Android decompression program for OC

There are a few recognized decompression apps on the market for phones and tablets, for examples, MultiDeco/ Vplanner, PastoDeco, etc. But for quite some time there is a new app on Android called TechDeco.

It is still on beta stage but I run the numbers and for my range of diving and, the results tables are good and have the right features.

The UI is very simple and have the following features:

Calculate decompression profiles based on ZHL-16C with gradient factors for open circuit dives. You may set gradient factors (GF-L/H) for the dive, but also an alternative GF in case you need to abort. For example if you use GF (45/85) for the dive, you may choose a GF(90/90) for an emergency; that way you can review how the decompression behave under this circunstance.

In the same tap; settings, you choose with a slide the number of “deco” gase, from 1 to 3.

Bellow you assign the bottom gas from air up to trimix by entering the number in this format O2/He.

As you see this is pretty straightforward. The application calculate gas consumption, minimum gas required base on cylinders volumes. To that end; you need to enter a series of data, like: SAC for both portions, bottom time and deco, in liters per minute and available tank cylinder pressure. Other factors needs to be set up that are known, for example: descent rate, ascent rate, water density, deco gas ppO2, ascent rate after the first stop and minimum gas calculation.

If you are a lake (fresh water) diver, you need to remember to change the water density and the altitude acclimatization.

There’s an experimental feature called “Ascent rule” that slowed the ascent rate while off-gassing and to my understanding this should only affects the first stage of the dive and deep stops.

The output data

Tables are printed and have an easy acces to modified the profile by adding +3 meters or + 5 minutes and review the alternate gradient factor with a selection bottom.

On the same window you may choose your gases.

All data are shown in a continuous window that you scroll down.

Conclusion

This is a good program with a subtle set of variables and characteristics. It’s well suitable for an Open Circuit Diver to use on the field for last minutes review and run different profiles.

What is lack is an alternative windows to run second or third dives in the same day.