Working with tanks within Subsurface

[obstm...@gmail.com]

Hello!

I'm using the dive planner within Subsurface (4.5.3 Windows).  In the Available gasses section, I can select a tank.  There is a decent selection of tanks to select from, but I have a few issues:

1) As a diver in the US, I'm mainly interested in the AL/LP/HP tanks.  I am not interested in the #l tanks.  Also, I dive doubles.  So what I want to see would be, say, Double LP85.  I see that there are D#l tanks, but not double US-style entries.  Is there a way to manage the tanks that I will and will not use?

2) In many cases, the pressure of the tanks as dived may be significantly different than the stated working pressure.  For example, when splitting a set of doubles between two dives, among other possibilities.  It would be *very* useful to have both the working pressure *and* the fill pressure, to express both the nominal capacity of the tanks *and* the actual capacity of the tanks as they will be used.

For now, I'm simply putting in quasi-random numbers for size and working pressure to get the profiles correct; but it would be nice to be able to put in the exact, correct details and let the computer work with the exact numbers across the board.

Is there a way of doing this that I have missed?  I've looked through the menus and the documentation and I don't see any mention of a way to manage tank settings.

Thank you!

[Linus Torvalds]

On Fri, Mar 18, 2016 at 1:17 PM,  <obstm...@gmail.com> wrote:
>

> 1) As a diver in the US, I'm mainly interested in the AL/LP/HP tanks.  I am
> not interested in the #l tanks.  Also, I dive doubles.  So what I want to
> see would be, say, Double LP85.  I see that there are D#l tanks, but not
> double US-style entries.  Is there a way to manage the tanks that I will and
> will not use?

You can just edit the tank descriptors. For example, I have a cylinder descriptor just called

 "Dual LP85"

and then the size is set to 170 cuft.

> 2) In many cases, the pressure of the tanks as dived may be significantly
> different than the stated working pressure. 

That has absolutelly no meaning.

The "working pressure" has nothing to do with the actual fill pressure. You should fill in your beginning and ending pressuires in the start and end fields respectively.

The working pressure is a cylinder-specific thing that is usually 2640 for LP tanks, 3000 for most "normal" aluminum tanks, and 3442 for HP tanks. 

And those numbers really have absolutely nothign to do with the fill pressure. You can fill an LP tank to 3000 PSI if you want to. I'm not saying that's a good idea, and your friendly scuba shop may well refuse (and has a good reason to do so), but it's not like it won't work.

More commonly, many scuba shops won't actually fill to 3442 psi, since the compressor (or bank) may not go that high (well, it likely _will_ go that high, but the shop doesn't want to run it that high because it just puts more wear on the compressor, and they may jwant to fill multiple tanks at once and prefer to fill them all to just 3000 instead).

Again, the fact that you only have a 3000 psi fill in a HP tank in no way changes the tank size or working pressure.

So for example, it could look like this:

     

(I have a recent version of subsurface, so the "size" field says "190(185)cuft", that's just because 190 is the theoretical size of a LP95, and 185 is what subsurface says it actually will fit).

So to create somethign like this, just do the following:

 - in that equipment tag, edit the type field to whatever you want. Say, "Dual LP80". That will clear the size and work pressure fields, because that cylinder descriptor is new for you.

 - then, fill in the work pressure *first*. That's important because if a cylinder doesn't have a work pressure, subsurface will assume that any size you fill in will be metric (wet size in liters). So you'd edit that workpressure to be 2640 psi (which is what the sizing ends up being for all LP tanks I've ever seen - it's called the "plus" size, and manufacturers inevitably use the plus size when they say "it fits 85 cuft".

 - last, fill in the size in cubic feet. For a dual LP80, that would be a total of 160 cuft.

Done.

The actual beginning and end pressures migth be filled in by the dive computer download, or you migth just fill them in from (bad) memory. The example above shows both: the Dual LP95 pressures come from a dive computer, and the deco bottle pressure is just made up (in theory I might have actually looked at it at the beginning and end of the dive - in practice I doubt I did)

              Linus

[Linus Torvalds]

On Fri, Mar 18, 2016 at 1:45 PM, Linus Torvalds
<torv...@linux-foundation.org> wrote:
>
>
>
> So to create somethign like this, just do the following:
>

> - in that equipment tag, edit the type field to whatever you want. Say, "Dual LP80". [...]

.. and just to clarify: once you have created that custom cylinder
model, subsurface should now remember it. So next time you use those
same tanks, you'll find the "Dual LP80" in the drop-down list, and you
can just select it, and subsurface will fill in the cylinder size and
working pressure you entered for you.

So you need to do the tank size settings only once.

Your beginning and end pressures you'll have to do per-dive, of
course, but if you have air integration on your dive computer,
subsurface will get it from there.

Linus

[obstm...@gmail.com]

On Friday, March 18, 2016 at 4:46:00 PM UTC-4, Linus Torvalds wrote:

On Fri, Mar 18, 2016 at 1:17 PM,  <obstm...@gmail.com> wrote:
>

> 1) As a diver in the US, I'm mainly interested in the AL/LP/HP tanks.  I am
> not interested in the #l tanks.  Also, I dive doubles.  So what I want to
> see would be, say, Double LP85.  I see that there are D#l tanks, but not
> double US-style entries.  Is there a way to manage the tanks that I will and
> will not use?

You can just edit the tank descriptors. For example, I have a cylinder descriptor just called

 "Dual LP85"

and then the size is set to 170 cuft.

As I mentioned in my original post, I am in the Dive *PLANNING* screen.  You cannot change tank types in that screen.  I can click, double-click, right-click, etc. and I see no way to change this.

(Now, from your post I'm guessing that if I were to make whatever changes I want to see here in the Dive *LOG* screen, I'd probably see those changes here.  But when it comes to planning, I will select all *kinds* of different sizes of things just to see what difference it makes...  That's why it's *planning*!  :)  I would have expected to be able to do that right from the planning screen.)
 

> 2) In many cases, the pressure of the tanks as dived may be significantly
> different than the stated working pressure. 

That has absolutelly no meaning.

The "working pressure" has nothing to do with the actual fill pressure. You should fill in your beginning and ending pressuires in the start and end fields respectively.

<Fill discussion snipped>

 

Again, the fact that you only have a 3000 psi fill in a HP tank in no way changes the tank size or working pressure.

I agree.  And what I'm asking for *is* a way to enter the starting pressure.  But again, in the dive PLANNING screen, there is no ability to change the starting pressure.  It only works with the WORKING pressure, and you and I have outlind several reasons why my starting pressure will *not* be the same as the working pressure.  The planning software certainly needs to know this.  But I don't see a way to tell it!  :)

Screenshot:



That one I don't see a way to get around, short of mangling the size and working pressure to simulate a theoretical tank that contains how much gas I'm going to be diving with, rather than entering the *actual* tanks I'm diving with and the starting pressure I'm going to use.

[Linus Torvalds]

On Fri, Mar 18, 2016 at 2:08 PM, <obstm...@gmail.com> wrote:
>
>
> As I mentioned in my original post, I am in the Dive *PLANNING* screen.

Ahh, I missed that indeed. I've only ever used it for some very basic testing.

Yeah, it looks like the planning screen needs a starting pressure
thing, and you may have to create the cylinders on the diving side
first. It would be better to use the same editing widget, I agree.

Linus

[obstm...@gmail.com]

On Friday, March 18, 2016 at 5:37:36 PM UTC-4, Linus Torvalds wrote:

On Fri, Mar 18, 2016 at 2:08 PM, <obstm...@gmail.com> wrote:
>
>
> As I mentioned in my original post, I am in the Dive *PLANNING* screen.

Ahh, I missed that indeed. I've only ever used it for some very basic testing.

So far, dive planning is the only feature I've actually used!  (That's probably why I missed the fact that tanks were editable in the dive log screen.  I *did* check the menus and documentation...)  My Shearwater Perdix is not (yet) supported by libdivecomputer, and I'm working with them to get it added; and I'm still working on getting my logs from my previous computer's software.

A dive planner that supports Buhlmann and VPM-B is pretty rare in the first place;  one that is GPL is just so much better.  It's a pretty compelling feature.  I really like the layout and graphical data it provides.  The actual plan details are kind of weak (that's in another post), but the rest of the capabilities are really pretty nice.

Yeah, it looks like the planning screen needs a starting pressure
thing, and you may have to create the cylinders on the diving side
first. It would be better to use the same editing widget, I agree.

Well, at least I'm not crazy, but it sounds like there isn't a better way to address this other than mangling the size and pressure to approach that of what I'm actually diving.  Which is what I've been doing.

Thank you very much for your reply. I appreciate it.

[Robert Helling]

Hi,

On 18.03.2016, at 23:11, obstm...@gmail.com wrote:

So far, dive planning is the only feature I've actually used!  (That's probably why I missed the fact that tanks were editable in the dive log screen.  I *did* check the menus and documentation...)  My Shearwater Perdix is not (yet) supported by libdivecomputer, and I'm working with them to get it added; and I'm still working on getting my logs from my previous computer's software.

Subsurface version 4.5.4 that just came out supports the Perdix, see https://subsurface-divelog.org/category/news/

A dive planner that supports Buhlmann and VPM-B is pretty rare in the first place;  one that is GPL is just so much better.  It's a pretty compelling feature.  I really like the layout and graphical data it provides.  The actual plan details are kind of weak (that's in another post), but the rest of the capabilities are really pretty nice.

I am very much interested in that post. Maybe it is the planning of alternative versions of a dive (deeper, shallower, longer, shorter, lost gas etc). That can be done with a feature that is not so obvious, namely „Edit dive in planner“ from the Log menu. There you can just change one parameter of the dive and then end the planning session with „Save new“, which saves this modified version of the plan alongside of the first, unedited version.

Yeah, it looks like the planning screen needs a starting pressure 
thing, and you may have to create the cylinders on the diving side 
first. It would be better to use the same editing widget, I agree. 

Well, at least I'm not crazy, but it sounds like there isn't a better way to address this other than mangling the size and pressure to approach that of what I'm actually diving.  Which is what I've been doing.

OK, the planner was obviously worked on by people who use the metric system (where you call a cylinder by its actual volume or „wet size“). It uses that logic also when displaying imperial units, that is, when you change the working pressure (which should there better be called the starting pressure since that is what it is), it also changes the „size“, i.e. the amount of gas in that cylinder while keeping the cylinder, i.e. the wet volume constant. So I guess it is already doing what you are asking for, it’s just the display that is a bit strange. 

And I agree, you should also be able to add cylinders in the planner which you currently can’t. But at least it offers you all the cylinders from the logbook. So you could always create a fake dive there first with all the cylinders that you need for planning and then start the planner you you will have your cylinders. For some reason, I, on my Mac, currently cannot edit the cylinder name even in the logbook, since it is greyed out. But that clearly is a but, it worked before. And did you know, the cylinders that the planer starts up with are the cylinders of the currently selected dive in the logbook. So, you could create a fake dive for your favorite set of cylinders and fills.

Best

Robert

[obstm...@gmail.com]

On Friday, March 18, 2016 at 7:26:35 PM UTC-4, Robert C. Helling wrote:

Hi,

Subsurface version 4.5.4 that just came out supports the Perdix, see https://subsurface-divelog.org/category/news/

Very nice!  However, I just reported a bug (?) in processing logs from my Perdix on dives with gas switches to mixes that did not exist before the dive and uploaded the logs to Jef yesterday, with more details supplied today.  A quick glance at the git log shows that nothing's been checked in for 7 days so I suspect that it's not yet updated for that issue.  But I'll test and see.

I am very much interested in that post. Maybe it is the planning of alternative versions of a dive (deeper, shallower, longer, shorter, lost gas etc). That can be done with a feature that is not so obvious, namely „Edit dive in planner“ from the Log menu. There you can just change one parameter of the dive and then end the planning session with „Save new“, which saves this modified version of the plan alongside of the first, unedited version.

My issues regarding the dive planning details are unrelated to how the dive profile is created.  Also, I actually tried to use the "Edit dive in planner" option but literally nothing happened when I clicked on that menu.  I'll test it further and see if it is something I did or not.  But that's probably better discussed in another post!  :)

Yeah, it looks like the planning screen needs a starting pressure 
thing, and you may have to create the cylinders on the diving side 
first. It would be better to use the same editing widget, I agree. 

Well, at least I'm not crazy, but it sounds like there isn't a better way to address this other than mangling the size and pressure to approach that of what I'm actually diving.  Which is what I've been doing.

OK, the planner was obviously worked on by people who use the metric system (where you call a cylinder by its actual volume or „wet size“). It uses that logic also when displaying imperial units, that is, when you change the working pressure (which should there better be called the starting pressure since that is what it is), it also changes the „size“, i.e. the amount of gas in that cylinder while keeping the cylinder, i.e. the wet volume constant. So I guess it is already doing what you are asking for, it’s just the display that is a bit strange. 

First, I fully acknowledge that the Metric way of measuring tanks is superior.  Having said that, I live in the US of A, and it's just not done that way here!  :)

I briefly played with the planner after you described it.  It does seem to work as you describe:  If I put 2640 in the working pressure and then put 170cf in the capacity, and *then* change the pressure to whatever I want it to be, the CF size changes.  Given the way you describe it, that should work.  But for us Metric-challenged Americans, a better UI would be appreciated.  From the screenshot Linus included, something very similar to the actual dive log interface would be fine!

<Discussion of adding tanks to dive log snipped>

Now that I know how to add tanks to a dive plan in a way that works correctly, adding them to the dive log, while convenient, is not particularly necessary at the moment.

But one thing Linus missed:  how do I get *rid* of the dozens of foul metric tanks that now sully my beautiful list of 'merican sizes?  :)  (Besides, doesn't Linus do most of his diving here in the US?  Why am *I* the only one with this problem?  :)  )

Tim Massey

[Linus Torvalds]

On Fri, Mar 18, 2016 at 6:17 PM, <obstm...@gmail.com> wrote:
>
> But one thing Linus missed: how do I get *rid* of the dozens of foul metric
> tanks that now sully my beautiful list of 'merican sizes? :) (Besides,
> doesn't Linus do most of his diving here in the US? Why am *I* the only one
> with this problem? :) )

Yeah, I'm afraid you can't get rid of the standard cylinders.

You almost never need to see them, though - the cylinder types
auto-complete (well, again - in the divelist they do, I didn't check
the planner), so you can just start typing "L" or "A" or "D" and
you'll see just the LP/AL/Double tanks.

So you can _amost_ entirely ignore the sane part of the world.

And yes, I dive mostly US sizes myself. I think I've only seen people
use metric cylinder sizes on two of my divetrips, both in Europe.

Linus