Swim throughs - what could possibly go wrong?

[Foxfish]

I am aware the instruction agencies offer such courses. I probably should have made it clearer I'm referring to dive shop instructors that offer cavern courses intended for the caverns I've described. The only one I've come across mentioned above are intended as a prelude to cave diving. Thanks anyhow.

 

[fbk]

Where did you do the course? What parts did you find particularly useful?

I did it in Mexico last year. Apart from incredible diving in warm clear water and not having to get on and off a boat with tech gear on, the most useful aspect of the course was probably learning that despite having 500 or so dives and thinking my buoyancy trim and awareness were pretty good, I realised how much more I could improve. Likewise with being comfortable in the water, I always have been, then again I'd never had to do zero vis (blindfolded) exits from caves sharing air, recovering lost line blindfolded, dealing with simulated valve failures, light failures, etc. With the proper skills and equipment you learn that you can deal with almost any situation underwater IF you stay calm and follow your training. It is a good feeling to have regardless of whether you are deep in a cave or swimming around under a boat looking at fish.

 

[Foxfish]

I did it in Mexico last year. Apart from incredible diving in warm clear water and not having to get on and off a boat with tech gear on, the most useful aspect of the course was probably learning that despite having 500 or so dives and thinking my buoyancy trim and awareness were pretty good, I realised how much more I could improve. Likewise with being comfortable in the water, I always have been, then again I'd never had to do zero vis (blindfolded) exits from caves sharing air, recovering lost line blindfolded, dealing with simulated valve failures, light failures, etc. With the proper skills and equipment you learn that you can deal with almost any situation underwater IF you stay calm and follow your training. It is a good feeling to have regardless of whether you are deep in a cave or swimming around under a boat looking at fish.

Mexico? Were you diving the cenotes. I've seen some videos of them and they do look amazing. I can see the value of training that extends your diving skills and emergency responses and accept it would be hard to find training at that level outside the cave diving context.

 

[fbk]

Yes the Cenotes.. I could have done my training in SA or the Nullarbor but it's not the same as a diving holiday in Mexico, it was brilliant. I can't wait to go back.

 

[Storker]

The OP is using a debating technique not dissimilar to the one in this trainwreck of a thread: Repeating arguments ad nauseam, refusing to listen to counter-arguments and just ever-so-slightly slightly modifying his original arguments¹ on the way. I don't know if he's just trying to grind the other participants to exhaustion to "win" the debate, if he's trolling, or if there's something else going on I'm not aware of.

Now, lets's get back to the OP's initial post:

Assuming:

• There is only one clear path and no chance of getting lost;
• The floor is course sand that won't silt even with a group of divers swimming through the cavern;
• It is so spacious that many divers can pass through at the same time;
• The cavern has multiple large entries and exits; and
• It is well illuminated.

(bolding & emphasis mine)

"Assuming" is still the key word for me. In this thread, we assume. And for the academic exercise of a discussion, we might well enough assume. However, I am discussing diving, and I'm on this board to learn more about aspects of diving which I can apply to my diving. And as such, a purely theoretical discussion around assumptions is pretty much meaningless.

Let us take the topic out of the theoretical discussion domain and into real world diving. The type that can kill you if you do it wrong. Personally, I don't want to bet my life (and a nasty death) on an assumption. When I dive I want to know, without reasonable doubt, that I'm going to surface alive, unbent and without embolisms. Who is deciding whether the overhead environment is safe? The OW diver with no overhead training? The buddy? The guide? The former isn't, in most cases, qualified. If one of the latter makes the decision, the dive turns into a "trust me" dive. We have enough examples of "trust me" dives in overhead environments that have ended with casualties. The Blood Grotto in southern Italy the summer of 2012 is one excellent example of that.

Using the "crossing the street" analogy, as far as overhead environments go they are a crosswalk, with boom gates, on a single lane road, in a country town, on a Sunday.

For the purpose of discussion, let's take this claim at face value: The specific caverns the OP is talking about are benign. So benign that even a vacation OW diver with poor trim and ditto finning technique can dive them safely without a line, redundant air supply and a couple of backup lights. And how does a run-of-the-mill OW diver decide whether or not they are that benign? Is the run-of-the-mill OW diver competent to assess that? I'm certain that I'm not. So, instead of going through a complicated checklist - currently up to twelve points¹ - posited by the OP, whose qualifications I don't trust since his only credentials are words on an Internet message board, I choose the simple and perhaps dull and cowardly approach: I stay out of overheads unless and until I am trained and qualified to enter them. If I, some time in the future, should wish to start diving overhead environments, I can afford a cavern course. That should make me qualified to do the assessment myself instead of trusting a guide or a dive buddy, and the course is a lot cheaper than dying because I over-estimated my abilities or failed to identify a major risk factor.



¹ For an example of keeping the basic conceptions and presumptions in the OP's first post, while adjusting the minor points, consider:

The list to date:

- Avoid diving in confined areas where there is strong surge or current.
- Ensure you always have adequate room for easy access to your buddy and your octopus.
- Don't dive in caverns where silting can obscure and prevent exiting the cave.
- Only dive in caverns with adequate natural lighting.
- Only dive in caverns with open and ready access to and from all parts of the cavern.
- Only dive in caverns where there is no chance of getting lost.
- Avoid caverns or overhangs that appear fragile.
- Avoid diving in caverns with incompetent divers or divers prone to panic.
- Know how to deal with a displaced mask and BCD inflator stuck open.
- Stay close to your buddy in case of an OOA emergency unless you both have an independent gas supply.
- Be aware of dangerous animals that may live in these regions and how to avoid triggering aggressiveness.
- Only dive in these caverns if you can maintain neutral buoyancy and fin without stirring up the bottom.

 

[MXGratefulDiver]

The OP is using a debating technique not dissimilar to the one in this trainwreck of a thread: Repeating arguments ad nauseam, refusing to listen to counter-arguments and just ever-so-slightly slightly modifying his original arguments¹ on the way. I don't know if he's just trying to grind the other participants to exhaustion to "win" the debate, if he's trolling, or if there's something else going on I'm not aware of.

It's like playing chess with a pigeon ... no matter what you do, the pigeon just craps on the board and then struts around like it won ...

... Bob (Grateful Diver)

 

[victorzamora]

It's like playing chess with a pigeon ... no matter what you do, the pigeon just craps on the board and then struts around like it won ...

... Bob (Grateful Diver)

I'll have to remember that one. It's incredible how accurate it is.

 

[tkdgodess]

Don't forgt to wear a beanie for your bald head to protect it from scrapes on these swim thrus... (A purchase i overheard recently). Head scratches is a really big concern...

 

[Foxfish]

Don't forgt to wear a beanie for your bald head to protect it from scrapes on these swim thrus... (A purchase i overheard recently). Head scratches is a really big concern...

Or a hood, especially if you've got a bare patch on the top of your head.

Went for a shore dive last night with a buddy - and hundreds of stingers. I was warned to wear a hood. Got stung a number of times on the lips and between the hood and mask. My eyes were watering for most of the dive and I've got fat lips today. They need to design a hood or regulator that gives some protection to your lips.

 

[Redshift]

Much has been said and there are two extreme positions being taken by some people here that don't allow for any compromises.
I don't know if the OP is trying to validate his actions or asking in general if a diver without cavern training can do those dives and if so, how to minimize the risks.
Of course many skills taught in cavern courses can be learned outside the course. Everything can be learned! The first cave divers didn't have any courses. Many of them died.
A big problem here is not knowing what you don't know. And if the other divers who tell you that it's fine to dive those caverns without certification are not cave divers, they won't know it either. Many OW instructors have died in caverns because they they thought they had the skills to dive them.

You have dived those caverns and know how they are and, assuming you know your capabilities (these assumptions keep coming up...), you think the risk is very low. It may be the case, but you haven't been put through the situations practiced in a cavern course to really know how it would be if...
Looking at those caves, it's probably ok for certain divers to dive them. But do you always know all the divers in the group? How are their skills and how would they react in emergency situations?
And then comes another problem which is, the precedent. If done on those caverns, then people going to other places see some caverns and think "Oh, this is easy, I've done it", but the caverns will be different, accidents will happen.