using a pony bottle to extend bottom times?

[DJ457]

All,
This may be a really dumb question but what are the views or thoughts on using a 40cf pony slung on the side to extend bottom times but staying safely within recreational limits? Here is the reason I ask. As of right now, I am a gas hog. I definitely have been working on my breathing, maintaining better buoyancy throughout the dive...etc. to help BUT I never seem to come even remotely close to NDLs. For example, 100ft dive on air NDL is 20min per tables and 16min per my dive computer. Any time I have dove to 100ft I have started my accent at 11-13min into the dive (about when my aluminum 80 is at 1100psi) and I reach the surface with 600psi (this includes a 50ft 3min stop and a 15ft 3min safety stop). So instead of buying a larger tank or doubles...etc, why not use the 40cf pony I already have? I tow this pony for safety anytime I dive deeper than 60ft. Why not use the air at the end of the dive to slightly extend bottom times? just curious, not that I would actually do this. Please don't make this a bashing thread and yes I am saving for doubles and continued training. Again just curious.

I usually dive with an OMS steel LP112. I would never do a deep dive with an AL80. I use a pony bottle as well (40cf). The pony I'm using is not to extend my bottom time, but as a backup air supply if something should go wrong with my primary system. I never do any deep dives on my own, but some of the buddies I dive with are not the best and I don't trust them in an emergency situation. In July I'm doing the PADI self reliant diver specialty, so I'll use the pony on all my solo dives just in case of an emergency. Not to increase bottom times.

Like everyone has said, look at possibly getting a steel 100 at least. Also, slow your roll! Your air will last a lot longer, and you get to enjoy your dives more too.

 

[Wookie]

So Wookie. If a diver on your boat decided to sling a 40, start the dive by breathing it down to a set level, switch to back gas and finish the dive, all to a predetermined dive plan, you would have an issue with this?

Yes. If the 40 is your pony, that isn't what it's for. If it's your stage, we don't allow stages or doubles on recreational trips. We do have trips where stages and doubles are welcome. Single tank trips are not those trips.

 

[uncfnp]

Yes. If the 40 is your pony, that isn't what it's for. If it's your stage, we don't allow stages or doubles on recreational trips. We do have trips where stages and doubles are welcome. Single tank trips are not those trips.

Understood. Thanks for clearing that up for me.

 

[Yoyoguy]

Yes. If the 40 is your pony, that isn't what it's for. If it's your stage, we don't allow stages or doubles on recreational trips. We do have trips where stages and doubles are welcome. Single tank trips are not those trips.

seriously not trying to start a war here but what if one guy showed up with a single 100 steel and his buddy had an 80 and a 30cf stage...both want to do recreational dive...you are saying the guy with the 100cf steel is ok but his buddy with an 80cf and a 30cfstage is not? I am just playing devils advocate here.

 

[Doppler]

seriously not trying to start a war here but what if one guy showed up with a single 100 steel and his buddy had an 80 and a 30cf stage...both want to do recreational dive...you are saying the guy with the 100cf steel is ok but his buddy with an 80cf and a 30cfstage is not? I am just playing devils advocate here.

Simple question for you... have you ever dived off the Keys when the current is blowing and you are entering and exiting the water fully kitted? If you look at Frank's profile, you'll see that's where he operates.

 

[RJP]

I have never understood why anyone uses a 40 for a pony on recreational depth dives but that is another thread, in fact several.

So that you only need to buy one "extra tank" which can serve as a pony now and deco bottle later in your dive career.

 

[Eric Sedletzky]

Some people just have a naturally higher SAC rate than others, and to be fair maybe you're one of them. There's nothing wrong with that and that's what bigger tanks are for.
You might just be too big to use an 80 to do those types of dives. Consider going to a 100 or a 120/130
or you could double up a couple 72's on your back or go side mount.
A pony should only be used as an emergency bailout and your dive should be planned with your primary supply including enough for your buddy if there was an OOA situation. The pony should be for unforeseen and catastrophic mechanical failure of your primary system.
A stage bottle is a different thing than a pony, at least in theory and practice.
At least that's what I was taught.
To me a 40 seems a little big for a bailout just doing recreational dives. A 30 would be a little less bulky and you might even be able to use something smaller. It's just supposed to get you to the surface safely with no unnecessary doddling.

 

[uncfnp]

So that you only need to buy one "extra tank" which can serve as a pony now and deco bottle later in your dive career.

I know. I see this all the time but I guess I'm more of the right tool for the job kinda gal. And for me it's worth buying two tanks. Not to mention another chance to buy more gear!

 

[Eric Sedletzky]

Yes. If the 40 is your pony, that isn't what it's for. If it's your stage, we don't allow stages or doubles on recreational trips. We do have trips where stages and doubles are welcome. Single tank trips are not those trips.

OK, I have a question though, what if someone showed up with a set of doubles like twin 72's but only had one air outlet like a center post and treated the set like a big single. But let's say they like the balance of the twin 72's and buoyant characteristics better that say a modern mega single tank the size of a water heater. Would you consider that to fit the recreational criteria?
Because if they were filled to 2250 then that would be basically like a 130.

 

[nimoh]

I know. I see this all the time but I guess I'm more of the right tool for the job kinda gal. And for me it's worth buying two tanks. Not to mention another chance to buy more gear!

the difference of slinging a 19 and a 40 in the water is pretty negligible. Carrying them out of the water is about an 8 pound difference. So, a 40 is a good tool for both jobs. Not to mention that it frees up money to buy more gear!

---------- Post added June 30th, 2015 at 02:29 PM ----------

OK, I have a question though, what if someone showed up with a set of doubles like twin 72's but only had one air outlet like a center post and treated the set like a big single. But let's say they like the balance of the twin 72's and buoyant characteristics better that say a modern mega single tank the size of a water heater. Would you consider that to fit the recreational criteria?
Because if they were filled to 2250 then that would be basically like a 130.

answer seems pretty clear to me... he said "we don't allow stages or doubles on recreational trips". It's not even an unreasonable rule.