Quote: (Originally Posted by
Drmike)
I never let the CL fill so much on ascent that the opv has to open - no need, and no need to crush lungs manually. On ascent I simply shut the adv off and nose vent to keep min loop and that also helps keep setpoint too at same time (high) People not maintaining min loop and letting OPVs control lung vol an ascent is probably one reason you seldom see ECCR divers with horizontal trim during ascents
I suspect if people find they cant keep up with expanding CL volume on ascent by nose/mouth venting they are probably ascending too fast.
Yes, I'm sure you're right that if somebody were to let their CLs fill up to the point that the OPV opens on it's own, their trim will be lousy and they're going up too fast. In my case, the OPV is high up on the lung, where the most of the volume is and only takes me lightly putting my hands on the lung or OPV to get the excess gas out.
Quote: (Originally Posted by
Drmike)
If mouth venting you only break lip seal when you sense a pressure differential. No water should enter the dsv then provided you maintain depth or are ascending. Unlike nose venting, the trouble with mouth venting is you cant maintain min loop vol this may effect trim adversley during ascents
OK, maybe I get water in the DSV through mouth venting for some other reason, maybe it was because I was using it for the fine tune at the stop and not so much during the ascent itself.
Quote: (Originally Posted by
Drmike)
why dont they lower the opv opening pressure when diving by unscrewing it? (thats how its designed to be dived and how I dived my inspiration) Locking it down is done for over pressure testing only.
I don't know, maybe they just didn't want to bother with it. But I remember at least one of them saying that even when it's opened all the way, it's still too stiff.
Quote: (Originally Posted by
Drmike)
Dont you mean the other way around?. Rich dils aid overshoot
Maybe, I've only used a 1.8 MOD dil a few times and I remember the solenoid firing less frequently during the descent. My ascents tend to be a bit fast though.
Quote: (Originally Posted by
Drmike)
What do people think will happen if they spike their ppo2 to say 2bar on descent for a few seconds before further descent causes the adv to fire in dil that will lower it? - sweet FA I should think
personallly I always spike my ppo2 momentarily well over setpoint on descent as I want to test for current limitation
before the dive not after
Yes, I have never had a problem doing this and yes the dil does in fact, dilute the O2 when the ADV fires, who knew?