Tech diving, double tanks and SAC

Discussions about Diving Log 6.0 - questions and hints
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Long John Silver
Posts: 25
Joined: Tue Jun 28, 2011 08:45

Tech diving, double tanks and SAC

Post by Long John Silver »

Hi all,

I'm just experimenting with a trial version to see how technical diving is implemented so I have few questions.

Double tanks: I see that you have size like 10,12,15,18,20,24 liters then you can check double tank. What does it means? I have a double 20L so It's a 40 liters total. Should I use 20L and then check for double? Or should I enter 40L and then check double just as remainder?

Double 16L form Eurocylinder is a very common tank used in technical diving but there is no 16L selectable. I can enter it manually but would be nice having thsi size by default. Actually if the size entered is the total size of the double tank then we need defaults for serious dives: 32L, 36L, 40L aka D16 D18 D20.

SAC. I see we can use up to 10 tanks per dive. Is it possible using the same tank/mix in several parts of the profile? I explain why: on OC dives with extended O2 deco times, it's compulsory have a 6 minutes break every 12 minutes of oxygen to avoid pulmonary inflammation. So for a 30 minutes stop at 6 meters, on my profile I would have 12' O2 + 6' bottom mix + 12' O2. Similar procedure on Nitrox 50, usually on very long deco, the 9 meters stop is made with bottom mix.

Thank you in advance
Long John Silver
Posts: 25
Joined: Tue Jun 28, 2011 08:45

Re: Tech diving, double tanks and SAC

Post by Long John Silver »

After continuning experimenting I think nearly understood everything:

Checking Double it multiplies the tank size per 2.

Once I configure the tanks used, I can add whatever gas switch I want.

Would be nice having:

SAC per tank
Zoom on the profile (I did not find it)
A better resume of gas used per tank


PS
PDF export does not print the profile line but only the grey dots of gas switch while the print function works.

A very nice program
Long John Silver
Posts: 25
Joined: Tue Jun 28, 2011 08:45

Re: Tech diving, double tanks and SAC

Post by Long John Silver »

I made a test exporting to UDCF.

Tank volume is wrong (doesn't take in account doubles)
Mix used is lost: always air.
Temp min and temp max is lost (I don't know if it's a UDCF limitation)

Bye
divinglog
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Re: Tech diving, double tanks and SAC

Post by divinglog »

Hi

I can add 16 liter to the tank list, but as you already said, you can enter anything into the tank size field. You can use any tank as often as you want within the profile. The SAC is calculated for each tank and displayed in the tank management window on the left side (along with the gas usage per tank) and cumulated above the profile (there is also a separate SAC field in the extended logbook layout) More about SAC here: https://www.divinglog.de/blog/?p=765

Profile zoom function is currently only available in the Diving Log Viewer (from the main toolbar). Yes, UDCF and UDDF export make not yet use of the new functionality like double tanks and gas management. This has to be added in future.

Kind regards,
Sven
Long John Silver
Posts: 25
Joined: Tue Jun 28, 2011 08:45

Re: Tech diving, double tanks and SAC

Post by Long John Silver »

divinglog wrote:Hi
I can add 16 liter to the tank list, but as you already said, you can enter anything into the tank size field. You can use any tank as often as you want within the profile.
Maybe a tooltip on the single/double tank icon indicating that the capacity will be multiplied x two would be clearer.
The SAC is calculated for each tank and displayed in the tank management window on the left side (along with the gas usage per tank) and cumulated above the profile (there is also a separate SAC field in the extended logbook layout) More about SAC here: https://www.divinglog.de/blog/?p=765
I saw what you mean.
Actually, from a tech diver perspective, would be nice having on the first page of the logbook reporting all the gas used.
Once I insert all the gas and switches on the profile, I expect to find all the gas used on the main page of the logbook.
I see that I can customize the layout (and I made it) but If I add 4 gas for a dive I would like to see them automagically on the main page. Gas and tank used in a logged dive it's of primary importance when planning a new dive in a spot already dove.

In the attached image I tried to have a layout where for every tank used I have a clear group (something lika a row ofr every tank). I added two separators. I don't know how to add a nitrox 50 and Oxygen group.

Bye
Attachments
layout.png
layout.png (19.88 KiB) Viewed 10512 times
divinglog
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Re: Tech diving, double tanks and SAC

Post by divinglog »

I want to add some kind of tank list panel (view only) for the logbook window in future. For editing you will still have to go into the tank management window.
Long John Silver
Posts: 25
Joined: Tue Jun 28, 2011 08:45

Re: Tech diving, double tanks and SAC

Post by Long John Silver »

divinglog wrote:I want to add some kind of tank list panel (view only) for the logbook window in future. For editing you will still have to go into the tank management window.
Perfect!

Thanks
AndyDragon
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Location: Penetanguishene, Ontario
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Re: Tech diving, double tanks and SAC

Post by AndyDragon »

Not to hijack this post, but I have something that's similar (feature request), the ability to set a category of dive for SAC calculations. I think this is vital for a diver like myself who wants to use this information for base gas consumption when planning technical dives when I do several different types of dives. I would like to have a category like 'Instruction', 'Gas Sharing Drills', 'Normal', etc. so I can group my average SAC rates based on this category. Often my SAC rate is abnormal when dealing with students or when doing gas sharing drills and I would like those to not affect my average SAC for normal dives. I do enough instructing that it's not small enough to be an anomaly, it does affect the value.

Either a drop-down/editor for SAC category (and subsequently SAC average calculations for each category) or the ability to mark a particular dive as 'don't include in SAC average calculation' for the summary page. This way I can either categorize the dives or at least keep non-normal dives out of the average SAC calculation...
Andrew Forget
PADI IDC Staff Instructor 212158
Long John Silver
Posts: 25
Joined: Tue Jun 28, 2011 08:45

Re: Tech diving, double tanks and SAC

Post by Long John Silver »

Nice feature request,

Actually given that the field "Deco" is already there, would be nice having an optional input field to indicate how much deco was planned.

In the meantime I'm playing with the layout editor to get a clear indication of the tanks used but no way.

I'm aiming to a single line for bottle:

Size - Gas - Start Bar- End Bar - SAC
--- ---- ----- ------ ----
--- ---- ----- ------ ----
--- ---- ----- ------ ----
--- ---- ----- ------ ----
--- ---- ----- ------ ----

Size field has the double/single icon which doubles the size indicated.
divinglog
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Re: Tech diving, double tanks and SAC

Post by divinglog »

Hi Andy

SAC categories are unfortuntely no likely to happen, because the SAC calculation is already very complex and I do not want to add another level. But I will add filter options to the statistics window to show statistics for just a subset of your logbook, so this could work for you.

Kind regards,
Sven
Long John Silver
Posts: 25
Joined: Tue Jun 28, 2011 08:45

Re: Tech diving, double tanks and SAC

Post by Long John Silver »

I tried to log a new tech dive and I have some problem adding gas switch.

I used a stage bottle (11L) filled with 15/55 then after ten minutes I passed to my back gas (Double 20L always 15/55) then for deco I used nitrox 50 and oxygen.

No problem adding gas switch for the deco time but for the bottom time, the gas-switch combo box has two 15/55 and doesn't accept switching two tanks with the same mixture. Furthermore once I add all the tank used there's no way to understand which tank the software is using by default given that they have the same mix.
Would be possible (in the next release) specifying the tank used from the beginning of the dive?
For extended bottom time in tech diving usually we start the dive with a stage bottle with the bottom mix, then we switch to the back gas. Of course the back gas tank is considered the default tank used but when I add gas switch in the profile, the back gas tank is not the default one.

Sorry, I know that tech dives are a PITA :)

I attach two images:

- Tank used
- Gas switch combo.
Attachments
gas-switch.png
gas-switch.png (5.71 KiB) Viewed 10463 times
tank-gas.png
tank-gas.png (16.21 KiB) Viewed 10463 times
divinglog
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Re: Tech diving, double tanks and SAC

Post by divinglog »

Yes, I noticed that the gas switch combo box is confusing when using 2 tanks with the same gas mixture, so I improved that now and it shows tank type and size:
Gasswitch.jpg
Gasswitch.jpg (17.28 KiB) Viewed 10460 times
You can switch already from 15/55 to 15/55, but you must figure out which of the gas items is which tank (pick in one list the first item and in the other list the 2nd item).
Long John Silver wrote:Would be possible (in the next release) specifying the tank used from the beginning of the dive?
You can do that already by using the "Reset Gas" function in the logbook toolbar in the profile tab. That lets you specify a gas for the whole dive and then you can start adding gas switches.
Long John Silver
Posts: 25
Joined: Tue Jun 28, 2011 08:45

Re: Tech diving, double tanks and SAC

Post by Long John Silver »

Great,
When we will find the new improvement? Next release?

Thanks
divinglog
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Re: Tech diving, double tanks and SAC

Post by divinglog »

Extract in the Diving Log program folder: http://www.scuba-divelog.com/dl50/Divelog.zip
AndyDragon
Posts: 110
Joined: Tue Nov 14, 2006 08:38
Location: Penetanguishene, Ontario
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Re: Tech diving, double tanks and SAC

Post by AndyDragon »

divinglog wrote:But I will add filter options to the statistics window to show statistics for just a subset of your logbook, so this could work for you.
Sven, that would be a huge improvement, very cool. Thanks!
Andrew Forget
PADI IDC Staff Instructor 212158
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