1st time to Cozumel need help finding a dive shop

[caseybird]

Perhaps they've updated their policies. That's a good thing.

"It is also important to note that most of all the dives in Cozumel will be in
performed in drifting conditions. That means the group must stay together during
all parts of the dive, from descent to exit." -- Aldora Divers of Cozumel

"Only dive restriction was that we come up with at least 500 psi. We tended
to come up in a group (never more than 6 divers on the boat); if someone
was sucking air, the divemaster would feed her/him air through an octopus
with 10' hose."
Cozumel and the Mexican Yucatan Diving Review of Aldora Divers, 2007/02

" As a part of his briefing he told us that he would not send divers to the surface one at a time. When one had dived the tank limit, we would ascend as a group. "
http://www.scubaboard.com/forums/cozumel/320016-kudos-aldora-divers.html

and, of course, this entire thread:
http://www.scubaboard.com/forums/cozumel/342882-air-sharing-part-dive-plan-coz-dives.html

Not the way I remember it. Perhaps the web site is not entirely accurate, and the DM's are not as rigid as some imagine. I think there is some flexibility allowed as the dive op sorts out the skill level of the divers. YMMV.

 

[Mossman]

And YOUR opinion of who the "best" dive op on the island is YOUR subjective opinion.

No kidding. I didn't mean that my "best" would have been the same as the "best" that others would have chosen, merely that my "best" wasn't on the this particular top 5 list and I bet others would agree their "best" wasn't listed either. I was just trying to point that out without going into the detail you did, but I fully agree with your assessment. And BTW subjectively I would still put you in the top 5 on my list, but (subjectively) I like 120s. Non-airhogs MMV.

I know that you qualified your statement with "IMO" - but I still cringe when anyone says that ANY ONE dive operation is THE BEST on the island, including mine. This is entirely subjective. Everyone has their own perception of "THE BEST" - but seriously - what do you base that statement on? Have you dove with every single shop on the island under the same conditions? To say that "Shop A, B or C is excellent" with statements of why you think so is one thing, but to say that ANY shop is THE BEST is simply inaccurate.

Yup, as I said, I fully agree with you. I find it ridiculous when someone says something is the best without trying the rest.

That said, perhaps there would be some benefit in an objective comparison (if at all possible) of all the dive ops on Cozumel. That would require a lot of time and a lot of diving. However, provided all this wasn't at my expense of course, I could be selfless enough to undertake such a heroic task, to be the "consumer reports" of Cozumel diving. Surely there would be some value to the diving community to have a complete unbiased evaluation and ranking of all Cozumel dive ops and I believe I'm up to the task. I suggest starting some sort of fund, and we'll get me a fancy uniform/wetsuit to wear for the duration (hopefully with the Scubaboard endorsement and generous sponsorship). One week of diving with each dive op on the island should be OK and I'll report back in about a year-and-a-half.

As I remembered from class the less tired thing was unproven but antecdotal?

Seriously, what part am I getting wrong? How can less nitrogen loading not decrease the risk? I mean MORE nitrogen is the prime factor right? Isn't that why we have the table that say if you get more than this amount of nitrogen you are screwed? What am I missing? How could you stay down longer than air if that wasn't true?

Quoting the DAN Guy: Although nitrox can be used to lower DCS risk, it is important to understand that nitrox dives are not inherently safer than air dives. They can be made safer (from a DCS-risk perspective) if the diver uses nitrox but dives within the NDL of an air dive to the same depth. On the other hand, nitrox can also be used to increase a diver's bottom time, but this eliminates the protective effect. — Brian Harper, EMT, DMT, Alert Diver medical editor

I agree with you. However, statistics do not. Apparently, there is no statistical basis to the theory that less nitrogen vis a vis diving nitrox on air tables actually reduces incidence of DCS. Why? Because incidence of DCS for divers that do not exceed the guidelines of air or nitrox tables is rather random and rare. There's simply no evidence that using nitrox instead of air on these same profiles would statistically reduce the risk of getting randomly bent.

That said, I personally believe there must be a benefit just as you do. Less nitrogen = less nitrogen. It's as simple as that. If all "undeserved" hits were simply up to statistics, then what's the purpose of hydrating, doing slow ascents, etc. Or, the way I see it, nitrox use, even if on "air tables" might mitigate other 'negative' factors like dehydration, hangover, etc. That's only my theory, but I've put my money where my mouth is and shelled out the cash for nitrox even if I didn't statistically need it. So far my theory has worked like a charm, no matter what the hangover, I still haven't been bent. YMMV so please don't take my advice without consulting your own physician or priest.

 

[cvchief]

That said, perhaps there would be some benefit in an objective comparison (if at all possible) of all the dive ops on Cozumel. That would require a lot of time and a lot of diving. However, provided all this wasn't at my expense of course, I could be selfless enough to undertake such a heroic task, to be the "consumer reports" of Cozumel diving. Surely there would be some value to the diving community to have a complete unbiased evaluation and ranking of all Cozumel dive ops and I believe I'm up to the task. I suggest starting some sort of fund, and we'll get me a fancy uniform/wetsuit to wear for the duration (hopefully with the Scubaboard endorsement and generous sponsorship). One week of diving with each dive op on the island should be OK and I'll report back in about a year-and-a-half.

I checked on this for you. Sadly the Cozumel Tourist Association estimated the cost of your bar bill you insisted be included actually exceeds the GDP of the island, :shocked2: so they have decided to pass on your idea.

I agree with you. However, statistics do not. Apparently, there is no statistical basis to the theory that less nitrogen vis a vis diving nitrox on air tables actually reduces incidence of DCS. Why? Because incidence of DCS for divers that do not exceed the guidelines of air or nitrox tables is rather random and rare. There's simply no evidence that using nitrox instead of air on these same profiles would statistically reduce the risk of getting randomly bent.

That said, I personally believe there must be a benefit just as you do. Less nitrogen = less nitrogen. It's as simple as that. If all "undeserved" hits were simply up to statistics, then what's the purpose of hydrating, doing slow ascents, etc. Or, the way I see it, nitrox use, even if on "air tables" might mitigate other 'negative' factors like dehydration, hangover, etc. That's only my theory, but I've put my money where my mouth is and shelled out the cash for nitrox even if I didn't statistically need it. So far my theory has worked like a charm, no matter what the hangover, I still haven't been bent. YMMV so please don't take my advice without consulting your own physician or priest.

Ok, I get there are probably not that many diving with hangover studies. However for 'regular' divers you are saying their are no statistics to support that the the larger margin of safety you included between you and your no decompression limit increases, the safer you are? I mean I get that diving nitrox table with nitrox is relatively the same as diving air with air tables. And the DAN article I quoted seemed to be primarily saying if you dive nitrox on nitrox tables you DON'T increase your chances nor decrease your chances. That seems to be the focus of everything I could find to read.

Looking at this article: Divers Alert Network : Alert Diver Articles which is basically about comparing diving EAN table versus Air tables, Dr. Peter Bennett says:

You should remember that if you do use EAN tables or computers, which compute more time at depth for the lower nitrogen in the nitrogen-oxygen mixture, if you breathe to the limits of the EAN — rather than the original air table — the risks will be the same. After all, decompression injury is a function of the tissue nitrogen tension before ascent, which will be the same.

Isn't he saying then if you dive air tables on both EAN and Air, EAN WILL be safer?

On the other hand I have finally gotten to the point that I hit deco on a 100 AL Air. I finally gave up and went back to the AL 80 in Nitrox (to extend bottom time NOT to be safer...) and actually am keeping up with the girls.....

 

[weeezer]

I concur with those who suggest Aldora. I've had 100s of dives with them since they opened in the 90s. Like all dive ops, they have some DMs that I like more than others. But I know them to be very safety conscious. They will pare you with a small group of folks of similar experience.

 

[Mossman]

I checked on this for you. Sadly the Cozumel Tourist Association estimated the cost of your bar bill you insisted be included actually exceeds the GDP of the island, :shocked2: so they have decided to pass on your idea.

There goes my idea of combining the dive evaluation with a comprehensive objective margarita tasting at Wet Wendy's. Maybe if Undercurrent and Rodale's also chip in? This truly would be a great benefit to all Cozumel divers. I'll chat with the Presidente if Dave D. can give me the hotline's phone number, perhaps we could raise the marine park fee to afford my services. Or dive shops could simply bribe me to get good scores. Like just about everything in Mexico, I'm easily corruptable for the right price.

Ok, I get there are probably not that many diving with hangover studies. However for 'regular' divers you are saying their are no statistics to support that the the larger margin of safety you included between you and your no decompression limit increases, the safer you are? I mean I get that diving nitrox table with nitrox is relatively the same as diving air with air tables. And the DAN article I quoted seemed to be primarily saying if you dive nitrox on nitrox tables you DON'T increase your chances nor decrease your chances. That seems to be the focus of everything I could find to read.

Yeah, DAN rejected my application to volunteer for hangover studies. I figured the membership dues and insurance profits could easily support my bar tab, but I was foiled yet again.

Here's how it works: Assume that for every 10,000 recreational dives within the NDC limits, 6 people get bent. Supposedly, if you had all 10,000 divers using nitrox on air tables for the supposed "safety factor", exactly 6 people would still get bent. The 6 bent divers are a random anomaly that comes from imperfect understanding of decompression physiology: the tables (or dive computer algorithms) are almost perfect for almost everyone almost everytime, but occasionally something goes wrong. That "occasionally", at least according to statistics, won't be changed any by substituting nitrox on air tables.

Personally I believe that if you really did the studies with a large enough sample, there would be some variation. However, you're taking a teeny tiny risk and making it just a teeny tiny bit safer, so the impact really is negligible and that's why some people believe it to be a waste of money to dive nitrox on air tables. This only relates to "undeserved" hits, however, the ones that have people shaking their heads because they can't figure out what happened. Personally, however, I believe that the reduced nitrogen/extra oxygen helps to mitigate other factors like dehydration, hangover, etc. that might otherwise push someone into a "deserved" hit. It's entirely possible that I would have been bent many times in my diving history had I not decided to suck nitrox instead of air during the dive. Also, the higher ppO2 does wonders for clearing hangover headaches, so it's sometimes worth the extra price just for that.[/QUOTE]

Looking at this article: Divers Alert Network : Alert Diver Articles which is basically about comparing diving EAN table versus Air tables, Dr. Peter Bennett says:

You should remember that if you do use EAN tables or computers, which compute more time at depth for the lower nitrogen in the nitrogen-oxygen mixture, if you breathe to the limits of the EAN — rather than the original air table — the risks will be the same. After all, decompression injury is a function of the tissue nitrogen tension before ascent, which will be the same.

Isn't he saying then if you dive air tables on both EAN and Air, EAN WILL be safer?

Yes, he is. The most recent DAN symposium had renowned speakers saying the same thing. Wienke says the same thing in his Basic Decompression Theory and Application. However, according to some statistics lovers who will get red in the face discussing the issue, they're all dead wrong. Or, as I believe, they're referring to my theory of mitigating other potentially causative factors.

On the other hand I have finally gotten to the point that I hit deco on a 100 AL Air. I finally gave up and went back to the AL 80 in Nitrox (to extend bottom time NOT to be safer...) and actually am keeping up with the girls.....

Congrads. My air consumption has actually regressed, so I love the bigger tanks available in Coz vs. most other places in the world (managed to get AL100s in Grand Cayman and Wakatobi, and 112s in Truk, but it's otherwise 80AL or smaller everywhere else I've been - except for Florida and California where there's a big local dive scene).

If you want to hit deco on air using an 80, simply go deeper and set your computer for maximum conservatism (BTW, don't run out of air trying this as that's potentially dangerous to your health). Or just get a Suunto. I can get my D9 into deco in the bathtub using a snorkel.

 

[driftin' by]

Is it just me or does it seem like cvcheif and Mossman are indifferent in every thread regardless of the topic?

The truth is that because there are so many shops here, there IS a perfect FIT for each individual. It's up to each individual to decide what he/she is looking for in an operation and find his/her own perfect fit. Some are looking for the cheapest deal they can find and don’t care about how the operation is run, whether the boats are owned or rented, whether the staff is paid legally or under the table, etc. Some people want a boutique service and find value in the services even with a more premium price. Some prefer steel tanks, others prefer 80’s. Some prefer large slow boats so they can spend as much time socializing as diving, others prefer the fast boat rides out with longer SI’s on the beach and more dive time – I could lit 1000 different scenarios, but it doesn’t matter – because each person is different and has different ideas of what makes the “best” for them!

Poetic, now that is simply poetic. Very nice Christi! I'll be quoting this in the future.

 

[Mossman]

Is it just me or does it seem like cvcheif and Mossman are indifferent in every thread regardless of the topic?

Maybe you should blame the topic. How many times a week does someone ask "who should I dive with in Cozumel"?

Fortunately cvchief and I keep it far more interesting by discussing the intricate nuances of DCS statistics.

 

[driftin' by]

Maybe you should blame the topic. How many times a week does someone ask "who should I dive with in Cozumel"?

Fortunately cvchief and I keep it far more interesting by discussing the intricate nuances of DCS statistics.

I'm not blaming anyone just observing. But you're right, it gets asked all too often and your discussion is interesting although not the first time in the last couple weeks I've heard it either!

Carry on...

 

[joel smith]

These are the two I have heard so much about I will be diving in coz Nov 11 for the first time and will be diving with aldora, LOVE THOSE STEEL 100 TANKS.

Dive with Martin may offer free gear rental but check. Of course anyone can add on the price of rental gear. My preference is

aldora.com

 

[cvchief]

Is it just me or does it seem like cvcheif and Mossman are indifferent in every thread regardless of the topic?

I don't cook worth a darn..... I'm just saying....

And I have been accused by another frequent poster of being a irate5: just cuz I mentioned the restaurant he was organizing his birthday dinner was a great little place that sadly had closed for lunch.

Maybe not anyone else, but I found the nitrox discussion interesting.....

And back to the topic: http://www.scubawithalison.com/ Scuba with Alison. Big FAST boat, great capitan, like diving with friends, even the first time. :cheerleader: :cheerleader: