Tank not turned on all the way

[CamaroChick]

I thought I'd share a scary experience we had last week while diving in Roatan. This was our Deep Dive certification class and my husband's air wasn't turned on all the way

The DMs had us set up our gear on the pier (including turning on the air and testing everything), and then the captain would haul it into the boat and turn off the air before we rode out to the dive site. Then he'd turn it back on right before we got in. Well, the tank valve was a bit "sticky" and it felt like it was all the way on, but still had a few turns to go. Hubby said his gauge read 3000 PSI and he breathed normally until we got down to 90'. He said then it got harder to take breaths, and when he did, his pressure gauge would drop down to zero and then slowly inch back up to the actual PSI. Somehow he stayed calm and did the whole dive like that. Then when we were doing the safety stop, he signaled to me that he was out of air, which I thought was strange because just a few minutes ago he was at 1000 PSI. I gave him the octo, thinking maybe he was just practicing the skills. He actually wasn't getting any more air from the tank, even though there was still about 1000 PSI left.

We told the DMs and they blamed it on a faulty first stage (even though our equipment was brand new). After thinking all day about what the real cause could have been, he figured out it might have been the tank valve. He did a little experiment and was able to reproduce the incident with a tank that was only partially turned on. It appeared to be a combination of an older tank valve and the first stage rubbing against the rubber cover of the tank valve that made it feel like it was on all the way.

Very scary!! I don't know how he stayed so calm, but I'm glad to have him as my buddy. I know you're always responsible for your own gear setup, but this seems like a mistake that could easily happen in this kind of situation. So our lesson learned is - always turn that value yourself before you put on the BC!

[bassplayer]

thanks for sharing that experience

[waytooslow]

wow he must have nerves of steal - I wonder how I would handle that ... Sounds like the whole trip had some issues

[mwhities]

I'm glad he's ok. That's why my buddy and I double check everything. With the tank, we turn it on all the way and when it stops, try turning a little more with a strong arm. Then we back off a half turn.

[CamaroChick]

Originally Posted by waytooslow

wow he must have nerves of steal - I wonder how I would handle that ... Sounds like the whole trip had some issues

Yeah, but I swear we had a good time! I'll start posting about the good stuff soon... promise!

[BSea]

Based on what he described with it dropping to zero then inching back up, I'd say you're correct in assuming it was the valve not being turned on all the way. Many times a DM will check your valve to be sure it's open all the way. It's not unheard of for someone to have their tank valve on, and the DM think it's closed. Then turn it off & open it a half turn. This happened on a trip I was on to another diver.

An easy way to check is to purge your reg before your dive & watch the pressure gage. If the tank is turned on all the way, you won't notice much of a change in pressure. If it drops significantly & goes back up, then you might have a problem with the valve not being turned all the way on. It could be other things, but this is a good quick check.

[JimHar99]

I'm glad your husband is OK.

I don't think I would have done a dive like that. If my SPG went to zero every time I took a breath, I would have my buddy check if my valve was open all the way. If he signaled that it was, I would ask to share air and abort the dive.

This is also the reason that I don't trust anyone to setup my equipment for me. I also had a problem once where the crew was taking care of equipment for us.

[ianr33]

Originally Posted by BSea

An easy way to check is to purge your reg before your dive & watch the pressure gage. If the tank is turned on all the way, you won't notice much of a change in pressure. If it drops significantly & goes back up, then you might have a problem with the valve not being turned all the way on. It could be other things, but this is a good quick check.

I keep my valves all the way open.Do not turn them back at all.Less chance of mistakes that way.It either works or it does not.

Take some strong breaths from each reg on the surface while looking at the spg.If valve is open spg will not move. If valve is closed will be very obvious.

I had a buddy once start a dive with a valve 1/2 turn open.It breathed OK at the surface and the spg did not move.Got very hard to breathe at 90 feet though. We shared air,I fully opened the valve and we carried on.

How many divers can actually reach their valves in the water? A great skill to have. (I mainly dive doubles these days which makes it much easier.)

[CompuDude]

I agree... a bouncing pressure needle is a classic sign of the valve only being partially open. It will pressurize the line, but not quickly, so it takes time to refill/repressurize, thus the bouncing needle.

It's good that he's ok, and now that you've seen this happen, if it ever happens again you'll know how to quickly and easily fix things underwater.

This is how we grow as divers.

This is one reason why I'm a big proponent of rigs that allow you to reach your own valves. I turn my own gas on at the water's edge quite frequently... because I can, and because then I KNOW everything is as it should be.

[ReefHound]

It could also be a clogged filter.