Is my approach to diving with Nitrox logical?

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except if your nitrox computer malfunctions then what? :) best to have both computers set for the gas you use and just cut some time off your dive. Same thing but more accuracy if you lose a computer on a dive
then It would be abort the dive, but that is a good point
 
Why on God's blue ocean would you lie to your dive computer(s)? If you are using a second computer as your backup in case your main goes down, then it should be set exactly as your main not set with false information. If your main goes down, or the backup, then you are Shiit out of luck. Also, trying to mange using two different dive computer with two different set of "settings" and two sets of dive limits underwater with increased narcosis effects is just too much and confusing especially when there is too much going on around you. This is asking for trouble.

There is a very simple way to handle what you are concerned about, whatever your O2% is, configure your dive computer according to this % and your backup dive computer just the same. If you want a physiological advantage of using Nitrox, then set your "conservatism" factor in your dive computer(s) to a higher conservatism factor and you get more conservative NDL and, at the same time, correct MOD and CNS, etc. from your dive computer without any confusion or additional task loading managing two dive computers with different settings and erroneous limits displayed.


If custom mix is available for me without too much headache, I will pick a best mix for my anticipated dive's max depth - 2%. 2% less than the best mix % gives me a slight margin for when the boat has to go to another dive site that maybe a little deeper than planned. The boat isn't going to go to a much more deeper alternate site most likely anyways.

Don't lie to your dive computer(s) so it won't lie back to you!! TELL the computer to be more conservative with the correct settings and the computer will do its job properly and accurately. Do NOT lie, otherwise God will send you to hell!
great points. Im going to have to look into conservatism factors about dive computers I am not all that familiar with it, but it sounds like what I want to do. Thanks!
 
That gives a variable cushion depending on the mix you actually breath. I think a better approach is to use a computer using the ZHL-16GF algorithm (Buhlmann+Gradient Factors) and tell it the truth about what you're breathing. In return, it will give you a consistent cushion for the actual gas you're using. Another option is to regard an NDL of 5 mins (or 10 or whatever) as the "do not exceed" point, and again, don't lie to your computer.
im going to have to look into gradient factors and algorithms, that is all new to me but it sounds like a great solution for me. Thanks!
 
great points. Im going to have to look into conservatism factors about dive computers I am not all that familiar with it, but it sounds like what I want to do. Thanks!

EACH dive computer out there, recreational types, allow you to change the conservatism factor from the default (default is usually the least conservative).
 
im going to have to look into gradient factors and algorithms, that is all new to me but it sounds like a great solution for me. Thanks!

You need not worry about gradient factors if you haven't done training to learn what this is all about. As a recreational diver, just user a higher conservatism setting in your dive computer. If the default is "0," just set the dive computer to "1" for example. You don't need to go crazy with setting the conservatism factor to very high limits to the point where you don't get any dive time.
 
One other option for increasing conservatism without lying to your computer, changing the conservatism settings, or leaning about gradient factors and getting a computer that uses them, is to set for yourself an artificial NDL cushion. Mine is 5 minutes; when the NDL gets down to that, I begin my ascent. If I'm swimming in toward shore on a gradual slope such that my NDL continues to go down as I slowly ascend, I come up off the bottom to keep the number at 5 or above. I treat 5 like it's zero, and in the event I fail and go below 5 into fake deco, I do a longer safety stop. You can set a higher number if you like. You can set an alarm for it, on some computers. That way, you always know where the line really is, but you always stay above it.
 
You should not lie to or trick your computers. This will eventually or at least potentially cause confusion or worse. And computers do quit, now twice for me. I am old school enough that while I do now use two computers for some years now, I can run multi-level dives in my head (well, I used to could good enough).

Set your computers to the mix you are using. Set the GF and conservatism setting to your comfort level, use an adaptive or hard 5 minute safety stop (dare I mention a deep "pause"). Even as suggested use an additional self imposed wall (5 minutes before NDL or whatever).

Some computers do not have adjustable settings, the altitude has to be increased, I suggest if you have such a thing it might be time to visit your LDS or Amazon or something. But do not trick or lie to your computer, that is a bad pratice that leaves everybody guessing (you, your buddy, buddies, the DM). And, all dives should have a plan, Plan A, B etc. Does not have to be elaborate, it might be swim down and then swim along the wall for 30 minutes at maximum 80 feet, ascend to reef top at 40 feet and swim in the return direction and then swim up with X safety stop. So, when you are near 45 minutes and have not turned your dive yet and your computer is beeping low NDL, deco required or such, do you or do not you, what is right, what do you do? That is the question. Set the computers correctly please, dive your plan.

James
 
You should not lie to or trick your computers. This will eventually or at least potentially cause confusion or worse. And computers do quit, now twice for me. I am old school enough that while I do now use two computers for some years now, I can run multi-level dives in my head (well, I used to could good enough).

Set your computers to the mix you are using. Set the GF and conservatism setting to your comfort level, use an adaptive or hard 5 minute safety stop (dare I mention a deep "pause"). Even as suggested use an additional self imposed wall (5 minutes before NDL or whatever).

Some computers do not have adjustable settings, the altitude has to be increased, I suggest if you have such a thing it might be time to visit your LDS or Amazon or something. But do not trick or lie to your computer, that is a bad pratice that leaves everybody guessing (you, your buddy, buddies, the DM). And, all dives should have a plan, Plan A, B etc. Does not have to be elaborate, it might be swim down and then swim along the wall for 30 minutes at maximum 80 feet, ascend to reef top at 40 feet and swim in the return direction and then swim up with X safety stop. So, when you are near 45 minutes and have not turned your dive yet and your computer is beeping low NDL, deco required or such, do you or do not you, what is right, what do you do? That is the question. Set the computers correctly please, dive your plan.

James

Lying is BAD, a BAD SIN!!
 
Well, we are not lying to God, ourselves or other living things, just to an electronic device, not sure that is really a sin but to the gods of diving! But yes :wink:.

N
 
https://www.shearwater.com/products/peregrine/

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