Are swim-throughs really caverns?

[Alex777]

Although I have almost 1000 logged recreational dives, there is one very basic issue I have never really understood. I would like to get the advice of some of the qualified tech divers on this board.

In my OWD course I was told that rec divers don't enter overhead environments. Period. No exceptions. In all subsequent courses (AOWD, Rescue, Master S D), no one ever contradicted that basic premise.

Yet, on Grand Cayman and throughout the Caribbean, it is universally assumed that ANY certified OWD can enter a "swim-through". Most DMs will guide a group of divers through swim-throughs routinely, without any prior warning and without any knowledge of the experience level of the divers. Obviously, almost none of these divers have cavern (or cave) experience and no one seems to use the long hose configuration. A few DMs, the minority, will say something like "if the swim-through makes you uncomfortable, pass it up." Most just assume everyone will follow them through.

Many "swim-throughs" are overhead environments of 25 to 100 feet in length. Trinity Caves, which many of you will know, is an example. Since you can always see daylight, I suppose these are technically "caverns". The word "cavern" is never used; I have never heard that word in a dive briefing. On the other hand, "swim-throughs" are said to be a signature feature of Cayman Islands diving. Almost anyone who comes here on a diving vacation will have been guided through a swim-through. If you ask a a Cayman Islands DM about "cavern diving", you will be told that we don't have any. Just swim-throughs.

So, what's the story? Why is it OK to enter swim-throughs when we are forbidden to enter caverns without cavern training? Is there a difference? Am I missing something, or are we courting disaster when DMs take groups of once-a-year OWDs with little experience and rental gear into swim-throughs?

 

[JahJahwarrior]

Well, technically I think PADI forbids me to go deeper than 60 feet. I've gone down to 130 feet.

The important thing to keep in mind is that PADI will never kill you--the water might. You need to have a greater respect for the situation as you see it, than as PADI sees it.

I have no problem entering an "overhead" environment, but not a cave. Most of the "overhead" I'm in is like a ledge, if you swim straight up you'll hit rock. However, when I am in "overhead" like that, I turn the dive at thirds. I also carry a spool with me, and occassionally use it, even though I'm not in a place where I'd have any trouble getting out. (though one place I dive can get very silty and disorienting, I have gotten confused there before, but because I always turn at thirds, I know I have plenty of air, and I just chill for a few minutes and then make my way back out--I can usually tell where I have been and where I haven't due to the silt, but it's also hard to convince myself that I'm heading the right way. It's a wierd feeling, and I don't like it

Would I have a problem with a swimthrough? As long as I'm turning at thirds, am diving with a buddy, and have multiple lights, probably not.

But, if PADI had police I'd be on death row by now. And is it advisable for people to enter "overhead" environments (be they ledges, caverns or swimthroughs)? It really depends on how much they want to live, how experienced they are, and the rules they have set for themselves. I really don't ike guided dives, becuase I have no clue where I'm going. I really need to know, because if I am going through a swimthrough, I'll run a line through there. But what if we aren't coming back through there? Eh, I guess I can't run a line then, can I? I want to plan my dive and dive my plan, not get on a boat, have the DM plan the dive, and I dive his plan.....

And yes, I think any diver entering an overhead environment should strive to follow cave rules. I don't know them all, but I carry a line with me, multiple lights (not always three, but usually two) and turn at thirds.

Anyways....

 

[BKP]

I've seen definitions of a 'cavern' being any overhead environment where natural light is visible at least every 200ft., which, I assume, would include swimthroughs.
I've also seen references to cavern diving, in that they can only be led by cave-certified divers, with a maximum of 4 to a group (which is obviously open to interpretation).

 

[Rick Murchison]

A swimthrough is only a swimthrough (not an overhead) if it meets the following criterea (my definition):
(1) You can see the exit from the entrance, and for the entire swim through the swimthrough.
(2) You can see that there's plenty of room to make the swim without entanglement hazard and without any "squeezes" (restrictions).
(3) The total distance from the entrance to the surface is less than the distance you can perform a CESA; in no case more than 130'.
Some things that never qualify are rooms, caverns and caves where you must turn around and swim back the way you came in to get out - those are overheads and require a continuous guideline to a spot from which a direct ascent to the surface can be made. (And proper equipment and training)
Please see the attached article, which explains why.
Rick

 

[Gombessa]

Useful discussion. I've swum under reef overhangs and arches, none of which were longer than the length of my body, and have never considered them "overhead" environments. It never occurred to me that there was (or was not) any technical definition.

 

[Rick Murchison]

Useful discussion. I've swum under reef overhangs and arches, none of which were longer than the length of my body, and have never considered them "overhead" environments. It never occurred to me that there was (or was not) any technical definition.

I don't think you'll find anyone willing to issue any "official" definition. Mine is my own opinion; it carries no authority and it isn't advice, and I don't represent it as coming from any agency or anyone else. For me, it's a working definition (one I think worth sharing) for a situation where I don't require my use of overhead/cavern/cave protocol - I'll go through a swimthrough as I define it without using a line or light or redundant gas supply. The overarching requirement (please pardon the pun) is that all the way from the entrance there is a direct path (with the one turn at the exit) to the surface that can be completed without any obstruction, help or navigating.
Rick

 

[Aspendiver]

I think that there is a big difference between going through a swim thru with a guide, a bunch of other divers, and a boat overhead with redundant air, than on a dive in unfamiliar territory with just a buddy.

Jah jah says, "The important thing to keep in mind is that PADI will never kill you--the water might. You need to have a greater respect for the situation as you see it, than as PADI sees it."

Well said.

Some of the best dives I've done have technically been cavern or maybe even cave dives- "Mary's Place" in Roatan and "Punta Sur, Devil's Throat" in Cozumel. I have to say that they were worth the additional risk. Hopefully, the training that a diver gets makes him capable of assessing those risks.

 

[spectrum]

The overarching requirement (please pardon the pun) is that all the way from the entrance there is a direct path (with the one turn at the exit) to the surface that can be completed without any obstruction, help or navigating.
Rick

That would fit with anyone being above to do the Horseshoe at Blue Grotto or Paradise Spring down to the 99 foot room.

In these environments that are in effect loopholes to the NO OVERHEAD edict it really comes down to the diver. At Blue Grotto my wife said no thanks to the horseshoe but thoroughly enjoyed the main cavern. The presence of permanent guide ropes in the "caves" probably mitigates some risk as well.

Let's face it, there are plenty of ways to get yourself into a bad situation in the sport, and life for that matter. It will never boil down to a neat set of airtight rules. Be true to yourself, your training, experience and comfort and remember to listen to "the voice".

Pete

 

[MurkyRockDiver]

. I have gotten confused there before, but because I always turn at thirds, I know I have plenty of air, and I just chill for a few minutes and then make my way back out--I can usually tell where I have been and where I haven't due to the silt, but it's also hard to convince myself that I'm heading the right way. It's a wierd feeling, and I don't like it

What if you had an equipment failure while you were chilling and were confused as you tried to race out to the surface? Yor are already on death row as you put it you just don't know it is all.

 

[GDI]

never do a trust me dive - trust me on that