Gas calcs

[Juz]

Originally Posted by MATTBIN

2 x 3L x 200 bar = 1200L

you playing fair Nigel?

Matt

Fair point. Well made.

Juz

[ahar]

Originally Posted by nigelH

I don't carry 800L of gas!

I'm sure on a lot of dives you do: 2 x 3ltr x 200 bar = 1200ltr. You just might not be able to use it all at depth

I use rule of thirds for gas management - always plan to surface with at least 1/3 of my gas left. That should cover the most likely failure modes

[nigelH]

Originally Posted by MATTBIN

2 x 3L x 200 bar = 1200L
you playing fair Nigel?

How long were you taking to get from 6m to the surface?

You said single tank so I wondered how much deco was in 800L as it seemed a bit high for no stop.

Anyway 200bar? What is this? Third dive of the day?

1440L if you want to count the oxygen.

[MATTBIN]

Just calculating (on DDplan) 30mtrs 27mins run time ascent at 7m/min and 25l/min sac. Based on air profile looks like 800l to surface.
Shows stop
15m 3mins
12m 1 min
9m 2 mins
6m 14mins
to surface 1 min (I'll do it slower). We'll be using 36% but running an air sched for safety, also boys pooter is air model so dont want to bend it.
Be nice if he loses all his gas I can get him up on mine His Mum might appreciate it.

Matt

[nigelH]

Originally Posted by MATTBIN

Just calculating (on DDplan) 30mtrs 27mins run time ascent at 7m/min and 25l/min sac. Based on air profile looks like 800l to surface.
Shows stop
15m 3mins
12m 1 min
9m 2 mins
6m 14mins
to surface 1 min (I'll do it slower). We'll be using 36% but running an air sched for safety, also boys pooter is air model so dont want to bend it.
Be nice if he loses all his gas I can get him up on mine His Mum might appreciate it.

*nod*

If somthing really goes wrong I think you'll both appreciate the fact that that is a no stop dive on 36%.

[DannyB]

Originally Posted by tom

sure it doesn't need saying but remember to budget for a higher than usual SAC in case of a tits-up situation - I work out the reserve on the basis of 30 l/m

edit: and also budget for a bit of time at max depth for sorting out the 'incident' and starting ascent

From experience, work out that your "Stressed" breathing rate is 3-4 times your normal rate. My normal OC sac is about 25-30l/min. I got very, very stressed a couple of years ago, according to the AirX I averaged 100l/min on the ascent.

Danny