Full on, and a little off
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faze
Contributor
Thanks GRF88... that was the article that prompted this thread - I'm more than familiar with it - my original question stands
I have heard the some of the early scuba valves had a tendency to jam if they were left in a full on position and this was the origin of this technique. I do not know if this was actually the case but the method was taught for many years. At this time most of the diving agencies have changed their recommendation to full on, no need to jam it against the stop but turned on all the way.
AfterDark
Contributor
I've been backing valves off the open stop since I've been 18 years old. Scuba, tanks, propane tanks, any valve. One quarter turn? I don't measure, just open to the stop and take it off. It maybe 1/4, 1/8, 1/16, or 1/32 turn, it just ain't touching the stop. The reason is to be sure it's not so hard against the stop that it can't be turned off except by the Hulk.
claymore
Contributor
In some applications there is a reason for the quarter turn back from full open. In applications where the valves are open for long periods of time and or exposed a nasty environment, steam and chemical lines come to mind, the quarter tun back help keep the valve from seizing to the back stop.
Scuba valves do not fall under either of these conditions.
Scuba valves do not fall under either of these conditions.
Bottom line:
Last thing I always do before going into the water is to take a couple of deep drags on the reg while looking at the pressure gauge.
Saved my tail in Cancun where a member of crew claimed my gear was all ready to go. [Type of operation where you back roll off the boat and pass gear back onto boat before climbing aboard. Gear set up by the time you get to it.]
Last thing I always do before going into the water is to take a couple of deep drags on the reg while looking at the pressure gauge.
Saved my tail in Cancun where a member of crew claimed my gear was all ready to go. [Type of operation where you back roll off the boat and pass gear back onto boat before climbing aboard. Gear set up by the time you get to it.]
LeadTurn_SD
Contributor
Your question was answered. In the early days, we were taught to open the valve fully, then back it off a hair (but not a quarter turn). This is what I was taught when I started diving in 1976, and was told we did this to prevent the valve from getting stuck in the open position... FYI, 1/4 turn is quite a lot, actually way too much. Tank valve do not require very many turns to open or close fully... if you feel the need to back them off, just a tiny "smidge" is enough.
I was taught the very same thing with valves on oil tankers... 'cuz you really do not want a valve stuck open on a ship.... but I digress.
There is nothing wrong with backing off the valve just slightly (I back mine off a millimeter or two), unless you one those folks (and you know who you are) who forget which direction opens and closes valves.... "Righty-Tighty, Lefty-Loosey" is the proper engineering terminology.... and once again, I digress....
For my kids and anyone who cares to listen, I just always tell them open all the way or close all the way, unless I am absolutely sure they are not "Righty-Tighty / Lefty-Loosey" challenged. That way they will never accidentally jump in the water with a partially opened valve.
Best wishes.
LowDrag
Contributor
IN my SSI OW course we were taught to open fully then back off 1/4 turn. After reading this thread I believe I will go full open/close. It just makes sense.
markmud
Self Reliant Diver--On All Dives.
Hello all,
I was a tankerman and was taught the 1/4 back method. I also remember instructing deckhands on barges the 1/4 back method after they jammed valves and delayed 40,000 barrel transfers. Valves, bolts, and propellers definitely have a left and a right hand. No bull.
On one boat dive, I jumped in the water with gear that was tested on the bench. Unfortunately, the vessel's master turned off the valve on the way to the swim step.
I now check my reg while on the swim step with my SPG in my hand to watch the results of my breathing test.
Also, I was taught to dive by a former commercial diver--he and I were on the same wavelength in regard to the ocean being a hostile environment that likes to kill things (like me!). He made sure that I was aware of contingency actions that were required when things went south. Things always go south on the ocean.
When I jumped in the water with my valve off, exhaled and then could not breath while sinking, I prepared to do a CESA from 3 fsw. I had my BC off and ready to ditch, but then when I checked the valve it was closed. I turned it on and filled up my lungs with air and became neutral. I put my BC back on and went diving.
My point is this: No matter if your valve is full on or 3 degrees backed-off, some idiot, which includes you, could have it "righty-tighty." If you don't have the training and mental capacity to be self-reliant, maybe you should not be diving. If you are an instructor who isn't teaching students to ditch their sinkers or gear, or realize at 30 feet that if their regulator is working oddly, and then at 40 feet the issue is worse, and then to automatically abort the dive, why are you teaching SCUBA?
The pressure gradient in the ocean is linear. A diver who dies because they can't breath at 60 fsw because their valve is 1/4 on had indications of trouble at 30, 40, and 50 fsw. This reminds me of my friend whose computer was screaming at her regarding staged decompression. She did not know what her computer was telling her (I helped her). When we got on the boat, she said: "What was my computer screaming about!" And then she said: "Oh, what is staged decompression." Who the F trained her to dive?
My valve-off incident (less than 15 dives into my diving career) combined with a completely defective first stage (cracked body from the factory; it died on my 25th dive), convinced me to always take a pony bottle rig when I dive. If I want to survive the trouble that the ocean will always dish-out, I had better be self-reliant. I was not going to rely on a buddy who ditched me when my reg took its final dump (true story), nor was I going to rely on my buddy to turn on my air while I was sinking to the bottom.
IMHO, markm
I was a tankerman and was taught the 1/4 back method. I also remember instructing deckhands on barges the 1/4 back method after they jammed valves and delayed 40,000 barrel transfers. Valves, bolts, and propellers definitely have a left and a right hand. No bull.
On one boat dive, I jumped in the water with gear that was tested on the bench. Unfortunately, the vessel's master turned off the valve on the way to the swim step.
I now check my reg while on the swim step with my SPG in my hand to watch the results of my breathing test.
Also, I was taught to dive by a former commercial diver--he and I were on the same wavelength in regard to the ocean being a hostile environment that likes to kill things (like me!). He made sure that I was aware of contingency actions that were required when things went south. Things always go south on the ocean.
When I jumped in the water with my valve off, exhaled and then could not breath while sinking, I prepared to do a CESA from 3 fsw. I had my BC off and ready to ditch, but then when I checked the valve it was closed. I turned it on and filled up my lungs with air and became neutral. I put my BC back on and went diving.
My point is this: No matter if your valve is full on or 3 degrees backed-off, some idiot, which includes you, could have it "righty-tighty." If you don't have the training and mental capacity to be self-reliant, maybe you should not be diving. If you are an instructor who isn't teaching students to ditch their sinkers or gear, or realize at 30 feet that if their regulator is working oddly, and then at 40 feet the issue is worse, and then to automatically abort the dive, why are you teaching SCUBA?
The pressure gradient in the ocean is linear. A diver who dies because they can't breath at 60 fsw because their valve is 1/4 on had indications of trouble at 30, 40, and 50 fsw. This reminds me of my friend whose computer was screaming at her regarding staged decompression. She did not know what her computer was telling her (I helped her). When we got on the boat, she said: "What was my computer screaming about!" And then she said: "Oh, what is staged decompression." Who the F trained her to dive?
My valve-off incident (less than 15 dives into my diving career) combined with a completely defective first stage (cracked body from the factory; it died on my 25th dive), convinced me to always take a pony bottle rig when I dive. If I want to survive the trouble that the ocean will always dish-out, I had better be self-reliant. I was not going to rely on a buddy who ditched me when my reg took its final dump (true story), nor was I going to rely on my buddy to turn on my air while I was sinking to the bottom.
IMHO, markm
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