David Novo
Contributor
From 40 m, a safe ascent would take 4 minutes. Let's take 5. My SAC in normal conditions is between 9 (fit) and 15 (tired) l/min. In a very stressful situation, even though I am cold as ice in stress, people told me that I should triple my SAC. Let's take 45. From 40 meters, let's be very conservative again. If I consider, for the sake of the science that I stay 1 minute at 40 meters, 1 minute at 30, 20, 10 and 2 minutes (to make it 5 minutes) between 10 and surface.I would consume 45*(5+4+3 +*2*2)= 720l. I would need a 3,6 liters pony. let's say 4 as you mentioned. What's the volume of a SpareAir? Anyway, I would need a pony that I can travel with meaning empty and take it apart before flight check in and fill it up the destination dive shop.
@Dody you need c. 4L at 200 bar, assuming:
- SAC of 30 L/min (twice, not three times the base one you considered)
- 9 min from 40 m to surface (1 to solve things in the bottom, 4 to get to the safety stop, 3 at the safety stop and 1 to the surface).
I am sure it does not look as conservative as when you wrote it.