What is the "typical" surface interval for two tank boat dives in Cozumel?

[SEMO Scuba]

I have done 5 trips diving at Coz. Looking at my computer logs a few of the SI were under one hour, 53 minutes being the least, while most were 70 minutes or longer. My original post regarding time/depth was in reference to Columbia Deep for a first dive, then Columbia Shallow next. SI between those was about 20 minutes.

That said I don't think 60 minutes should be the minimum SI for other dives. Dive a profile that is safe for you, and safe for others in the group. As Christi said the dive masters will likely need a longer SI than the guests anyway.

 

[gasgirl]

Hi gasgirl,

I've enjoyed reading both your threads in their entirety. Computer aside, you do seem a bit nervous concerning your upcoming trip to Cozumel. Hopefully, the additional information you've learned will increase your confidence. I'm certain you will enjoy your trip and have wonderful dives.

My son and I had a recent week trip to Cozumel and dived with Aldora and their 120 cu ft steel tanks. First dives each day were on air though only a single dive exceeded the MOD of EAN 32 (yes, this was Punta Sur, Devil's Throat, 127 feet). It would have been nice to use nitrox on some of these dives. Second dives were all on EAN 32. First dives averaged a max depth of 102 feet, avg depth of 56 feet, and avg dive time of 68 minutes. Second dives averaged a max depth of 81 feet, avg depth of 49 feet, and avg dive time of 84 minutes. Our SIs averaged 1:55 with a range of 1:44-2:15. BTW, we dive Oceanic computers running the DSAT algorithm. Before that, for me, it was a Cochran.

Enjoy Cozumel, I look forward to follow up,

Craig

Glad to hear you enjoyed it.

I confess to a healthy sense of paranoia? LOL.

My experience has been that the more I invest in research before I go, the more enjoyment I get out of the trip exponentially.

I was just reading about seahorses, pipefish, toadfish, turtles, and nurse sharks... oooh! I can hardly wait!!

Thanks for posting your data - I do find the information extremely useful!

Tanks and Best Fishes!

 

[Tunaman68]

On a totally positive note - make sure to save some time for a nice slow afternoon or especially a night dive out in front of the Blue Angel. 30 feet max, and lots of critters hiding in the little coral heads and rubble. Grab a free tank, head into the current (usually) to the left past the sting ray pen for as far as 1/2 your air gets you, then turn around and fly on home!

Have fun!!

 

[cascas]

It never hurts to ask though

I am not going there... As i think asking will actually hurt... well, not the asking, but what comes just after that.

---------- Post Merged at 06:58 AM ---------- Previous Post was at 06:57 AM ----------

Haha! Cascas - who do you do your cave diving with?

I am doing the course with Zero Gravity. I am staying in Puerto Aventures.

---------- Post Merged at 07:01 AM ---------- Previous Post was at 06:57 AM ----------

>>snip<<

You better know it .... ( I really dig Austin Powers )

 

[gstrek]

5 trips to Scuba Club Cozumel over several years and using a Suunto Vyper. Surface intervals were between 65 and 95 minutes and dives as deep as 130 feet. Never a problem with the Suunto although it often called for longer safety stops.

** addendum **

Surface intervals on a dozen trips to Grand Cayman were in the 45 - 60 minute range. Pushed the NDL limits of the Suunto but never got locked out but have spent a few extra minutes at 15 feet. I do pay close attention to the nitrogen load graph and adjust my depth accordingly.

 

[Lorenzoid]

No, thanks. I clearly stated I did not want to get a different computer and specifically said so in my post.

Okay, with the now-dozen or so pages of responses muddling my thoughts, I didn't get it that you felt strongly that you want to keep your Suunto, and so I suggested that maybe you should reconsider. Anyway, I think my reaction was understandable--my understanding is that you never would have posted this thread in the first place if you didn't have a Suunto. It's what prompted this whole discussion. So it's now my understanding that the bottom line is that you like your Suunto because it's served you well everywhere so far and you don't want to get a different computer, but you feel you have to jump through some additional hoops in Cozumel because of it that the other divers in your group (presumably) will not have to be concerned about. I know you found threads where Suunto divers have said their computers barked at them in Cozumel, but is Coz really that much of an outlier data point in terms of dive profiles? If so--if Coz diving is just abnormal--then perhaps having to deal with the Suunto's, er, shortcomings, is not a problem, at least if it's not in your future to dive in Coz often. But if the Coz-style diving you anticipate doing (e.g., deep wall followed by shallow 2nd dive) is really not all that uncommon in the world, I still don't see why you would keep the Suunto. That would mean you would face the same "problem" again. As I think I mentioned, my Suunto has made me end my dives before the rest of the group in more places than just Coz. I think that's fine, but if it's such a concern to you that it requires THREE threads (one in the Computer forum, too, eh?) and a poll to figure out a "strategy" to get through the ordeal, why not do yourself a favor and get a different computer? As I tried to say, diving (at least of the tropical vacation-ey kind in Cozumel) shouldn't be an ordeal.

This is what you said word for word: "And yes, the surface interval stats would be interesting. If there is some reason to believe that dive ops in Coz are not following as conservative practices as dive ops elsewhere in the world and that's leading to a higher incidence of DCS, then that would be interesting to know."

You chose to misquote yourself and amalgate your sentences together to make it sound like I misquoted you.

Holy cow, are the two quotes not saying the same thing? I certainly meant them to. I used the word "bent" instead of DCS the second time, but other than that they look like the same thing to me.

Also, I would like to respectfully suggest that IF there is something that is of more interest to you than what is posted then you should start your own poll.

Look, the only reason I chimed in was that it appeared to me (incorrectly, I now see) that the original poster was going off the deep end in preparing for a trip to Coz and perhaps worrying herself needlessly. I had hoped to provide some reassurance and at the same time see if I could find out what you meant by the implication that Coz dive ops may not be providing long enough surface intervals to keep people safe, because the latter would be of major interest to anyone who dives in Coz. You've now made it very very clear that you enjoy this kind of discussion and planning and you're looking forward to your trip with not the least bit of trepidation. You need no reassurance, you're confident and well prepared. Okay, great! I "admit" I should never have chimed in

I asked Suunto divers to help me find a strategy to avoid having to engage in what could be considered unsafe dive practices that could potentially put me at increased risk of having an incident.

And there it is again. What does diving a Suunto or any other given computer have to do with engaging in unsafe diving practices? Regardless of what computer it is, follow what it tells you and you will not be engaging in any practices judged "unsafe." If by "having to engage in unsafe diving practices" you meant NOT following your computer, well, I never thought about someone "having to" not follow their computer. I guess I just assumed everyone always follows their computer, whether it tells them to ascend or to do a short unplanned deco stop. So I still don't see how the fact that you have a Suunto is relevant to whether your dive is unsafe or you "have to" do something unsafe. Everyone has a different computer, and yours just happens to be at the conservative end of the scale. You may have to ascend first, but the next person likely will be just a few minutes behind you, etc.

And again, there you are looking for a "strategy"--a workaround. If this is something that's not unique to Coz (and I don't know if it is or not), then I would again suggest that you have the wrong computer to suit the type of diving you do (or plan to do). It seems to me that if one needs a "strategy" to manage to dive with a particular computer on any kind of regular basis, then that computer is not suitable for that person's diving. But if diving with a Suunto and then having to employ a "strategy" to enjoy your vacation in Coz is not at all a bother to you, then by all means nobody should suggest you do anything differently. I take back any suggestion that the Suunto may not be right for you.

 

[fire_diver]

Gasgirl, I don't know what your diving history is but I would offer one bit of advice. If you are used to diving in cold and dark waters, keep a VERY close eye on your depth guage when diving the Caribbean. My first dive there I hit a couple minutes of deco on my computer. I was used to lake diving and the fact that there is no noticeable change from 30 to 130 can be very deceptive. I hit 120 on a wall without ever realizing until I looked at my download.

 

[Christi]

I never remotely suggested that I felt the dive op is risking my safety - I always take responsibility for my own safety.

What I said was I wanted to avoid going into unplanned deco or having to ascend early and separate from the group.

I asked for people to share their own experiences so I could get some insight into how to avoid what was, in my opinion, a bad dive plan.

Gasgirl,

I am impressed with your concern for safety and wanting to understand what you are getting into, I wish MORE divers were like this. You would probably be mortified to know how many "experienced" divers we see that don't even know how to set their computers, let alone use them properly. With that said, and I don't mean this with any disrespect - I do think you are over analyzing this just a bit.

Of course the surface interval is important and plays a factor, but it's not going to make much of a difference on the first dive of the day, which is the dive that has the most potential to put you in unplanned deco. It is the deepest dive and the way the SUNNTO algorithms work is that they load you up at depth. Where some computers start giving you credit back as soon as you start ascending, the SUUNTO basically requires you to get to the 30 to 40 ft mark before it will start giving you credit back - so many SUUNTO users end up with a few minutes of "unplanned deco" pretty frequently.

I am not ENCOURAGING you to go into "unplanned deco" but I'm just trying to put it in perspective for you. This is not TRULY deco, and not a reason to be concerned - conscious and alert of it, yes, but you are not going to get bent because you were a couple of minutes into "SUUNTO deco". If you get bent, I assure you there are other factors playing into it (that's another totally different topic). The explanation is far too in depth to go into here, but maybe one of the real techies will have the time and energy for it.

The bottom line is as you said, be responsible for your OWN safety and dive plan and WATCH your computer.If you hit that "unplanned deco" point, signal the DM that you need to ascend. Ascend to the point you need to and you will see your computer clear within a few minutes...and another VERY SIMPLE (I KNOW there is more to it, especially for true deco dives) rule is if you have a deco obligation, CLEAR it! As log as you clear it in an instance like this and then follow with a proper safety stop (I never do less than 5 minutes), you haven't "put yourself in danger."

If you watch your computer throughout the dive, and do a true multi-level dive not spending too much time at the max depth, you will be ok. But if you do need to ascend shallower than the rest of the group, signal the DM and stay above them if you can until you have completed your stop(s). There is not a DM worth his/her salt that wold force you to stay down if your computer is putting you in violation mode. The really good ones will also deploy a signal marker/sausage for you so that you are not surfacing in the "dark" - and so that the boat captain knows he has a diver surfacing. Discuss this with your DM on the boat as part of the dive plan to make sure you are on the same page - you'll probably find that you are.

I think you will be pleasantly surprised at how professional and qualified the DM's here are if you are with a quality operation, and you ARE booked with one. Unlike the weekend warrior DM's and Instructors (some of who claim to have more dives than DM's that have been diving 15 years 5-6 days a week - cracks me up because in most cases it would be impossible - it's a chest thumping thing) , these guys are diving every single day in the open water and manage divers of every level, every personality, have seen every computer, and know every dive in their sleep. They've handled more real life situations than you can imagine.

I'm not saying to go on a "trust me dive" - but I am saying that you are in good hands and you are not going to be given an unsafe dive plan. I said it before, but the guides are also planning the profiles for themselves, they dive virtually every day, week after week - they need to keep themselves safe as well. If THEIR computers are not going into unplanned deco, then yours shouldn't be either if you are following the dive plan!

I hope that was all as clear as mud - haha!

Moral of the story, hydrate, relax, hydrate, have fun, hydrate and WATCH YOUR COMPUTER - oh and HYDRATE!

 

[scubadada]

Glad to hear you enjoyed it.

I confess to a healthy sense of paranoia? LOL.

My experience has been that the more I invest in research before I go, the more enjoyment I get out of the trip exponentially.

I was just reading about seahorses, pipefish, toadfish, turtles, and nurse sharks... oooh! I can hardly wait!!

Thanks for posting your data - I do find the information extremely useful!

Tanks and Best Fishes!

I'm pretty O/C about diving myself, ask my family. I do extensive research, especially before choosing a new destination and/or operator. It has served me very well and now I have a relatively long list of good destinations and operators I can honestly recommend to others and use again myself. I record my dives in some detail and download to my computer. I have a very good handle on my gas consumption, exposure protection, and weighting requirements over a wide variety of circumstances. Lastly, it gives me confidence to have a good understanding of dive physiology, especially around nitrogen and oxygen exposure. I'm very familiar with my dive computers and the decompression algorithm I've been using for 10 years now.

I'd be the last to chastise you for doing what you need to do to adequately prepare for a dive trip to a new location, enjoy Cozumel.

Best, Craig

 

[cvchief]

My Mares is a little conservative too, I think. As my air consumption got better over the years, I found that on my 100 air, I was hitting deco way too often following the wife on her 80 Nitrox and then I was swimming with my hand over my head, constantly looking like I was asking a question. Every foot counts right? I didn't want to go for a less conservative computer. I found that I got to the point I could switch to Nitrox 80s and still keep pretty close to her. The deco on the Mares was a pain too. It seems to have a much narrow range of depth to clear it. I really had to get my buoyancy perfect to stay in the range and clear it. Still I like to know that I am a little more conservative, though perhaps not as conservative as a Suunuto.