1/4 Turn Revisited

[lexvil]

Thats illogical though, when done with the tank you don’t turn it all the way closed then a 1/4 turn open, do you?
The root problem of jammed valves is poor maintenance, really poor maintenance actually.

Also, strapping BCDs to cylinders like that is why the fall off often, that is not the proper way to use those (most popular?) cam bands.
I didn’t watch the whole thing

Logic has little to do with it, it comes from years and years of working with valves. If it is jammed open you may walk up and think it’s closed or you may check it to find out if it’s open and if you’re not in the habit of checking both directions a wrong assumption can result, it just habit for me right or wrong.

an anecdote from home; a few days ago my with went out to water and assuming someone (many contractors coming and going lately) had jammed or over tightened the hose valve, while trying to open it she managed to unscrew the bonnet and pow a nice shower of cold water.

I guess the point is never jam a valve that you don’t intend to repair or replace.

if turning a valve back is controversial and don’t know why, no harm or damage will result from the practice.

 

[happy-diver]

Yeah well I only open my valves one and a half turns or so, so

but I will always do a quarter turn back, beacause it also applies to life, and is the right thing to do

but the righty tighty lefty loosey immature useless as tits on a bull crap when all you have to ask is
how do you turn on the shower


It's good that the video is inclusive

 

[rx7diver]

I watched only until the diver stepped into the water. My routine is very different. For example:

1. When I snap the cylinder into the BC, I immediately check to see if things are sufficiently tight (by oppositely pulling and pushing on the tank valve and the BC backpack).

2. Before connecting my reg, I check to ensure that I can orally inflate my BC to "max", listen (put my ear against the BC) to hear whether the BC is leaking air, check to ensure that I can manually trip the OPV and dump valve, check to ensure that I can dump air using the power inflator/AIR 2 and the OPV and dump valve.

3. Many more steps, including several steps to test whether all of my regs seem to be functioning properly.

If this video is meant to show a recommended "best" sequence of steps to complete before jumping into the water to commence a dive, I think it does NOT do a very good job. It is NOT thorough enough, IMHO.

rx7diver

 

[happy-diver]

Yeah you pull the webbing out of one slot and pull to tighten as closing the buckle then feed the web back

When you feel your wrist cartilages popping as you close the buckle there is no need to checking anything

ever

wet webbing completely unnecessary: myth busted

 

[Pavao]

Logic has little to do with it, it comes from years and years of working with valves. If it is jammed open you may walk up and think it’s closed or you may check it to find out if it’s open and if you’re not in the habit of checking both directions a wrong assumption can result, it just habit for me right or wrong.

The problem with the practice is that if a wrong assumption is made, which often is indeed made, the 1/4 turn practice has no mechanism to detect that the wrong assumption was made.

The 2 methods (1/4 turn and turned all the way) has 4 potential valve positions;
- 1/4 turn open
- 1/4 turn closed
- fully opened
- fully closed
Anyone who has ever worked on a dive boat can attest that frequently divers stand up ready to jump in the water with valves fully closed or 1/4 turned open (shoot, I’ve done it myself, checked SPG during the dive and saw needle drop all the way with every breath). The ones with a valve fully closed just simply failed to do a pre dive check. The ones with a valve only 1/4 turned open, would have not caught that with a pre dive check, and are the ones who made the wrong assumption that their valves are 1/4 turned closed, they may have verified their valves are open, they turned it both directions and it turned freely, they just wrongly assumed it was open all the way and closed 1/4 turn.

So, if we just did fully open and fully closed, there’s only 2 scenarios, it’s either open or closed, if it only turns one direction, and you wrongly assumed it’s open when it was actually closed, a simple pre dive check would detect that instantly.

.

if turning a valve back is controversial and don’t know why, no harm or damage will result from the practice.

The problem with diving a valve that is only partially opened, as in 1/4 turn opened, is that it may not deliver sufficient gas at depth, they’d perform just fine on the surface, at 1 ata, bypassing your SPG/reg function tests during pre dive check, but the deeper you go, the more likely you’d be to find resistance while breathing, and worse, were you to share gas with someone on a emergency, things would get ugly fast. So, there’s the harm!

 

[Endler's]

1/4 turn is an artifact, from the early days of using pillar valves on SCUBA cylinders.
It is not needed on modern valves. Alec explains it here:

 

[greeniguana]

What's with all the clapping and pointing? Looks like I'm watching a dog training video. I'll turn my valve off a 1/4 turn if I get a treat.

 

[lexvil]

The problem with the practice is that if a wrong assumption is made, which often is indeed made, the 1/4 turn practice has no mechanism to detect that the wrong assumption was made.

The 2 methods (1/4 turn and turned all the way) has 4 potential valve positions;
- 1/4 turn open
- 1/4 turn closed
- fully opened
- fully closed
Anyone who has ever worked on a dive boat can attest that frequently divers stand up ready to jump in the water with valves fully closed or 1/4 turned open (shoot, I’ve done it myself, checked SPG during the dive and saw needle drop all the way with every breath). The ones with a valve fully closed just simply failed to do a pre dive check. The ones with a valve only 1/4 turned open, would have not caught that with a pre dive check, and are the ones who made the wrong assumption that their valves are 1/4 turned closed, they may have verified their valves are open, they turned it both directions and it turned freely, they just wrongly assumed it was open all the way and closed 1/4 turn.

So, if we just did fully open and fully closed, there’s only 2 scenarios, it’s either open or closed, if it only turns one direction, and you wrongly assumed it’s open when it was actually closed, a simple pre dive check would detect that instantly.


The problem with diving a valve that is only partially opened, as in 1/4 turn opened, is that it may not deliver sufficient gas at depth, they’d perform just fine on the surface, at 1 ata, bypassing your SPG/reg function tests during pre dive check, but the deeper you go, the more likely you’d be to find resistance while breathing, and worse, were you to share gas with someone on a emergency, things would get ugly fast. So, there’s the harm!

There are some people who don’t only turn scuba cylinder valves in life, I know the valve is closed before I put the regulator on, after that it’s muscle memory.

 

[lowwall]

I quit doing the 1/4 turn back years ago. For those worried about stressing something, just don't slam it open. If you really, really want to turn it back, then do a 16th turn.

 

[RIHappyDiver]

I was certified in the 70s when you had to do the 1/4 turn. When I got back into diving I was told not to. Sometimes I do, usually I don’t, not a big deal to me.
HOWEVER, having a certifying agency teach something that even DAN has said is not a good practice is a bit off putting.

Erik