DIR- GUE Min gas (MGR) table?

[rsingler]

We're talking open water here. Nobody is questioning that overhead environments require different rules.

I got that. But the point is the same that @mer is making above: you need to adjust your default values for the reality of the dive. For the same reason as you don't pick a number off a table, you need to think about contingencies.
Okay, there's no deco obligation and no wreck. But you could still have an entanglement that will take more than a few seconds of huffing and puffing at more than your usual RMV to get out of. Or your buddy goes OOA and takes a bit to settle down to keep from rocketing to the surface.
And you look at your (shared air) gauge at 100' and there's already a thousand psi gone. That's all I'm saying.

 

[huwporter]

I got that. But the point is the same that @mer is making above: you need to adjust your default values for the reality of the dive. For the same reason as you don't pick a number off a table, you need to think about contingencies.
Okay, there's no deco obligation and no wreck. But you could still have an entanglement that will take more than a few seconds of huffing and puffing at more than your usual RMV to get out of. Or your buddy goes OOA and takes a bit to settle down to keep from rocketing to the surface.
And you look at your (shared air) gauge at 100' and there's already a thousand psi gone. That's all I'm saying.

Of course you need to think about contingencies, of course you need to adapt to the realities of the situation. Only internet blindness is making you think that anyone is suggesting anything different.
But you do need a starting point to start to adapt from. All this is saying is, hey, for open water no-stop diving, here is a moderately conservative minimum starting point for the least amount of gas you would want to consider retaining. Of course you can increase (never decrease) that minimum amount for changing circumstances.
But if you are going to base all your (open water, no deco) gas planning around "OK, I could get into a major entanglement simultaneously with someone going OOA, and also several minutes inside a wreck, oh yes and also being attacked by a giant squid and having a bulkhead collapse on me and..." then you are rapidly going to plan yourself out of ever getting in the water.

 

[rsingler]

Lol, then we agree!

 

[Ouvea]

@SaltyWombat :

You're overthinking this. If you want absolute certainty, write down the stuff in a table on your wetnotes. There is a more practical solution to this. Calculate the gas you require to solve your emergency. Be honest about the time required and your SCR in an emergency. Use 3-4 minutes, if that's really what you require. Once you have the volume, convert to your tank pressure using your tank factor.

Next calculate the gas requirement for the target depth. At 33ft, you require twice, at 66ft, three times and at 99ft, four times. Well, my depth is at 40ft what do I do? That's midway between 33 & 66 so you're at 2.5 ATA, hence 2.5x the gas required. If you're at 45ft, how long will it take you to ascend? Will you ascend to 50% of actual depth prior to ascending at 10ft/min.

Personally, I find that cumbersome. At 50ft & shallower I'll ascend at 10ft/min to the surface. Makes my ascent gas calculations easy. If I'm deeper than 50ft, I'll ascend to 50ft at 30ft/min. That means, at most I need two minutes to ascend from 100ft. That's fairly easy to calculate on the fly. Hence I have a shallow (50ft) and a deep (100ft) ascent profile with the matching MG. I can extrapolate the actual MG from any depth between my low & high ascent profiles.

O.

 

[SuperSeaMonkey]

When is your Fundies class with Beto? Are you on the BAUE Facebook page? Perhaps you could reach out to Beto with some of your questions. There are some active beach divers in the BAUE group. Perhaps you can find a few mentors to help answer some of your questions you have. SCUBABoard is a good resource, but instead of "asking the audience" which sometimes garner a wide range of different answers. It might be better to answer your instructor directly so you are doing things the right way (no pun intended).

I was in the same boat you were in a few years ago myself. I was excited and eager to start my Fundies class. Luckily I had a few mentors that helped answer my numerous questions about gear configuration, setup, etc. Sometimes asking questions and having discussions with my mentors was a little easier than reaching out to my instructor. A lot of your questions will be answered during your Fundies class with Beto as well.

Once again, reach out to Beto and see if he has any recommendations on mentors for you or try asking on the BAUE FB page.