Double Ponies?

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jfrano

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Well I've been diving 130cuft with a 30cuft pony as backup air source.
On my deep dives upto 150ft, what typically happens, is that I'll still have air in my 130, and my deco obligation grows and grows, bringing me up early. So as we begin a new dive season in the North East. I've been giving it some thought for a resolution. One was to hang a deco bottle off the boat, perhaps 80% thus greatly reducing my deco time. I just seem to have misgivings hanging the bottle off the boat. A second though was to carry this additional 30cuft pony. I'm not sure that I've seen this configuration and was looking for thoughts.
 
Thought 1: Get doubles

Thought 2: Get some training.


These two things should answer your questions and make you safer.

Good luck
 
A second though was to carry this additional 30cuft pony. I'm not sure that I've seen this configuration and was looking for thoughts.

Without touching on anything else in your post, slinging more than one stage bottle is not uncommon. Some sling them both on the left, others sling them one on each side depending on their training. But you'd know this if you had advanced nitrox/deco training, right?

One was to hang a deco bottle off the boat, perhaps 80% thus greatly reducing my deco time.

If you're diving 80% and into deco, then you had training on advanced nitrox and deco, yes? Then you should already have covered this in your training. Your profile says nothing, though.

Big question if you have no training and are doing the dives you say you are: if you sling this extra tank, what kind of procedure will you use to be sure you don't get confused and breathe 80% below its MOD?

*Ha, PerroneFord, you beat me to it.
 
Well I've been diving 130cuft with a 30cuft pony as backup air source.
On my deep dives upto 150ft, what typically happens, is that I'll still have air in my 130, and my deco obligation grows and grows, bringing me up early. So as we begin a new dive season in the North East. I've been giving it some thought for a resolution. One was to hang a deco bottle off the boat, perhaps 80% thus greatly reducing my deco time. I just seem to have misgivings hanging the bottle off the boat. A second though was to carry this additional 30cuft pony. I'm not sure that I've seen this configuration and was looking for thoughts.

I dont know how you have your pony configured but it is not uncommon to have multiple bottles slung on your left side with your deco gases.

I am not a GUE-F trained diver but this link is a good picture of what I am talking about.

http://www.gue.com/files/page_images/equipment/Config/rhea_tech02-cayman330.jpg
 
I dive large single steel tanks for deco in around 200 ft and I wear a 13 cu-ft pony back mounted as a bailout bottle and will carry a 30-cu-ft stage bottle of oxygen clipped to the right side of my harness. I often have dead fish clipped off to the left side, so I prefer to have the stage bottle on the "wrong" side.

Not taking your deco bottle with you on an ocean dive is not something that I would consider as an acceptable risk for my own diving.
 
My current pony is strapped to the 130. I know during the advanced deco class we would sling the deco bottle. While that's a possibility, my thought is that I might prefer strapping them both to the 130. I've done double 100's and backed off that configuration after a surgery I had(which is fully recovered).
 
One was to hang a deco bottle off the boat, perhaps 80% thus greatly reducing my deco time. I just seem to have misgivings hanging the bottle off the boat.

Not taking your deco bottle with you on an ocean dive is not something that I would consider as an acceptable risk for my own diving.

Nor mine. If you are relying on that deco bottle, don't put it somewhere that you may not be able to get to when you need it.

Also, why 80%?

A second though was to carry this additional 30cuft pony. I'm not sure that I've seen this configuration and was looking for thoughts.

If they contain different gases (particularly one 'hot' gas), make sure you have a 'foolproof' method of getting the right one at the right depth. As far as I can tell, that means keeping them where you can see them.

Also, given back problems that preclude double 100s, hard mounting two tanks to a heavy single seems questionable. If you sling, you can get wet with just your backgas and have someone hand you the bottles while the water is helping you carry them.

All things considered, hard mounting may not be the best way to go.
 
Thanks...guys. Yes, I added up all the weights, last night, if I were to do this and I'm pretty much back to doubles! I had planned on putting the spare air on my right side as is typical and the deco on my left with second stage on my left, clearly marked with even a weak tie wrap over mouth piece, perhaps as a double failsafe from accidental use. The 80% comes from discussions I had with the dive shop owner some time ago, that the gain from using 100% vs 80% is minimal, especially when you consider the additional toxicity issues.

Hanging a bottle off the boat, is not uncommon in NE wreck diving and has been suggested to me by others. The advantage is of course 30 lbs less physically on me during the dive...maybe I'm just being paranoid.

If anyone does this, can you tell me your experiences pro and con? The web site must be doing well, they had a booth at Beneath the Sea last weekend!
 
Thanks...guys. Yes, I added up all the weights, last night, if I were to do this and I'm pretty much back to doubles! I had planned on putting the spare air on my right side as is typical and the deco on my left with second stage on my left, clearly marked with even a weak tie wrap over mouth piece, perhaps as a double failsafe from accidental use. The 80% comes from discussions I had with the dive shop owner some time ago, that the gain from using 100% vs 80% is minimal, especially when you consider the additional toxicity issues.

Hanging a bottle off the boat, is not uncommon in NE wreck diving and has been suggested to me by others. The advantage is of course 30 lbs less physically on me during the dive...maybe I'm just being paranoid.

If anyone does this, can you tell me your experiences pro and con? The web site must be doing well, they had a booth at Beneath the Sea last weekend!

If I am carrying a gas that might put me into convulsions and kill me, I want to be able to verify what I am breathing. In other words, I want my oxygen rigged as a stage bottle, not back mounted with funky mouthpiece covers.

I also dive from a boat where we hang an oxygen bottle (actually it is now a 20 ft long hose), however this is for safety NOT part of our planned deco. Hanging a deco bottle that you need for cold, dirty water wreck diving is not a good option in my mind. What if you get lost? Do you blow off deco?


The 80% versus 100% issue is not nearly as big of a deal...I prefer 100%
 
https://www.shearwater.com/products/swift/

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