Question re: Alternating Primary reg. & Octopus on dives

[sytech]

I have been having a discussion with a friend regarding what his dive instructor told him in a Wreck Diving Class last week.

My problems with the Instructor's advice is articulated below. I actually like to be proven wrong especially regarding an activity that could cause a fatality so I really would appreciate any and all comments and feedback.

Thanks,

Sy






"Joe

I've been thinking about what you told me about your Wreck Diving Instructor's philosophy Re: Using Octopus on return leg of dive and I think it makes very little sense and can actually be dangerous. Here's why:

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..

" IF" someone wanted to adopt your Instructor's philosophy it would make much more sense to use the octo (again because of most octos being inferior breathers in most cases than the primary reg.) on the front leg of the dive although that could add it's own set of problems having to adjust to a different breathing pattern on descent because of the lesser air flow on the descent, though the increased ATM pressure could offset that. It is true that as you ascend your air usage (all other things being equal-which they rarely are) decreases but I don't see why someone would have to switch regs. for that reason.

In fact with all the marginally (at best) qualified goofballs in the water, the very act of taking the primary reg. out of your mouth, remembering to let bubbles out (unless you are not ascending) and putting and clearing the octo. into your mouth could be a problem for lots of people not to even mention them being nervous and possibly losing hold of the reg., then needing to do a "sweep" to recover the reg. and that if they don't find it very quickly they are set up for possibly a "catastrophic" panic situation which they themselves created and for no good reason. Then drowning.

No doubt that one should use their octo periodically just to keep it from getting "rusty" but that's common sense anyway.

Why don't you ask him what his rationale is?

If I'm wrong I'm always glad to be corrected".

 

[Dockmaster]

Although I can see your side of the coin, I have been known to switch from my primary to my octo from time to time. I feel that it's good to practice the emercency skills needed to pull it off (removing primary, letting out bubbles, finding octo & putting it your mouth, purging octo, and resuming breathing) before you need them for real. When planning my dive, I always tell my buddy that I'll be making the switch so that they don't freak out when they see me breathing off my octo. I also take the primary out and hold it with my left hand while I find my octo with my right; that way, I have a working reg in hand at all times. Once I'm breathing off my octo, I clip my primary into my BC so I can find it easily in an emergency.

As far as having a substandard octo of questionable quality goes, I guess you can make your own gear choices. I was always told that in an OOA situation, the diver needing air will go for the reg that they see working, which means the one in their buddy's mouth. Would I want to trust my life to a crapy octo?, no, so I buy a quality octo and make sure that it works and is serviced. I feel that a few extra dollars for essential equipment that I may never need is well worth it.

Just my .02.

 

[NorthWoodsDiver]

I dont dive an octo but I have to ask, why compromise quality and buy an octo thats any different then your primary...

there are various threads on the subject already, but it may be something to look into for you because thats where your primary argument is.

 

[hudson]

If the mere act of switching to the secondary reg could cause a fatality, or even mere discomfort, then the diver should not be in the water. (I really dislike such statements in general, but as far as being comfortable with your regulators, it's certainly true)

I don't think it is necessary to switch and breathe from the secondary the whole time on either the outgoing leg or on the return leg, but it's certainly common sense to switch to and breathe from the secondary for a while during the early dive just to ensure everything's ok with the secondary. There are two main reasons to stick with the primary during the majority of the dive though:

1-The primary could indeed be a better breather (nothing necessarily wrong with this)
2-The primary could be on a long hose, so you should maintain your configuration for an emergency donation to ensure everything goes smoothly.

If neither of the above apply, then the instructor's advice is sound, if a little overkill.

As for the breathing differences - while I don't mind a noticeable difference (which could save you some money *shrug*), the safe second should not be so crappy or tuned down so much that it's significantly harder to breathe to cause discomfort. You don't want to experience that in an emergency situation, besides there is no reason for any reg to breathe that bad.

 

[Hatul]

Some of the octos, including my Oceanic Alpha, are purposely detuned to a higher cracking pressure to prevent free flow, and this makes breathing harder.

Adam

 

[rstofer]

I have always swapped between the primary and octo. In my first setup I had an Air II integrated inflation device. I would practice swapping just to ease the boredom. FWIW, the Air II worked fine at 113 fsw.

Now I am using an octo that matches the primary and I routinely switch back and forth.

Yesterday I tried swapping between a double hose and a conventional octo. Now that is a bit more of a challenge. It takes quite a blow to clear the exhaust hose. Not that it has to be done with the last breath from the octo but it still needs to be cleared and it holds a lot of water.

So, given that there are no air source issues (isolated doubles, pony tank, etc) I would suggest swapping every few minutes. Just to have something to do.

Richard

 

[Indian Valley Scuba]

Lot's of interesting views here, but let's think about one important aspect of Octo ownership and intended use. The reason we have one (and that nearly all dive boats and operators require the divers to be equipped with one) is to ensure a safe, easy to access source of breathing gas to another diver while at depth. The benefits of this are obvious. And keep in mind that the person that is in need of that gas may be in some level of distress at the point that you are offering it to them.
So, you pass them your octo, and they get a) a mouthful of water, b) difficulty in sucking gas through it, or c) broken mouthpiece, upside down orientation, or some other issue that stands in the way of them achieving the goal, which is to satisy our mammalian needs to have something to breath. So what happens at that point? No one can accurately predict, but most of the choices fall into the "bad" to "terrible" category.
How can we reduce the risk of this? First, by purchasing and maintaining a decent quality redundant breathing source, just in case. This is no place to go cheap - if anything your octo should perform better at depth than your primary, since it will most likely be employed by a diver that is under significant stress, and may be breathing harder or faster than a relaxed diver. Second, by testing that octo, on each and every dive - first during your pre-dive check on the boat or shore, then again, after you have gotten to depth, and while you are enjoying the beginning of your dive, switch over to your alternate air source and breath from it for a minute or two.....make sure it is as ready as you are to pass it to someone else. And, with the increasing popularity of on-board octo's integrated into BCD inflators, that someone else may just be YOU!
In the technical diving community the standard has always been to pass your primary regulator to a diver in distress, the thought process behind that being that it just delivered a good breath to you, so it should be good for them.
All of our instructors teach and reinforce this practice with every diver, from open water classes to instructor candidates. Think along these lines when selecting, maintaining and testing your alternate air source on every dive. The life you save may very well be your own.

 

[LeadTurn_SD]

sytech: If you are concerned with the performance of your octopus, upgrade it immediately. You could be the one breathing from it in an emergency (failure of your primary 2nd stage, OOA diver grabbing your primary, whatever). You should be comfortable performing any dive, start to finish, with your octo as your primary.

Having said that, you do not need to spend a fortune to get a decent octopus! Any decent, well designed, no-frills, non-balanced, non-adjustable downstream 2nd will do the trick. It will deliver all the air you need, just at a slightly higher inhalation effort. And sometimes, the difference in performance between your primary and secondary will be so slight when you compare them underwater (on every dive!) that it is really a non-issue.

Best wishes.

 

[sytech]

Let me be clear on something. Both my regulators are Atomics and they are among the top of the line

I agree with you on using it in a "practice scenario" and to make sure it's working properly. That's not what's involved here.

The Instructor told my friend that as a matter of course and that during every dive he makes he (the Instructor) switches from Primary on the outbound leg and Octopus on the Inbound leg of the dive.

To make a practice of that on each and every dive makes absolutely no sense to me.

Although I can see your side of the coin, I have been known to switch from my primary to my octo from time to time. I feel that it's good to practice the emercency skills needed to pull it off (removing primary, letting out bubbles, finding octo & putting it your mouth, purging octo, and resuming breathing) before you need them for real. When planning my dive, I always tell my buddy that I'll be making the switch so that they don't freak out when they see me breathing off my octo. I also take the primary out and hold it with my left hand while I find my octo with my right; that way, I have a working reg in hand at all times. Once I'm breathing off my octo, I clip my primary into my BC so I can find it easily in an emergency.

As far as having a substandard octo of questionable quality goes, I guess you can make your own gear choices. I was always told that in an OOA situation, the diver needing air will go for the reg that they see working, which means the one in their buddy's mouth. Would I want to trust my life to a crapy octo?, no, so I buy a quality octo and make sure that it works and is serviced. I feel that a few extra dollars for essential equipment that I may never need is well worth it.

Just my .02.

 

[LeadTurn_SD]

Let me be clear on something. Both my regulators are Atomics and they are among the top of the line

I agree with you on using it in a "practice scenario" and to make sure it's working properly. That's not what's involved here.

The Instructor told my friend that as a matter of course and that during every dive he makes he (the Instructor) switches from Primary on the outbound leg and Octopus on the Inbound leg of the dive.

To make a practice of that on each and every dive makes absolutely no sense to me.

Your original post indicated you wanted to be proven wrong about a practice that "could cause a fatality".

I think test-breathing the octo at the surface, during the bubble-check, and at depth would probably be more than sufficient for most divers. That is what I usually end up doing.... although I'll admit I'm often pretty lazy and just test it on the surface, and maybe give it a couple test breaths underwater at the beginning of the dive, stow it and enjoy the dive (although these days I dive with a 5' primary and my secondary bungied around my neck, so "stowing" the octo is a non-issue).

I agree that you don't have to breathe your backup for 1/2 the dive to know it is working, that is a little over the top.... but I'd have no safety concerns at all doing so. You really should test the octo every dive, both on the surface and briefly underwater (I think we are on the same page here?).

Your original post indicated you wanted to be proven wrong about a practice that "could cause a fatality": I don't see a safety issue at all with the instructor's practice.

If there is an issue, then either the diver's equipment or the diver's training needs to be improved until the issue is resolved (I'm not referring to you, just making a general statement).

Best wishes.