Subsurface

[stuartv]

ps. It doesn't matter what tank size you have, 0 psi is 0 psi. If you have 3000 psi and you are dropping 100 psi per minute, then you will be at 0 in 30 minutes.

 

[GlennL]

Hmmm. I am following you all. I personally don't depend on the ATR function of my computer, but I do notice changes when I use a lift bag or I am breathing heavily etc. so to go back to subsurface that shows sac or in my opinion rmv, does it use multiple data samples or just overall usage start of dive to end of dive?

 

[dmaziuk]

Well I think if you average over all your multiple data samples you should arrive at the same answer as if you just go start to end. So if you're looking at the number on stats tab, that should be it. The momentary RMV number on the pop-up would be something else, based on the samples around that point.

Unless I'm misunderstanding again, without looking at subsurface code, and all that.

 

[tursiops]

Well I think if you average over all your multiple data samples you should arrive at the same answer as if you just go start to end. So if you're looking at the number on stats tab, that should be it. The momentary RMV number on the pop-up would be something else, based on the samples around that point.

Unless I'm misunderstanding again, without looking at subsurface code, and all that.

You also need to know the average depth over the start-to-finish, to get the gas consumption back to the "surface." Otherwise, it is not an SAC, just an AC.

 

[dmaziuk]

You also need to know the average depth over the start-to-finish, to get the gas consumption back to the "surface."

Not really: if you want GC in unit-of-volume-per-unit-of-time units, you can get it from cylinder size. If you're content with unit-of-pressure-per-unit-of-time units you don't need it at all. You only need need it to show "momentary" GC in unit-of-volume-per-unit-of-time units on the pop-ups.