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

[fire_diver]

Just thought I would share a link to this urine colour chart I found online earlier this year: http://www.urinecolors.com/dehydration%20chart.pdf

And no, this is not a passive aggressive way of telling anyone to piss off!

Yeah, they pound that urine color chart into us in the Army, and you often find them hanging in all latrines in hot areas. One thing to keep in mind is that the color shown would be the color if you were looking through a sample cup. When you look into the diluted urine in the toilet, figure the real color is about double the one shown and hydrate accordingly.

 

[gasgirl]

Yeah, they pound that urine color chart into us in the Army, and you often find them hanging in all latrines in hot areas. One thing to keep in mind is that the color shown would be the color if you were looking through a sample cup. When you look into the diluted urine in the toilet, figure the real color is about double the one shown and hydrate accordingly.

One of my friends pointed out that the colours were very similar to the pallette my interior designer chose for our main floor of our house!!

 

[fire_diver]

One of my friends pointed out that the colours were very similar to the pallette my interior designer chose for our main floor of our house!!

Oh.... please say you didn't go with the modern incarnation of the classic 1970's "Harvest Gold" that was in half the kitchens in the country! :shocked2:

 

[gasgirl]

Oh.... please say you didn't go with the modern incarnation of the classic 1970's "Harvest Gold" that was in half the kitchens in the country! :shocked2:

OMG! You NAILED it!!!

 

[Christi]

Oh.... please say you didn't go with the modern incarnation of the classic 1970's "Harvest Gold" that was in half the kitchens in the country! :shocked2:

Hahah! Well AT LEAST it wasn't AVOCADO GREEN!

 

[cascas]

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.

I do tech dives, I do deco, but I do not consider myself a deco expert.
What I can say is this : Deco in itself is not a problem. As long as you deal with it the proper way.
I also do not advertise going into planned deco untrained. What you do need to consider however is that EVERY dive is in fact a deco dive. The No deco limits are the dives that let you get away without deco/safety stop ( which are not the same btw).
A really simple way to deal with this is slow ascents (and hydration, moderate alcohol consumption, enough sleep etc) and always a safety stop.

If your computer ( and I remember my Suunto doing that a lot of years ago) shows you have a "ceiling" that means you are actually what is called "in deco". Now watch what happens... You start ascending a bit and the ceiling disappears. If you stay at that depth your ceiling may come back etc... In effect you are doing deco stops, you just don't realize it.

If dealt with properly (and is properly trained), you can do really hardcore deco dives with the same SI as rec dives without (serious risk of) getting bent. (there is ALWAYS a risk).

Personally, if I were gasgirl, I would not worry about the surface intervals too much. If you would take your good old recreational dive planner table and calculated some repetitive dives you will see that only if you get to pressure groups W/X (PADI table for air) then you should have a SI of 1 hour or more. If you stay within those limits you will be fine...

Off course it never hurts to increase your margins. And if you find yourself unable to prolong a SI, just stay shallower that the rest of the group. There are a lot of methods to increase your margins... Knowing how to deal with deco is one, but I realize not everyone has that drive...

I hope this helps...

 

[gasgirl]

Hahah! Well AT LEAST it wasn't AVOCADO GREEN!

Nope! It's OLIVE green!!!

---------- Post Merged at 02:32 AM ---------- Previous Post was at 01:50 AM ----------

I do tech dives, I do deco, but I do not consider myself a deco expert.
What I can say is this : Deco in itself is not a problem. As long as you deal with it the proper way.
I also do not advertise going into planned deco untrained. What you do need to consider however is that EVERY dive is in fact a deco dive. The No deco limits are the dives that let you get away without deco/safety stop ( which are not the same btw).
A really simple way to deal with this is slow ascents (and hydration, moderate alcohol consumption, enough sleep etc) and always a safety stop.

If your computer ( and I remember my Suunto doing that a lot of years ago) shows you have a "ceiling" that means you are actually what is called "in deco". Now watch what happens... You start ascending a bit and the ceiling disappears. If you stay at that depth your ceiling may come back etc... In effect you are doing deco stops, you just don't realize it.

If dealt with properly (and is properly trained), you can do really hardcore deco dives with the same SI as rec dives without (serious risk of) getting bent. (there is ALWAYS a risk).

Personally, if I were gasgirl, I would not worry about the surface intervals too much. If you would take your good old recreational dive planner table and calculated some repetitive dives you will see that only if you get to pressure groups W/X (PADI table for air) then you should have a SI of 1 hour or more. If you stay within those limits you will be fine...

Off course it never hurts to increase your margins. And if you find yourself unable to prolong a SI, just stay shallower that the rest of the group. There are a lot of methods to increase your margins... Knowing how to deal with deco is one, but I realize not everyone has that drive...

I hope this helps...

So, cascas, I said it earlier but I will say it AGAIN:

...my curiosity stemmed from some very strong opinions voiced on the other thread so I thought it would be an interesting exercise if we actually polled the SI times based on hard data - ie. looking in your logbook (or software) - rather than recall that they went with a dive op that said they had a 60 minute SI policy....

And I am not worrying about the surface interval - the dive op has reassured me that they will be doing a surface interval that is appropriate for the 1st and 2nd dives planned that day - an approach that makes more sense than an arbitrary 60 minute policy.

Here is a link to the other thread that prompted me to post this poll if you are interested: http://www.scubaboard.com/forums/advanced-scuba-discussions/429369-bad-dive-plan-cozumel.html

I took a LOT of heat in that thread from the deco trained divers for just asking about the Suunto deco issue:

...My questions for those familiar with Suunto computers are :
1. Would you allow the Suunto computer to go into deco and assume it will clear as you slowly ascend (10 ft/min) with mulitlevel stops for several minutes at 50 and 40 and 30 feet?
2. If yes, what is the maximum deco obligation that you would incur (assuming, of course, that this still falls within the gas plan)?

FWIW, I did do a search on SB forum and found numerous comments condoning this type of practice to counter the overly conservative limits of the algorithm...

What's really interesting is that I just read a Sticky Post on the Advanced Scuba Forum where I had started this other thread.

Here are some key excerpts I noted from GDI:

I could post this in the tech diving section but then I think it might be missed by those who are considering venturing into this disciplined area of diving and by those who just want to go diving in general.

KNOW YOUR EQUIPMENT AND HOW TO USE IT, DEVELOP AWARENESS and PRACTICE YOUR BASIC SKILLS

Given a situation that occurred this past weekend I thought it best to review some historical notes on other divers having the same level of experience and training (at least on paper). These notes I am referring to are of diver's who did not receive their certification for the training they set out to complete, at least not by this instructor.

The failure of these students to reach their objective was in part more or less a result of a few things:
1. They did not know their equipment and how to best use it;
2. Their skill was not where it should have been prior to starting the training
3. Their Awareness level was lacking
4. Their abilities to handle multiple tasks or prioritize tasks was limited


... I could list many examples ranging from divers subject to peer pressure, not knowing their equipment, arrogant and unsafe attitude, to just lacking the basic skill set but I would rather just simply pass on these few points of guidance to those divers thinking of taking more advanced levels of diving...

...Prepare and know your equipment, Learn your equipment, it's function and capabilities, work with it and practice using it in all capacities. Even if you have little guidance to go by the time you take to understand your equipment and how to use it will never be wasted...

Hmmmm... seems like I was doing exactly what GDI said to do...

The good thing though is that I learned a lot about safe ascent practices as well learning about the equipment!

 

[cascas]

Nope! It's OLIVE green!!!

---------- Post Merged at 02:32 AM ---------- Previous Post was at 01:50 AM ----------



Well, I am going to give you the reponse I gave to ddeborahdelamar earlier in this thread when she asked the reason why I posted this thread when I was booked with Blue Angel - a dive op that has a reputation for providing safe service:



I took a LOT of heat in that thread from the deco trained divers for just asking about the Suunto deco issue:



What's really interesting is that I just read a Sticky Post on the Advanced Scuba Forum where I had started this other thread.

Here are some key excerpts I noted from GDI:



That was exactly what I was trying to do!!!

Knowing your equipment is one part of the equation. Understanding the mechanics of deco and knowing what to do is the other part (imho the largest part). That computer is just a thingy telling you the outcome of an algorithm. If you are not able to understand the consequences (and I am not saying you don't) of your dive computers output it is not much more than an expensive piece of jewelry.

As I said... a SI can be any amount of time AND be safe as long as you are aware of what is happening and you know what to do to prevent problems. 50 minutes, or 70 minutes.. it all doesn't matter much if you adjust other parameters.
And that all is really independent of which computer you use...

 

[gasgirl]

Knowing your equipment is one part of the equation. Understanding the mechanics of deco and knowing what to do is the other part (imho the largest part). That computer is just a thingy telling you the outcome of an algorithm. If you are not able to understand the consequences (and I am not saying you don't) of your dive computers output it is not much more than an expensive piece of jewelry.

As I said... a SI can be any amount of time AND be safe as long as you are aware of what is happening and you know what to do to prevent problems. 50 minutes, or 70 minutes.. it all doesn't matter much if you adjust other parameters.
And that all is really independent of which computer you use...

Agreed... as I said... we will be doing a surface interval that is appropriate for the 1st and 2nd dives planned that day - an approach that makes more sense than an arbitrary 60 minute policy

I posed two separate sets of questions in that thread:
1. How best to use Nitrox to extend NDL while not exceeding MOD for the dive sites in Cozumel and
2. How to understand the Suunto computer questions...

What emerged from the responses on that thread was a debate about the safe surface interval... it was not the question I asked but I thought it would be interesting to take a survey.

 

[Lorenzoid]

gasgirl, I'm not "criticizing" you or anything you said. I had read your original posts in their entireties before I replied, and I was interested because I dive with a Suunto that I like very much AND I like to dive in Cozumel. I'm sure that by the time I chimed in after having read dozens of replies in two different threads I did not recall every statement in your original post accurately (which you most recently quoted in its entirety for my benefit), so maybe I re-hashed things that you had already felt were settled by previous replies.

As I said, I was only trying to be helpful, like the others who replied. Maybe my tone is more direct than, say, Christi's. Even she who I believe is supremely knowledgeable about Cozumel diving also suggested (perhaps more politely than I) that you might be "over-analyzing" the situation.

It has also been pointed out that Cozumel divemasters by and large know what they're doing and aren't going to lead you into unsafe diving practices. I don't advocate blind "trust-me" diving, but I do tend to take a relaxed approach to diving in Caribbean resort areas because I feel it's my vacation and I'm damn well going to let someone else do the heavy lifting as far as thinking about the sites and dive profile--at least to the extent that the briefing doesn't raise any yellow "possibly unsafe" flags to me. If I want to plan obsessively, I'll dive here at home in the lake. There are currents in Cozumel to watch out for, but diving there shouldn't have to require the kind of preparation that diving in the North Atlantic or a cold low-vis lake might. Cozumel is the kind of place that wants their visitors to relax and have a good (yet safe) time. The current may or may not give me problems on any given day on any given site, but even as relatively unprepared as I may be there always seems to be someone in the group whose diving is much worse than mine. Places like Cozumel attract inexperienced divers. In fact, on my first trip there, when I was quite inexperienced, I believe they chose sites based on the experience level of the divers, and we probably avoided some of the hairier sites. I'm not sure that I even now want to dive the most difficult sites that might push my personal limits. Again, this is a reason I feel Suunto's conservative algorithm fits my diving well. Some of what I said in my replies was based on an assumption that other divers--maybe even you--have similar views. So I put out on the table the possibility that you might enjoy yourself more if you analyzed just a little less. It's clear now that picking apart a problem and discussing it for pages and pages is part of the enjoyment for you. Perhaps for you the planning and preparation is as much fun as the trip itself. If I had known that, I wouldn't have suggested otherwise. We're all different.

Amid all the replies, it seemed to me that things were getting muddled as to what related to your Suunto computer and what related to possibly unsafe diving practices, and I pointed out that the two things are not necessarily related and suggested that discussing these issues separately might be more helpful than muddling them. This is all I was getting at. I'm sorry you felt I was somehow attacking you or debating with you.