In an effort to pass on any hard earned lessons, I figured I would offer up this recent issue on my SF2. I’ll post later about what we figured out happened.
I was on a three-day monitoring trip, checking out off-shore rigs, and the unit had performed flawlessly for the first three dives, and it was time to change out the scrubber after the first dive of the second day. Repacked, rebuilt the unit and followed my checklist. Cells calibrated fine, MV was an appropriate range. No problems.
First dive was to be 150’ for 20 minutes. I had swapped out my primary CCR tanks for my backups that were 2L instead of 3L, but they were both full (2300, and 3200 psi of O2 and Dill respectively). I had a 40 of basically air (23% maybe) and a 40 of O2 for bailout. I was shooting pictures with a full sized dSLR, so my hands were full for the most part.
We go down to the rig at about 100’, I changed my set point to 1.3 after bringing it up manually. I usually keep it on the low set point and dive it manually, but with the task loading of the camera I decided to use the high setting.
At about 130 I see some cool stuff to take pictures of, spend a minute or two there, get underneath it of it to shoot up and get a good sunball as well and continue down to 150. As I go to take a shot once we have reached depth I notice my HUD is flashing red for cell 1. That’s no good. Check my hand set and cells are reading 1.67, 1.28 and 1.29. Solenoid isn’t going crazy, so I do a dill flush to confirm that cell 1 is the bad one. I really lay on the MAV, circulate the loop, nothing seems to be changing. I realize that once I get a slug of air from my bailout I’m not going to be thinking clearly, but I’ve done the trimix to air swap at depth before so at least I know what I’m in for. So I switched to OC on my BOV, get my buddies attention to pass off the camera. Get instantly narked. Whoo-hoo! I get back on the loop, flush again, now cell 1 is 1.3, and 2 and 3 are 1.6. I have probably floated up to about 130 at this point. Maybe I’m not circulating the gas enough? I exhale out my nose/loose lips until the counter lung bottoms out and nothing happens with gas addition. Manually add, no gas addition. WTF? Check my dill SPG and it is empty.
Still narked, swap back to OC, plug in my off board addition and then back on the loop once I have something to breathe. I then think of all the stories I’ve heard of people getting off the loop, addressing a problem, getting back on the loop and being dead five minutes later. I get off the loop before taking a breath and call the dive. Turns out Shrimp BOVs work great at 150’, I didn’t even swap out to my regular second stage until I switched gasses at 20’.
So any guesses as to what was going on?
-Chris
I was on a three-day monitoring trip, checking out off-shore rigs, and the unit had performed flawlessly for the first three dives, and it was time to change out the scrubber after the first dive of the second day. Repacked, rebuilt the unit and followed my checklist. Cells calibrated fine, MV was an appropriate range. No problems.
First dive was to be 150’ for 20 minutes. I had swapped out my primary CCR tanks for my backups that were 2L instead of 3L, but they were both full (2300, and 3200 psi of O2 and Dill respectively). I had a 40 of basically air (23% maybe) and a 40 of O2 for bailout. I was shooting pictures with a full sized dSLR, so my hands were full for the most part.
We go down to the rig at about 100’, I changed my set point to 1.3 after bringing it up manually. I usually keep it on the low set point and dive it manually, but with the task loading of the camera I decided to use the high setting.
At about 130 I see some cool stuff to take pictures of, spend a minute or two there, get underneath it of it to shoot up and get a good sunball as well and continue down to 150. As I go to take a shot once we have reached depth I notice my HUD is flashing red for cell 1. That’s no good. Check my hand set and cells are reading 1.67, 1.28 and 1.29. Solenoid isn’t going crazy, so I do a dill flush to confirm that cell 1 is the bad one. I really lay on the MAV, circulate the loop, nothing seems to be changing. I realize that once I get a slug of air from my bailout I’m not going to be thinking clearly, but I’ve done the trimix to air swap at depth before so at least I know what I’m in for. So I switched to OC on my BOV, get my buddies attention to pass off the camera. Get instantly narked. Whoo-hoo! I get back on the loop, flush again, now cell 1 is 1.3, and 2 and 3 are 1.6. I have probably floated up to about 130 at this point. Maybe I’m not circulating the gas enough? I exhale out my nose/loose lips until the counter lung bottoms out and nothing happens with gas addition. Manually add, no gas addition. WTF? Check my dill SPG and it is empty.
Still narked, swap back to OC, plug in my off board addition and then back on the loop once I have something to breathe. I then think of all the stories I’ve heard of people getting off the loop, addressing a problem, getting back on the loop and being dead five minutes later. I get off the loop before taking a breath and call the dive. Turns out Shrimp BOVs work great at 150’, I didn’t even swap out to my regular second stage until I switched gasses at 20’.
So any guesses as to what was going on?
-Chris
