Stupid me

[gbf]

Breath off both and check inflator before splash.

Then I always switch to my backup when I hit my stop - clip my primary, and finish the stop and exit on my secondary. My secondary gets used on every dive, and my primary on the long hose is out of the way for the exit.

 

[scubadiver888]

Breath off both and check inflator before splash.

Then I always switch to my backup when I hit my stop - clip my primary, and finish the stop and exit on my secondary. My secondary gets used on every dive, and my primary on the long hose is out of the way for the exit.

Oh, this reminds me, check all your dump valves as well.

 

[DA Aquamaster]

Wasting gas? Like the Owl wanting to know how many licks to the center of the tootsie pop, how many breaths are in a tank of air?

If I hit my safety stop with 600 psi, at 15 ft how many breaths do I have left in that tank? 200?300?400? I can't see a couple of breaths making any difference at all, so I've got 398 breaths left in the tank when I board the boat instead of 400. I don't think holding the purge button down for 10 seconds, 3 times to test before a dive would make a bit of difference, let alone a couple of breaths of the tank to test it. There is a huge reserve of gas left over in a typical recreational divers tank at the end of a dive. A couple of breaths pulled on a tank to test it is nothing in the scheme of things, it's like worrying about a grain of sand on the beach.

You're a little hard to follow but the gist is that we agree? Right? You are after all advocating "a couple of breathes" just like I am.

If you read my post that's pretty clear, and what I think is a waste is the diver sitting on the boat sucking 3-4 deep breathes out of each reg in the name of reg testing. It just is not required and 3-4 breaths tells you nothing more than 1-2 breaths.

What 4 breaths does do that 2 breaths does not is pre-cool the first stage twice as much, and that can be a really bad thing just before splashing on a cold water dive.

The point is that testing should have a point and should be done in the context of the dive, not just done by rote because someone specified "4 deep breathes from each reg".

---------- Post added January 5th, 2013 at 11:03 AM ----------

Someone correct me if they feel I'm wrong but I believe there is a philosophy amongst more experienced divers that your octo should actually be "cheap". What I mean by that is not "poorly made" but rather of a very simple design. For instance, it should not be a balanced design. Balanced designed regs are not built to be more reliable, but rather to be easier to breathe off. This makes your diving more comfortable and you're less prone to fatigue and headaches. However, in an emergency you want theoretically most reliable regulator, which would be unbalanced. I think a lot of equipment companies actually design their setups w. unbalanced octos (for instance Scubapro uses the R190 a lot) for this reason.

I've seen people suggest that high-end second stages should be used as octos because "in an emergency, wouldn't you want the best?" But I don't think they realize why high-end seconds are high-end.

It's possible I misunderstood your comment but thought I'd throw this out there in case I didn't.

The idea in technical diving circles is that if your primary reg is balanced, having your back up reg be unbalanced means it will (theoretically) be simpler and more reliable with fewer parts, and have an entirely different failure mode reducing the chances of both second stage failing for the same reasons.

Sadly, it's mostly just intellectual masturbation and/or catastrophizing in absence of the facts. The fact is that a balanced poppet regulator like the Scubapro G250V is a very simple design that is no more complex or failure prone than an unbalanced and much lower performing design like the Scubapro R190.

So, IMHO divers who do this to improve theoretical reliability are forcing themselves to accept a lower performing back up second stage, and are increasing the number of parts kits needed to service their regs for no gain in real world reliability.

 

[TSandM]

DAA, I have to pull four breaths out of my long hose to know my valve is open -- either that, or I have to watch my gauge while I breathe (which is what I usually do).

Except in very cold weather, it doesn't MATTER how many breaths you do to test a reg. If the gas you use doing this is going to matter at the end of the dive, you need to read NW Grateful Diver's gas management article

 

[DA Aquamaster]

I don't think anyone really mentioned this but... It is probably more important to test the regulator with the air turned OFF. If you get air when sucking then the second stage is cracked, the diaphram is messed up, the exhaust valve(s) are fouled etc. If you breath off the reg on the boat when the reg is turned on, none of these problems will be evident, unless there is "a big part missing".

Sucking on the regs before they are turned on (then exhaling through them) and pressing the purge button after the reg is turned on and checking the spg is probably quicker and more useful.

Ideally, all the reg breathing people mention above will be done on the surface with the second stage under water. If it's not then it's largely a waste of gas as inhaling through a reg with a torn diaphragm or an improperly seated exhaust valve will feel normal and give a false sense of security after the reg test - as the reg will still flood or breathe unacceptably wet once in the water.

For a diver having to do the pre-dive testing on a boat deck, testing against a closed tank valve is the only reliable way to go as it's the only way to test if the second stage is truly sealed with intact diaphragm, exhaust valve and case o-rings.

You can 1) connect the reg, inhale to do a vacuum check, then turn on the valve, and do the breathing test, or you can 2) pressurize the reg, turn off the tank valve, then breath it down.

My preference is to do the former, then shut the valve off and see if the reg holds pressure over several minutes. If the SPG reading drops, then the system has a leak somewhere - how big equating to how fast the SPG reading drops.

On the first dive of the trip, I'll also pressurize the reg with an IP gauge attached, check the swing during the breath test, then leave it pressurized a few minutes to ensue the IP is stable.

 

[Diver0001]

DAA, I have to pull four breaths out of my long hose to know my valve is open -- either that, or I have to watch my gauge while I breathe (which is what I usually do).

Isn't your spg on your secondary?

Frankly, this discussion over 2, 3, 4 or how many breaths doesn't make sense to me. What does it take to convince yourself (and your buddy) that everything is working?

R..

 

[DA Aquamaster]

DAA, I have to pull four breaths out of my long hose to know my valve is open -- either that, or I have to watch my gauge while I breathe (which is what I usually do).

Except in very cold weather, it doesn't MATTER how many breaths you do to test a reg. If the gas you use doing this is going to matter at the end of the dive, you need to read NW Grateful Diver's gas management article

Lynn, I agree the volume of gas used is minimal, my point is that doing what ever you do should be done for a reason, not by rote, and ideally should apply to multiple environments.

The cold water problem I frequently saw in the frozen north was exactly this - divers testing the hell out of regs to no purpose, then freeze flowing on the dive. The problem was that they used the same rote learned test procedure they always used without thought or regard to why or the ramifications of it. In most cases, they'd have been far better served taking 1-2 breaths than fours breaths in warm or cold water - so if a diver is always going to use the same procedure, why would a diver hand-cap themselves with a test protocol that only works in warm water?

You can disagree, but then you're choosing to selectively apply a basic concept only where you feel like making it fit.

----

Gas management is not the issue. Two breathes or four, the reality is that you're taking the test breaths off the penetration "third", so each test breath will shorten the penetration and exit by a similar volume and will essentially result in twice the gas used for testing ending up in the reserve. But it's still a waste of gas done for no useful purpose.

---------- Post added January 5th, 2013 at 11:31 AM ----------

Isn't your spg on your secondary?

Frankly, this discussion over 2, 3, 4 or how many breaths doesn't make sense to me. What does it take to convince yourself (and your buddy) that everything is working?

R..

That's basically the point. My standards on the first dive of a trip are high (and realistically IP test before I even leave home). On subsequent dives that day or on subsequent days, a single breathe done with each second stage (with the stage submerged) looking at the SPGs can tell me all I need to know. What is far more important is confirming that you can deploy the back up reg as that's a far higher probability for failure.

The exception to the one breath test for me is a hot drop in current where I enter the water negatively buoyant. Here I want to double check/cross check breathing and SPG needle response to ensure the valves are properly set.

What it takes should depend on the specifics of the dive, not on a diver doing something by rote - or worse by rote with no idea what they are doing or why.

 

[wedivebc]

DAA, I have to pull four breaths out of my long hose to know my valve is open -- either that, or I have to watch my gauge while I breathe (which is what I usually do).

Do you have an SPG on the reg that your long hose is on?

 

[DaleC]

One of the benefits of diving independent doubles is that I breath both regs every dive. And I will usually have about 1000psi in both tanks when we begin to surface if you want some...

I did away with the BWRAF pre dive mnemonic I learned in the past. Anything that requires an unrelated jingle to remember is already doomed to forgetting, particularly by divers who only go out occasionally or who are perpetually narc'd like me. Instead I favor the simpler acronym BAR. Hey, stencil it on your WS/DS sleeve if you want!

Buoyancy: Test wing and DS inflators, make sure shoulder exhaust valve opens and closes / ensure left hip dump toggle isn't fouled.

Air: Breath both regs while looking at SPG (tells me valve is open not cracked, volume and performance). If diving a longhose I also do a donate move to ensure it isn't trapped under something.

Releases: Touch them, harness and weight system - particularly that pesky crotch strap I always forget. Come on, touch them...

As far as equipment goes, that pretty well covers it.

One can make it more complicated but there is, for me, a balance to be struck between comprehensiveness and practicality. As I began solo diving early on I needed to develop a stategy that would work, and that I would remember. I recognize I just can't/won't remember a long mnemonic. Things like dive site surveys, dive plans etc... I keep as a separate discussion from the minimum physical equipment check I need to do, in order to dive safely. When alone, I can do the BAR checklist as I walk from my car to the water.

The pre-dive equipment check also has two components for me. One I do at the dive site"BAR", along with laying my gear out the same way, every time.

The second is at home, where I pack in such a way that I include what I need for the event. I usually bind my computer, compass and second cutting tool (which has a whistle taped to it) together with the computer strap so they are together when I suit up. My other cutting tool is attached to my rig. Either a lift bag or SMB/spool is placed in my DS pocket or bungied to my tank and my lights are tested. With SM (when shore diving) my regs are attached to my tank and pressure is tested.

I've taken to this after having arrived at dive sites minus fins, boots, masks, hoods and once even air in my tanks.
____________________________________________________________

I think Lynne is right about conventional octos being held in holders that are hard to reset. Especially in cold water diving where bulk makes fine motor control even more challenging. I also think conventional set ups don't require breathing off the octo by the diver so it can be forgotten.

 

[billt4sf]

Ideally, all the reg breathing people mention above will be done on the surface with the second stage under water. If it's not then it's largely a waste of gas as inhaling through a reg with a torn diaphragm or an improperly seated exhaust valve will feel normal and give a false sense of security after the reg test - as the reg will still flood or breathe unacceptably wet once in the water.

For a diver having to do the pre-dive testing on a boat deck, testing against a closed tank valve is the only reliable way to go as it's the only way to test if the second stage is truly sealed with intact diaphragm, exhaust valve and case o-rings.

You can 1) connect the reg, inhale to do a vacuum check, then turn on the valve, and do the breathing test, or you can 2) pressurize the reg, turn off the tank valve, then breath it down.

My preference is to do the former, then shut the valve off and see if the reg holds pressure over several minutes. If the SPG reading drops, then the system has a leak somewhere - how big equating to how fast the SPG reading drops.

On the first dive of the trip, I'll also pressurize the reg with an IP gauge attached, check the swing during the breath test, then leave it pressurized a few minutes to ensue the IP is stable.

I hate to say this, but I am not going to do all that before every dive, or even before the first dive of the day. I do not see people doing this and I do not hear people recommending this.

I am not disagreeing that it is a great idea -- I just don't see it happening.

I think I am oriented now towards taking a few breaths off the primary while watching the SPG, and taking a few breaths off the alternate air supply under the surface on the first dive of the day or trip, maybe as I first descend. The main concern I have is divers (especially newish divers like me) ASSuming that the alternate works fine and never actually using it until you have to. It would be a BIG, BAD surprise (and maybe a panic situation) if it doesn't work well and immediately for any reason when it is needed.

- Bill