Another question about no-fly times

[Thiad]

Two things come to mind... Most of the dives I did in Palau were fairly deep - the 70 to 100 foot range. Looking at my own profile, I wanted plenty of time to off-gas. So, we spent the last day touring around and seeing the sites. It's a lovely island.

But there's also the question of getting bent in a country where finding medical care could be an issue. DocVikingo posted a letter about the local chamber not being available full time (this was in the June/July 2012 timeframe). That could be a really unhappy situation if you get hit and need transport to Guam. Getting an emergency flight out of there may not be too easy and if you get sick mid-air, it could be a very long and uncomfortable flight.

 

[Thalassamania]

There is no absolute, clear and simple answer. Is 9 hrs. enough? Is 12? Is 18? Is 24? Is two weeks? No one knows. All that can be said, with absolute assurance, is that the longer the time to the last dive the lower the odds of betting bent on your flight. So you need to understand the factors involved. If all my dives were relatively deep, short, no-D dives ... I would not be too worried about it, even with the last dive being 9m for 30 minutes. However, if I was filling up with nitrogen on long shallower dives during the previous days, and always entering the water with significantly reduced residual nitrogen time, well ... I'd be much more circumspect. If I had to make the dives, and I had to make the plane (and I have been in this sort of situation) my approach would be to use the highest oxygen mix that I could for each my dives (taking into account both MOD and the O2 clocks). I'd watch the available bottom time on my computer before each dive. If I saw that on the succeeding days my bottom time was significantly reduced I'd start using pure oxygen at extended safety stops (maybe 10 minutes or more? Again, watch your clocks). I'd surface breathe at least two hours of pure oxygen prior to getting on the plane. This is the sort of diving situation that just screams for a rebreather.

 

[endurodog]

Two things come to mind... Most of the dives I did in Palau were fairly deep - the 70 to 100 foot range. Looking at my own profile, I wanted plenty of time to off-gas. So, we spent the last day touring around and seeing the sites. It's a lovely island.

But there's also the question of getting bent in a country where finding medical care could be an issue. DocVikingo posted a letter about the local chamber not being available full time (this was in the June/July 2012 timeframe). That could be a really unhappy situation if you get hit and need transport to Guam. Getting an emergency flight out of there may not be too easy and if you get sick mid-air, it could be a very long and uncomfortable flight.

These are all great points. All of the tables and all of the suggestions they make on no fly times and everything else never completely eliminate the risk of DCS. I'm ok with the 18 hours but if someone is not I fully understand that also. I also like to take the last day to do my site seeing or relax. Gives a chance for the gear to dry and to maybe soak my liver too!!!!

 

[xyrandomyx]

There is no absolute, clear and simple answer. Is 9 hrs. enough? Is 12? Is 18? Is 24? Is two weeks? No one knows. All that can be said, with absolute assurance, is that the longer the time to the last dive the lower the odds of betting bent on your flight. So you need to understand the factors involved. If all my dives were relatively deep, short, no-D dives ... I would not be too worried about it, even with the last dive being 9m for 30 minutes. However, if I was filling up with nitrogen on long shallower dives during the previous days, and always entering the water with significantly reduced residual nitrogen time, well ... I'd be much more circumspect. If I had to make the dives, and I had to make the plane (and I have been in this sort of situation) my approach would be to use the highest oxygen mix that I could for each my dives (taking into account both MOD and the O2 clocks). I'd watch the available bottom time on my computer before each dive. If I saw that on the succeeding days my bottom time was significantly reduced I'd start using pure oxygen at extended safety stops (maybe 10 minutes or more? Again, watch your clocks). I'd surface breathe at least two hours of pure oxygen prior to getting on the plane. This is the sort of diving situation that just screams for a rebreather.

I can't think of any recreational diving situations where someone has to make a dive and has to make a flight. Different story if professional commitments have been made. But for those of us who do it purely for fun, adding a day of sight-seeing seems the best option in pretty much every case.

 

[vladimir]

I can't think of any recreational diving situations where someone has to make a dive and has to make a flight. Different story if professional commitments have been made. But for those of us who do it purely for fun, adding a day of sight-seeing seems the best option in pretty much every case.

Spoken like a man who has never been sightseeing on Chuuk. But there's always reading in a hammock.

 

[xyrandomyx]

Spoken like a man who has never been sightseeing on Chuuk. But there's always reading in a hammock.

OK, sure. My last dive trip was to a one-horse town, my last day got rained out. So sightseeing wasn't an option for that either, but the guesthouse I was staying at had a nice collection of DVDs.

 

[Dive the World]

It's actually been changed to 18 by DAN and PADI

ok, so that new info for me.

BUT

1. For a single dive within the no decompression
limit, a minimum preflight surface interval of
12 hours is suggested
2. For repetitive dives and/or multiday dives,
a minimum preflight surface interval of 18
hours is suggested.
3. For dives requiring decompression stops, a
minimum preflight surface interval greater
than 18 hours is suggested.

If the above is the new standard, is there anything about multiple dives? are considering all the previous dives a person has done?

Does cosmographer known how to calculate multiple dives and residue of nitrogen? If they are nitrox, would they go through the trouble of calculating Cns/UPTD?

One dive to 9m for just 30 minutes is not worth the trouble of risking possible bends at 30,000+ feet.

my 2cents - enjoy the beach and view, read a book out in the open, get a tan.

 

[endurodog]

The guidelines are pretty self explanitory. For a single dive 12 hours, repetitive dives or multiday dives 18 hours. If your dives involve deco then longer than 18, no set time. Figuring tables beyond deco doesn't matter with reference to group. If you have dived repetitive or multi day then 18 hours. Residule nitrogen is not a factor in the simple guidelines.

 

[Thalassamania]

Guidelines are great, for those who lack sufficient background to make intelligent and informed decisions on their own. Either live with the guidelines or learn enough about decompression that living with them is not your only option.

 

[endurodog]

Thal it isn't always background so no need to talk down to people here. Using these guidelines are inteligent and knowing them is being informed. Not knowing these guidelines at all is not being informed and the OP is making himself informed by asking. The vast majority are very happy with the guidelines and following them not because of lack of background but because the guidelines are simple and straight forward. Like with anything if you want to learn more there is more indepth information that can be had by researching decompressio theory.