double 104's

[Karl_in_Calif]

Spectre once bubbled...
You want to explain where you got your NDL time?

I sum to 120 for the EAD. So, 60 ft = 60 mins.
70 ft = 50 mins.
80 ft = 40 mins.
etc.

Spectre once bubbled...

What about gas for the ascent? You have nothing about how much gas it will take to get from depth to the surface... Are you talking 40 minutes BT or 40 minutes run time? If 40 minutes run time, what time do you start your ascent? How much gas do you and your buddy need for that ascent?

Thats covered in the rule of thirds, for this NDL dive.

 

[Spectre]

Karl_in_Calif once bubbled...
EANx solves that problem however.

No it doesn't. Not if you don't know what your doing. If you plan a 100 ft dive on EAN 32, and use the EAD to plan your bottom time, you're not any safer than if you were diving air to that EAD depth. In fact it's arguably less safe, as you are farther from the surface.

 

[Karl_in_Calif]

Spectre once bubbled...


No it doesn't. Not if you don't know what your doing. If you plan a 100 ft dive on EAN 32, and use the EAD to plan your bottom time, you're not any safer than if you were diving air to that EAD depth. In fact it's arguably less safe, as you are farther from the surface.

Ok you can agree with LAL and I will agree with Burke, and we can agree to disagree.

 

[Spectre]

Karl_in_Calif once bubbled...


I sum to 120 for the EAD. So, 60 ft = 60 mins.
70 ft = 50 mins.
80 ft = 40 mins.
etc.

Hmm.. never heard of _that_ method. How many dives have you logged on that theory? It seems a bit aggressive to me, as the original 120 rule was in the old navy tables, designed for divers in impeccible shape with chambers close by.

 

[Karl_in_Calif]

Spectre once bubbled...
It seems a bit aggressive to me, as the original 120 rule was in the old navy tables, designed for divers in impeccible shape with chambers close by.

You are right again!

By the way, the "old navy tables" are still the NEW NOAA TABLES. They have just slowed down the stated ascent rate to 30 ft per min.

As for your other question, about pushing the NDLs. I do not recommend pushing the NDLs. Nor do I push them.

I was trying to verify Burke's calcs, and they do make sense, either on an aggressive basis, or else with a big reserve of gas.

 

[Dryglove]

Karl_in_Calif once bubbled...


EANx solves that problem however.

No EANX does not solve that problem as you can still easily exceed NDL limits on nitrox depending on your tank sizes and dive profile.

 

[Karl_in_Calif]

Spectre once bubbled...
If you plan a 100 ft dive on EAN 32 ...

Are you married to EAN32 ??

EAN32 is the best mix for a dive to 111 ft.

P(total) = PO2/FO2 = 1.4 / 0.32 = 4.375

(4.375 -1 ) x 33 = 111 ft

If my MOD was 100 ft my best mix would be EAN35

FO2 = PO2/P(total) = 1.4 / 4.0 = 35%

 

[Karl_in_Calif]

lal7176 once bubbled...
No EANX does not solve that problem as you can still easily exceed NDL limits on nitrox depending on your tank sizes and dive profile.

so show us the calculations then.

your conclusion statement carries -0- support with it.

 

[Dryglove]

Karl_in_Calif once bubbled...


so show us the calculations then.

your conclusion statement carries -0- support with it.

It doesn't take a rocket scientist to see that a person wearing double 95's, 104's, etc using 32% gas could easily exceed the NDL of 25min at 109 ft. It does ease things a bit compared to 21% at 110ft for 15min NDL.

 

[Big-t-2538]

Karl_in_Calif once bubbled...

If my MOD was 100 ft my best mix would be EAN35

MOD is different than NDL....I think LAL is trying to tell you that it doesn't matter what size tank you have...at 100' there is not a lot of NDL time for EAN32 for someone with decent air consumption.