How did my K-valve get turned "Off" during a dive?

[>--Zen-Archer-->]

I was making a dive at the local dive hole and ran into a problem... At a depth of 36 ft I was looking at my air integrated dive computer and noticed my PSI go from 2600 to about 1000 PSI... I was quite surprised. I check if I had a leaking octo or BC hose what have you... Didn’t see any leaks.. Neither did my dive buddy. Then I went form about 900 PSI to 0 PSI a moment later. I had to grab my buddies octo. My buddy started looking closer and we found that the K-valve was shut off.. He re-opened it and my dive computer showed a bout 2300 PSI. After that we decided to go ahead and end the dive to find how it happened. Once we made it to shore, the only thing we could figure that would have happened was that the Octo hose may have rubbed against the valve handle and slowly closed the valve. I was able to duplicate the problem with the Octo hose and it did slowly close the valve. Has anyone experienced this problem before?... What have you done to remedy the issue?... Don’t want to make another dive until I figure this one out.....

 

[mart1]

Another possibility is the valve was not turned on all the way. This happens more often than you would think and it results in a regulator giving enough air at the surface, but not at depth. Also it would explain the computer readings.

 

[>--Zen-Archer-->]

I believe this may also be true or a combination of both. What worried me was the ease how the Octo hose being moved back and forth was able to slowly close the knob of the valve... I wonder if I need to have my tank secured higher on my BC?

 

[Aquanautchuck]

I think Mati1 is more than likely right. When I do a pre dive reg check on the surface I watch my gage. If it dips or drops quickly the usually means that the valve is not turned on completely. I had a instructor I was DM for on a open water class have this happen to her. She still has not lived it down yet. I think it would be hard for me to believe that if a valve is turned completely on that a octo could turn it off that many turns.

Charles

 

[>--Zen-Archer-->]

Your are probally rigth Aqaunautchuck. Something I dont commonly have a problem with but of course these things can happen. I will double check that valve in the future. Thanks for all your comments.

 

[ianr33]

My guess is that the valve was opened once. Then it was closed in error (thinking it was being opened) and backed off a quarter turn or so. That will leave the valve slightly open.It will breathe fine on the surface but will get increasingly difficult at depth. Happened to a buddy of mine once.He was very happy I was close by.

How to avoid this:
1) have valves either full on or full off,no confusion then
2)Make sure that you can reach your own tank valve

 

[jpcpat]

I'd be shocked if an Octo hose could turn the valve that many turns. One possibility is that you "cracked" the valve to pressurize the reg and then got distracted and forgot to turn it on all the way. The tank might be giving enough at the surface, but not at depth.

It's not impossible that someone turned your air off as a joke. Good save in the OOA situation

 

[LSDeep]

i would second the not fully opened / just cracked valve. u usually can see that fast at the surface by taking a couple quick deep breath of the reg and watch your gauge needle, it will drop and go back up. as you go down and the pressure increases it is like breathing to a straw due to increased gas consumption up to the point that you dont get anything anymore. i never saw / heard about / experienced any hose closing my (or anybodies) valve - but def not argue it, especially since you say you could replicate that. its time to do a serious re - setup / rerouting of your hoses i guess. beside that make sure your valve is really open predive! i personally dont believe in the open it fully and than turn back about half turn at all. its something coming from caving and the potential friction between valveknob and cave ceiling and might have some credebility, it seems more like an urban legend to me (i know some ppl will yell at that). i rather have valves open "full blast" and it never seemed to be a prob.
anyway, reroute your hoses so they dont touch the 1st stage, make sure your valve (s) are open fully at the beginning of the dive.
happy it all worked out without probs, good luck

sven

 

[>--Zen-Archer-->]

Thanks for your comments Sven (LSDeep). I will be reviewing the steps I took in setting up my BC/Tank/Req and how my hoses are routed. Once the needed modifications are made I will test this in a controled enviroment (i.e. my swimming pool) with a buddy to see if I continue having issues. Thanks again.

 

[Ben_ca]

If this should happen again (hopefully not) can you reach your valves?

http://www.scubaboard.com/showthread.php?t=142232