Info Why are tables not taught in OW classes anymore?

[dmaziuk]

The point I was trying to make is that the recreational limits usually restricts divers from entering any type of overhead. I'm not advocating CESAs, but if you are unable to do a CESA to the surface it's a technical dive by definition (at least by most agency standards).

There is an ass-sumption that you will ascend no faster than a certain rate. If you do, CESA or not, the ceiling will clear before you get to it. Does that ceiling really exist?

The converse is to assume that the diver can teleport to the surface in zero time: then they can actually hit that ceiling. That's obviously absurd.

 

[boulderjohn]

The point I was trying to make is that the recreational limits usually restricts divers from entering any type of overhead.

You will be able to find many quotations to support this, but it turns out not to be wholy true. I found this out when debting with PADI about wreck diving standards. It turns out that short swim throughs are considered open water. A 20+ year old training bulletin even says it is OK to take OW students through a short swim through during a training dive.

 

[Cheizz]

You will be able to find many quotations to support this, but it turns out not to be whooly true. I found this out when debting with PADI about wreck diving standards. It turns out that short swim throughs are considered open water. A 20+ year old training bulletin even says it is OK to take OW students through a short swim through during a training dive.

What is 'short'? How long can a swim-through be before it does get into overhead/cavern territory?

 

[Vicko]

What is 'short'? How long can a swim-through be before it does get into overhead/cavern territory?

Are you able to take out the reg from your mouth and get to the surface without drowning?
If yes, congrats, you were doing a recreational dive.
If no I have a freediving course to sell you.


Sounds silly but that's the in the spirit of the rule.

 

[Cheizz]

Makes sense. Thanks.

So, no set standards then (measured in m/ft)?

 

[steinbil]

You will be able to find many quotations to support this, but it turns out not to be whooly true. I found this out when debting with PADI about wreck diving standards. It turns out that short swim throughs are considered open water. A 20+ year old training bulletin even says it is OK to take OW students through a short swim through during a training dive.

Fair enough. I doubt surpassing NDLs and clearing it on the way up will be as kosher...

What's your take on the GUE MDL table with depth averaging? I have yet to see any problems with it, and if it is in fact a safe way to do multilevel dives while staying within the same safety margins as following the computer, then why say you can't use tables for multilevel diving? Do you have any examples of problems using this approach that should change my mind?

 

[boulderjohn]

What is 'short'? How long can a swim-through be before it does get into overhead/cavern territory?

Makes sense. Thanks.

So, no set standards then (measured in m/ft)?

As it turns out, the length of a swim through that is acceptable depends upon the diver's judgment. Different divers with different levels of experience and different equipment can make different decisions.

This was decided only a couple years ago, and a version of that new language was included in the 3rd quarter publication of the Undersea Journal, PADI's professional journal, a couple years ago. It was to be included in the new wreck diving course when it was done.

I wrote it.

 

[boulderjohn]

What's your take on the GUE MDL table with depth averaging?

As it turns out, I know quite a bit about this. When I was trying to write my article on different NDL ascents, I contacted GUE and asked for an explanation. I was given a very detailed description of why they do what they do. This was after a thread on ScubaBoard in which different GUE divers gave their own explanations. None of them were right.

I wrote earlier that there is no indication of an ascent rate that is too slow, as long as it does not put the diver into deco. The GUE MDL ascent will not put the diver into deco, so it is most likely safe. What most people don't know about it is that the primary reason for the stops at the end is the belief that the shallowest part of the ascent should be done slower than the deepest part. Doing a series of stops accomplishes that and mirrors the process of ascending from a decompression dive.

This is not remotely close to what most people consider a multilevel dive. As I wrote several times in another thread, I did a maximum depth 126 foot dive on EAN 32 with a total dive time of 88 minutes. That is a multi-level dive.

There is, however, no research supporting the GUE MDL table. It is all based on their belief.

 

[Eric Sedletzky]

As it turns out, the length of a swim through that is acceptable depends upon the diver's judgment. Different divers with different levels of experience and different equipment can make different decisions.

This was decided only a couple years ago, and a version of that new language was included in the 3rd quarter publication of the Undersea Journal, PADI's professional journal, a couple years ago. It was to be included in the new wreck diving course when it was done.

I wrote it.

That’s still really vague.
How about something like
“You are allowed to go through a swim through if: A) you can see an exit visible from the entrance before entering the swim through that appears to be large enough to allow an passage.
B) The swim through is 25’ or less in length.
C) If the visibility is too low to see out the other side and the swim through length is unknown and potential hazards unknown, then do not enter.”

This would be something comprehensive with at least some written rules.

 

[scubadada]

I'm not advocating CESAs, but if you are unable to do a CESA to the surface it's a technical dive by definition (at least by most agency standards).

I am reasonably sure that this is incorrect. SB members who know agency standards should comment. You need to be able to CESA from 130 ft for it to be a recreational dive, I don't think so.