Question re: Alternating Primary reg. & Octopus on dives

[Web Monkey]

MOST Octopuses, being that they are "backup" devices are not manufactured to have the same breathing specs. (EOB-"Ease of Breathing" and other critical specs) as the primary regs and that's why among mainstream brands you'll notice that they are much cheaper than the primary regulator. The exceptions to that rule would be the absolute "top of the line" models (like Atomic, Apexs etc.) where they specifically engineer the Octo. to have just about the same capabilities as the primary reg..

My primary is an Atomic M1. So is my backup. Unless you were looking closely, you would have no idea which one I was using.

In any case, when the brown stuff hits the fan, the last thing you want is a crappy reg for either yourself or some other guy who may be millimeters from full-blown panic. The entire concept of a detuned or cheap backup reg is a disservice to the entire diving community.

Terry

 

[rstofer]

About detuned octos: I understand why the cracking pressure might be set a little higher but I wonder if you were to use a 2d stage with one of those 'pre-dive = dive' selectors if that wouldn't suffice. The reg won't freeflow under many conditions but it can still be switched to a well turned 2d when necessary.

I don't have one of those regs so I have no experience. Anyone?

Richard

 

[Hatul]

About detuned octos: I understand why the cracking pressure might be set a little higher but I wonder if you were to use a 2d stage with onto of those 'pre-dive = dive' selectors if that wouldn't suffice. The reg won't freeflow under many conditions but it can still be switched to a well turned 2d when necessary.

I don't have one of those regs so I have no experience. Anyone?

Richard

A switch or lever on the regulator to alter the cracking pressure makes sense, but then you have to remember to flip the switch under emergency conditions, and it makes one extra thing to worry about.

Adam

 

[Puffer Fish]

About detuned octos: I understand why the cracking pressure might be set a little higher but I wonder if you were to use a 2d stage with onto of those 'pre-dive = dive' selectors if that wouldn't suffice. The reg won't freeflow under many conditions but it can still be switched to a well turned 2d when necessary.

I don't have one of those regs so I have no experience. Anyone?

Richard

There is a big difference between the "dive - Pre-dive" switch and adjustable cracking pressure.

The pre-dive switch is a physical piece that attemps to prevent a free flow. It moves in and out of the air stream with that level.

Most shops, given an octo will detune it.. regardless of the quaity... you have to ask, and usually insist. All mine are the same as my primary, with adjustable cracking pressure.. and all are adjusted the same as my primary.

And yea, you have to turn it back if you use it very deep, but at least you have the option.

 

[frankc420]

From my point of view, I believe if your getting into wreck diving (penetration), then you have switched over to the technical side of diving. Primary reg and octo are part of recreational diving, not technical.

To me, in technical diving you would call them primary reg and backup reg (not octo), both being of same quality, both have adjustable air control so that you can adjust the cracking pressure while diving.

As far as switching to an octo/backup, I honestly don't see how that could be fatal? Sure, accidents happen but if you know what your doing, everything should be fine.

My opinions, take them with a grain of salt, but I feel I'm right, no need in trying to sway me

 

[LeadTurn_SD]

There is a big difference between the "dive - Pre-dive" switch and adjustable cracking pressure.

The pre-dive switch is a physical piece that attemps to prevent a free flow. It moves in and out of the air stream with that level.

Most shops, given an octo will detune it.. regardless of the quaity... you have to ask, and usually insist. All mine are the same as my primary, with adjustable cracking pressure.. and all are adjusted the same as my primary.

And yea, you have to turn it back if you use it very deep, but at least you have the option.

Exactly.

And remember, when we talk about a "detuned" 2nd stage being used as an octo, we are talking about just a slight increase in cracking pressure to prevent freeflows when the reg is not in the divers mouth. We are not talking about the overall airflow once the valve "cracks" on inhalation.

If done properly, most divers would have a hard time detecting the difference between their primary and backup (assuming a properly "detuned" backup).... I dive non-adjustable, classic downstream 2nd's (Mares Abyss), and with my eyes closed really cannot tell the difference between my primary and secondary reg. Maybe at a heavy workload I could, but not under normal diving conditions at depth. The difference in cracking pressure between the two is just not very noticeable.

Best wishes.

 

[matt_w]

Why not breathe the octo on the way back? It is certainly a fair test of the quality of the octo and would clearly reinforce the idea that the octo should not be a piece of junk.

However, this does pose an interesting problem for the long hose people. If you are breathing your octo, the reg in your mouth is probably tied around your neck and the normal primary is probably clipped to your right chest D-ring. Just like in the Essentials video.

Now, when your buddy goes OOA, things get complicated. You probably can't pass the octo you're breathing because it is tied around your neck. Certainly some necklaces will pull off of the mouthpiece but I have seen at least one recommendation to put the bungee necklace UNDER the mouthpiece tie wrap. That 22" hose is going to seem very short! Passing the octo isn't going to be easy!

You also can't pass your normal primary because it is clipped to your harness and, should your OOA buddy go for it, it is probably upside down. That, and it will take precious seconds to unclip the reg; for either of you. And you had no advance notice like the fellows in the video.

For the normal hose divers, the issue could be the same. The octo usually has some kind of quick-release clip. That's fine, unclip the octo and breathe it. Now, where do you hang the primary? The normal hose diver may not have a snap hook on the primary. So, stuff it in a pocket.

Yup! The OOA buddy has a problem either way. But I don't see a problem for the individual diver.

I actually like the discipline of using the octo for half the dive. I don't see that it matters whether it is on the way out or on the way back. Unless there are gas source considerations...

Richard

But you did describe why you would not do that If you are diving a long hose, you have the primary, it is working and your not breathing it you are likely to make any air emergency worse. Your backup reg gets enough practice during S-Drills.

As to the OP point, while the instructor sounds a little quirky, I can not see how it would be particularly dangerous. The only down side is similar to the long hose, open water divers are taught to look for the yellow reg in the triangle. Presuming he clips the primary where the octo was, it would not be a huge problem. If his buddy was to go ooa, they would need to go through an extra step of re-arranging the regulators. The fact that he is doing this on the return trip, the most likely time for an OOA emrgency is a little strange.

 

[Wayward Son]

even for recreational diving, if your octo isn't safe to breathe at whatever depths you're diving, you need a better one. What's the point of using gear that isn't capable of performing when needed?

 

[rstofer]

But you did describe why you would not do that If you are diving a long hose, you have the primary, it is working and your not breathing it you are likely to make any air emergency worse. Your backup reg gets enough practice during S-Drills.

Yup! It's a problem. But I swap anyway. I may just hold the primary as suggested by someone earlier but I ALWAYS spend time with my octo. Probably not more than a few minutes but always something.

I don't spend any time worrying about OOA situations. I watch my SPG and I watch my buddy's SPG - like a hawk. It's not in my nature to trust other people.

Richard