Unusual OOA

[JerseyJersey]

I had an interesting discussion with someone about the merits of allowing training dives to extend to thirds or just planning shorter dives with specific skills and ending the dive when they are done. My feeling was there was a lot to be learned in regards to your gas management from continuing to thirds….IF you are paying attention. An unusual situation arose I thought I would share for discussion including both an OOA and if I was paying attention.

I dive a Nomad XT and broke a bungee; I was unable to get the same length one to replace it so ended up with 2 bungees the next length longer. Unsure how much this would affect where my tanks sat I joined two other divers on a test run down the Waterhole Tunnel at Peacock. I dive 85’s and my two team mates used larger tanks.

We started off with me in the middle and it didn’t take long to realize there was an issue with the tanks hanging too low. I found myself having to either lift them in the tighter areas or push the tanks back to inflate my wing and I corrected my buoyancy much more often because I was not used to having something hang lower than my chest during a dive. This was not really an issue just a PIA and I fiddled a bit with my butt plate attachment and pulling up the tank necks as I swam looking for better trim.
We reached the breakdown at the end of the Waterhole Tunnel, an area of silt bottom with the occasional rock sticking up, and turned the dive and I don’t think we were 2 minutes on our way back when an inhale brought me no air. Now your first thought is disbelief, that you made a mistake, another inhale and you will get air. When that doesn’t happen the string of words that run through your brain would make a sailor proud and I did not let them down.

I was lucky to have not one but two different instructors during my training that focused on two things. Managing an emergency and managing gas. I of course switched to my other regulator and in trying to manage my buoyancy I realized that my inflator was not working either. I got to the side where there was more rock than silt and made sure I had my team’s attention. This is where I now realize I owe thanks to these instructors as I had already assessed all my options without looking at my tank yet. From training and using my thirds, I knew how far I could go, what fiddling could cost me in gas and how far back I could get on what was left in my remaining tank. I also knew what should be in that wayward tank and that it didn’t just sneak out while I wasn’t looking. I was paying attention and it is a little unnerving to know how tight it was going to be getting out without help.

Now steadied, I started assessing my regulator and tank when I noted my gauge hose was limp meaning one of two things. My tank was really really really empty….. or the valve had rolled off. An unusual thing to happen sidemounting so therefore not my first thought. Roll off it was and it happened once more on my way out.

In constantly adjusting my tanks and pushing them back to use my wing and drysuit inflator I had slowly rolled the valve off on my left side….. and in swimming out I managed to do it again and much more quickly. The rub of my suit against the valve as I repeatedly pushed it back.

Knowing my gas management and use, and being able to put rough estimates in my head helped quickly assess the problem and not stress too much. Knowing my team had big tanks that were still flowing was even better. Staying calm and doing all this in under a minute I am appreciative of my teachers and mentors.

It was a great dive; I always enjoy the Waterhole Tunnel and Peacock System. Just sharing an unusual type of OOA for others to file away just in case and a reminder to others in training to make sure they take advantage of all you can learn in your courses.

[sskasser]

Thank you, Cheryl. I'm glad it all turned out well and appreciate you sharing this.

[skip]

roll off in sidemount? never thought of it. thanks for the heads-up. cool head too, way to go.

skip

[Greenwood_60]

How are your tanks clocked? I have considered a roll off in side mount, but only long enough to decide it was nearly impossible.

[FW]

How are your tanks clocked? I have considered a roll off in side mount, but only long enough to decide it was nearly impossible.

It is pretty hard to roll-off in sidemount, but not impossible. If you rub the tanks against yourself, like "J.J." did, it can happen. I "clock" my tanks with the 1st stages up, to keep them from dragging on rocks, and the valve knobs towards my body, so they can't rub on rocks, and possibly roll-off, or get damaged.

I have to agree she was really cool. If it weren't for her flashing me, I wouldn't have known there was a problem, even when I was watching her solve the problem. Most times in the past when a buddy had a gas issue, they came flying at me to get gas.

[Greenwood_60]

I "clock" my tanks with the 1st stages up, to keep them from dragging on rocks, and the valve knobs towards my body, so they can't rub on rocks, and possibly roll-off, or get damaged.

I basically do the same, but reversed. My tanks are flopped from BM, regs in towards my body, handles up. Puts the post in prime position for a loop bungee.

[a64pilot]

Mine are reg down and valve out. I used to only partially open the valve as the only equipment failure I have ever had was on my Tr-Mix check out dive, very first breath from the Deco bottle I heard a pop and the reg went to free flow. I had plenty of back gas to deco out on, so I wasn't real worried but it was easy to feather the valve, this taught me to only open the valve a couple of turns so I could turn it off fast if needed. Fast forward to me diving in PC open water with my kids, one of the "wrecks" had a stair case that I swam through and the valve must have rolled against the steel sheet side of the stair case and rolled off. I knew I couldn't be out of air, but didn't figure it out until after I switched regs. Of course I didn't suck a vacuum until I had no air in the lungs, and let me tell you when your lungs are empty, air hunger sets in real quick. Now I do the full open and close only a little thing that I was taught so long ago, again. I think it was the flat smooth steel against the rubber valve handle that made it happen so easily.

[JCGoodwin]

Force of habit I check valves often not even always knowing it anymore.
Not just cave dives but all dives.
BM or SM it keeps valve drills and or emergency issues sharp.

I was on a dive with a new SM diver in OW that had a rub off as well.
It was a good learning experience for both of us.
Thus even if diving a single tank I make it a practice to check the valve.

JCG

[Greenwood_60]

I have a habit of purging my reg to clear it on switches, rather than exhaling to do so. I figure it's better to find out it's off with my lungs full rather than empty.

[AB8CD]

I have a habit of purging my reg to clear it on switches, rather than exhaling to do so. I figure it's better to find out it's off with my lungs full rather than empty.

+1 on this method.