Plotting air consumption

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nibl

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Is there any (free) tool for plotting air consumption during a dive with data from AI computer?
 
Diving Log 6.0 tracks everything and provide some great basic charts and statistics. It's not free, about $35 IIRC, but cheap enough. Good support, too.

upload_2016-8-14_7-55-44.png
 
I think the OP wants to look at SAC during a single dive using AI data, not compare SAC across many different dives. I'm not aware of any programs with that function, but it could be done with a simple excel spread sheet (assuming you've already got the dive data on your computer.)
 
Diving Log 6.0 reports/stores air consumption data every 30 seconds. I suppose it would be exported to a spread sheet and the SAC/RMV calculated.

I'm curious as to what use this would be.
 
This is probably not what you're looking for, but try it and see if it's helpful. I wrote this specifically so I could play around with how much gas I would need for an ascent portion of a dive, but you could also use it for an entire dive. Just insert your SAC at the top and then insert a time value for each depth (in minutes or fractions of minutes). The spread sheet will then automatically calculate your total consumption at each depth and your total gas consumption for the dive (at the bottom). I've got a SAC and some time values in the spreadsheet now, you can just delete those and put in your own.
 

Attachments

  • Gas consumption calc.xlsx
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I've looked at one or two dives in excel this way, and it mainly shows the obvious: high SAC swimming into current, low SAC on the way back, and *shock* average SAC overall.

My PDC records depth and pressure every 15 seconds, but the pressure seems to be +/- 5-10 psi. As a result there is a lot noise in the RATE v. time unless you average over 2-3 minutes. Then it looks pretty reasonable, although it doesn't show you much you wouldn't have expected anyway. Wow, my RMV looks great at the safety stop! :wink:
 
Subsurface is free (Subsurface | An open source divelog)
If you turn the option on, it plots air consumption and color codes the plot line to show whether you are breathing at a higher rate (red) or a lower rate (green) or....shades of color....relative to the average rate on this particular dive:
Undersea gas plot sample 160814 from Belize dive last summer.png
 
@David. Nice graph, it seems to indicate that you are consuming MOST OF YOUR AIR at the beginning of the dive. My wifes does the same thing. She needs 5+ minutes in order to calm down. Now we are trying to decrease nervousness and excitement at the surface just before going under. Seems to work.

Just an idea, looking at your chart. You have A OT OF DIVE REGISTERED, so consumption is certainly not an issue, so please don't get offended. Cheers.
 
It turns out "it's all relative"; that dive, from a live aboard in Belize, was unusual for a lot of reasons; we did cover a lot of distance over the terrain against a current in the first part of the dive. The overall SAC rate for that dive was .53 cu. ft./min, so the red at the beginning of the dive is relative to that dive's average. Here's what the subsurface manual says about the color coding:

"...Here the color coding is not relative to some absolute values but relative to the average normalized air consumption during the dive. So areas that are red or orange indicate times of increased normalized air consumption while dark green reflects times when the diver was using less gas than average."

[I'm not easily offended....I'm 68 years old; have been diving for 49 years off and on....I'm just glad to be able to still be putting data on the chart....]
 
I use subsurface for this as well. I really like the program and often recommend it. I switched dive computer brands a year or two ago from Scubapro to Shearwater. I had no problems, just started using the shearwater, and everything worked fine. Except the shearwater doesn't track air consumption data so that datapoint is missing from dives with the new computer.

Anyway, another vote for subsurface. It's free, works with every dive computer I've ever heard of and then some. Also, it works on Windows, Mac OSX, and Linux. So if you ever switch dive computers or personal computers - everything will be the same. Oh yea, and like DavidFL said, it's free.

I'm kind of a nerd so the fact that Linus Torvalds is a contributor is pretty awesome in my opinion. If you don't recognize the name, he's the creator of Linux.

Downloads | Subsurface

Subsurface also integrates with google earth. You get some neat features for tracking divesites you've visited as a result.
 
https://www.shearwater.com/products/teric/

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