On using a small tank to increase bottom time and provide redundancy

[SouthernSharktoothDiver]

@NW Dive Dawg I'm not actually that familiar with transfill whips. Is it safe to use one without getting the occasional hydro test? I would assume it carries a similar risk of pressure failure as a compressor, but as I said, I know very little about them.

 

[MaxBottomtime]

@MaxBottomtime not trying to like, cause an argument or whatever, but I don't really get how the pony bottle was the issue for this guy. He didn't leave enough gas to turn around. That's bad diving, and I fully agree that you have a right to kick him off your boat for that, but what's the pony got to do with it? If he doesn't know to leave a reserve, it wouldn't matter if he had one tank or 40.

Like the OP, he wasn't using the pony as an emergency reserve, but to extend his dives. Twice, he even had inches of water in his pony from purging it while it was empty. I told him if he doesn't have a pony with him, he can't abuse it. We later decided it was better just to keep him off our boat.

 

[happy-diver]

I wonder if that type of behaviour naturally follows those with ideas of blundering around in high current
low vis, hunting shark teeth, with no buddy, unsure of CESA, so incorporating in their plan a pony instead

 

[NW Dive Dawg]

@NW Dive Dawg I'm not actually that familiar with transfill whips. Is it safe to use one without getting the occasional hydro test? I would assume it carries a similar risk of pressure failure as a compressor, but as I said, I know very little about them.

Here's a snip of my transfill whip. Its a means of either equalizing two tank pressures.......or utilizing a higher tank pressure to "fill" a smaller cylinder. My whip is DIN on both ends with pressure relief valves on both ends and a gauge to monitor and confirm the transfer. If transfilling from a DIN tank to a Yolk tank then I use adaptors.

For example, my 19cf pony is AL with a max rated pressure of 3000psi. My steel 100's and 120's are HP rated to 3500psi. So if I deplete my pony at all for any reason then I can transfill it back up to max working pressure.

Since I am transfilling myself and the risk is all on me, then I am fine forgoing the annual VIS inspections...... but I still make sure to keep all of my tanks in current Hydro.

Hope that makes sense.....

 

[SouthernSharktoothDiver]

@happy-diver if you’re going to criticize my plan, would you please explain why what I’m doing is a bad idea? Cause the whole point of this thread was get an actual, fact based reason what I have in mind is a bad idea. “I think you’re too dumb to watch an spg” is not a valid reason, since even if that were true, it’d be equally true no matter what gear I carried.

If you have an actual, substantive reason why what I’m doing is a bad idea, I’d love to hear it. If not, I’m really not sure what you think you’re accomplishing being snarky on the internet, but I hope it works out for you

 

[SouthernSharktoothDiver]

@NW Dive Dawg this makes sense to me. I don’t have my setup ready to go yet anyway, so I may as well look into using a transfill in the mean time, cause the $10-20 per year viz fee always did kinda rub me wrong. Thanks for the advice!

 

[ontdiver]

The whole notion of "extending a dive" using a pony bottle runs counter to my own solo diving training and experience. While I understand what the OP wants to achieve, it does not meet - IMHO - what I would consider to be a conventional dive plan. And when you add variables in weather, viz, water temp, etc, I think you are elevating the risk unnecessarily.

 

[LI-er]

The whole notion of "extending a dive" using a pony bottle runs counter to my own solo diving training and experience. While I understand what the OP wants to achieve, it does not meet - IMHO - what I would consider to be a conventional dive plan. And when you add variables in weather, viz, water temp, etc, I think you are elevating the risk unnecessarily.

There no elevation in risk whatsoever, in fact it's SAFER to carry a pony even if used to extend the dive.

Take 2 divers on a dive boat. One has an AL80 and dives with a buddy. The other has an AL80 + 19cf pony and dives solo.

They both do their dives. The solo diver has the redundancy of the pony throughout the dive, and then at the end of the dive (assuming the pony bottle is not used), has a full 19cf of reserve air to finish the dive plus whatever small amount is left in the main tank which combined will usually be a lot more than the AL80 diver has, who also has to account for an out of gas emergency with their buddy. A solo diver needs no such "extra gas" factored in.

 

[MaxBottomtime]

I've seen regs free-flow and others bubbling throughout a dive. It's a scary thought when you need a pony only to find out it's empty. I prefer watching my spg.

 

[grantmac]

Regs shouldn't be bubbling through a dive since they are either in your mouth or under your chin.