Environment Tank Data

Environment Tank Data

Postby jimmyelq » Tue May 22, 2018 5:00 am

Thank you for developing a great app, I have non-divers that enjoy looking at the stats (geeks, gotta love em).
What is the significant of the value x.xx ft³/min? How is that value determined? For a particular dive, I have .38 ft³/min. 1213 PSI used @ avg 30.3 feet for 44 minutes.

Any news on integrating a maritime navigation app for direction to the dive site?

Thanks again for the great app.
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Joined: Tue May 22, 2018 4:42 am

Re: Environment Tank Data

Postby support » Tue May 22, 2018 9:38 am

That number is the "gas consumption rate" calculation or the number of cubic feet of air that you used per minute normalized to the surface pressure (since you need more cu ft of air for each breath the deeper you go due to gas compression). This is a calculation that factors in your tank size (and in the case of US/Canadian tank measurements the working pressure as well) your average depth, gas consumed and dive duration. This particular calculation is often called "RMV". Another popular calculation is "SAC" (surface air consumption) and does not factor in the average depth (it just considers the total gas used per minute). The RMV calculation is more appropriate for getting a sense of your gas usage between dives regardless of depth where the SAC calculation is more suitable for comparing two dives of similar characteristics.

Here is a blog post that talks about more about this particularly in our Mac application (which can calculate both SAC and RMV):


and here is a general discussion of ho two calculate the two values:


and finally a DAN article on the same subject:


I hope this is helps explain the values.

I'm sorry that I don't have any update on adding support for linking off to a maritime navigation app directly fro within Dive Log. However, one option is to use the "copy" option for a GPS coordinate (just long press on the "coordinate" row of the dive site to bring up the "Copy" menu then tap "Copy" ... you can then paste that coordinate int your favorite navigation app.


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