Scuba diver dies after being found floating at Kurnell, NSW, Australia

[gypsyjim]

There's a reason J-valves fell out of favor ... it had less to do with the SPG than it did with how easy it was to misuse the J-valve and find yourself without any reserve at all.

Any piece of equipment is only as good as the willingness or ability of the user to use it correctly ...

... Bob (Grateful Diver)

Amen to that first. A real bad surprise when I reached for that valve on one dive in Maine, to discover I had tripped it when I fell doing a surf entry.

OOPS! Dive over, NOW!

 

[agilis]

There's a reason J-valves fell out of favor ... it had less to do with the SPG than it did with how easy it was to misuse the J-valve and find yourself without any reserve at all.

Any piece of equipment is only as good as the willingness or ability of the user to use it correctly ...

... Bob (Grateful Diver)

Those of us who grew up using J valves, and there are not that many of us still diving, quickly learned that the pull rod attached to the valve needs to be checked frequently. I developed the habit of checking mine about every 10 minutes. It is an effortless thing to do, since the circular bottom of the actuator rod sat just behind the hip at waist level within very easy reach. A simple push upward insured that the valve was closed. Diving in rocky inlets, along jetties, and on wrecks involved frequent contact with structure, so finding the actuator rod in an open down position was not infrequent. It was a simple fix if you did the check frequently. Just push the rod up the less than 2 inches needed to lock in the last 500 or so pounds of air.

People used to SPGs playing with J valves as vintage equipment may not have this vital habit as ingrained as we did. This is probably very dangerous when diving around kelp. I still have an occasional motor reflex reaching for the non-existent pull rod to check its position, four decades down the road. It really was vital, in every sense. That reserve, about a quarter of your air supply, was indispensable in the days before SPGs. People who did not do this activator rod check are like people who distain to frequently check their SPGs.

"Look mom, no hands!" The same infantile mentality.

 

[DaleC]

Though one would think a diver would check the position of the J valve at least as often as they check an SPG

edit: agilis just posted the same sentiment.

I remember thinking about many of these issues after reading about Tony Maffatone. I like to dive odd equipment and though about the lessons his death could teach regarding over complication, weight, lack of releases etc... It propelled me into viewing my emergency exit strategy as an important part of the actual intended dive. How will I get to the surface? Does it work? Is it tested.

 

[MXGratefulDiver]

Though one would think a diver would check the position of the J valve at least as often as they check an SPG

Yes ... one would think ... and that does get back to my earlier point ...

According to a DAN study, about 40% of scuba accidents can be traced back to people running out of air. And why do you suppose so many people run out of air?

... Bob (Grateful Diver)

 

[rhwestfall]

And why do you suppose so many people run out of air?

the irony, and we always see it, is the new diver. They usually can be noticed by their swimming arounf with their SPG in their hand in almost a death grip. Somehow, they are "almost" right...... complacency, it can kill....

 

[Bob DBF]

...how easy it was (is) to misuse the J-valve (SPG) and find yourself without any reserve at all.

Any piece of equipment is only as good as the willingness or ability of the user to use it correctly ...

... Bob (Grateful Diver)

Just wanted to make an addition to your comment (in red) and point out that you already had answered the substance of your question, and my short response.


In addition

There's a reason J-valves fell out of favor ... it had less to do with the SPG than it did with how easy it was to misuse the J-valve and find yourself without any reserve at all.

... Bob (Grateful Diver)

As one using the J and K valve prior to the SPG, the SPG gained favor on it's own merits, just as the J-valve before it.

• At the time we were using unbalanced regs and you could feel the reg breathing harder as the tank pressure dropped, why do you think K-valves continued to be used by many. Balanced regs gave little to no notice on tank pressure.
  
• The J-valve gave the warning and air reserve for balanced regs.
  
• Although it was a PITA, running out of air and doing an expeditious ascent (since it happened on a regular basis it was not necessarily an emergency) was not a once in a lifetime life threatening event that it is now.
  
• Gas planning and monitoring was a lot trickier without an SPG. A J-valve giving you a warning at 400# does little good if you need 600# for deco.
  
• As others have stated, there are almost as many tricks as there are divers, to insure that the reserve remained intact. Other tricks would be reversing the lever so should it snag it kept the valve closed, and taking off the rod and directly manipulating the valve, both used in kelp country.

The change over to the SPG was done because it was a newer, more useful bit of technology, available to the public. This is the reason we now wear BCs, use computers, and have bigger tanks. That is why J-valves also became ubiquitous, in their time.



Bob
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Trained when J-valves solved the OOA problem.

 

[dive_turkey]

And another thing I've been wondering about: is it possible that in some of the cases where we think 'panic', the diver didn't panic at all, but rather lost consciousness suddenly? I imagine that the length of time it takes to reach the point of hypoxic blackout is highly variable; and that the amount of 'warning' (symptoms) is probably just as variable. In cases where we're thinking 'why didn't they just drop their weights?' is it possible that in some cases, it was because they were relatively calmly executing a CESA, still quite confident that they'd reach the surface when they suddenly blacked out?

Symptoms of hypoxia do vary per person. This is a very good thought you're having here. Back in my aeromedical days we used to train in the hypobaric (altitude) chamber. At one point in the training you would ascend to 26k ft and then each person would be given a test and taken off oxygen. You complete as much of the test as you can until you recognize three symptoms of hypoxia in yourself. At this point you should "self-rescue" by putting yourself back on O2. One of the symptoms of hypoxia, and a fairly common one from my experience, is denial. Quite often you would see folks plugging away at their test, doing math on their fingers, working out word problems, etc... When the instructor asks how many symptoms they are experiencing they start counting 4, 5, 6-7-8... and then the instructor forces them back into their mask and that guy is considered a no-go. The point was to learn to recognize your specific symptoms so that you would notice if there was a problem with the oxygen systems in the aircraft. Otherwise, the crew would eventually just get nutty and fly into a mountain every time a hose came disconnected. And that gets expensive.

So yes, I do believe it is possible for a diver to be in denial of their situation until the point of simply passing out and then drowning while unconscious. From what I understand, this is a fairly high threat when diving rebreathers. Maybe someone here with more knowledge on that subject can add to it?

 

[Bob DBF]

It propelled me into viewing my emergency exit strategy as an important part of the actual intended dive. How will I get to the surface? Does it work? Is it tested.

And not just to the surface, you need to be safely back on the beach or boat. Exhaustion and hypothermia have their chance at you even though you solved the air problem. The big picture involves getting back home kissing the wife and cracking a beer, any part can change the outcome.



Bob
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The most important thing to plan when solo diving is to make sure that you are not diving with an idiot. Dsix36

 

[Darnold9999]

Had to laugh - had the same auto reflex to reach to check the j valve - even after not diving for over ten years. Local diving is in/around kelp so the habit was very very well ingrained. No SPG, so hitting the reserve and actually having it was important.

 

[beaverdivers]

The change over to the SPG was done because it was a newer, more useful bit of technology, available to the public. This is the reason we now wear BCs, use computers, and have bigger tanks. That is why J-valves also became ubiquitous, in their time.

I remember using J-valves with an SPG. I could set the reserve on the J-valve to have 750 PSI or 400 PSI. It was a beefy J-valve that took a significant pull to engage the reserve.

Now, we have new technology ( since the mid-90's ) that allows us to set a tank reserve. You can set it at 1500 PSI, 1000 PSI, 750 PSI or whatever you choose. It will show a visual and/or audible alarm.

Furthermore, it will show you a visual and/or audible alarm when you are almost Out Of Air (OOA).

This device is an air integrated computer. We train divers with this device. It can solve the OOA problem, if used properly.