Best Nitrox Mix/ Profile at 100'

[Steve_C]

If you feel lucky go to a higher o2 mix. 40 percent at 100' you can do over 40 minutes of bottom time before going into deco per vplanner with a 0 conservative factor. You will slightly exceed 1.6 ppO2 but if you are lucky it just might work.

And if they are not lucky? (on this or the next one or the next one).

 

[dumpsterDiver]

My advice... get a pony bottle, extend your bottom time and push the limit to closer to the no-deco limits. Run the dive like a mandatory deco dive with a 2 minute stop at 50 feet and 4 minutes at 15-20 feet. See how you feel, see how much gas you have. Progress slowly.

Also, if you are only using an 80 tank to get close to the deco limit on nitrox for one dive, you have a pretty low SAC rate. Be somewhat cautious as you extend your time, because if you get in difficulty deep, your SAC rate may go much higher than it is now.

 

[DaleC]

Am I missing something. RB pilot, instructor, not understanding MOD's or deco?

Edit: Unless, as Chilly suggests below, one is trying to gain overall BT (not time at max depth). In that case it is just a matter of understanding the function of the computer. Otherwise, it's increase the ppO2 you are comfortable with (not so safe) or prepare oneself for simple staged decompression.

 

[chillyinCanada]

Feels like I'm missing something too. Even with square profile, wouldn't computers start giving some credit for shallower portions of dive? Wouldn't a couple of minutes at 50' start a credit?

 

[RJP]

We would like to increase our depth too, 122-130'.

Is your dive buddy using a different computer? Not sure how he/she "does a little better" than you when it comes to NDL? A

Also, as asked above, what do you mean by "getting into the caution zone"?

PS - Why do you want to "increase your depth"? Is there something at 122-130ft you want to see... or is it "deep for deep's sake" you're seeking?

 

[DivemasterDennis]

I with Lapenta on this one- more training because you are moving beyond simple recreational diving now into technical and deco stuff, which is plenty safe WITH PROPER TRAINING.
DivemasterDennis

 

[nimoh]

I'm with Lapenta as well. Trying to squeeze every last minute of NDL out of your computer is likely to get you bent...eventually. By taking advanced nitrox and decompression procedures you can safely double your bottom time.

 

[rhwestfall]

returning with gas is a good thing. What is your rock bottom number for the needed gas for the dive you are doing?

 

[divad]

What would happen if you used your rebreather?

 

[TSandM]

There is effectively no limit to the amount of time you can spend underwater, if you have the gas. All it takes is the training to understand mandatory decompression and its gas requirements . . . and a willingness to undergo the complete change of mindset that is involved in accepting that you have put yourself in a position where you CANNOT surface, and you must deal with all the repercussions of anything that happens on a dive right where you are.

Anything else involves pushing NDLs or pushing O2 toxicity limits -- you almost certainly raise the risk of your dives far more by doing this, than by doing them as proper staged decompression dives with the appropriate gases.