Gas Management Questions?

[Hatul]

You're measuring with a micrometer, marking with chalk and cutting with an axe. I agree with all your numbers, more or less, now ... show me an SPG that makes that all meaningful. 1160 PSI, 830 PSI, really?

The Safety Stop RB should read 3*2* (15/33+1) = 8.7 cu ft

it has a typo, but I'm afraid to edit it as the editor removes all spacing and results in a mess. Yes in practice you don't need to bother with the last two digits in the psi, just round up to nearest hundred.

 

[Thalassamania]

Even rounded up to the nearest 100 is meaningless unless you calibrate your SPG, a badly overlooked problem in the recreational diving world.

 

[Akimbo]

You're measuring with a micrometer, marking with chalk and cutting with an axe...

I concur, but the intellectual exercise is more important than the actual values… especially to lurkers just getting their toes wet. Most people’s competitive spirit makes them pay attention to the real numbers over time and make corrections. This creates awareness faster than the other extreme — those that hit X PSI in “whatever’s on their back”, regardless of depth, before leaving bottom.

Of course a minor entanglement, leaking regulator, a toothy swim-by, or even a distraction turns that ax into a haversack of C4 anyway.

 

[Akimbo]

… but I'm afraid to edit it as the editor removes all spacing and results in a mess...

Not sure if this is the cause but that’s why I set me default editor to “Source Mode” rather than WYSIWYG. About the only time I temporarily switch to WYSIWYG is to paste a table generated in MS Word or edit it.

 

[Hatul]

Not sure if this is the cause but that’s why I set me default editor to “Source Mode” rather than WYSIWYG. About the only time I temporarily switch to WYSIWYG is to paste a table generated in MS Word or edit it.

In the editor setting in my profile I saw wysiwig, text and standard editor. I did not see Source Mode. Where do you set to Source Mode?

 

[Akimbo]

Hatul:

Basic is Source Mode. Check the button at the top right of the Quick Reply box near the bottom of the page. Let your pointer hover over the A/A button and you will see the terms “Switch Editor to WYSIWYG Mode” and “Switch Editor to Source Mode”. I had the same problem until I changed back to Source/Basic. Hope it helps.

Edit: BTW, if you go back and correct the post above, a good trick is to use strike through on the typo so future readers don’t get hosed up.

Example: [-]This is wrong.[/-]

The source code looks like: [-]This is wrong.[/-]

 

[Thalassamania]

I concur, but the intellectual exercise is more important than the actual values… especially to lurkers just getting their toes wet. Most people’s competitive spirit makes them pay attention to the real numbers over time and make corrections. This creates awareness faster than the other extreme — those that hit X PSI in “whatever’s on their back”, regardless of depth, before leaving bottom.

Of course a minor entanglement, leaking regulator, a toothy swim-by, or even a distraction turns that ax into a haversack of C4 anyway.

That's why I dive with a comrade, we each have an appropriate Bingo number and that prevents the haversack of C4 from shredding our dive plan, even in the face of entanglement, leaks, teeth or distractions.

 

[guyharrisonphoto]

I do have another question (told you so!).  If rock bottom is a plan for emergency, then for no-decompression diving do you need to calculate the safety stop?  If an OOG situation happens is it better to skip the safety stop and get to the surface, so long as your ascent rate is proper and you are within the no-deco limits?

Also, where are good resources (written or web) to learn the formulas?

 

[dumpsterDiver]

I do have another question (told you so!). If rock bottom is a plan for emergency, then for no-decompression diving do you need to calculate the safety stop? If an OOG situation happens is it better to skip the safety stop and get to the surface, so long as your ascent rate is proper and you are within the no-deco limits?

Also, where are good resources (written or web) to learn the formulas?

Of course it is BETTER to do a safety stop. The question is, do you want to save that much air on each and every dive to do one in the unlikely event of a total failure of one person's scuba unit?

 

[Mr Carcharodon]

Rock bottom assumes you will make your stops. The gas for the stops is part of the plan. If you are doing a safety stop you plan for that. But if it is questionable if you have enough gas it is better to be at the surface or very close to it. The DAN statistics show that deaths from running out of gas out number DCS deaths by more than 50 to 1.