-trained, ill-equipped, "partner" that is not watching my back.

 

[Buccaneer]

Thanks for all the feedback! some really good points have been made. As someone suggested, I was planning on attending a solo diver course first, and for reasons of personal comfort I will probably limit my depth to max 60ft. Thanks for the input! I need to refigure my SAC I haven't done it in awhile, then I will make my decision.