Split from Exploration dives without a computer

[Charlie99]

can I frame this? laminate it, whatever?

Yep. And either take it diving with you or use it as a target with darts.

But in exchange I'd like you to post the 2 most common multilevel profiles done off your boat.

 

[TheRedHead]

Personally, I wouldn't do a dive to 127ft on air, on a single tank. Too much potential for problems. And I don't think anyone who is DIR would either.

*looking around to make sure I'm not in the Kool-Aid shop*

I don't think 127 feet on air is unreasonable. My favorite place to dive is Cozumel and we dive air on deep walls because of the potential for down-dwelling currents. It makes sense and is safer in that situation. We usually dive EAN32 on the 2nd dive.

 

[TheRedHead]

I would hardly consider that specific to DIR, it seems like a no-brainer.

On scubaboard, it seems that tourists are taken on hair-raising, trust-me dives, but in real life, I think it is rather rare.

 

[TheRedHead]

Actually.... DIR likes standard mixes, which EAN28/29 is not.
The DIR 'proper mix' for a 127' dive would be 21/35

So divers who are not Trimix certified cannot diver deeper than 100 feet?

 

[PerroneFord]

Yes. In hope that actual DIR divers will take a few minutes correcting me, and perhaps dispelling some myths that have been propogated, or some information that might simply be wrong.

So until I have a fairly complete understand of DIR, I will keep posting, asking questions, and I suppose I will continue to the butt of your jokes. Meanwhile guys like Pug, Bob, and others further my knowledge and help me correct my mistakes.

 

[JeffG]

So divers who are not Trimix certified cannot diver deeper than 100 feet?

Pretty much. Gue has a rec Triox course that uses a 30/30 mix for > 100ft rec dives.

 

[Diver Dennis]

*looking around to make sure I'm not in the Kool-Aid shop*

I don't think 127 feet on air is unreasonable. My favorite place to dive is Cozumel and we dive air on deep walls because of the potential for down-dwelling currents. It makes sense and is safer in that situation. We usually dive EAN32 on the 2nd dive.

I agree Red. Most places I go to regularly dive that deep and beyond on air. That might not be the very safest way to do deeper diving but it is how the majority of divers do it. Frankly I do it any time I dive beyond the MOD of EAN32.

 

[TheRedHead]

OMG, an unfortunate quote from Ronald Regan regarding Thomas Jefferson has popped into my mind. Here Peronne, take this cat and make it a real catfight! I like the animation better than Jeff's cat.

 

[Thalassamania]

Rock bottom (or as you call it, "bingo") is 100psi per 10' + 200, never less than 750.

No, Bingo is a calculation for each diver expressed in PSI, using each diver’s SAC rate, that sums the gas needed by both divers for ascent at 30 ft/min, the gas needed by both divers for a 3 minute stop at ½ max depth, the gas needed for a 3 minute stop at 15 feet and the gas needed for a 2 minute stop at 10 feet (for one step over the line). It is not where you turn; it is where you CALL THE DIVE. If you’ve good sense you’ve turned before Bingo.

US Navy no deco limits, using standard square profile table calculations. These can be roughly approximated as NDL + Depth' = 120 minutes.

I have no idea what you are approximating, U.S. Navy Standard Air Table No-Decompression limit, plain and simple.

Each dive ends with 1/2 depth stop of 3 minutes, plus 3 minutes at 15'. (Naked USN table is rather agressive, but with these stops becomes pretty conservative).

I do not view the U.S. Navy Standard Air Table as particularly aggressive. I’ve used them with exactness and precision for almost a half century without incident to either my team or myself. I feel that most of the issues concerning these tables have more to do with diver error (especially ascent rate) rather than any special problem with the tables themselves. I added the two stops back in 1989 base on things that I’d learned, but if I needed to I would not hesitate to dive raw naked U.S. Navy tables.

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You didn't call out these rules, but a couple of useful approximation on equivalent air depth are:

4. Use 80% of actual depth on EAN32 and 75% of actual depth on EAN36 as the equivalent air depth.

I do not use equivalent air depth except when discussing equivalent narcosis depth. If I dive any brew I dive tables specific for it with the same calculations I did for air in the examples, but done for the specific mix of the dive. I have always thought that doing it right (in small letter, not caps) always involved having the right table for the mix of the day.

 

[PerroneFord]

No need. I broke with my own rules regarding posting here, and I should have known better. It's done.