DIR Answer Required

[JeffG]

What is the air limit?

Air is for tires. <ducks...looks around, just did 2 air dives today....OMG I'm going die.>

(max depth 41 ft)

 

[onfloat]

<cough, stro#e, cough>

 

[onfloat]

dang, did I type that out loud?

 

[JeffG]

dang, did I type that out loud?

Was that my outside voice? LOL

 

[Snowbear]

**** MOD POST ****

OK all ~ most of the non-DIR 'answers' to the original post, as well as the ensuing discussion, have been split off and moved over here so that discussion could continue.

A few posts were irrelevent and out of place after the split, so were deleted

And of course ~ the requisite reminder of the DIR forum 'special rules'

**** END MOD POST ****​

 

[Snowbear]

oh. well I am not sure I am smart enough to do all that computing in my head. maybe you could come out here and demonstrate. (smiling)

can you really do that? I will have to think about that. so, you are saying, plan an "open ended dive". So, if you see a huge manta at a depth outside of the limits you have set, then you need to pass on going deeper. You can't drop deeper and then cut your dive time to compensate?

What do you mean the right equipment if we are speaking about depths above 130?

Are you using wet notes or calculating all the contingencies mentally?

About all the "computing" that needs to be done is keeping a running average of your dive. I take a "snapshot" about every 5 minutes. All I really need to keep track of is the average.

First - as has already been noted, 130' on air is not DIR. I would be doing these dives on EAN32 to ~ 100' or 30/30 to ~ 120'. I use the 120 rule for 'NDL' and on EAN 32 or 30/30 figure an 80% depth advantage (i.e. 100' is figured as 80' and I get to spend 40 minutes there).

Here's a totally hypothetical example.... say at the first 5 minute mark, I'm at 100'. So my average is 100' for 5min.
Say at 10 min, I'm still at 100', so my average is 100' for 10 min.
I'm going to start heading up, so say at 15 min I'm at 80', making the average 90' for 15 min.
Another 5 at 80' makes the average 85' for 20 min. Being on EAN32, I'm still well within my NDL
At 25, I'm at 70'. At this point, I want to keep it simple in my head, so instead of saying 77.5 at 25, I'll call it 80 at 25.
Etc, etc....

To plug in your scenario of the manta spotted at 90' when I'm up at 70'... depends on the gas I and my buddy have left. At 25 minutes into the dive with an average of 80' on EAN32, dropping back to 90' for a few minutes won't hurt me as long as I have enough gas to do spend the time shallow for the time spent deep (that deco curve thing . Oh, and I'll generally be on a 119cf tank. So at 30 min, my average would then be 85'.

I realize this is not a precise average, but when I check it against my Vyper's (in guage mode of course ) average depth at the end of the dive, it's surprisingly close - like within 5'. In addition, my dives are so conservative with respect to the ascent and deco curve that a few feet off on the average won't bend me.

As you can see, there's really no complicated math calculations going on, just staying aware of where you are in the dive profile and the gas you (and your buddy) have left. After just keeping a running 'average' like this for a couple dozen dives, it will start seeming simple and you'll wonder why it seemed so complicated a couple weeks prior.

 

[Cacia]

oh, good explanation. thanks. I will give it a try. still, I am not sure about the running average bit. I will have to think about that tomorrow once I have some Kona Java. You are averaging the numbers sequentially...i will play with the numbers on some hypothetical profiles tomorrow. For me to do anything q5 minutes I would need an alarm!

I do like the 120 rule and cannot believe I dived so long without it and that it is not brought up more often. Very easy even if mildly narced.

we should do a mental exercise thread...

 

[Snowbear]

You mean you don't look at your guage/computer that often anyway :huh:

 

[Cacia]

well, what I strive to do is square what my computer says with what I have actually dived. I use the 120 rule to do my "cross check" and confirm that the computer is not only correct, but more importantly, that I am interpreting the values correctly...

I am a bit ADD so I admit time passes without me being as aware as I should. when i do check the gauges I practice "pete's rule" and ask myself what i think the reading will be before actually looking. This hones my abilty to become a more intuitive diver, my personal goal.

 

[DiveTub]

You Guys just make the whole thing too difficult

1: Plan The Dive

2: Dive The Wreck

3: Wreck The Plan

See its not the hard

Cheers
Chris