Idiotic, I know, but I went diving to about 100fsw and checked my NDL and it was roughly 30 minutes. Checked my buddy's and it was 15 minutes. We were both diving on air and I had forgotten to switch from Eanx 28 (from diving on a liveaboard the previous week). I followed my buddy's computer (wrong I know) and sat out the remaining dives of the day. I'd like to know when it will be safe to dive again on air using the same computer on correct settings? I surfaced at 15.30 h. Will I be OK to dive tomorrow morning?
Forgot to switch dive mode from nitrox to air for my first dive of the day. Now what?
- Thread starter Lochard
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Yes, you will be fine diving tomorrow
What you can do:
1. Use planning SW using the same computer to simulate your current condition before repetitive dive.
2. Check your pressure group after the first dive (nitrox table) and use it while planning another dive based on air tables - I kindly ask someone to confirm this as I never done it myself.
Either way, I would not trust your computer on NDL on a repetitive dive same day after 1st dive on leaner gas than set - I could give you longer than your actual NDL, as you were breathing more nitrogen than your computer thinks you did.
What you can do:
1. Use planning SW using the same computer to simulate your current condition before repetitive dive.
2. Check your pressure group after the first dive (nitrox table) and use it while planning another dive based on air tables - I kindly ask someone to confirm this as I never done it myself.
Either way, I would not trust your computer on NDL on a repetitive dive same day after 1st dive on leaner gas than set - I could give you longer than your actual NDL, as you were breathing more nitrogen than your computer thinks you did.
Your personal risk tolerance will fully answer the question.
I'd use the no fly recommendations as my guide for a safety margin when I've sufficiently off gassed to a negligible level.
An alternative method would be to consult tables you trust and look at the longest surface interval required by any recreational dive to get back to an "A" pressure group.
I consider that my "reset" where I start over when diving recreationally.
Enjoy your dives,
Cameron
I'd use the no fly recommendations as my guide for a safety margin when I've sufficiently off gassed to a negligible level.
An alternative method would be to consult tables you trust and look at the longest surface interval required by any recreational dive to get back to an "A" pressure group.
I consider that my "reset" where I start over when diving recreationally.
Enjoy your dives,
Cameron
24 hours if you want to follow your computer; at that point it'll be completely cleared out and your body should be too.
Otherwise you can plan off tables starting from that original 1st dive to know what your NDL will be for this upcoming dive. With that option, if your tables calculation happens to be more minutes of NDL than what your computer would showcase, you'll still have to follow the computer to avoid locking it out in a Deco-Violation.
Some computers will allow you to swap to Gauge mode before the 24hour period, at which point it's just a glorified dive watch to use in conjunction with dive tables.
Check your computer manual. Some have a setting where if you forget to set Nitrox on each dive it defaults back to Air.
This is dangerous of course if you are diving Nitrox the next dive and computer defaults to Air, as you won't have an MOD alert and could risk an O2 toxicity issue if your max bottom is very deep. But on the plus side you'll have a much more conservative NDL.
Otherwise you can plan off tables starting from that original 1st dive to know what your NDL will be for this upcoming dive. With that option, if your tables calculation happens to be more minutes of NDL than what your computer would showcase, you'll still have to follow the computer to avoid locking it out in a Deco-Violation.
Some computers will allow you to swap to Gauge mode before the 24hour period, at which point it's just a glorified dive watch to use in conjunction with dive tables.
Check your computer manual. Some have a setting where if you forget to set Nitrox on each dive it defaults back to Air.
This is dangerous of course if you are diving Nitrox the next dive and computer defaults to Air, as you won't have an MOD alert and could risk an O2 toxicity issue if your max bottom is very deep. But on the plus side you'll have a much more conservative NDL.
nolatom
Contributor
There are differing degrees of "wrong", like misdemeanors, felonies, capital murder.
Following your buddy's computer, as long as you both stayed close enough to have the same profile, is in the "wrong, but many of us have done it without ill effect" category. Can we let you off with a verbal warning? You are already spending the rest of the day in "dive jail" anyway, which is the right thing to do.
Following your buddy's computer, as long as you both stayed close enough to have the same profile, is in the "wrong, but many of us have done it without ill effect" category. Can we let you off with a verbal warning? You are already spending the rest of the day in "dive jail" anyway, which is the right thing to do.
CT Sean
Contributor
At least according to the PADI table, if you dive to 100 feet, and stay there for the full NDL of 20 mins, a surface interval of 16 hours (15:30 to 7:30 the next morning) is way more than long enough for that next-morning dive to count as a "new dive" with no residual nitrogen.
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Jeez, I'd a thunk in the old days PADI wanted three days off for that kinda behavior. They really have gotten liberal.
By tomorrow it shouldn’t matter. But if you ever do it again, put your computer in gauge mode and run tables.
caruso
Banned
You'll be fine for tomorrow morning. You followed your buddy's computer- while not recommended it's not going to kill you. If it was me I wouldn't have skipped todays dives at all, just kept my dives conservative, certainly within your buddy's computer limits. Why the heck didn't you dive nitrox on a 100' dive? The minor additional cost is well worth the extra bottom time and/or safety.
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