Inspired O2: how good are You?

[DiveNav]

How good are You at managing the PO2 levels when diving CCR?

Let's say you are exploring the USS Oriskany and your dive profile has a max depth of 50m with a 10m saw tooth in the middle.
Your planned PO2 level for the dive is 0.9 switching to 1.2 when you begin your final ascent. Your diluent is Trimix 15/50.

How good are you at keeping your PO2 close to 0.9ATA? Specially during the descent legs of your dive?

What is your MO?

Do you have graphs to back it up?

Alberto (aka eDiver)

 

[w ripley]

I'm not one for changing my set point during a dive, and do my best to maintain the planned PPO2. I fly my unit as an eCCR, and give my unit time to adjust as depth varies, or help it along when I need to.

Because I tend to do long dives, my set point is selected base on the maximum PPO2 I'm comfortable with + the exposure time table. A 3-hour dive, for example, would start and end with a PPO2 of 1.3, regardless of the profile. That gives me a 180 min max for a single dive, so I wouldn't want to increase that exposure by pushing up my PPO2 on the ascent.

I also look at the other dives I've done prior and that I want to do after that, if on a multi-day dive trip; All of that oxygen does add up. If I'm only doing a single dive, and I cut it short for some reason, I will push up the PPO2 at the end, just to get out of the water faster, especially if the water is very cold.

I don't worry too much about my PPO2 as I decend, as I can usually breathe it down in a minute or two. If it gets crazy I'll dilute it, but normally I'll let it go down on it's own.