Double 80s

[teknitroxdiver]

I hope to take IANTDs Advanced Nitrox course sometime in the relatively near future. I want to use doubles for the class and for that kind of dives after that, so that I will be comfortable with them by the time I can move up to Trimix. I figure that double AL80s and an AL30 for the 50% tank would be best. Is this a good choice? I'll be diving wet (a 6/3 with hood). Double 80s are neutral or negative when empty right? How do these dive? Is it overkill considering that you're limited to 10 minutes of deco?

Thanks,

 

[teknitroxdiver]

Oh, and this place (http://www.seatasea.com/shop.html?target=dept_201.html&lang=en-us) has double 80s with Halcyon 300 bar vavles/manifold and Highland SS bands for $640. How is that price?

thanks again

 

[Curt Bowen]

I hope to take IANTDs Advanced Nitrox course sometime in the relatively near future. I want to use doubles for the class and for that kind of dives after that, so that I will be comfortable with them by the time I can move up to Trimix. I figure that double AL80s and an AL30 for the 50% tank would be best. Is this a good choice? I'll be diving wet (a 6/3 with hood). Double 80s are neutral or negative when empty right? How do these dive? Is it overkill considering that you're limited to 10 minutes of deco?

Thanks,

Double 80's will be just fine.

 

[teknitroxdiver]

Is there any specific kind I should get? Luxfer, Catalina, Genesis, etc?

Thanks

 

[Curt Bowen]

Is there any specific kind I should get? Luxfer, Catalina, Genesis, etc?

Thanks

Any kind is OK

 

[fgray1]

I hope to take IANTDs Advanced Nitrox course sometime in the relatively near future. I want to use doubles for the class and for that kind of dives after that, so that I will be comfortable with them by the time I can move up to Trimix. I figure that double AL80s and an AL30 for the 50% tank would be best. Is this a good choice? I'll be diving wet (a 6/3 with hood). Double 80s are neutral or negative when empty right? How do these dive? Is it overkill considering that you're limited to 10 minutes of deco?

Thanks,

AL80 are positive 4 Lbs when empty. they are only about neg 3 when full.
That means you will have a Pos 8 lbs if ran dry. You'll have to carry extra weight. Not a real big problem but something to think about.
I use steel lp 85s Doubled up they are neg 7 when full and neg 1 when empty. I use a al80 for my deco gas with a 40 or 50% mix. I also use a steel lp72 for my O2 gas for the final deco stops less than 20 ft.
I too dive wet but I have a double blatter. You'll learn all this in the adv Nitrox and deco course. You will have to have a redundant lift for the class.
Fred

 

[teknitroxdiver]

Do you know if using a lift bag and reel counts as redundant lift? I didn't see anything to that effect on the website I read.

Do the SS bands, valves, and regs not balance out the buoyancy?

thanks

 

[fgray1]

Do you know if using a lift bag and reel counts as redundant lift? I didn't see anything to that effect on the website I read.

Do the SS bands, valves, and regs not balance out the buoyancy?

thanks

I dive a 7mm semi dry and When I dive in just my doubles in the caves with a light and reel I just make it without weights.
WHen I did my Deco and Adv Nitrox course I used the config I said before and at the end of the second dive the deco bottles were going psivite on me and I could feel the differance but they didn't pull me up with the gas I had left in them. Which was 1000 psi in the al80 and 700 in the st 72. I was wearing a canister light as well. In your case you'll be in al 80 as well as al deco and when you get low I gas you may have a problem staying down.
Curts got about 10 million dives in maybe he knows for sure.

 

[Don Burke]

Do you know if using a lift bag and reel counts as redundant lift? I didn't see anything to that effect on the website I read.

With AL80s and a wetsuit, you do not need redundant buoyancy, just enough ditchable weight to get you out of a BC failure with full tanks.

I can get there with a steel backplate. Some need to go to aluminum.

The "Doing It Right" book will answer many of these questions.

 

[fgray1]

With AL80s and a wetsuit, you do not need redundant buoyancy, just enough ditchable weight to get you out of a BC failure with full tanks.

I can get there with a steel backplate. Some need to go to aluminum.

The "Doing It Right" book will answer many of these questions.

To make a controlled accent and not have to shoot to the surface like a rocket. If your doing a 150Ft dive the wet suit loses allot of it bouyancy and if you dump your weights and you have al tanks there will be no chance for deco, Increased risk for DCS or serious injury. Now if your not going to do deep dives then maybe it might not make much differance. Although he never said how deep he was planning on diving. Either way I perfer a controlled accent over dumping weights and a chance of injury.