Rodale's pushing deep air.

[Spectre]

Out of interest what was the article defining as "deep" ?

To reference travel mixes, one would be inclined to infer we're talking about depths that involve hypoxic mixes. To go with that inference, that would imply that the depth is beyond a safe depth in regards to the oxygen partial pressure, which further diminishes the credibility of the article. We're either talking about depths where travel mixes are required due to hypoxic mixes, in which case air increases the risk of oxygen toxicity, or we are talking about normoxic trimix depths, in which case the travel mix argument is moot.

Granted, I've not read the article, I'm going off the quotes that Mike provided in his original post.

 

[Diver0001]

was a nice companion piece to the comprehensive spare air review last month...

Or any article written by Dread Gilligan.

Mike, just being picky but when you said

Also one-third is not reserved for ascent and decompression. This is a completely false statement

I couldn't find where he said that. Maybe you didn't quote the part where he said that but the part you did quote said something else.

R..

 

[Rick Murchison]

To reference travel mixes, one would be inclined to infer we're talking about depths that involve hypoxic mixes. To go with that inference, that would imply that the depth is beyond a safe depth in regards to the oxygen partial pressure, which further diminishes the credibility of the article. We're either talking about depths where travel mixes are required due to hypoxic mixes, in which case air increases the risk of oxygen toxicity, or we are talking about normoxic trimix depths, in which case the travel mix argument is moot.
Granted, I've not read the article, I'm going off the quotes that Mike provided in his original post.

As a matter of fact, it has been my experience that using a travel gas with air is more common than with trimix. For example, a typical deep air dive would be EAN32 to 120, air on the bottom at 165, EAN32 from 120 to 20, O2 from 20'... Using a 21/50 Trimix would eliminate the travel gas entirely.
Rick

 

[caveseeker7]

I used to read that magazine briefly some years ago, but once I moved away towards books and textbooks I quickly discovered that RSD isn't worth much.

I saw the article as making blatantly false statements about equipment, the number of gasses that must be used (when and why) and gas management.

I doubt anybody ever accused them of much knowledge, even less so when it goes past pink jacket BCDs or 70ft. rec dives.

a couple of points made by the author that sent my BS meter straight through the roof.

Happened to me a couple of times, that's why I stay away from it.

Again I call total BS and I can’t believe that they put this trash in print.

That sums it up quite nicely. The sad thing is that there are many divers out there that won't know any better and trust the magazine to give them good info.

That's why I like both your post and where you placed it. Badly needed. Thanks.

Some books I’d recommend to get a feel for the history of some of this stuff would be “Caverns Measureless to Man” by Sheck Exley and the “Cave Divers” by...Burgess?...I don’t remember but I’ll look it up if any one needs it.

Robert F. Burgess, and I second your recommendation on both books.

was a nice companion piece to the comprehensive spare air review last month...

Extended range on air only ... they'll be using lots of those.

Nice write up Mike.... you should start your own diving magazine! One where you point out the flaws and total BS in other magazines...

Maybe not a magazine, that's rather costly. A new section here on the board would do.

Stefan

 

[MikeFerrara]

Or any article written by Dread Gilligan.

Mike, just being picky but when you said


I couldn't find where he said that. Maybe you didn't quote the part where he said that but the part you did quote said something else.

R..

I quoted it in the original post

Another step in safe deep-air diving is air management using the so-called rule of thirds. One-third of the gas is used for descent and movement away from the ascent point, one-third is used for return to the ascent point, and one-third is kept in reserve for emergencies and ascent. Many divers mistaken this rule as leaving one-third for gas sharing. Statistics show that a diver is much more likely to use his one-third reserve supply for dealing with his own delays or problems.

I don't have it with me now but it's in the onl'y section where he talks about gas management. When I get home I can give a page number.

 

[MikeFerrara]

Nice write-up Mike. Send it to Scuba Diving Magazine.
Rick

My wife sent them an email inviting them to join this discussion.

 

[MikeFerrara]

For some further insight you might want to have a look at this link...technical diver boot camp

 

[Diver0001]

I quoted it in the original post



I don't have it with me now but it's in the onl'y section where he talks about gas management. When I get home I can give a page number.

A page number won't help. I don't have a subscription to Rodales. It kind of suprises me that you do, actually. .

Anyway, In this bit:

One-third of the gas is used for descent and movement away from the ascent point, one-third is used for return to the ascent point, and one-third is kept in reserve for emergencies and ascent.

I'll agree he doesn't understand the basics but I wondered how you read something about decompression into that...

R..

 

[Diver0001]

I just took a look on the Rodales website. They really should put some of this stuff in a scuba-humor book.

Here is one of the tips they give for when you find yourself swimming into a heavy current (like it's a given that you have to do this):

If this is going to be a difficult swim, better drop that game bag. If it's really hard, dump your weights. If it's life-threatening, say goodbye to the Nikonos. Bulk and weight both mean drag.

Brilliant stuff. This is going to be a fun read. Thanks for the tip Mike.

R..

 

[MikeFerrara]

A page number won't help. I don't have a subscription to Rodales. It kind of suprises me that you do, actually. .

I don't LOL They just send it to me free. I guess cuz I'm so special.

Anyway, In this bit:

One-third of the gas is used for descent and movement away from the ascent point, one-third is used for return to the ascent point, and one-third is kept in reserve for emergencies and ascent.

I'll agree he doesn't understand the basics but I wondered how you read something about decompression into that...

R..

Only because we usually deco during the ascent.

Regardless, that third "third" isn't for any part of the ascent.
If you have to tap that last third to get to the surface that means that you did not have double the gas needed to get back from the furthest point in the dive (ie, get another diver back) gas matching aside.

That's not to say that all dives must be planned using the rule of thirds but if you did it that way in a cave (where the rule comes from) whith no flow and your buddy lost all gas at max penetration, one of you WILL die because there isn't enough gas to get you both out.