Caves in Mexico that Allow Unguided TDI Intro Divers?

[halocline]

Basing penetration on <whatever fraction> of a mythical full tank when you don't start with a full tank seems like a bad plan. Turning at 1500 from a 2k start is diving 4ths, not 6ths.

This is exactly the misunderstanding of the 1/6 penetration limit for intro divers that I was talking about. The rule (as I was taught by an extremely reputable teacher) is not about gas planning, it’s about limiting the distance of penetration regardless of available gas.

As an example, in the old days (lol) there were divers that took cavern and even intro on single tanks with H valve, and for those divers, the penetration rule was 1/3, or exactly the same amount of useable gas for penetration as 1/6 with doubles. I honestly don’t know if anyone still takes those courses with a single tank/H valve, but it demonstrates that the penetration limit is not about gas planning. Of course you still have to gas plan, and any competent instructor is likely advise students not to dive to thirds unless in ideal conditions. (I.e 3 person team, downstream exit, familiar cave, etc..)

 

[halocline]

We like Taj a lot. Do you know if they’d let us dive w/o a full cave cert?

I dove there a lot as an intro diver.

 

[Norwegian Cave Diver]

Thank you. We were told by our former instructor “no jumps, no tees”.

Ok. Thanks. Thought that might be how your diving but didn’t want to make that assumption.

Consider Mayan Blue. Ask if they require a full cave cert.
have yiu or your buddy been there?
Do you want/need a map?

 

[halocline]

There are certainly cave only sites that don’t ask for a cert card. (CH) would be one of them. Not a delicate cave or a silty cave. Line at the surface, so need to jump in. Easy main line to follow and some jumps in the West South West direction of the cave. A bright clean feeling cave. Dive starts with - down the hill - T Left- T Left - and you be on the main line in that WSW direction.
Or
Down the hill and T Left and at that next intersection T Right. It will be a circuit that brings you back to your exit. That circuit might be short enough that you can do that on full tanks and 1/6th. If not then it will be close.
Keep in mind that you will be in a cave that has only one exit for you.
If you have more questions send me a PM

As far as how I was taught, Intro level divers are not supposed to do jumps or even tees. I feel like that’s a more ‘important’ limitation in Mexico than the 1/6 penetration limit. Navigation in Mexican caves is challenging and it’s easy to get in real trouble with a navigation mistake.

There might be other agencies or standards that allow intro divers to make a single navigation decision, I seem to recall hearing that, but for me, it was mainline only, turn the dive if I encountered a T. And no restrictions.

 

[AndyDoesScuba]

Ok. Thanks. Thought that might be how your diving but didn’t want to make that assumption.

Consider Mayan Blue. Ask if they require a full cave cert.
have yiu or your buddy been there?
Do you want/need a map?

We definitely will consider Mayan Blue. We’ve been there during training, but we don’t have a good map. If you can point us toward one, it would be helpful. We were told by an instructor we met in Tulum that Tunnel B is a good choice.

One reason we wanted other options is that Mayan Blue it’s past Tulum and we live in Playa del Carmen. Not a huge deal, but something closer would be nice as an option.

Thanks for your help.

 

[tursiops]

For reference:

TDI Intro Cave, from the TDI S&P, 19.2, Qualifications of Graduates::
1. Penetration is limited to 1/3 of a single diving cylinder or 1/6th if using doublecylinders.
2. 40 Metres/130 Feet maximum depth.
3. No decompression diving.
4. No restrictions. No areas too small for 2 divers to pass side-by-side.
5. Maintain a single continuous guideline.
6. Proper cave diving equipment is used.
7. No removal of life support equipment shall be permitted within the overhead environment.

GUE 3.2.10.4 Cave Diver Level 1 Specific Training Standards:
a. Student-to-instructor ratio is not to exceed 6:1 during land drill or surface exercises; it cannot exceed 3:1 during any in-water training.
b. Maximum of 1/3 of 2/3 of the total gas supply can be used for penetration. [edit: this is 25% more than 1/6th]
c. Maximum depth of 100 ft/30 m.
d. Minimum 100 ft3/2800 L of gas is required to begin a Cave 1 dive.
e. No passages may be used in which divers are forced to travel single file for a prolonged distance (i.e., approximately 10 ft/3 m).
f. No complex navigation (jumps, traverses, circuits).
g. Navigation beyond one permanent intersection (also known as a “T” or “Y”) and an unlimited number of temporary intersections is permitted. Permanent intersections are identified by the lack of a visible jump spool; temporary intersections provide visual access to a diver’s jump spool. All intersections that appear permanent should be marked with non-directional markers.
h. Trainees may navigate gaps; a gap occurs where the main line ends and begins again a short distance later. Normally this occurs where the line has reached another entrance/exit point.
i. All dives must be within minimum decompression limits (MDLs), i.e., no required stops.
j. No DPV diving.
k. No exploration.
l. No stage cylinders.
m. Students must complete GUE Rescue Primer or equivalent from a recognized training agency prior to certification.

 

[inquis]

The rule (as I was taught by an extremely reputable teacher) is not about gas planning, it’s about limiting the distance of penetration regardless of available gas.

If I have full 108s, I can penetrate a distance of X ft (based on ⅙ of that full tank). From what you're saying, if my 108s only have, say... 160 cf in them, I can still penetrate X ft (same SAC/speed/etc.). However, if those 160 cuft were contained in AL80s -- which are full, mind you -- then I could NOT penetrate X ft.

Does that not sound contradictory to you?

I agree the point is to stay near the front. However, ⅙ of the actual starting gas does that as well. It also gives the new cave diver practice doing the numbers and ingrains the process they'll use when full cave.

 

[Norwegian Cave Diver]

We definitely will consider Mayan Blue. We’ve been there during training, but we don’t have a good map. If you can point us toward one, it would be helpful. We were told by an instructor we met in Tulum that Tunnel B is a good choice.

One reason we wanted other options is that Mayan Blue it’s past Tulum and we live in Playa del Carmen. Not a huge deal, but something closer would be nice as an option.

Thanks for your help.

Here is a link to Mexico Cave Maps…

Quintana Roo cave maps

 

[Norwegian Cave Diver]

If you look at the three maps listed for Mayan Blue…
The third map is a cleaner view with lines showing.
Tunnel “B” Two entrances - one is about half way down the swim and a large tree is above the entrance, second is farther down and left around a corner.

Tunnel “B” is cleaner and whiter.

 

[DiveLikeAMuppet]

This is exactly the misunderstanding of the 1/6 penetration limit for intro divers that I was talking about. The rule (as I was taught by an extremely reputable teacher) is not about gas planning, it’s about limiting the distance of penetration regardless of available gas.

There is one specific shop in Mexico that teaches this peculiar approach to 1/6 limit and I had a massive disagreement over it with a buddy. If you dive 1/6 of available gas (or 1/3 of 2/3 if GUE) your risk profile on each subsequent dive on the same set of tanks is identical and you always reserve plenty of gas for higher SAC rate. If you dive 1/6 of "rated" (aka original) pressure on the second dive on the same set of tanks, your risk profile on the second dive is very different - you could be diving close to 1/4. I'm not saying it's wrong, but I would rather admit that I feel stupid brave so I will dive 1/4 and push the limits than play games with the strange math.

Honestly I think in Mexico you also need a mental limit - you can get really far away from home in Nohoch because it's so shallow even on 1/6.

My buddy and I have all our own gear and transportation. We would like to build skills before taking the full cave course. Always having to go with a guide gets expensive and is frankly unnecessary given what we’re trying to accomplish.

I am aware of only one cenote near Tulum where TDI intro to cave divers are supposedly allowed to dive unguided. That being Cenote Escondido. Does anyone know of any others? We are safe, conservative divers, and only plan to dive well within our certification and, more importantly, our skill level.

Next to Escondido (aka Mayan Blue) is Naharon and they are not checking cards either, but the cave is quite dark and the line run is really long - some people run the line past the first jump to avoid violating intro to cave rules. If you dive out of a shop and they know you, they can "sneak" you into Carwash (nice practice intro cave and some really cool places with full cave), Nohoch and possibly Eden/Ponderosa. Dos Palmas is a brilliant intro dive but I don't know if you need to tag along with a guide to get in. Corazon is pretty nice too (but downstream is spooky).