Minimum gas (rock bottom) calculator
Find the reserve at which a dive has to end so that two divers can reach the surface on one cylinder.
Metric units: m, bar, L, kg.
Result
- Minimum gas (reserve)
- 120 bar
- Gas needed, for both divers
- 1,347 l
- Team breathing rate
- 80.0 l/min
- Sorting out the problem at depth
- 1.0 min · 320 l
- Ascent
- 2.8 min · 611 l
- Safety stop
- 3.0 min · 360 l
- Last metres to the surface
- 0.6 min · 56 l
The form starts on example values.
How it works
Minimum gas, or rock bottom, is the pressure you must still have when you start your ascent, so that two divers sharing one cylinder can reach the surface from the deepest point if one of them has a problem there. It assumes both breathe at several times their normal rate, a minute to sort the problem out at depth, then the ascent and an optional safety stop.
The gas volume is turned into a pressure for your cylinder and rounded up to the next 10 bar. Your turn pressure has to leave at least this much in the cylinder. It is a planning aid built on these assumptions; your training and judgment still apply.
Plan minimum gas with your logged SAC in Loggerfish →
The same calculations run in the Loggerfish app.