Sidemount

Discussions about Diving Log 6.0 - questions and hints
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poisons
Posts: 10
Joined: Sun Sep 30, 2012 10:28

Sidemount

Post by poisons » Sun Oct 20, 2013 22:45

Hi,
sidemount is becoming more popular, even among recreational diver.
I, for example, dive in sidemount configuration.
In sidemount we have 2 tanks, locked respectively on the left and right side.
We've to change the tank from where we breathe every 30-40 bar, to avoid trimming problems due to the different weight.

in diving log this feature is not supported or I'm not able to visualize what I need
- In the Logbook I cannot add a view for left tank and for right one. I mean, in the layout designer the fields relative to the tanks are only for a tank.
- In the profile view I cannot have a "unique" graph with the data of both tanks merged. Ok for the profile of each tank, but it's useful to have a merged profile view. In sidemount I can breathe only from a tank per time, so it's easy to overlap the two graph moving the descendant lines to continue from the point the other tank stopped being used.
- When I try to add a second tank, the sac is calculated for each tank and this has not much sense. It would have sense if it excludes from the calculation the time the tank has not been used. Useful would also be a sac calculated on both tanks merged.
- I'm not able to associate a tank profile to the second tank I added. No computer has sidemount feature (except lynx, the new fature will be presented on november), so we need to set the second tank as buddy. On diving log we've this as bottle 2, but I cannot set for it the capacity, material, working pressure and so on. I can only add a new tank and insert manually the start and end pressure point
- In the profile editor if I select a tank pressure graph (1 or 2) I don't see anymore the grey circle for the air change. I continue to see the status bar for it but the crossing lines are visibl only in the gaph area

thanks

divinglog
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Re: Sidemount

Post by divinglog » Mon Oct 21, 2013 21:32

Hi

Thank you for the suggestion. Yes, sidemount setup is indeed currently difficult to enter in the logbook. You can add up to 10 tanks in Diving Log, but you would also have to add actual gas(tank) switches to the profile data to get correct SAC rate information. Then Diving Log knows when you used each tank. See also:

https://www.divinglog.de/english/tutorials/tec.php

https://www.divinglog.de/blog/?p=692

Or you enter both sidemount tanks as one double tank, then the SAC rate would be also correct. So technically the functionality is in place, but it depends on how you enter your data or how you recorded it with the dive computer.

poisons
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Re: Sidemount

Post by poisons » Tue Oct 22, 2013 15:23

Hi Sven,
Thanks for your reply.

Please help me to understand :)

When I import datas to divinglog they appear both the tank datas. I record both tanks.
In sidemount, as you can see, I breathe from a tank per time, swithing more times per dive, to keep the weight of the two tanks almost similar. In the meantime I breathe from bottle 1, bottle 2 remain stable in pressure (more or less, I attach the BCD inflator to a tank and the drysuite inflator to the other tank)

Image

It's useful to keep the graph of the two tanks, but in case of sidemount it would be nice to have the graph for the total air consumption over time. If I overlap the two graph I will not obtain the final one, the right one at least. Probably I should sum the datas of the 2 tanks with the time values fixed to obtain the final graph. Is not possible to set a tank tipe as sidemount? In this case we can assume two tanks of the same size/material and associate the profile tank pressure datas to the two tanks. In fact, as you can see, I record pressure for two tanks, but when I open the tanks and gas dialog I can only see one tank

Image

Of course the Sac Calculation is wrong. So I manually add the second tank (same WE, material and capacity of Tank 1)

Image

DivingLog automatically set the min and max PPo2 and calculate the MOD (but only for tank 2 the newly added one).
I've to manually enter the start and end pressure for the Tank, because I'm not able to associate the profile Tank 2 datas (I've recorded) to the tank I've just added.

Image

As you can see it doesn't calculate the SAC, even wrong as tank 1, for this tank.
Now try to add the gas change. I go to the Profile Editor but I'm not able to add gas swithes. If I select the tank 1 graph when I right click on the graph in the point I would like to add a gas change (in my case tank switch, the gas is the same :) ) the option to add it is greyed. And if I select the depth graph I can add only one gas switch. So I close the profile editor and back to the log editor. From here I'm able to add as many gas swithces I want

Image

As you can see anyway, the SAC calculation remains equal as before (the wrong one for a tank only) and it's very difficoult to understand from the status bar wich tanks are you breathing from, it's always air :) Right side air or left side air, but always air. Of course :)

divinglog
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Re: Sidemount

Post by divinglog » Wed Oct 23, 2013 20:43

As I said, the current gas switch and tank management is not optimized for this scenario, it is for technical divers who switch to different gas mixtures and who switch also the gas in the dive computer, which is then downloaded automatically into Diving Log.

When diving sidemount, you don't switch anything in the dive computer because you don't change the gas type and that's the reason this kind of data cannot be imported automatically. The tank pressure charts are not used for SAC calculation or anything else. It's just recorded tank data which is then displayed in Diving Log. A combined tank pressure chart is planned.

The SAC calculation for multiple tanks are explained here: https://www.divinglog.de/blog/?p=765

In order to calculate the SAC rate correctly, each tank has to be applied to some part of the depth profile (for average depth calculation). When entering the data for the 2nd tank, the SAC can only be calculated when it is actually used in the profile, which you've done afterwards. When you've inserted the tank switches, the SAC rate should be calculated.

whodunit68
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Re: Sidemount

Post by whodunit68 » Mon Dec 09, 2013 13:08

I dive sidemount and enter as doubles. All works fine. I get my SAC rate and any other required information is available. If I really wanted to compute something different, I would enter the tanks individually, enter them as different gases in my computer, record each switch on my computer, and go from there.

For anyone else reading this thread, please, consider that you don't switch breathing tanks for weighting and trim (if you can't manage your trim, you shouldn't be diving sidemount.) You make switches for SAFETY!
Imagine if you were breathing one tank all the way down and you could keep your trim (hello single tank divers diving sidemount (which is just weird),) and you switch to the other tank and for whatever reason it doesn't give you gas/isn't working, you have a big problem. I realize this forum isn't for discussing sidemount but I could not just leave that without commenting.

poisons
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Re: Sidemount

Post by poisons » Sun Dec 15, 2013 19:46

whodunit68, if the switch would be only for security purposes (redundancy) you could just switch on a longer interval, no need switching every 30bar
You can manage the different trim (as for single tank sidemount conf) but it's simpler to be well trimmed and streamlined.

Anyway if you want to discuss sidemount configuration open another topic please, don't go off-topic here.

Backing in topic acting as a double tank is a work-around of course it doesn't reflect the reality.
My request was to have a combined view, just to view and record the different tanks and the gas switches.

After Sven answer I'm just waiting for the lynx to fully support sidemount records to see how divinglog manage the records

tomik
Posts: 3
Joined: Sat Jun 28, 2014 15:12

Re: Sidemount

Post by tomik » Sat Jun 28, 2014 15:14

I'm missing SAC / sidemount tank inserting too.

Please fix this.

divinglog
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Re: Sidemount

Post by divinglog » Fri Nov 21, 2014 21:54

Hi everyone

I've created an update which supports correct SAC calculation for sidemount dives. Please download this zip file and extract it into your Diving Log program folder.

There are two changes in the SAC calculation in this update:

1. Additional tanks, which are not used in the dive profile, will be now added to the first tank when calculating the SAC rate. Both tanks show the same SAC rate in the tank & gas window. It is important to know, that the first tank in your tank & gas window has to be one of the sidemount tanks, not a deco tank for example. You can switch any time to another gas/tank, e.g. during deco. All unassigned tanks will be always added to the first tank.

2. Dive with no profile and more than one tank will have correct SAC display. All tanks in a dive will be added to the first tank during SAC calculation.

Please try this new update soon and let me know how this works for you, because I'm going to release it as official update soon.

Here you can see a possible sidemount configuration. Tank 1 & 3 are sidemount tanks. Tank 2 is the deco gas. Tank 3 is not used in the dive profile and thus it will be automatically added to the first tank.
Tanks4.png
Tanks4.png (39.64 KiB) Viewed 4997 times

joebar66
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Re: Sidemount

Post by joebar66 » Sat Nov 22, 2014 10:38

Hi Sven

Thanks, works for me.

Now I am waiting for More Mobile Software :wink:

Regards
joebar

divinglog
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Re: Sidemount

Post by divinglog » Sun Nov 23, 2014 23:24

Thank you joebar, good to hear it works! :)

divinglog
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Re: Sidemount

Post by divinglog » Mon Nov 24, 2014 21:59

Official update is now online: https://www.divinglog.de/blog/?p=1610

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