Equipment tab - maybe some additional fields in the table

[Andjela Tomic]

Dear all,

This should not be very difficult to add in the code, but we can of course discuss whether it is really needed.

In the Equipment tab, in the Cylinders table, could we add one field for Cylinder type (e.g. aluminium, steel, carbon fibre)? This would fit nicely alongside Weights in the same tab.

Also, after Start pressure and End pressure, could we add Total pressure (simply start − (minus) end)? It would be very useful to have this value shown immediately for quick visual reference.

Warm regards,
Anđela Tomić

[Dirk Hohndel]

I always struggle with constructive responses to posts like this.

(1) if you have never contributed to a project and have no idea about the code in question, please don't tell developers whether something would be "not very difficult" to add.
(2) The cylinder type is part of the name already. AL80 stands for an Aluminum 80
(3) Why would we give three data points (start, end, difference) when one of them is clearly redundant. And given that the pressure drop by itself is meaningless without the wet size of the cylinder in the first place, and not a value that the user ever actually sees (the diver sees start and end pressure if they check their SPG), I don't see how that would be useful. And, with all due respect... most people might be able to quickly do a simple subtraction of two integer values in the three to four digit range in their heads...

So my constructive response is:

Thanks for your suggestion. After thinking through the details, I think we won't be able to implement this.

/D

[Andjela Tomic]

Dear Dirk,

My apologies, I didn’t notice the full list in the Type dropdown in the Cylinders table. That one is on me, and thank you for the explanation.
Regarding gas usage start-end pressure, it’s simply a nice statistic to have, and it’s something that is stored in many different dive logbooks.

The reason I made this suggestion is that I’ve been a hardcore software developer, hacker for over 40 years. I started coding long ago on 8bit CPUs in machine language, likely before you were even born. I've worked on hundreds of projects in all possible and impossible languages, custom database systems, custom hardware, custom protocols.... 

There's really no need for an arrogant tone, just because I am a woman. Everything can always be explained clearly and respectfully, and being kind isn't difficult.

Warm regards,
Anđela

[Michael Keller]

Hi Anđela.

You know what comes across as arrogant in community driven open source projects like Subsurface? People on the outside telling people on the inside that implementing feature X (that they want) should not be that difficult to implement.

In this project, like in many others similar to it, there is a massive overhang of features that are desired by users compared to the free time and motivation that is available from volunteers to implement these features. Which means 'code written' is currency in here, 'features requested' are just a distraction from other features desired by other users.

Since you seem to have the skills to 'scratch your own itch' and implement the feature that you want, can I suggest that you go ahead and put in the effort to get familiar with the project, and then open a pull request to implement it? This will give everybody a much better starting point to discuss what needs to happen for this to be accepted.

On 8/01/26 07:35, Andjela Tomic wrote:

Regarding gas usage start-end pressure, it’s simply a nice statistic to have, and it’s something that is stored in many different dive logbooks.

I suspect that this is a 'value of convenience' that is a left over from the days of paper logbooks, where it was something that users could calculate in their head without having to do complicated operations. But it has only value as long as you are always diving with the same tank size - as soon as you do dives with different tank sizes it becomes meaningless.

So, a better value to track in a computerised logbook (where we don't worry about being able to calculate values in our head) will be the gas volume used (in liter or cubic feet) - this will allow you to compare gas usage across dives with different tank sizes. 

Or even better, we could then factor in the duration and average depth of the dive, and we'd get the volume of gas consumed by the diver every minute of the dive, normalised for surface pressure - this is also called the Surface Air Consumption (SAC). This will be a useful proxy for workload, effectiveness, and training level.

And lo and behold, Subsurface already supports this, and it can be used to filter dives, and generate statistics:

As I said above, if you still feel that Subsurface is missing something here, feel free to open a pull request to propose a change to implement it.

Ngā mihi

  Michael Keller

[Dirk Hohndel]

Hmm.

I gave you a structured, polite response that addressed the issues that I perceived with your post in a logical and respectful manner.

You then take this to an ad-hominem attack on me, based on your assumption that I should have been aware of your gender - which I wasn't, and outside of your statement below I am still not, and you make assumptions about my age and condescend in the way you belittle what you assume is my experience as a developer.

I will ignore those attacks and not waste my time responding to them and instead continue to simply politely respond to what you are writing, without making assumptions about your age, gender, experience, or competency.

And I will stick to my earlier assessment. This is not a useful feature and implementing it would add a UI distraction and very limited "value".

Respectfully

/D

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[Andjela Tomic]

Dear Michael and Dirk,

I truly love Subsurface, and one of its core values, is for sure, the ability to import data from many different formats and devices -> is something I deeply appreciate. I can clearly see how much time, care, and love you’ve both put into this project.
I fully understand what you’re saying, and I respect it.

As I mentioned in my previous message, I’ve been flipping bits all my life, while diving gives me peace and meaning. In some ways, making bubbles is better than flipping bits. I’ve also discovered that I love diving in extremely cold water, below 5 degrees Celsius, Arctic conditions, even under ice.

From that perspective, I didn’t intend to create any kind of stress. As Michael correctly noted, I simply shared something that was on my mind while looking at my dives. It was not meant as a demand, a command, or an attack on anyone.
I appreciate your suggestion. I’ve already had a look at Github, and if I find a way to contribute in a really meaningful, logical way, you’ll certainly hear from me. Otherwise, I look forward to seeing you at the dive sites.

As I said, there’s no need for negativity. Being polite isn’t difficult, and it makes everything better.
Diving truly makes people better.

Warm regards and a big hug,
Anđela