O2 Bottle for Cavern, Cave or Deep OW

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MikadoWu

Contributor
Messages
371
Reaction score
119
Location
Florida
# of dives
200 - 499
Hello All,

Presently I am taking a the TDI Cavern/Adv Nitrox/ Deco Procedure classes. I have not yet decided on Full Cave Cert yet.

My instructor is mildly pushing me to have a bottle dedicated to Oxygen. Yes I can rent one, but his point is you do not want to rent it if you do not need to use it at the end of the dive. In each of my dives, we have been require to have the O2 bottle which we stage at 20 feet.

I only have 1 friend that is Certified at Adv Nitrox/ Deco Procedure equivalent (IANTD) and OW instructor and he insists I do not need Oxygen bottle. His teaching was you only save a few minutes versus a travel bottle at 32% and another at 40 or 50 so you have off gas soon, plus you have gases that can be used deeper in case of emergency.

Are both right, are both wrong or is this a Cave practice versus open water?

Again, I am still eLearning, and need to know the right questions to ask my instructor.

Thanks
 
You can deco on Air if you want but you must have redundancy first and foremost and gas plan. Evaluate how you will be diving, what type of deco you'll do and get a bottle for that is suggested.
 
Skipping the cavern part, just looking at the Advanced Nitrox and Deco procedures, that is where the O2 bottle and reg come in to play. The whole idea of that class is to get into planned deco and use high levels of O2 to help clear the deco. With that in mind, AL40s with a strong Nitrox mix (usually NOT 100%, more like 80%) is what you use.

How the cave part plays into this, I can't answer.
 
Who is the instructor? Friend sounds like he’s not very well versed or poorly educated. AL40 of 100% more useful in your cave progression bc of the profile of the more common FL caves and the full cave 100’ END limit. AL80 of 50% more useful if you’re diving the wrecks in the deeper end of the range AN/DP certifies you for. Where are the cert dives?
 
A few minutes? I remember doing a dive as part of my full cave course. Average depth like 60 feet, but it was 2 hours long. The instructor not thinking that I would be able to do a 2 hour dive (as all our prior dives were in high flow caves like Ginnie) didn't bring his deco bottle. He had 20 minutes of back gas deco, I had 5 minutes on Oxygen. Getting out of the water 15 minutes sooner is worth the $5 in oxygen that it cost (though obviously we got out of the water at the same time after he finished his deco).

Now that being said at the cavern level, you won't need it. Deco is prohibited on all cavern certs, and most first level cave certs. I started bringing my O2 bottle when I was in the intermediate level between the first level and full cave (called Apprentice Plus under the NSS-CDS program). As I was diving to thirds and deco wasn't unusual.

But if you are planning to do AN/DP level dives, having it will often save you money in the long run unless your shop follows typical cave country pricing (ie bottle is $X per day it comes full, and you pay to fill it back at the end of the rental at $Y per cubic foot along with filling it up as needed throughout the rental period).
 
So weird to me...

How would you possibly develop and built your AN/DP experience without having your own deco bottle/gas? I don't know of a single entry level deco diver who doesnt own at least one deco cylinder.

32% is a worthless deco gas. Fill your al40 or al80 with 100% or 50% depending on the dive/profile. Typically O2 for cave dives (you wont have any cave deco) and 50% for squarer wreck type profiles where you are trying to keep your rock bottom backgas reserves reasonable.

If you are carrying and dropping an O2 bottle during a cavern class your instructor is violating standards.
 
I can't speak to the cavern/cave cert, but in terms of deco, oxygen is always a good option. I have to agree with the responses upthread, if you are considering any serious deco diving, just invest in a dedicated O2 bottle. It's just not that much money in terms of the overall costs of tech diving.
 
Who is the instructor? Friend sounds like he’s not very well versed or poorly educated. AL40 of 100% more useful in your cave progression bc of the profile of the more common FL caves and the full cave 100’ END limit. AL80 of 50% more useful if you’re diving the wrecks in the deeper end of the range AN/DP certifies you for. Where are the cert dives?

Thank you for the feedback. I rather not pass on instructor names, as I may be the idiot not explaining things correctly. We are diving Gennie Springs, Bufford, Paradise Springs, and another north of Gennie I do not remember.
 
Just to add, I agree that 32% is not a useful deco gas. Your dives may differ, but 28% EAN is a common bottom mix for me. So to move to 32% or even 36% for a deco gas would not really be helpful.
 
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