First vacation to Cozumel, suggestions?

[gopbroek]

I know someone who got bent in Coz recently, just a little. He took two chamber rides, had to move plane reservations and isn't supposed to dive for 6 months. His computer, well be it an Oceanic, never went into deco and he wasn't diving much or the day before. The dive itself I am told was a relatively long one, but nothing unusual otherwise.
QUOTE]

Chief, I was diving with someone last week that uses EAN36 on every dive. He is a good diver in good physical shape and 4 years back while diving to a max of 72' and well withing limits and he took a random hit. He spent 4-5 days in Dr Piccolo's chamber. Sometimes sh%t just happens but I think adding EAN lessens the odds. I dive pretty agressive and use as much nitrox as my wallet and computer (an Oceanic) will allow, usually EAN36 unless I plan on going deep along the wall. I agree with others that Cozumel prices for nitrox are high but getting bent comes with a much higher cost.

 

[AdivingBel]

I can see the benefit of Nitrox in Coz, but I can also see BDSC's point. Because of the DM led aspect of Coz, the dives are going to be scripted with the meat of the dive in the first 40 min or so. Now if you are a regular and dive alot with the same op maybe you get the "nod" to go it alone and meet us at the marker, but most vacation divers don't. The DMs want to see you. With Nitrox you can run a little deeper or hang around longer after the buoy goes up, but the meat and potatoes is already over. Now if everyone is a seasoned diver (with a good SAC or big tanks) and everyone is known to the op/DM and everyone agrees this is the plan, then a dive really taking advantage of Nitrox could happen. Most occasional visitors don't get that trifecta. Can you benefit from the added safety of Nitrox? Sure, by all means. Safety is a wonderful thing. Can you do two dives a day on air, really enjoy it, do the signature dives, and not get bent? Sure, easy peasy.

I tend to save my "Nitrox dollars" for locales where I'm not tied to the DM and regularly do more than 2 dives a day. Then even if I have depth and/or time limits placed by the op, I can script my own profile. All that said, I love diving Coz. I dive with a "dive your tank," valet op and have a great time diving the same dives as my fellow divers (who are mostly diving air). All IMHO. YMMV. Have fun.

 

[cvchief]

I can see the benefit of Nitrox in Coz, but I can also see BDSC's point. Because of the DM led aspect of Coz, the dives are going to be scripted with the meat of the dive in the first 40 min or so. Now if you are a regular and dive alot with the same op maybe you get the "nod" to go it alone and meet us at the marker, but most vacation divers don't. The DMs want to see you. With Nitrox you can run a little deeper or hang around longer after the buoy goes up, but the meat and potatoes is already over.

Well.... YMMV on that. I know several ops that let you dive your tank. Simply that. Not wander off or do strange things, simply dive your tank. My op, for instance, shoot the buoy and sends divers up from the group as needed. Well be it that I tend to dawdle a bit and I don't like being the press of divers at the front with the DM, so the missus and I hang back, but I do not dive a different profile, just a longer one than some. However, last week, I was only minutes longer than some other in the group. I also dove with a 'cheater; ie someone on 100 CF air. He stayed will us till the end more or less. I know he has to be close to my Mares NDL, because I used to use a 'cheater' as well. I didn't notice until I helped unload they tanks and discovered '2 of these things are not like the others.' He came up after me once and I had to suffer the boat shaming, ie sitting and waiting for someone with better air usage.

I know of other ops where the group stays together and pairs shoot their own buoy to go up.

My point being you can dive with the group and get real close to NDLs very easy with a dive your tank op.

All that being said, when I take my nephews diving, they blow through a tank in no time flat. They are the exception that proves the rule and I do not buy them nitrox.

And Gopbroek, holy cow. That multi-day rides after diving 36? I think I would get an echo and look for the hole in the heart, get bent thing. (Or maybe I wouldn't and just keep diving 36 with my fingers crossed!) But you make the exact point: Nitrox lowers the odd for the same profile. Less nitrogen=less risk. And as a total unproven, anecdotal fact believed by many, me and missus especially feel less tired on nitrox than on air.

 

[gopbroek]

And Gopbroek, holy cow. That multi-day rides after diving 36? I think I would get an echo and look for the hole in the heart, get bent thing. (Or maybe I wouldn't and just keep diving 36 with my fingers crossed!) But you make the exact point: Nitrox lowers the odd for the same profile. Less nitrogen=less risk. And as a total unproven, anecdotal fact believed by many, me and missus especially feel less tired on nitrox than on air.

No originally, as I understand it, he was diving air when he took a random hit, now he dives 36 for added safety. And I agree with the unproven anecdotal stress agument and to me it does not matter if it is only a plecebo affect, if you 'feel' less tired then thats a benifit also.

 

[halocline]

This is a good thread on the topic of nitrox and post-dive fatigue:
http://www.scubaboard.com/forums/ne...ng/519006-enhanced-air-does-help-fatigue.html

I always use air in Cozumel, because I'm rarely doing more than 2 dives/day, maybe an additional very shallow shore dive. But, I do ten minute safety stops, sometimes longer, typically starting at 20 feet for three minutes and then 10-12 ft for the rest. I also arrange my profile to include some time at about half my maximum depth, and I really avoid going deeper once I've spent time at shallower depths on the same dive. These strategies have very significantly lowered my post dive fatigue. I use nitrox on liveaboards and a place like Bonaire, where I'm doing 4+ dives per day.

There is some good info in the PADI encylopedia about basic deco theory and how it impacts recreational, NDL diving. It's not too difficult to read and is oriented towards recreational divers. Basically, once you understand in basic terms how the multiple time-driven compartment theories work, and a little about the formation of microbubbles, it's easy to manage your dive profiles to help-alot- with post dive fatigue.

But, back to the original topic, PM sent!

 

[DandyDon]

No originally, as I understand it, he was diving air when he took a random hit, now he dives 36 for added safety. And I agree with the unproven anecdotal stress agument and to me it does not matter if it is only a plecebo affect, if you 'feel' less tired then thats a benifit also.

DAN has done more studies than anyone else on the benefits of diving Nitrox, and they find...
(1) Gives you more bottom time.
(2) Does not increase safety - seems like it would, but doesn't work that way I guess.
(3) The feel-good effect is a placebo, and costs more than beer.

 

[cvchief]

You are making it confusing.

DAN has done more studies than anyone else on the benefits of diving Nitrox, and they find...
(1) Gives you more bottom time.

Yes. Your NDL increases as you take on less nitrogen.

(2) Does not increase safety - seems like it would, but doesn't work that way I guess.

So, that can be true or it is incorrect depending.

I am going to make up numbers for illustration.

If you dive air for say 30 minutes at 80 feet and come up when you reach your NDL limits that would be equal to say diving for 60 minutes at 80 feet and coming up when you reach you NDL limits.

You have absorbed the SAME amount of Nitrogen in either of those examples. This is diving limited by your NDL in both examples.

However, that is NOT what happens to say me in Cozumel. I am limited by my [-]AIR [/-]GAS SUPPLY.

Let's say I dive for 50 minutes on air at 80 feet. My computer says I have reached my NDL and I have to come up. I have air left and I have maxed out my nitrogen load. On Air I am still limited by NDL. However then I dive Nitrox, I do that same dive for 60 minutes at 80 feet. I NEVER reach my NDL. My computer says I STILL have bottom time, however I come up because I am out of GAS. With Nitrox I am limited by GAS SUPPLY.

In this example I have a max load on air, but NOT a max load of nitrogen on nitrox. So I dive longer, but still surface 'safer.'

(3) The feel-good effect is a placebo, and costs more than beer.

I believe they said there was NO EVIDENCE they could find to prove it. Which may not disprove it.