First Dive Trip Without Instructor - Need to Rent Gear & Help Planning

[tbone1004]

Yep, probably will do Vortex then (will it be dive-able?) as we are staying in Destin and Jackson Blue is a 3 hour drive from Destin.

I only mentioned 36% as it would have even more conservative max depth. 32% is fine.

I'd argue that 32% is more conservative of a nitrox mix because of the deeper MOD. You can always limit the MOD by using a lower ppO2 max, but you can't go deeper if you have to.

Vortex should be diveable.

 

[CavernFrog]

Different definitions of conservative! If you mean conservative in terms of being safer from Narcosis, having a wider range for depth error, then yes, I see what you are saying.

Thanks for the info re: Vortex.

 

[boulderjohn]

Morrison Springs is where I discovered a rare diving malady--shallow water helium narcosis.

A friend and I drove from Colorado to Pensacola in a van filled with scuba tanks with the goal of diving the Oriskany. The rest of our group flew and joined us there. Our doubles (mostly cave-filled LP 108s) were all filled with 18/45 (for those who do not know, that is 18% oxygen and 45% helium)--very expensive fills. The weather in Pensacola was perfect, with clear blue skies and not a breath of wind. As has happened every time I have gone to dive the Oriskany, the dive shops there told us the weather was much too bad to dive the Oriskany. Out by the wreck, we were told, the seas were too rough. The forecast showed more of the same for the entire time we would be there.

So we took our doubles filled with 18/45 and dived Morrison Springs, where we suffered from shallow water helium narcosis. We simply could not concentrate on our diving because our ability to think was impaired by constant images of dollar signs flying away.

 

[tbone1004]

Different definitions of conservative! If you mean conservative in terms of being safer from Narcosis, having a wider range for depth error, then yes, I see what you are saying.

Thanks for the info re: Vortex.

Oxygen is narcotic and is treated equal to nitrogen when doing trimix calculations. Unfortunately many instructors incorrectly tout nitrox as being less narcotic nearer their MOD's, but that is not the case

 

[CavernFrog]

I was mixing up narcosis and toxicity.

So is 32% Nitrox safer than air at depths shallower than 100ft or not?

 

[tbone1004]

I was mixing up narcosis and toxicity.

So is 32% Nitrox safer than air at depths shallower than 100ft or not?

"it depends". Which variable are you trying to minimize the risk of? Oxygen toxicity? Air is safer due to lower ppO2. Does it matter? Depends on your exposure time.

Are you trying to minimize the risk of DCS? Nitrox wins due to a lower ppN2

Probably best left to a new thread or pm though.

Also if you're renting gear, since you were asking about the lights, I would still deviate out to Cave Adventurers to rent whatever gear you need on your way down, including whatever lights you want to try, even if diving Vortex or somewhere else

 

[CavernFrog]

As I posted on CDF:


Spoke with Edd last night. He may not have full kits to rent as he is taking gear to an event this weekend. I already ordered my lights online (Big Blue) but will get the rest of my gear from Edd and of course if I ever want a more powerful spot light for full cave I will go to Edd.

 

[boulderjohn]

I was mixing up narcosis and toxicity.

So is 32% Nitrox safer than air at depths shallower than 100ft or not?

I recently encountered some information related to this that I had not previously known. This was contained in an email from Karl Shreves, Technical director from PADI. The email was on a somewhat related topic, but it contained the following useful tidbit regarding this question.

When I took my nitrox course nearly 2 decades ago, it was far more technical and math-based than the present course. The present course has eliminated a lot of the stuff I had to learn. I found out that the reason is that research has indicated that a lot of what people thought was important back then really doesn't matter. In terms of this question, one of those findings is that if you stay within recreational depths and keep your PPO2 at 1.4 or below, you can pretty much dive all day with no ill effects. Consequently, if you are diving in Morrison Springs with EANx 32 and don't bring a really good shovel, you should have no concerns about oxygen toxicity.

 

[Diver0001]

So we took our doubles filled with 18/45 and dived Morrison Springs, where we suffered from shallow water helium narcosis. We simply could not concentrate on our diving because our ability to think was impaired by constant images of dollar signs flying away.

Diving Trimix requires constant resuscitation.

 

[CavernFrog]

if you stay within recreational depths and keep your PPO2 at 1.4 or below, you can pretty much dive all day with no ill effects.

According to the PADI EANx 32 dive table....

You can get 25 minutes at 110 ft. Depths greater than 110 ft are not allowed. You can get 220 minutes (3hr 40min) at 45 feet.