OOA after only a few minutes with a full tank at 17m

[Dan]

The Quarter Turn That Kills - Cave Diver Harry

 

[Aaron Harmon]

Happened to me once. Worked fine to about 50 feet. As I got deeper and my consumption went up, it suddenly felt like I had an empty tank. I guessed what the problem was and fixed it myself at depth. Scared the hell out of me though. I was in Cozumel and it was maybe my 30 dive or so. I always double check now.

I will say this though. Reading through this thread, I see people saying not to use the quarter turn, that way its either on or off, nothing in between. That sounds really smart to me, but to be honest, I was taught (just a few years ago) to do this. Can anyone explain how/where this practice came from and why its no longer needed. Id love to simplify this part of my routine.

 

[Aaron Harmon]

The Quarter Turn That Kills - Cave Diver Harry

Thanks. Please disregard my request for further info on the practice. I a changing my routine as of now.​

 

[JohnnyC]

Well, I'm with @The Chairman . Sorry @JohnnyC ! Rec diving isn't caving, and I'm not worried about rolling a valve shut on the overhead.
The problem with "lefty loosey, righty tighty" is that not everyone gets it. As pointed out above in this very thread, folks have had friendly boat crew roll their valve off!!! And someone who is uncertain about which way to turn may take my fully on valve and, thinking it's off because it's tight, really honk the handle in the open direction. I don't need boat crew stripping my plastic handle, even if it leaves the tank on for the dive. And damage to the sealing oring on the valve spindle neck from opening it too hard, was described above.
With the tank handle cranked back a hair (not even a quarter turn), I can feel the crew's check on the rail before I jump. If it's a one second check, they probably felt my loose handle and opened it further, against the stop. If they take longer, then I know they're turning it in the wrong direction, and I step back off the rail and check it myself.
As The Chairman noted,

I get a little irritated with folks that are adamant that their way is the only right way. I get what you others are saying. You're not wrong. But for the reasons I just stated, I teach my students to crack it back, while also telling them that they're going to eventually run into a know-it-all who may yell at them for doing it that way, and that they need to decide for themselves what they want to do.

The quarter turn has nothing to do with cave diving. I'm sorry, but the fact is that your "turn it back" procedure is EXACTLY what caused the OOG situation in this thread.

What we have is a situation where we're actually creating a problem because we can't be bothered to make sure what we know what we're doing. And we're allowing ourselves to abdicate our responsibility to know our gear, know how to use our gear, and know how to rectify a problem with our gear in the event that we're unsure if someone else has touched our gear.

The errant DM excuse is a poor one. One, there's no reason to allow them to touch your stuff if you don't want them to. You can quite politely inform them that you won't be accepting their help in the form of turning valves, analyzing tanks, etc. Two, there's no reason you shouldn't be confirming your own gas supply. It takes no time to reach back and check yourself if you are unsure.

The worn o-rings are just that, worn. That may be many many cycles of that valve, and a few errant cranks are not going to destroy anything in your valve, and if they manage to crank hard enough to strip your valve handle, then you get them to buy you a new one. Remember, an object at rest tends to stay at rest, and object in motion tends to stay in motion. A static valve handle that is fully open will take much more force to get it to move enough to do damage. However, a diver with a loose valve wheel presents a much easier target for a DM to aggressively open their valves all the way, and the o-ring will be under much more force when the valve stops fully open. A static screw is much harder to strip than a moving one.

What is preferable, jumping off the boat and being able to do your dive, only to find that you need a new valve handle, or jumping off the boat and your tank being unable to deliver gas at all? You posit that you'll be able to feel a DM messing with your valves, but you also posit that "righty tighty lefty loosey" is too complicated for some people to remember. You seem to think that those people will also have developed the innate ability to feel a DM messing with their valves behind their head on a rocking and pitching boat while trying to make their way to the swim deck. So what you get is a diver who descends, has their gas supply cut off, and then is forced to deal with an OOG situation at depth. You can't on one hand say that it's too difficult for students to understand that most simple component of how a valve works, yet proffer that they have the intelligence, foresight, and situational awareness to understand what the DM is doing out of sight and out of mind while a bunch of other things are going on.

There are plenty of quick turning valves in the scuba industry. Are you expecting one of your students to understand the difference when the DM is walking them to the back of the boat?

The turn back in the modern scuba industry is purely an anachronistic holdover from a time when a stuck valve was a real potential. I has no place in modern scuba diving because it causes more problems than it prevents. And those problems it causes are potentially fatal.

Call me a know-it-all if you feel like you need to be insulting, but "it can cut off all your gas underwater" far trumps "the boat might owe you a hand wheel."

 

[rsingler]

I knew I could count on you for a forceful defense of your position, @JohnnyC !
We'll have to agree to disagree on this one.
It's a long way from a quarter turn back to "so barely open that gas density became an issue." So I don't know what really caused the original incident. Was it the diver, or the crew?

But we agree on two things: nobody touches my gear, and the valve goes all the way open (with a little disagreement over what that means ).
It takes awhile for some new divers to acquire the experience and courage to politely argue with a crewmember. That's why I teach the way I do.

I've done that ever since the time I watched a confused newbie "check" her already open valve, first going the wrong way, then second guessing herself, reversing course and quickly hitting the stop. Hitting the stop reminded her that she'd done it properly the first time, and I saw her nod to herself. Without that feedback, for someone who was indeed "lefty loosey challenged" she would have turned the valve all the way closed, checked, discovered her error, and only then turned it all the way open. If you're not sure which way is open...

You don't need to do that.
I don't need to do that.
Nobody touches our gear.

But I still teach it the other way.
Good discussion, though!

 

[rsingler]

Well, I'm going to eat crow here.
I just read
The Quarter Turn That Kills - Cave Diver Harry
And I'm going to admit that the argument made there trumps my logic.
It's not about "making sure we know what we're doing". It's not about "abdicating our responsibility to know our gear."
It's about human error.
The article points out that even the famous Sheck Exley closed his valve all the way, then opened it a quarter turn. BACKWARDS! SHECK EXLEY!

The take away for me was the danger of the quarter turn open, if you make that mistake. Just like the OP of this thread, whether he did it or a crew member did it. If Mr. Exley did it, so might I. Human error. Not the fact that I know my own damned gear. Not the fact that I know which way to turn a screw, for Pete's sake. Human error.

Therefore the logic that trumps my prior reasoning is that the only foolproof test of a valve is one which looks at only two conditions: either all the way open, or all the way closed. If that's what you were trying to tell me, @JohnnyC , I missed it. If a diver has one state or the other, and nothing in between, he'll be able to tell before he splashes.
I'm going to change the way I teach.

 

[NAUI Wowie]

Hi All,

Had a little surprise this week.. We were three divers and I did my pre-dive check, on the surface, with buddy number one. Gas Ok - 220 Bars, Regulators Ok - Three deep breaths on Primary and Octopus, BCD Inflation Ok, the usual stuff.

We headed of into the water, reached our descent point and proceeded with our dive plan, heading of to our deepest point at 20m.

At the 17m mark I felt an unusual response from my regulator, I didn't understand what it was initially, it felt as though though something blocked the regulator after 1 second. After trying to take a second breath, same result. At this point I signaled to my buddy that I was OOA. Everything went calmly, he passed me his Octopus and we made a controlled ascent. There was no need to make a safety stop but at 8 m we slowed the ascent down, we had plenty of gas and everyone was together and the situation was calm..

Back on the surface, I inflated my Stab manually. And then I tried my Regulator again, everything was working fine....strange....both primary and secondary...

We returned to shore and verified everything, turned out that my bottle had not been fully opened. It had been opened enough to make gauges and regulators work on the surface but not enough that it could supply at depth...

I have no idea what happened that day, usually I fully open the valve and then do a half turn back.. Which is our standard procedure. Why it was only open at 10% or so I will never know.

Later I spoke to our instructors who mentioned that we should do a secondary test around the 3 - 5m mark, whereby you take a few breaths and carefully watch the SPG, if the needle wobbles even a little bit it could be sign of a non-fully open bottle..



Do any of you have any other techniques that could possibly help avoid this kind of situation.

( Went diving yesterday and to no-ones surprise I made a big point of controlling that the valve was fully open , we also did some tests whereby we progressively opened the valve and studied the SPGs reaction when breathing from the primary, it really doesn't take more that a quarter of a turn of the valve for the needle on the SPG to remain static and fool you into believing that all is OK, at least on the surface.)...

You did not check to see if your tank was open at dive start. Thus this thread. Not to sound like a jerk but before every dive you need to open your tank. you open it all the way. Counterclockwise till it stops.

Done.

thats it.

no turning back to close it a bit....nothing.

THEN.....when you are about to jump in and fully geared up check again is it fully open? I had a fool of an employee at truth aquatics on the Conception walk by after I fully opened my tank and he closed it. I had walked a few feet away to get in my bag for some defog and turned around and saw him do it. I was a newer diver so didnt say anything then. Now id likely go ballistic on him. This event happened just a year ago

 

[NAUI Wowie]

FWIW, I still turn my knob back a quarter turn and teach it that way to students. A valve all the off or all the on feel exactly the same. A valve a quarter turn off, feels "loose" and easily differentiated between all the way off. Yeah, I check all my students' tanks before we splash.

yet this process puts a lot of people at risk to this day. its only for your personal comfort yet its dangerous as people do the opposite .....

you can easily CHECK it by twisting it then fully opening again. You are the most knowledgeable person on this forum yet you tell people to do something that when they are not paying attention can end in stupid mistakes.

you want to feel a LOOSE knob so you KNOW its right....but that loose knob to other divers youve trained could easily be a quarter turn open .....i.e. almost shut. because they messed up.

 

[NAUI Wowie]

In theory we should all be opening the valves holding the handle only fingertip tight anyway, this should prevent it being jammed into the stop and knackering the internals or binding.

I personally crack the valves back so they’re fractionally off the stop, literally a degree or two of rotation.

WHY

 

[DeepSeaExplorer]

It’s amazing this can be so over analyzed and group think still comes up with the wrong answer.

This was a situation of someone that didn’t know left from right, or CW vs CCW. Has nothing to do with backing off once open.

The origins of backing off didn’t come from SCUBA and that’s because divers don’t know jack about valves. It came from pipe fitters to keep someone from using a big wrench to open a supposedly jammed closed valve that was actually already open. It happens a lot in industrial because steel valves get frozen. Frozen open, frozen closed and frozen in between.

Turning the valve back slightly allows a little give so that someone with a big wrench can feel it and hopefully realize it’s already full open. Backing off slightly is not going to reduce the gas flow in a noticeable way. That includes SCUBA valves. It has zero to do with “modern valves.”

Backing off allows someone to quickly realize the valve is already open instead of a hard close. It’s a great method used by way more people than divers: pipe fitters, plumbers, welders, and virtually everyone in industry.

Just because divers are sometimes confused by valves doesn’t mean the method is wrong. It means divers lack experience with valves and can be confused.

The real answer here is don’t allow other people to jack with your gear when you’re setting up - including the crew. I’ve had crew start twisting on my valves just a as I m about to jump in. This should cause a full stop. And I’ll stop right here...