Mike Walker
Contributor
I've had the exact same thing happen. It is definitely possible to get to a point where the valve is barely open but breathes fine at the surface (deep breaths watching SPG) but then has issues at depth. In my case SPG/transmitter pressure started bouncing a couple minutes into the dive. No OOA, but breathing was a bit more labored than normal.
It was an awkward/rough entry with a go-around/false start before we dropped. It's possible it was someone 'doing me a favor' that got things out of sync. I've always been particular that once my valve is on, it's on, even if I lose a bit of air to leakage in a long dingy ride or similar. That being said, there were also some leaky o-rings on both tanks that day so I may have broken my own rule....
Since that - and based on some reading here and elsewhere - I now leave valve fully open or fully closed. No turning it back a bit - a procedure that apparently is completely unnecessary with modern valves. If the valve is at a hard stop and the needle doesn't bounce it gives me better certainty of on or off.
It was an awkward/rough entry with a go-around/false start before we dropped. It's possible it was someone 'doing me a favor' that got things out of sync. I've always been particular that once my valve is on, it's on, even if I lose a bit of air to leakage in a long dingy ride or similar. That being said, there were also some leaky o-rings on both tanks that day so I may have broken my own rule....
Since that - and based on some reading here and elsewhere - I now leave valve fully open or fully closed. No turning it back a bit - a procedure that apparently is completely unnecessary with modern valves. If the valve is at a hard stop and the needle doesn't bounce it gives me better certainty of on or off.