Ascent time

[rileymartin]

Is ascent time only used to calculate gas requirements or is it also added to your bottom time to calcuate your nitrogen group as well as your CNS% and OTUs?

Thanks,

Riley

 

[DiveNav]

Is ascent time only used to calculate gas requirements or is it also added to your bottom time to calcuate your nitrogen group as well as your CNS% and OTUs?....

It depends what "method" you are using .... but, your body, doesn't care if you are ascending, stable or descending while underwater .... it cares about instantaneous pressure.

Dive computers calculate your N2, CNS and OTU loading continuously - also while ascending.

Alberto (aka eDiver)

 

[gcbryan]

It depends on the table I would imagine. Each table has "rules" that apply including what the ascent rate is and when bottom time begins and ends. I assume you are talking about tables since you are using the term nitrogen group.

 

[rileymartin]

Yes, I'm using the US Navy dive tables.

 

[ae3753]

For the US Navy tables:

Actual Bottom Time (ABT): Time from leaving surface until
beginning a direct ascent to the surface

Direct ascent should not be faster than 30' per minute.

http://www.ndc.noaa.gov/pdfs/USNDeco1.pdf

 

[kanonfodr]

re: ascent time in relation to gas planning.

YES!!! But what calculation you use depends on some different things. For standard recreational dives, your gas plan for the ascent can be as simple as "At 750 psi, we head to the surface." Or it could be more involved, ie Rock Bottom where a failure is accounted for. I'm not going to talk about deco diving, since I'm not deco trained, but they account for gas used on ascent as well, part of which is tied into Rock Bottom.

Peace,
Greg

 

[miketsp]

My CMAS tables consider bottom time to be start of descent to start of ascent, but they also assume that you are making the ascent at the specified 9m/min.
So of course if you hang around on the ascent other than at the defined deco stops you need to be more conservative.

 

[LiteHedded]

howard stern fan?