To use argon bottle or not?

[stuartv]

I've planned a 40 minute dive (~90 minutes total runtime).

My tanks analyze at TX20/24.

The water will be around the mid-70s (e.g. 75'ish), I think.

I will be diving dry, for the redundant buoyancy.

I have a drysuit inflator bottle (AL6), which I have done 2 or 3 dives with it before.

Should I go to the bother of using it on this dive? Or does the low fraction of Helium, combined with the warm water temps mean that there is really no benefit and no reason to bother, versus just plugging my suit into my back gas?

 

[Tassi Devil Diver]

Fill your argon bottle with air, don't bother with argon as a suit inflation gas, the benefits are marginal at best and to get those benefits you need to flush your suit a number of times on the surface to get the argon percentage up high enough. As for using back gas, why waste preciouses trimix for suit inflation when you have a suit inflation bottle.

 

[stuartv]

Sorry. I should have been more clear. Yes. The suit inflation bottle is filled with air.

If an AL6 holds enough gas to handle my suit inflation for the dive, given that my mix is only 24% helium, it's not like I'll be wasting very much helium. My shop charges $1.50/ft3. So, if I used 6ft3 of back gas, it would still only be $2.25 worth of helium. And if an AL6 is actually big enough, presumably I will actually use less than 6ft3.

I'm planning for a max of 170'. That means an AL6 would give me an effective ~1ft3 of gas at depth. That seems like more than enough.

I'm really just wondering if the helium will result in me being unnecessarily cold.

 

[_Ralph]

I find I get around 3 dives in that range (51m) out of an AL6.

My rule for it is simple. Any He in back gas? Then use the AL6

I usually transfill it before a day of diving with 32% (or whatever I have available with no He - sometimes it's 50%) or in some cases, driven off a deco bottle at depth.


_R

 

[Jared0425]

Yes the 25% Helitrox will be noticble. I did a 25/25 mix and was noticbly colder than when I used air for a similar profile. That's when l got myself an "argon" bottle.

 

[Michael Guerrero]

I dived a 3mm wetsuit for all my Oriskanny dives. Drysuit with either backgas or air should be fine, depending on how many depth changes you make. There is a lot to see, so you may find yourself making more depth changes than anticipated. If you run out of air in your AL6 (I have an AL13) then you can hook up your LP inflator from your BC to your drysuit nozzle to keep going.

 

[stuartv]

Yes the 25% Helitrox will be noticble. I did a 25/25 mix and was noticbly colder than when I used air for a similar profile. That's when l got myself an "argon" bottle.

What water temps, though?

I'll be in water so warm, I'm not sure the extra thermal conductivity of the helium will matter.

I usually wear a 3/2 wetsuit down to around 70f. For this dive, it'll be 75-ish, and I'll be dry.

 

[stuartv]

I dived a 3mm wetsuit for all my Oriskanny dives. Drysuit with either backgas or air should be fine, depending on how many depth changes you make. There is a lot to see, so you may find yourself making more depth changes than anticipated. If you run out of air in your AL6 (I have an AL13) then you can hook up your LP inflator from your BC to your drysuit nozzle to keep going.

Thanks. It's the idea that maybe my drysuit bottle could possibly run out that is one reason I was thinking of just using back gas.

I am diving the Oriskany. And I know there is plenty of relief to explore. But, it'll be my first time there and I'm really thinking I will go straight to my max depth, around the hangar deck, and then work my way up, without much going back down along the way. But, I don't know...

 

[stuartv]

Oh, and I don't think my LPI hose would reach my drysuit inflation valve. But, if I use my drysuit bottle, I'll probably leave my drysuit inflation hose in my left post and just tuck it into my waist belt. That's what I usually do when I dive wet. So, I could pull it out and switch to that if my suit bottle runs out.

 

[Diver0001]

I've planned a 40 minute dive (~90 minutes total runtime).

My tanks analyze at TX20/24.

The water will be around the mid-70s (e.g. 75'ish), I think.

I will be diving dry, for the redundant buoyancy.

I have a drysuit inflator bottle (AL6), which I have done 2 or 3 dives with it before.

Should I go to the bother of using it on this dive? Or does the low fraction of Helium, combined with the warm water temps mean that there is really no benefit and no reason to bother, versus just plugging my suit into my back gas?

why don't you attach the drysuit to the nitrox stage?

R..