using a pony bottle to extend bottom times?

[JohnnyC]

Doubles do not mean technical diving!

Exactly!

 

[Eric Sedletzky]

There are a lot of us in the PNW who dive doubles on charters, because a) we have them, and b) it saves swapping out tanks on a pitching boat. We dive recreational profiles and respect boat dive times. Doubles do not mean technical diving!

I fully agree and that's why I originally Asked.
It's like going to a party and the host tells people they can only bring a single 24 oz can of beer instead of two 12 oz cans, same difference. I guess the logic would there is only enough room in the refrigerator and only so many coasters.

 

[Nemrod]

I agree with 100ft on an al80 may not be the smartest idea, but such is life.

I do not understand, if 80cf is enough, it is enough. Regardless of the capacity of the tank, if it is enough for the diver to complete the dive with adequate reserves then it is enough. I just did a 109 foot max on the Speigal Grove on 30% and pushed my computer to the edge of the red and was standing on deck with 1200 psi remaining and on an aluminum 80. I recall starting psi at 3200 psi. So I consumed 2000 psi. I followed my Rule of Thirds, 1/3 remained in reserve for emergency.

I do not understand either why the OP would want to use a pony or auxiliary gas that should be reserved for emergency consumption only as part of his supply, but if he calls it a hybrid (back and side mount) asymmetric sized independent doubles set, why not? This is not just a name game, the strategy for air planning an independent doubles SCUBA rig is different considerably from that of an auxiliary bottle augmented SCUBA rig. I think the OP is cheating on himself and is asking for trouble to come knocking.

N

 

[kwinter]

Me: "Runtime?"
He: "Put me down for 180."
Me: "Ok, 80 it is."
He: "No, no... 180."
Me: "Right... 80 min."
He: "No, no... One Eight Zero."
Me: "Ok... if you think you can make it back to the dock in 180 minutes."

They catch on eventually.

This reminds me of a situation where communication was not clear. When asked for my run time I said "one ten". The captain was a little pissed when I didn't come back for almost 2 hours. "One ten" meant 110 minutes, not 1:10.
It pays to be clear.


iPhone. iTypo. iApologize.

 

[nimoh]

I do not understand, if 80cf is enough, it is enough. Regardless of the capacity of the tank, if it is enough for the diver to complete the dive with adequate reserves then it is enough. I just did a 109 foot max on the Speigal Grove on 30% and pushed my computer to the edge of the red and was standing on deck with 1200 psi remaining and on an aluminum 80. I recall starting psi at 3200 psi. So I consumed 2000 psi. I followed my Rule of Thirds, 1/3 remained in reserve for emergency.

I do not understand either why the OP would want to use a pony or auxiliary gas that should be reserved for emergency consumption only as part of his supply, but if he calls it a hybrid (back and side mount) asymmetric sized independent doubles set, why not? This is not just a name game, the strategy for air planning an independent doubles SCUBA rig is different considerably from that of an auxiliary bottle augmented SCUBA rig. I think the OP is cheating on himself and is asking for trouble to come knocking.

N

since your reserve is 1050psi and you were on the deck with 1200psi, does that mean it only took you 150psi to ascend?

edit: Sorry, I think I misunderstood. By "on the deck" I thought you were referring to the Spiegel Grove deck, but perhaps you were referring to the boat on the surface

 

[oldschoolto]

I find the people that don't think he should use the pony , SILLY.... It's a name game... GAS is GAS.... He does his dive plan "KNOWING" he is using 600 psi from the pony/stage/2nd bottle... To make a big deal out of changing out second stages is down right funny... If you can't swap reg's without a problem , you should not be in the water...

My wife uses 500 psi a dive less then me on average, Not uncommon for me to go on her octo for a few minutes to even out the gas and give me a little more back gas for later use if needed.. It's easy and makes sense.. I'll dive my steel 72's and she is on a 80... or we are both on 80's , Or I'll let her use my octo if I'm diving my steel 72's as doubles with a 30 pony old school... It's all just gas management....

Killer...

Edited to add... I don't think using a " SPARE AIR " is good gas management ...

 

[TSandM]

I don't think swapping regs is much of a challenge, but stowing a stage reg can be. And there are a lot of reasons for stowing, rather than leaving the reg around your neck and clipped off, for example. At any rate, the challenges are absolutely solvable by careful practice, and if the OP doesn't do a "stage" dive until he's sure he knows how, I see no problem with it. As said recently above, gas is gas; what you need is a rational strategy for using it.

 

[Nemrod]

since your reserve is 1050psi and you were on the deck with 1200psi, does that mean it only took you 150psi to ascend?

edit: Sorry, I think I misunderstood. By "on the deck" I thought you were referring to the Spiegel Grove deck, but perhaps you were referring to the boat on the surface

Yes, the dive boat conveyance deck, lol. I would have stayed longer because as I moved up the wrecks profile my computer dropped back in the yellow as would be expected. I have gotten pretty good at riding the computer and stretching my dives by working my way up, poor practice or not . But, it was a nanny dive with a guide, only boat I could find out that day. The guide and the other two divers were 500ish on the deck. But, I stayed as long as I could at depth with the guide frantically waving at me and then shaking his fists at me and then emphatically pointing up, all 50 feet above me on the line as I continued to shoot photos of a now much more friendly goliath grouper, now that all the fuss was 50 feet above. Nice photo op for me though.

My point is if one knows their SAC rate then they can use that information to plan the dive and part of planning a dive is choosing an appropriate tank capacity that provides adequate reserves based on that divers SAC and whatever size cylinder that is, then it is enough.

N

 

[Doppler]

I fully agree and that's why I originally Asked.
It's like going to a party and the host tells people they can only bring a single 24 oz can of beer instead of two 12 oz cans, same difference. I guess the logic would there is only enough room in the refrigerator and only so many coasters.

This posting almost makes you an honorary Canadian.