CCR Bailout Planning

[Ran Maggs]

Hello,

Maybe I am doing something wrong. I am planning a simulated CCR dive, simulating a need to bailout at the end of the bottom segment. I am planning the bailout by adding a dive planner point at the same final depth (38m) as the rest of the dive (square profile), duration of 1 minute, using a second gas I set up in the available gases. The setpoint is set at 0. Total runtime of 23 minutes.

The dive plan modifies accordingly, but a warning triangle appears at 6m, stating that the planned waypoint is above the (9m) ceiling. It does seem that one of the tissues is just below the 9m mark... What am I doing wrong? Maybe I am oversimplifying this, but in my mind I was half expecting a stop to be added at 12m to take the conflict into account. Using a different planner (PastoDeco) I am indeed getting a stop at 12m. I am using GF 35/75, last stop set at 6m and dropping to first depth.

[Robert C. Helling]

Am Samstag, 9. Juni 2018 00:15:07 UTC+2 schrieb Ran Maggs:

Hello,

Maybe I am doing something wrong. I am planning a simulated CCR dive, simulating a need to bailout at the end of the bottom segment. I am planning the bailout by adding a dive planner point at the same final depth (38m) as the rest of the dive (square profile), duration of 1 minute, using a second gas I set up in the available gases. The setpoint is set at 0. Total runtime of 23 minutes.

We have done some work on bailout planning since the last release. Would you mind to try out the version from continuous build https://github.com/Subsurface-divelog/subsurface/releases ? 

[Ran Maggs]

Sure. I will run a few simulations and post comments here over the weekend.

[Ran Maggs]

The stops now appear as you would expect them, great.

A few points/requets:

Is there any chance of being able to modify the setpoint down to two decimals? Eg if you are diving on setpoint 1.3, it would be good to plan at setpoint 1.25.

To plan bailout contingencies, I am currently adding a 1 minute planning point at the same final depth, selecting a bailout gas prepared under available gases. CC setpoint set to 0 and Dive mode set to OC. I then re-run the plan with a bailout GF.

Is there any chance of having a separate set of GFLow and GFHigh for bailout? Perhaps labelled aGFLow/aGFHigh or BailGFLow/BailGFHigh?

Similarly, a bailout SAC would be useful, where it can be set to something like 75l/min to simulate a CO2 event, as opposed to changing the bottom SAC manually each time. We can have a discussion as to whether this is needed for Deco SAC.

With these features, is it possible to have a separate command to tell Subsurface to plan a bailout plan based on the 'proper' plan? This would make CCR dive planning a true breeze.

All of these are only suggestions, and based on how I am trained - I realise that different agencies may differ on some aspects. However it could be a starting point?

[Edward Robinson]

Just bumping this thread instead of starting a new one to say that I found it a little frustrating today to have the set point limited to 1 decimal as well, and being able to set 1.25 or similar would be appreciated!

[Stuart Vernon]

I’m just curious, as neither of my CCRs allow that. 

Are you diving a unit that has a set point controller that allows that? Or is that because you fly manually at 1.25?

On Dec 31, 2023, at 10:44 AM, Edward Robinson <wp.bob...@gmail.com> wrote:

Just bumping this thread instead of starting a new one to say that I found it a little frustrating today to have the set point limited to 1 decimal as well, and being able to set 1.25 or similar would be appreciated!

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[Michael Keller]

Hi Stuart, Edward.

On 1/01/24 13:41, Stuart Vernon wrote:
> I’m just curious, as neither of my CCRs allow that.
>
> Are you diving a unit that has a set point controller that allows
> that? Or is that because you fly manually at 1.25?

The APD Inspiration supports setpoint configuration in 0.01 bar increments.

>> On Dec 31, 2023, at 10:44 AM, Edward Robinson
>> <wp.bob...@gmail.com> wrote:
>>
>> Just bumping this thread instead of starting a new one to say that I
>> found it a little frustrating today to have the set point limited to
>> 1 decimal as well, and being able to set 1.25 or similar would be
>> appreciated!

https://github.com/subsurface/subsurface/pull/4010 should do the trick,
testing appreciated!


Ngā mihi

  Michael Keller

[Stuart Vernon]

Cool. Thank you!

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[Alvaro Aguilera]

Hi Edward,

at least in the mCCR world most people stay at 1.3 on the main computer
and set the backup computer at 1.2. That's quite universal and works
with any method you choose...

Regards
Alvaro

On 20.06.2024 15:58, Edward Robinson wrote:
> The other reason 1.25 gets used is (within BSAC at least) if you run at
> a 1.3 setpoint, you do your paper plan and tables at 1.25 to account for
> the under/overshoot, so even for CCR's which only support 0.1 increments
> it gets used in the paper planning stage. I know most people run 2
> computers these days, but it's still needed for bailout planning.

> https://groups.google.com/d/msgid/subsurface-divelog/b57fc111-646d-4383-b6fd-8faefd7431a4%40042.ch <https://groups.google.com/d/msgid/subsurface-divelog/b57fc111-646d-4383-b6fd-8faefd7431a4%40042.ch>.

>
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[Stuart Vernon]

How much difference does it make to the results if you do the planning at 1.2, instead of 1.25?

 

I’m not trying to be a smartass. I’m genuinely curious. And I know it’s a very general question. A couple of specific examples would give me the basic idea I’m wondering about.

 

From: subsurfac...@googlegroups.com <subsurfac...@googlegroups.com> On Behalf Of Edward Robinson
Sent: Thursday, June 20, 2024 9:58 AM
To: Subsurface Divelog <subsurfac...@googlegroups.com>
Subject: Re: CCR Bailout Planning

 

The other reason 1.25 gets used is (within BSAC at least) if you run at a 1.3 setpoint, you do your paper plan and tables at 1.25 to account for the under/overshoot, so even for CCR's which only support 0.1 increments it gets used in the paper planning stage. I know most people run 2 computers these days, but it's still needed for bailout planning. 

On Monday 1 January 2024 at 23:08:14 UTC Stuart Vernon wrote:

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[richm...@gmail.com]

Stuart

A lot of this 0.05 difference is a legacy approach. Modern BSAC training is dropping this approach... I think we are trying to split hair and bringing in false accuracy with this 0.05 consideration.

[Stuart Vernon]

That is definitely my suspicion (false accuracy).

 

But, that’s why I asked.

 

If BO planning at 1.2 vs 1.25 allows you 1 or 2 extra minutes of bottom time, I can’t see being remotely bothered by software that doesn’t support 1.25.

 

But, if it gives you 10 extra minutes of bottom time, then I can understand wanting it.

 

I suspect the former to be closer to reality.

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