devils throat

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From my decription, it sounds like you are doing alot of sawtooth diving, but in reality, you really aren't. You go through the tunnel first, which drops you out at 116ish to 120ish, this is where you hit your max depth, then you slowly profile up to 85ish to go through the throat. You do drop from 85 ish to 95ish to drop into the throat, but then you do a nice multi-level profile.

(I use "ish" because everyone's depth varies a little bit)

The average depth for the dive is between 75 and 85 feet. You don't get alot of bottom time for this dive, even with the most liberal computer. It is usually around a 35 minute dive with a fair 5 to 10 minute 10-15 ft stop. I also incorporate the 1/2 max depth stop (ie: spend some time at 60 feet, then some time at 30 feet) for several minutes before beginning ascent to safety stop.

If not done properly, it is potentially DCS waiting to happen. But also remember, DCS can occur without breaking the "rules." There are many, many variables both in and out of the water!

Dive safe!
 
The Devil's Throat, or La Garganta Del Diablo in Spanish, is a site in the Punta Sur area, with Columbia Reef to the north & Chun Chacaab to the south. It is not, however, one & the same as Punta Sur which includes other dive sites as well.

Devil's Throat is not a cave, but rather an extended swim-through. Although dark in spots & an overhead environment throughout, at all or nearly all points during the dive you will be able to see some a route of escape with ambient light, although at times this will be behind you. The entrance is not at 90', but rather 75'-80', and it exits at one of two main openings, one to the upper left at about 116', and another to the lower right at about 127'. It is quite a sight to exit and look out into the blue, but it is not abyssal--about 55'-65' from where you exit you can see an expanse of sand & patch reef bottom tapering downward. The dive is not accurately described as a vertical chimney, as it exhibits a relatively gradual slope through most of its extension & in many places has room for two divers either side-by-side or over-and-under.

For a diver qualified to do this site, an 80 should provide adequate gas to do it, a few of the side trips, any obligated deco stops & a safety stop--I have done so. I prefer to do it with a 100 or greater both because of the long string of other "throats" & swim-throughs that can be covered, and for a margin of safety. But, in many dives there I have never been seriously uncomfortable with an 80, and I'm not the world's most parsimonious on air.

Long live Coz.

DocVikingo
 
DocVikingo once bubbled...
. . .and I'm not the world's most parsimonious on air.

Parsiwhat?
 
You know, that little green vegetable they use as a garnish?

Parsimonious=frugal, sparing

Best regards.

DocVikingo
 
This summer I was with a group that had 3 divers go into deco on this dive. Remember YOU are the only one that has to keep up with your time and depth. These divers should never had been on this dive. They did not know how to use their computers or how to make a deco stop. My 15 year old daughter was on the dive and kept me in line with her computer (hers being more conservative then mine). I loved the dive, but it's not for everyone. If your going to make the dive, go over in your mind and dive buddy, what might be required if you run low on air or time.


:para: :m16:
 
Texasscuba once bubbled...
This summer I was with a group that had 3 divers go into deco on this dive. Remember YOU are the only one that has to keep up with your time and depth.
This dive is a good example of where I'm willing to go a bit beyond 1.4ata ppO2 for a brief period. The last time I dove it we met a group going the opposite way, and had to hang out for a couple extra minutes while the other group hung a left and went into the cavern area.

A lot of the other divers were into deco, while EAN31 gave me an extra safety margin on the N2 side (at the expense of some margin on the O2 side). Even taking the right hand 125' exit, I never exceeded the 132' 1.6ppO2 MOD of 32%. and since the total time at depth was short, the CNS clock never exceeded 30% or so. Actually, the CNS clock was lower than the 85' Columbia Bricks dive the day before, and the 80' Santa Rosa dive the following day, both also on 32%.

Charlie
 
I'm not comfortable doing nitrox on Devil's Throat. What happens if you get in a downcurrent ? Call me chicken, but I don't go below 110 on nitrox.
 
ronrosa once bubbled...
I'm not comfortable doing nitrox on Devil's Throat. What happens if you get in a downcurrent ? Call me chicken, but I don't go below 110 on nitrox.
Naw, I won't call you chicken. If diving it on nitrox were the norm, then I wouldn't have posted my comment. If you review your profile, though, you will see that the time period that you exceed 1.4ata on 32% is only a minute, perhaps 2 at the most --- and if you take the shallower exit, you might not even exceed it at all. The NOAA CNS O2 limit is 120 minutes for the 1.5ppO2 that you might see, and 45 minutes for the 1.6ata limit that you won't even touch.

In reviewing your profile, you should also note the down/up/down yo-yo profile of the dive. That's a good reason to try and keep down the N2 loading.

<rant on>A lot of people seem to ignore that CNS oxtox calculation is driven by both ppO2 AND time. Much like N2 loading and NDL calculations, it doesn't make much sense to specificy a depth unless you also specify the time period of exposure. IMO, what one should be planning and monitoring is the CNS clock, not just raw ppO2 without consideration of the time exposure. Although willing to momentarily spike to 1.6ata,
I am conservative on cumulative O2 exposure.

What do you do if another diver is in trouble below 110' and needs assistance? What REALLY is your rock bottom depth limit on EAN32 in an emergency? Perhaps it would be better to know what your real risks are rather than simply treating 1.4ata ppO2 (with no consideration of time exposure) as a bright line cutoff between safe and unsafe.

</rant off>.


you may now resume the normally scheduled program :D
 

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