Failed first stage

[John C. Ratliff]

You won't be allowed to dive with an operator without one eg. Philippines

What I found I showed up with a very good depth gauge, dive watch, and my NAUI Dive Tables/Dive Planning Worksheet with a pencil attached? After all, here's the Merriem/Webster definition of "computer."

Definition of computer
: one that computes, specifically : a programmable usually electronic device that can store, retrieve, and process data

Now, the advantage of my "computer" is that it is not dependent on electronics, and impervious to saltwater. It can be taken into the water, and computes up to three dives per day. A computer doesn't necessarily have to be electronic, it's just more convenient.

I had a computer IT guy come to my office to work on my dead computer, and I opened my front drawer, took out a different instrument, and he asked, "What is that?" So I told him, "That is my backup computation device for when the electricity goes out." What was it? A slide rule.

SeaRat
NAUI #2710

PS, I've been diving longer than many instructors have been alive.

PS1, no computer will help if a diver's first stage fails in the manner described here; only a buddy's safe second, or having pre-planned the dive to be a no-decompression dive, will help. The NAUI Dive Tables/Dive Planning Worksheet can be used to unsure no-decompression diving throughout the day of diving.

 

[Pearlman]

So what are the good mitigation strategies for this kind of failure? Apart from sticking close to buddy i.e which in practice I find does not happen 50% of a dive with insta-buddies on tourist dives in S.E Asia? I am really concerned now as I cant imagine how I would have coped with this situation in the ripping currents that I've experienced on few of the dives...

A pony bottle is one I suppose? As a vacation diver who only dives a few times a year is buying an own regulator that will sit in the cupboard for most of the year a safe practice? Especially in a country where the dive industry and hence servicing options are next to non-existent?

 

[Angelo Farina]

So what are the good mitigation strategies for this kind of failure? Apart from sticking close to buddy i.e which in practice I find does not happen 50% of a dive with insta-buddies on tourist dives in S.E Asia? I am really concerned now as I cant imagine how I would have coped with this situation in the ripping currents that I've experienced on few of the dives...

A pony bottle is one I suppose? As a vacation diver who only dives a few times a year is buying an own regulator that will sit in the cupboard for most of the year a safe practice? Especially in a country where the dive industry and hence servicing options are next to non-existent?

My strategy is to always use two complete first stages and two complete independent second stages. Two independent regs, both of my property and serviced by me. Very old, vintage equipment (Scubapro MK5+109), entirely reliable and ultra simple (very few parts inside).
And they are mounted on the two posts that are standard in any cylinder provided by a serious diving center. If your diving center only provides cylinders of insufficient capacity (11 liters instead of the 15 liters I usually employ) or with only one post, I generally prefer to switch to another diving center, which provides more serious equipment.
I understand that in some places in third world this could be more difficult to find, but till now I had never problems.

 

[Pearlman]

My strategy is to always use two complete first stages and two complete independent second stages. Two independent regs, both of my property and serviced by me. Very old, vintage equipment (Scubapro MK5+109), entirely reliable and ultra simple (very few parts inside).
And they are mounted on the two posts that are standard in any cylinder provided by a serious diving center. If your diving center only provides cylinders of insufficient capacity (11 liters instead of the 15 liters I usually employ) or with only one post, I generally prefer to switch to another diving center, which provides more serious equipment.
I understand that in some places in third world this could be more difficult to find, but till now I had never problems.

Will appreciate if you can post some pics of your gear for a visual understanding. Thanks!

 

[ofg-1]

Look, don't be embarrassed. Lots of people fail first grade.....Wait, you said stage?.............Nevermind.

 

[uw]

#deepfix: check out "Scuba Regulator Savvy" by Pete Wolfinger. Not just a how-to, but detailed explanations of the theory and specifics of regulator operation, with LOTS of diagrams. It is quite wordy and sometimes repetitive, but if you work through the content you'll either feel confident tackling your own reg maintenance (which could be a mistake!) or realize why it's worth spending the money to get it done by a tech you trust.

Search

Cheers,

 

[InTheDrink]

To the OP. Well done for not bolting. I reckon on dive 29 if this had happened to me I’d have bolted. Swimming down takes guts when suddenly you have zero gas.

In terms of mitigation strategies, as others posted above, redundancy would be my primary solution. I never dive without a pony or stage. It’s no bother and at recreational limits I’m pretty happy with either.

Even with the best buddy in the world I like to be my own rescue. Spares the drama

Again, well done for not bolting and to your buddy from stopping you both polarising

 

[John C. Ratliff]

I actually simulated this situation, of loosing the regulator's air after a first stage failure just after an exhale. I was in a pool that was 16 feet deep, but made an emergency swimming ascent that covered 25 yards of the pool (simulating an ascent from 75 feet depth). Not only was I able to accomplish it, I was able to blow bubbles for the last part as I ascended from 16 feet.

You see, there is always Air still in your lungs even after an exhalation. We have what is called out "tidal volume" in our lungs, which is the amount of air we normally inhale, and exhale when breathing. There is also what is called our "expiratory reserve," which is the amount of air which we normally don't exhale during our breathing cycle, but that we can still force out. Below that, we also have our residual volume, which is the amount of air still in the lungs which we cannot exhale, but is still there. Between the expiratiry reserve, and the residual volume, there is about a 2 liters of air still in our lungs. This is enough to swim 75 feet without too much problem (at least for me).

Now, let's do a mental exercise; if you are at ~100 feet depth (say 10 meters), and have this regulator malfunction where you cannot get air after a normal exhalation, and start with 1 liter of air in your lungs, how much air will you have if you do a slow emergency swimming ascent to the surface? Well, we know that we are at 4 atmospheres absolute pressure. As we ascend, that air expands due to lessening of the pressure. Because the air is 4 times as dense at 30 meters (4 ATM absolute), we can expect that air to expand by four times. So, heading to the surface, starting with only two liters of air in our lungs, that will translate to eight liters of air by the time we reach the surface. Most people have a vital capacity of only 4-5 liters of air, which means that in the CESA, we'd have to blow out some 3-4 liters of air to avoid lung over-expansion. Jacques Cousteau, in his book The Silent World, described Frédérick Dumas teaching some of the first scuba courses in the 1950s, and requiring for graduation that the students complete a CESA from 100 feet to give the students the confidence that it can be easily accomplished. This assumes a no-decompression dive, but this was done for a number of years.

When I went through the U.S. Naval School for Underwater Swimmers in 1967, we were required to complete a buoyant ascent, using the "blow and go" technique (blow out all the air from your lungs, then let go with an inflated life vest, and go to the surface from 33 feet. We were to continuously exhale throughout this buoyant ascent too, showing that there was still air in our lungs after the "blow" portion.

SeaRat

 

[Catito]

I actually simulated this situation, of loosing the regulator's air after a first stage failure just after an exhale. I was in a pool that was 16 feet deep, but made an emergency swimming ascent that covered 25 yards of the pool (simulating an ascent from 75 feet depth). Not only was I able to accomplish it, I was able to blow bubbles for the last part as I ascended from 16 feet.

You see, there is always Air still in your lungs even after an exhalation. We have what is called out "tidal volume" in our lungs, which is the amount of air we normally inhale, and exhale when breathing. There is also what is called our "expiratory reserve," which is the amount of air which we normally don't exhale during our breathing cycle, but that we can still force out. Below that, we also have our residual volume, which is the amount of air still in the lungs which we cannot exhale, but is still there. Between the expiratiry reserve, and the residual volume, there is about a 2 liters of air still in our lungs. This is enough to swim 75 feet without too much problem (at least for me).

Now, let's do a mental exercise; if you are at ~100 feet depth (say 10 meters), and have this regulator malfunction where you cannot get air after a normal exhalation, and start with 1 liter of air in your lungs, how much air will you have if you do a slow emergency swimming ascent to the surface? Well, we know that we are at 4 atmospheres absolute pressure. As we ascend, that air expands due to lessening of the pressure. Because the air is 4 times as dense at 30 meters (4 ATM absolute), we can expect that air to expand by four times. So, heading to the surface, starting with only two liters of air in our lungs, that will translate to eight liters of air by the time we reach the surface. Most people have a vital capacity of only 4-5 liters of air, which means that in the CESA, we'd have to blow out some 3-4 liters of air to avoid lung over-expansion. Jacques Cousteau, in his book The Silent World, described Frédérick Dumas teaching some of the first scuba courses in the 1950s, and requiring for graduation that the students complete a CESA from 100 feet to give the students the confidence that it can be easily accomplished. This assumes a no-decompression dive, but this was done for a number of years.

When I went through the U.S. Naval School for Underwater Swimmers in 1967, we were required to complete a buoyant ascent, using the "blow and go" technique (blow out all the air from your lungs, then let go with an inflated life vest, and go to the surface from 33 feet. We were to continuously exhale throughout this buoyant ascent too, showing that there was still air in our lungs after the "blow" portion.

SeaRat

Interesting. Thank you.

 

[stepfen]

I actually simulated this situation, of loosing the regulator's air after a first stage failure just after an exhale. I was in a pool that was 16 feet deep, but made an emergency swimming ascent that covered 25 yards of the pool (simulating an ascent from 75 feet depth). Not only was I able to accomplish it, I was able to blow bubbles for the last part as I ascended from 16 feet.

You see, there is always Air still in your lungs even after an exhalation. We have what is called out "tidal volume" in our lungs, which is the amount of air we normally inhale, and exhale when breathing. There is also what is called our "expiratory reserve," which is the amount of air which we normally don't exhale during our breathing cycle, but that we can still force out. Below that, we also have our residual volume, which is the amount of air still in the lungs which we cannot exhale, but is still there. Between the expiratiry reserve, and the residual volume, there is about a 2 liters of air still in our lungs. This is enough to swim 75 feet without too much problem (at least for me).

Now, let's do a mental exercise; if you are at ~100 feet depth (say 10 meters), and have this regulator malfunction where you cannot get air after a normal exhalation, and start with 1 liter of air in your lungs, how much air will you have if you do a slow emergency swimming ascent to the surface? Well, we know that we are at 4 atmospheres absolute pressure. As we ascend, that air expands due to lessening of the pressure. Because the air is 4 times as dense at 30 meters (4 ATM absolute), we can expect that air to expand by four times. So, heading to the surface, starting with only two liters of air in our lungs, that will translate to eight liters of air by the time we reach the surface. Most people have a vital capacity of only 4-5 liters of air, which means that in the CESA, we'd have to blow out some 3-4 liters of air to avoid lung over-expansion. Jacques Cousteau, in his book The Silent World, described Frédérick Dumas teaching some of the first scuba courses in the 1950s, and requiring for graduation that the students complete a CESA from 100 feet to give the students the confidence that it can be easily accomplished. This assumes a no-decompression dive, but this was done for a number of years.

When I went through the U.S. Naval School for Underwater Swimmers in 1967, we were required to complete a buoyant ascent, using the "blow and go" technique (blow out all the air from your lungs, then let go with an inflated life vest, and go to the surface from 33 feet. We were to continuously exhale throughout this buoyant ascent too, showing that there was still air in our lungs after the "blow" portion.

SeaRat

I agree with the reasoning and the maths given here. My worry is that it is not the volume of air (or its' lack), nor the lack of O2 that urges us to breath. To my understanding it is the amount of CO2 in our blood stream that signals our brains the need to breath.

Hence assuming a diver at 100ft/30m with "empty" lungs (2lt of air) after a normal exhale and suddenly he can't breath in fresh air (say for example due to first stage blockage). He already tried to breath, hence he already had the need for fresh air (i.e. he already had elevated CO2 level in his blood) - but no fresh air is available. He starts ascending, the gas volume in his lungs is indeed increasing but what about his blood CO2 levels and hence his urge to breath? To ascent safely from 100ft one would need 3 minutes minimum even for a dive within NDL. Will the drop of CO2 partial pressure in his lungs during the ascent combined with the gas volume reduction (some gas will hopefully be exhaled through CESA) be enough to "satisfy" his brain's need for fresh air for these 3 long minutes? I somewhat doubt it unless special trained...

That's a genuine question and the reason I don't dare to try this at home.
(Also that's the reason I prefer to carry a pony when I am not near a good buddy but I wouldn't like to open that can of worms here.)