Well, a new one for me tonight.
My husband and I met NW Grateful Diver and a newer diver for a night dive at a familiar local site tonight. Peter and I were both diving 32% Nitrox, both with tanks picked up from the same shop and I believe on the same day, although I'm not sure.
At the site, we agreed to dive as a foursome, but with two teams -- Bob and I were diving together, and Peter and Kelly were a second team. The plan was to go down to the bottle field (at approximately 90 feet) and spend a few minutes there, and then work our way upslope. A good gear check was done before descending, and descent and the swim downslope was uneventful. We spent about 20 minutes of total dive time swimming down and enjoying a number of small octopuses in the bottle field, and then we started up.
At about 70 feet, I saw a rapid light signal from behind me -- not an out of gas signal, but faster than our normal "look at the cool fish" signal. I turned around and saw Peter, who gave me the PADI "share gas" signal, the one that involves the hand going forward and back in front of the regulator. I was completely confused by this, but he shortly converted to a more normal out-of-gas signal across the throat. Although my immediate reaction was, "You're not even MY buddy, and what are you doing pulling a drill in 70 feet of water at night?", I obediently donated my reg. I have been asking to do more S-drills, and I honestly thought that's what this was. Except that, when I gave the "okay?" signal, I didn't get an answer. I repeated it, thinking maybe I hadn't lit my hand well, and what came back was . . . a thumb.
Oh, dear; something is clearly wrong, and we are now to do a free ascent from 70 feet in the dark. Peter signals Bob and Kelly to buddy up, and I go into my pocket to get my SMB (thank goodness I had it with me; I've done a few shore dives recently where I've been too lazy to put on pockets, and that won't happen again after tonight). I don't want to do a free, air-sharing ascent in the dark with no visual reference for vertical. But as I prepare to shoot the bag, Peter signals again, "expedited exit", and I realize whatever is wrong, he's okay with swimming upslope, rather than ascending where we are. So we begin to do that, and luckily, Bob intervenes with my navigation, because although I would have gotten us to shore, his route was quicker.
We do what is, for us, a rapid ascent (I think it took three minutes or so to get to 15 feet, where we spent about a minute, and then ascended.) On the surface, Peter told me he thought he had bad gas. He got a bad, oily taste at depth and began to feel nauseated. It got worse over a couple of minutes, so he wanted to have someone else's gas to breathe, to see if he felt better. He told me my gas tasted much better, but he was still nauseated and that's why he thumbed the dive.
Bob and I both breathed his gas once we got back to the car, and neither of us could detect anything odd.
Lessons from this dive: Some signals are simply commands, and you may not know why your buddy has given them, but you don't stop to ask. Asking for air is one of those, and the thumb is another. I didn't understand why either signal was given, and it didn't matter.
Second one for me, a team of four is confusing. Once Peter and I were sharing gas, to me, we were a team of two; I didn't make nearly a good enough effort to make sure the other two divers knew what was happening. Not that I knew what was happening, mind you, but at least I could have told Bob that Peter and I were going to ascend (which we ended up not doing). I believe he did see Peter's signal, but I was the unstressed diver, and should have made sure he and Kelly got it.
Third, the long hose gives you options. I had tons of gas, and once Peter felt he was on a clean breathing supply, there really was no reason not to swim upslope. Ascending where we were would have been more difficult (free ascent at night) and would have landed us on the surface a very long surface swim from shore.
And finally, any weaknesses in your dive will show up when something goes wrong. In this case, I did not identify the fastest route to shore. I was headed in, but too far south. The site is one I don't dive often, and we were off the routine navigation markers, and I didn't have time to look for them. Because Bob and Kelly stayed with us, we had better navigational information, because Bob practically lives at this site, and knew precisely where we were.
What made Peter sick is unclear. If there is anything wrong with the gas (which I doubt, since I'm pretty sure my tank was filled at the same place and at the same time) it wasn't apparent until we were at the deepest part of the dive. Is it possible that there is something in the gas that isn't a problem until it's concentrated? I suppose. But that still doesn't explain why my tank was fine.
It was a strange episode, not handled perfectly, but certainly handled well enough to get everybody home in good shape.
My husband and I met NW Grateful Diver and a newer diver for a night dive at a familiar local site tonight. Peter and I were both diving 32% Nitrox, both with tanks picked up from the same shop and I believe on the same day, although I'm not sure.
At the site, we agreed to dive as a foursome, but with two teams -- Bob and I were diving together, and Peter and Kelly were a second team. The plan was to go down to the bottle field (at approximately 90 feet) and spend a few minutes there, and then work our way upslope. A good gear check was done before descending, and descent and the swim downslope was uneventful. We spent about 20 minutes of total dive time swimming down and enjoying a number of small octopuses in the bottle field, and then we started up.
At about 70 feet, I saw a rapid light signal from behind me -- not an out of gas signal, but faster than our normal "look at the cool fish" signal. I turned around and saw Peter, who gave me the PADI "share gas" signal, the one that involves the hand going forward and back in front of the regulator. I was completely confused by this, but he shortly converted to a more normal out-of-gas signal across the throat. Although my immediate reaction was, "You're not even MY buddy, and what are you doing pulling a drill in 70 feet of water at night?", I obediently donated my reg. I have been asking to do more S-drills, and I honestly thought that's what this was. Except that, when I gave the "okay?" signal, I didn't get an answer. I repeated it, thinking maybe I hadn't lit my hand well, and what came back was . . . a thumb.
Oh, dear; something is clearly wrong, and we are now to do a free ascent from 70 feet in the dark. Peter signals Bob and Kelly to buddy up, and I go into my pocket to get my SMB (thank goodness I had it with me; I've done a few shore dives recently where I've been too lazy to put on pockets, and that won't happen again after tonight). I don't want to do a free, air-sharing ascent in the dark with no visual reference for vertical. But as I prepare to shoot the bag, Peter signals again, "expedited exit", and I realize whatever is wrong, he's okay with swimming upslope, rather than ascending where we are. So we begin to do that, and luckily, Bob intervenes with my navigation, because although I would have gotten us to shore, his route was quicker.
We do what is, for us, a rapid ascent (I think it took three minutes or so to get to 15 feet, where we spent about a minute, and then ascended.) On the surface, Peter told me he thought he had bad gas. He got a bad, oily taste at depth and began to feel nauseated. It got worse over a couple of minutes, so he wanted to have someone else's gas to breathe, to see if he felt better. He told me my gas tasted much better, but he was still nauseated and that's why he thumbed the dive.
Bob and I both breathed his gas once we got back to the car, and neither of us could detect anything odd.
Lessons from this dive: Some signals are simply commands, and you may not know why your buddy has given them, but you don't stop to ask. Asking for air is one of those, and the thumb is another. I didn't understand why either signal was given, and it didn't matter.
Second one for me, a team of four is confusing. Once Peter and I were sharing gas, to me, we were a team of two; I didn't make nearly a good enough effort to make sure the other two divers knew what was happening. Not that I knew what was happening, mind you, but at least I could have told Bob that Peter and I were going to ascend (which we ended up not doing). I believe he did see Peter's signal, but I was the unstressed diver, and should have made sure he and Kelly got it.
Third, the long hose gives you options. I had tons of gas, and once Peter felt he was on a clean breathing supply, there really was no reason not to swim upslope. Ascending where we were would have been more difficult (free ascent at night) and would have landed us on the surface a very long surface swim from shore.
And finally, any weaknesses in your dive will show up when something goes wrong. In this case, I did not identify the fastest route to shore. I was headed in, but too far south. The site is one I don't dive often, and we were off the routine navigation markers, and I didn't have time to look for them. Because Bob and Kelly stayed with us, we had better navigational information, because Bob practically lives at this site, and knew precisely where we were.
What made Peter sick is unclear. If there is anything wrong with the gas (which I doubt, since I'm pretty sure my tank was filled at the same place and at the same time) it wasn't apparent until we were at the deepest part of the dive. Is it possible that there is something in the gas that isn't a problem until it's concentrated? I suppose. But that still doesn't explain why my tank was fine.
It was a strange episode, not handled perfectly, but certainly handled well enough to get everybody home in good shape.
