"Advanced Divers Only..."

[shurite7]

The first time I dived Barracuda/San Juan, my feeling was "What's all the fuss about?" There was no current at all. We could swim in whatever direction we wanted. It was one of the easiest dives I ever did on that island. I did, however notice that the barrel sponges were twisted and deformed from the current.

The second time I dived it I saw precisely what the issues were. The current was doing its best to sweep us off the reef, and we had to be both skilled and strong to fight it. It would have been a disaster for a beginning diver.

When I dived Barracuda there was a down current that gave the group a bit of trouble. I had to inflate my BCD, a little bit, to get up on top of the reef. After the dive, the guide ripped into me about using the wrong fins; I was using spilt fins. Jorge, the guide, told me I should have been in blade fins. With hindsight I agree with him. The experience was a learning one - use the right equipment for the environment and pay attention to currents.

I haven’t been to Cozumel in years. It is place I would like to go to again hoping to dive Devil’s Throat and the north end of the island.

With everything that has been said on this post and working at a resort as well as diving and teaching in high elevation lakes (in short gaining a lot more experience) I like it when a dive-op conducts check out dives. When I did a study abroad in Egypt the guides did check-out dives. I was able to do things other divers were not, which was rather nice. When I lived in Cayman I saw all sorts of people at various levels. Luckily I didn’t come across a lot of incompetent divers to guide. What I did notice was a lot of people don’t know their gear. Part of my job was changing tanks during the surface interval. I probably learned more about gear than the customers learned about their own gear.

 

[Ayisha]

...We did 2 days, 4 dives before we were allowed to do Devil's Throat. It was an interesting dive, not terribly difficult...

It's because you first did Devil's Throat after Hurricane Wilma in 2005.

Hurricane Wilma devastated Cozumel and broke Devil's throat into 3 sections plus openings, making it a much less challenging dive.

DT was always at the end of a week of dives, after a dive op observed us. They would say to let your interest be known if you want to do it, and they will observe us closely, but it was only for the most advanced divers and "by invitation only". The first time, my LDS group of 77(!), with mostly divers, and 5 boats, ended up with 1 boat doing DT with mostly our instructors, DM's, and a few clients, including me. 2 DM's and many clients had been denied due to inadequate buoyancy control and not (horizontal) "attitude u/w".

To get to DT was the same. You had to be able to jump off the boat and quickly descend to about 80 feet with swift current. They would say that everyone had to make it or no one was going in and they would bypass. When we hit the entrance, buddy pairs had gotten separated in the wicked current.

I learned for the future to make sure that I was near the front because it would get a little silty as the line of divers went through. I was going through at a decent pace, admiring the brightly coloured corals inside with my light as I went, trying to keep up with the diver in front of me, but they were zooming. I lost sight of the diver ahead a couple of times in the twists and turns and I had to make a decision about which way to go at a couple of forks in the tunnel. I chose the way that had a tiny bit of silt once and the second time I really couldn't tell and guessed. I was very aware that I could be leading everyone behind me to who knows where. I breathed a sigh of relief when I caught up and just kept up.

When you exit at 120 feet, the sight of the apparently 1200 foot drop below was breathtaking. It was an awesome dive and one of my favourites. The dive then becomes a multi-level dive with lots of shallow time.

DT was one intact tunnel from 80 feet to 120 feet deep winding up and down and around along the way. Some of the parts were a little dark, plus there were offshoots from the main tunnel. There were areas that were not wide enough to share air side by side with a standard hose length or pass anyone if you had to. I was aware that if someone had an issue and blocked the way, everyone would be stuck behind them in the tunnel. The instructors from the LDS I was with said afterwards that it was a cave dive and absolutely not within 130 feet of the light zone. The linear 40 foot depth/length of the tunnel (starting at 80 feet) was winding at least double that length.

Since it was fully intact, very long and winding, fairly dark in places, narrow in places, and had confusing forks in the tunnel, it was very different from late 2005 on when it was broken into sections, has openings, and has light coming through.

 

[shurite7]

@Ayisha, thanks for the detailed info. I had overheard that DT was different after the hurricane. I now wonder if it would be an exciting dive for me. When I lived on the east end of Cayman there were lots of deep swim throughs, that we guided tourists through. Some were deep and long. A couple were reserved as staff dives only since they were deep or long with turns; one started at 80 feet and ended at 150 feet and came out in what looked like a comet landscape (think Armageddon with Bruce Willis) with all sorts of fissures and ridges; narcosis helped to give it an eerie look.

Nonetheless, I wouldn’t mind diving the north end again and trying out Devil’s Throat.

 

[Ayisha]

@Ayisha, thanks for the detailed info. I had overheard that DT was different after the hurricane. I now wonder if it would be an exciting dive for me...

I'm sure you'll still enjoy DT. It's just a little safer and more open than it used to be.

 

[seeker242]

So, what exactly does "Advanced Divers Only" mean or require?

There is no "exactly". It's their boat, It means whatever they want it to mean. It means a diver that they feel comfortable with taking them on such dives, AKA whatever they want it to mean.

 

[Jake 10]

I think (I could be wrong) it means they prefer divers experienced at +>30M, and like seeker said, "whatever the operator want it to mean".

 

[ChuckP]

I think (I could be wrong) it means they prefer divers experienced at +>30M, and like seeker said, "whatever the operator want it to mean".

Depth is merely one small fraction of experience - cold dark water and warm clear water are not the same. Attitude, awareness, listening, buoyancy, swimming ability, self survival maybe even - there are many things and the dive site itself drives how all these little items are weighed.

 

[boulderjohn]

I think the problem with the AOW certification being used for a standard for deeper recreational diving is that, depending upon the agency, you can do the AOW deep dive at 61 feet. Many dive shops have students barely past 60 feet, and in some cases they do it even shallower by using equivalent depth tables for altitude. That is because many locations do not have dive sites deeper than that. A few years ago there was a thread in which a poster said he was a DM working for a dive shop in Arkansas that told their divers that they were excused by PADI from doing the AOW deep dive because of a lack of an adequate site, and they told their students what the supposed "PADI approved" response on the QA questionnaire should be. I checked with PADI, and no one anywhere has permission to skip the AOW deep dive. The PADI person I talked to was very interested in knowing the name of that shop, but the poster refused to identify either himself or the shop for fear of being fired.

Here in Colorado, we have no local diving deep enough for the AOW deep dive, so we have to travel quite a distance for that. Most of our students who get AOW do so on shop sponsored trips or after long drives to deeper water. Consequently, I have conducted surprisingly few AOW courses, considering the number of years I have been instructing. When I have done AOW certifications at sites deep enough to get close to the limits of the standards, I have seen that the real eye-opener for the students, the true value in the dive, is in how much faster they go through their air at those depths. That is not just because of Boyle's Law. When some inexperienced deep divers go deep, their breathing rate increases, and it can increase dramatically. In one case in particular, my debrief with the student amounted to telling him that the most important thing he learned about deep diving was that he should not be doing it.

Because I believe students need to experience that for themselves and not just see some mathematical equation, I firmly believe that AOW dives should be conducted to at least 80 feet, and I am not talking about 80 feet on a theoretical altitude table.

 

[Coztick]

I get how you can simulate deco by using nitrox and setting computers to air but how do you effectively simulate depth by substituting tables?
"OK Billy, I realize the pool is only 12ft. deep but we're gonna be pretending that it's 120ft..." Do you use 19cu ft tanks to simulate gas consumption?
Some things can't be faked that easily.

 

[drrich2]

Because I believe students need to experience that for themselves and not just see some mathematical equation, I firmly believe that AOW dives should be conducted to at least 80 feet, and I am not talking about 80 feet on a theoretical altitude table.

Another issue is susceptibility to nitrogen narcosis. While it varies over time even in a given person, some are more susceptible to it than others. Enough 'tourist diver' dives are offered down to max. depths in the 80s (putting aside the popular Blue Hole dives out of Belize) to make some supervised time at depth a good idea. Years ago a popular and accomplished Scuba Board member mentioned she'd experienced narcosis as shallow as 70 feet, IIRC.

When I did the PADI Deep Diver specialty years ago, I wanted someone there in case I had an untoward reaction, and our instructor had another diver (not a student) sling a tank and have it handy just in case. And I deliberately went to 130 feet, as I wanted to see how it affected me.

It wasn't that long ago in one of the Accidents and Incidents threads, we read of a tragedy that started with a dive group gathering at a spot, and one guy wondered off deeper. Narcosis was suspected on the forum. I don't want to give anyone the idea a single 100 feet dive in benign conditions means you're always golden for all dives to 100 feet...but maybe it counts for something.