This past Sunday, I went for a dip in my local large body of water, Lake Tahoe. My typical dive is right around 100 minutes, on air, with some mandatory deco, and Sunday's dive was pretty typical. I went to Sand Harbor and dove Diver's Cove (not my favorite, but they shovel the snow here, so getting to the water is easy). Temps were around 32F/0C outside and 44F/7C in the water. I was diving two HP100s sidemount. In the parking lot, I had some trouble getting a reg to seat. I'm not a reg tech (yet), so forgive the following: the bit that takes an allen key and holds the DIN o-ring was a little loose. I tightened it by hand, put everything together, confirmed it was working, and thought nothing of it.
The first part of the dive went swimmingly. I took some pictures at the Project Baseline station to report on visibility, and then made my way to the deep portion of the dive. About an hour in, the reg that hadn't been seating properly started to bubble a little. When I reached back and grabbed the SPG to check tank pressure, the movement on the reg dramatically increased the amount of bubbling. At that point, it was time to turn the dive, obviously. I had 1600 psi in the free flowing tank, which I shut down, and 2,000 psi in the one I'd switched to. I also had 17 minutes of deco at 10 feet to complete (GF 65/80). On the ascent, I tried turning on the free flowing cylinder again, and it seated and worked for a couple breaths before starting to free flow again. I finished my dive on the other cylinder, even staying in the shallows for another 10 or so minutes after clearing my deco obligation. Ultimately, I exited with 600 psi and 1600 psi after 97 minutes, and the worst part of the dive was being lopsided from only breathing one tank.
I hesitated to post anything about this because it didn't even fluff up my SAC rate. It was a dive site I know well, using equipment I'm very comfortable with. I had factored in such issues and had plenty of gas to complete my deco, even considering one cylinder completely lost, which it wasn't. I've done more than 150 solo deco dives, and this is the first real incident. Even though the reg failed at basically the "worst" time (i.e., after I'd already racked up nearly the full amount of planned deco), planning, familiarity, and training made it a non-issue.
I recently picked up a set of doubles with the plan of re-familiarizing myself with the setup. I've been diving SM exclusively for a couple years, which I switched to from doubles. It occurred to me that the experience I described above would be different in a couple meaningful ways had I been in a twinset. First, identifying and addressing the problem would have been slightly more difficult with it behind my head. Second, after addressing the issue, I would have had access to all the remaining gas, not just some. A bit of a wash, but it has made me look at getting a hand mirror.
This is one I'm going to keep from my very understanding wife, but I wanted to share it somewhere, hopefully for someone's benefit. Safe diving!
Showing the camera the free flow while on deco
The first part of the dive went swimmingly. I took some pictures at the Project Baseline station to report on visibility, and then made my way to the deep portion of the dive. About an hour in, the reg that hadn't been seating properly started to bubble a little. When I reached back and grabbed the SPG to check tank pressure, the movement on the reg dramatically increased the amount of bubbling. At that point, it was time to turn the dive, obviously. I had 1600 psi in the free flowing tank, which I shut down, and 2,000 psi in the one I'd switched to. I also had 17 minutes of deco at 10 feet to complete (GF 65/80). On the ascent, I tried turning on the free flowing cylinder again, and it seated and worked for a couple breaths before starting to free flow again. I finished my dive on the other cylinder, even staying in the shallows for another 10 or so minutes after clearing my deco obligation. Ultimately, I exited with 600 psi and 1600 psi after 97 minutes, and the worst part of the dive was being lopsided from only breathing one tank.
I hesitated to post anything about this because it didn't even fluff up my SAC rate. It was a dive site I know well, using equipment I'm very comfortable with. I had factored in such issues and had plenty of gas to complete my deco, even considering one cylinder completely lost, which it wasn't. I've done more than 150 solo deco dives, and this is the first real incident. Even though the reg failed at basically the "worst" time (i.e., after I'd already racked up nearly the full amount of planned deco), planning, familiarity, and training made it a non-issue.
I recently picked up a set of doubles with the plan of re-familiarizing myself with the setup. I've been diving SM exclusively for a couple years, which I switched to from doubles. It occurred to me that the experience I described above would be different in a couple meaningful ways had I been in a twinset. First, identifying and addressing the problem would have been slightly more difficult with it behind my head. Second, after addressing the issue, I would have had access to all the remaining gas, not just some. A bit of a wash, but it has made me look at getting a hand mirror.
This is one I'm going to keep from my very understanding wife, but I wanted to share it somewhere, hopefully for someone's benefit. Safe diving!
Showing the camera the free flow while on deco
