DIR- Generic Min Gas Table for Wet Notes

[mainedvr]

If you were going to make (or already have) a table of min gas for various depths that would be in your wet notes for easy access on the fly, what depth increments would you/do you use. For example 100', 80', 60', or whatever. I know this could get elaborate if one wanted to and that is fine I realize there is always a wide range of ideas and schools of thought on how to do things, just curious what others do or think makes sense.

Thanks

 

[seeker242]

I list from 100', every 10', down to whatever gives a MG of 500 psi because you never go below 500 psi anyway.

 

[elgoog]

For quick reference right before the dive, I have a formula in my Wetnotes for min gas = depth (in ft) X 10 + "some-value" psi, where "some-value" is usually 100, 200 or 300 depending on which single tank I'm using.
I mostly dive doubles now and don't go below 100ft (yet) so min gas there is always 500psi.

 

[decompression]

I would write them out several times using a simple formula and run through them before every dive and soon enough they are memorized.

 

[Pilotmaverick]

I use a table I made more for the recreational realm. It is calculatet with a swift accent at 10m/min but adds time for the safety stop. Gas demand is 30l per diver. It is only suitable without any deco obligation and direct acces to the surcfase.

Something like this could possibly be made for other (tech-) diving scenarios.

 

[victorzamora]

I've got a chart that's every 10ft from 30-140ft. I chose those because of 130ft being the standard max rec depth limit and I went one increment deeper. As for 30ft, I found that that's notably below 500psi even on an AL80, and should be at 500psi on nearly any tank you'll encounter (it's 333psi for an AL63). I've also included the cubic footage for mingas for every depth, and the PSI in a couple common (to me) tank sizes.

Out of boredom, I also created one that gives "Bottom Time" and shaded in the cells that will put me into (or nearly into) deco:

 

[kirill egorov]

Good day,

All of these tables may be a great tool - but it is also important to remember that none of these numbers (bottom and deco times based on gas volume, MGR etc) are not something set in stone: equipment configuration (presence of scooters, cameras etc), in-water conditions, team experience, higher than normal consumption rate of one of the team members will affect all these calculations.

It is a way more prudent approach to go through calculations as a team, prior to a dive (or a project) and take in consideration all possible variables.

With best regards
Kirill A. Egorov
GUE Assistant Training Director