Over breathing your reg

[doctormike]

I think we agree far more than disagree. I think my main idea was that all divers, when encountering a problem should first consider two options: go up or consider trying to devise a solution on the bottom. That is the first step in the decision tree.

As you correctly indicated, the more experienced a diver is, the more likely he will be able formulate a solution at depth and implement it successfully.

Tech divers and/or divers with an overhead or deco may completely loose the option of going straight up.

So my suggestion is that (if possible) a recreational diver should be THINKING of staying and fixing and not going up. I won’t tell a diver NOT to go up or shame them for doing it in certain situations, because quite often it is the best solution and if you delay and don’t realize it soon enough, the viability of that option may expire.

With respect to the op’s predicament, if he was thinking his reg was wet and leaking water, then he should immediately consider going to the octopus and I mean right away.

If the problem is that the diver is out of breath than his first decision should be can I control my instinct to head up and simply rest and recover and worry about nothing else for 60 or 90 Seconds???? If the diver feels he can’t do that, then instinct is going to govern anyway and he will be compelled to go up right away.

Regardless, the end result is that the diver is going to ascend, since he is alone and could be expected to follow lost buddy protocol.

We are 100% in agreement! Thanks for hearing me out.

 

[IncreaseMyT]

If you say so!

Do you disagree? I am not saying it is possible to breathe more than a diaphragm reg can deliver, that is up in the air. I am saying a piston reg delivers more.

 

[doctormike]

Do you disagree? I am not saying it is possible to breathe more than a diaphragm reg can deliver, that is up in the air. I am saying a piston reg delivers more.

Not sure what your mean. For the depths that you are talking about, I don't think that there is any difference between piston and diaphragm regulators in terms of gas delivery, but I'm hardly an expert on that. If you fee that there is, then I'll stick with "if you say so".

I was commenting on this:

Thats why I use a piston reg, cause there is no chance you can over-breathe it. When I am spearfishing and shoot a big fish in 100 ft plus, I will suck down a 133 in no time. Ive seen the critically low warning on my Teric too many times lol

Regulator design has no impact on gas consumption. I don't think that it's good to describe unsafe diving practices (blowing through gas at depth to the point of getting a tank pressure warning) and then adding "lol". Doesn't set a good example for new divers.

 

[IncreaseMyT]

I think you misunderstood my post, and also I was not very clear. I was simply pointing out that I can use a lot of air, fast. So it bothers me when people say you can't over-breathe a diaphragm reg, that it is impossible. Piston regs do deliver more air cause they can open all the way up, a diaphragm cannot. It may be very unlikely but not sure if its impossible to over-breathe a diaphragm reg.

Me being 6'3 and 285 pounds I need more air delivery than the average person, especially when I am task loading, because I am like 2 human beings.

My point of seeing critically low too often, is if I shoot a fish at 1200 PSI and it gives me a hard time I may hit critically low before I get the fish in and on the stringer. Which is not easy to do, unless you can suck down some air.

Oddly enough once I go over 100 feet my air consumption becomes much closer to the people I am diving with, I assume it is because my lungs are collapsed and now my volume is much closer to an average person.

 

[doctormike]

I think you misunderstood my post, and also I was not very clear. I was simply pointing out that I can use a lot of air, fast. So it bothers me when people say you can't over-breathe a diaphragm reg, that it is impossible. Piston regs do deliver more air cause they can open all the way up, a diaphragm cannot. It may be very unlikely but not sure if its impossible to over-breathe a diaphragm reg.

OK, I see... thanks for the explanation! As I said, I'm not too much of an expert on reg design, and that makes sense that piston regs may have a higher maximum delivery rate than diaphragm regs. I guess the question is, does that difference come into play at times other than very deep diving with dense gas, or with extreme exertion at shallower depths? I don't know.

My point of seeing critically low too often, is if I shoot a fish at 1200 PSI and it gives me a hard time I may hit critically low before I get the fish in and on the stringer. Which is not easy to do, unless you can suck down some air.

Here is where I need to respond, because many new divers read these threads, and I don't want anyone to think that this is OK.

In this situation, the correct thing to do is to let the fish go long before you get critically low. If you need more time to shoot fish and more time to reel them in, then doubles and technical training might be appropriate (don't know if that's how you dive now), but even then, you shouldn't start any activity that will obligate you to extend your bottom time beyond your plan and gas reserves - spearing, wreck penetration, etc...

A low tank pressure alarm only goes off for three reasons. (1) catastrophic gas loss like a blown LP hose, (2) a lack of situational awareness resulting in an unnoticed drop in gas reserves, or (3) normalization of deviance where one assumes that because they have been able to surface safely in the past after draining a tank below safe reserve pressures, that they will always be able to do so in the future.

Don't do #2 or #3.

 

[IncreaseMyT]

I understand, but I am attached to the fish, so it can be hard to just let it go. Also keep in mind I dive a 133 so my critically low at 375 is about 600 PSI on a 80al. This gives me more than enough gas to safety and surface from under 100 ft.

But yes if I see and feel that alarm I get to my safety.

 

[doctormike]

I understand, but I am attached to the fish, so it can be hard to just let it go. Also keep in mind I dive a 133 so my critically low at 375 is about 600 PSI on a 80al. This gives me more than enough gas to safety and surface from under 100 ft.

But yes if I see and feel that alarm I get to my safety.

Then you let go of the speargun. You aren't attached to the fish, you are unwilling to manage a low gas emergency because of other considerations. I carry a $10,000 camera setup, but you had better believe that I would drop it if I had to.

First of all, SPGs become less accurate at the end of their range, so your estimate of remaining gas reserves may be inaccurate. 375 on the gauge may be lower than you think.

Second, even if you had 600PSI on an AL80, that is low for a normal ascent from 100 feet. For a big guy with a high SAC rate, after physical exertion, carrying a stringer and a speargun, it's even tighter.

Third, rock bottom calculations are done without contingencies. What if you have a free flow, or an ascent delay, or any other problem? Cutting your guesstimate of gas reserved to the bone because you assume you will be able to safely ascend is potentially dangerous.

Finally, you should never see the alarm. Ever. If it ever goes off, and it's not a catastrophic gas loss (i.e. blown LP hose) that means that there has been some failure on the divers part, either in planning or execution of the dive.

I'm not trying to be snarky, and I appreciate the dialogue. I'm just trying to help. I hope that what I am saying makes sense, for you and for any new divers reading this thread.

I would rethink what you are doing.

 

[IncreaseMyT]

I have multiple alarms that are color coordinated. It is the first in a set of 3 (yellow). I only use my watch for PSI. I burned out a tank to 100 PSI at my safety to see what it does. If I surface at my first alarm from say 80 feet, I will still have 250-300. It's not something I try to do, just saying it has happened. I don't burn much gas at my safety cause I am concentrating on doing that, instead of something else.

I appreciate the concern, thank you.

 

[scubadada]

As a very new diver I’ve had my first incident. This weekend I was diving with two buddies I’ve never dove with before. The dive started fine we descended and began dive. At about the 20 min mark is where it kinda got interesting. We stop check our air situation and decide to turn the dive. The lead guy takes off and basically leaves me and the other guy behind. Now the other buddy starts to get away trying to catch the first buddy. During this chase I became winded. I was able to get to the guy in front of me to let him know I got to ascend. The reg couldn’t keep up with my breathing and I began gasping. So now little air and I’m taking in water. I basically forgot what I had been taught about stopping and getting my breathing right. In between getting little air and swallowing and purging water from my mouth. I surfaced. How does one handle an inconsiderate buddy who basically leaves you behind. I know I’m never chasing down anyone ever again. I didn’t realize the implication of breathing to hard.

Hi @Marivan377

Over the years, I have spent a fair amount of time thinking about, and trying to educate myself, on this topic.

It's my impression that most, if not all, quality regulators are theoretically able to deliver sufficient gas so that it would not be the limiting factor. First stage regulators are able to deliver more gas than the second stage regulators, so delivery to the diver would be limited by the second stage. I believe that the feeling of shortness of breath may be more related to the work of breathing, which is increased at higher RMVs and at greater depth. The work of exhalation is greater than that for inhalation. I assume that an individual's onset of the feeling of shortness of breath due to physical effort is also related to one's overall cardiovascular fitness.

When I have felt short of breath with extreme exertion, it has seemed clear that work of exhalation was great. The solution is to decrease exertion and lower your breathing rate/RMV back to an acceptable level. The onset of shortness of breath increases anxiety, not helping in resolving the situation.

There was an interesting thread on the work of breathing a while back Latest ScubaLabs reg test - huh?

 

[jgttrey]

Oddly enough once I go over 100 feet my air consumption becomes much closer to the people I am diving with, I assume it is because my lungs are collapsed and now my volume is much closer to an average person

What ever it is, it is not collapsing of the lungs because that isn't happening.

With some folks, they relax "into the dive" after a while, so the bottom portion tends to have better consumption rate. Also, maybe you are doing things that tend to make you work harder shallow.