Multi Tank Suport for Sidemount

[junswort]

It is great to see the support for multi tank/gas, but is there plans to support multi tank for sidemount? Basicly this involves two tanks, with similar properties, although not always. I normally dive sidemount with 2 Al80 tanks and alternated between tanks at 300-500 psi increments. The individual tank consumption is not that important to me, rather the collective consumption over the dive. With similar tank sizes it is not that difficult to combine the tank data, but I've had recent experiencies with having to dive with differing Left/Right tank properties/sizes.

I would like to see the input for tank 1/2 Size, starting, ending, & working pressure to be combined into the SAC rate for the entire dive>

Jim

[divinglog]

Hi Jim

Do you mean with "sidemount" double tanks? That is supported by clicking the tank icon in front of the tank size field.

Sven

[junswort]

The sidemount scenerio is not exactly the same as Dual Tanks. My two tanks, which usually are the same size, are not interconnected by a mannifold. I breathe from tank#1 for 500 PSI., then switch to Tank #2 and breathe on it for 500PSI. After that the cycle repeats itself. At the end of the dive I may have something that looks like the following. I've used two different tank sizes to help demonstrate that I'm trying to resolve.

Tank #1 72 cu.ft, steel, 2250 PSI Working, start 2250 PSI, end 800 PSI
Task #2 100 cu.ft.steel, 2650 PSI Working, Start 2650 PSI, end 500 PSI

As with doubles, it is not important which tank I'm breathing our of, but rather the total consumption over the term of the dive which is used to calculate the SAC rate.

By the way, both tanks ALWAYS have the same gas, air or Nitrox.

Thanks...Jim

[divinglog]

Hi Jim

Thank you for the explanation! What is the reason for switching so many times? Why not empty just one tank and then switch to the other? The only way to do this at the moment in Diving Log is by adding both tanks to the tank management dialog and then adding each switch to the profile (or doing the switches in the dive computer while diving). Then you can see the SAC for each tank in the tank dialog and the overall SAC of the dive as usual. But you have to add every switch so Diving Log can calculate the exact dive time and average depth of each tank.

The SAC calculation in Diving Log is explained here: https://www.divinglog.de/blog/?p=765

That should work fine with your setup, but again, you have to switch between both tanks also in Diving Log, either by importing the switches from a dive computer or by adding them afterwards in Diving Log (right click in the profile > Add gas switch). In you case both tanks have the same gas mixture.

Kind regards,
Sven

[junswort]

Thanks for having a look at this scenerio. For the most part I can use the dual tank configuration and just use an average residual air, bit more complicated with different tanks, but that's not very usual anyways. As the the why switch so often, here is a very brief explanation.

My left tank has a short hose regulator c/w necklace as well at the low presure inflator for the BCD/Wing. My right tank has a regulator on a 7 ft hose as well as the low pressure inflator for my drysuit. If my buddy had a air issue, I would donate the regulator on the long hose for his use, and I would switch to the one on the necklace. If I had a personal air issue, I would simply switch to the alternate tank. By breathing alternatly off the two tanks, I keep my weight balanced and maintain two independent air supplies for the duration of the dive. Sidemounting is popular in the cave diving world as the setup is lower profile. I use the set up in a recreational mode so I have options to dive with my buddies using doubles.

[lloyd_borrett]

G'day Sven,

I experience virtually the same scenario when I dive with independent twin cylinders. That is no manifold, which is often the case when I'm away on a diving holiday and the dive centre doesn't have manifolded twins. Reg setup would be similar to using sidemounts, it's just that the cylinders are still on my back.

I typically draw down 50 bar and then switch cylinders, for the same reasons outlined by Jim. I record the gas changes into my Suunto HelO2.

To date I haven't been able to import the gas changes into Diving Log, though I believe this may now be fixed if I use the right Suunto import option. So I typically manually enter the gas changes into Diving Log.

Because the Suunto HelO2 can only handle one pressure transmitter, I just have to remember my start and end pressures for the second cylinder and manually enter them into Diving Log. I have to also do that for any stage cylinders I use as well.

Best Regards, Lloyd Borrett.

[divinglog]

Hi

I have an update for Sidemount, please try it and let me know how it works:

viewtopic.php?f=4&t=2116&p=10923#p10923

Kind regards,
Sven