Info Why are tables not taught in OW classes anymore?

[John C. Ratliff]

It is possible to get deeper than 23 feet in places that are not in the tropics.

Yes, but not at High Rocks on the Clackamas River.

Clear Lake, at 4,000 feet, is an example of where you can get deeper, but until I dive there, I don’t have to worry about it much. Another is off the Oregon coast, but this is winter, and it is fairly inaccessible right now.

SeaRat

 

[johndiver999]

That seems a risky dive plan - only a 20 minute SI and then riding to 0 NDL before ascending on the second dive (deco or not)?

Why? Do you have issue with the short SI or going into deco? Would you have less heartburn if he had a 1 hr SI and did the same thing?

 

[Blackcrusader]

Not enough air to get into a decompression situation with a single 72 cubic foot tank, especially if you need to surface with 500 plus psi. I’m not as sure about a single AL80, but the same reasoning goes.

SeaRat

Go to my post with my dive at 55 mins depth 15m 6 mins NDL. Pray tell how I could not continue this into a deco dive? As it was the dive time was near 80 minutes. Nobody has to always surface with 500psi some divers do so with less.

Also a dive I did to 50 Bar 750 psi a few years back below. You trying to tell me not enough air to do a deco dive on an AL80?
I could have done 10 mins deco and stayed at 34m depth and still have plenty of air to do a deco obligation. This dive on plain 21% air.

Info - Why are tables not taught in OW classes anymore?

Nerd on the loop, petral on the left wrist, perdix on the right. Or Perdix and Teric if diving open circuit. Either way I'm covered lol.

scubaboard.com

 

[Joneill]

Why? Do you have issue with the short SI or going into deco? Would you have less heartburn if he had a 1 hr SI and did the same thing?

I don’t have heartburn at all - I merely posted an opinion. Sorry if that is an issue for you?

My personal concern (and why I would not dive like this) is that the plan seems to push right to the edge… and the edge is not necessarily the safe limit to begin with. I prefer to not push to the limits like this.

 

[Blackcrusader]

Go to the Cozumel forum and you will find plenty of threads in which people talk about doing 60-80 minute dives using AL 80s. These are all multi-level, NDL dives using computers, but they would all be far past table limits.

No idea what the table limits would have been for my dives but that's why I use a DC. All on 21% on AL80.

 

[johndiver999]

I don’t have heartburn at all - I merely posted an opinion. Sorry if that is an issue for you?

My personal concern (and why I would not dive like this) is that the plan seems to push right to the edge… and the edge is not necessarily the safe limit to begin with. I prefer to not push to the limits like this.

It's not an issue for me, I was just curious what aspect of the dive made you feel this type of diving is risky.

I guess going to zero ndl and then coming up so slow that the computer starts going into deco is going past typical recreational diving profiles, but I'm not sure how much added risk it generates. As long as he clears the computer, the slower ascent should not cause additional decompression stress, but that assumes adequate air supply.

I wouldn't do something similar without redundant gas supply, normally.

 

[Joneill]

It's not an issue for me, I was just curious what aspect of the dive made you feel this type of diving is risky.

I guess going to zero ndl and then coming up so slow that the computer starts going into deco is going past typical recreational diving profiles, but I'm not sure how much added risk it generates. As long as he clears the computer, the slower ascent should not cause additional decompression stress, but that assumes adequate air supply.

I wouldn't do something similar without redundant gas supply, normally.

Understood - I would not do this and, remember, this is the Basic Scuba Forum.

 

[John C. Ratliff]

It's not an issue for me, I was just curious what aspect of the dive made you feel this type of diving is risky.

I guess going to zero ndl and then coming up so slow that the computer starts going into deco is going past typical recreational diving profiles, but I'm not sure how much added risk it generates. As long as he clears the computer, the slower ascent should not cause additional decompression stress, but that assumes adequate air supply.

I wouldn't do something similar without redundant gas supply, normally.

I think, if you'll look at the literature, a very slow ascent can add additional decompression stress, thus increasing the decompression commitment in shallower water. Nitrogen under pressure still is absorbed into the blood stream from the lungs, if at a somewhat slower rate in shallower water.

@Blackcrusader
I don't dive in a manner where I simply lay on the bottom and breath. I'm usually pretty active, swimming against a river current, and getting cold (this is not a warm-water area), and so probably use air at a higher rate than do you. For me, at least, a single 72 will not provide enough air at my depths to get into a decompression situation.

SeaRat

 

[tursiops]

No idea what the table limits would have been for my dives but that's why I use a DC. All on 21% on AL80.


View attachment 771825

On a table all of those dives would have been WAY over the NDL.

 

[Pressurehead]

this is the Basic Scuba Forum

Is the OP still reading this thread, or has he/she [or whatever] fallen into a coma?
Started off as a good read [and laugh] first few pages, the weird part is I can't stop reading it, back and forth and off topic.
I am going to wean myself off this topic, some here could not agree on the colour of an orange.