Aluminum Doubles??

[J_glenn06]

Does anyone dive Aluminum doubles??? Just curious

[OWSI176288]

I've only used double al80's in Mexico due to the caves being so shallow.

Definitely prefer low pressure steel tanks that can be jacked up to a proper "cave" fill for Florida caves.

[Mike Edmonston]

Does anyone dive Aluminum doubles??? Just curious

Hi,

They are used in Mexico with V-weights. I use them when training new divers with doubles. (Wetsuit / SS BP). Weight is still noticable, but not as bas as sticking a pair of steels on their back. Other than that, IMHO, they don't offer enough gas to make it a worthwile choice.

YMMV

Safe Diving

[JahJahwarrior]

I dove aluminum 100s for a while before getting a sweet deal on some Faber LP120s.

I had to wear weight on the belt. I had to wear egads of weight on the belt in a drysuit. I only had 200 cubic feet of gas, compared to....what, 325-350 depending on the fill with my current tanks.

That's 108 usable for penetration compared to 66 usable for penetration, which makes a difference. Plus, I don't need any lead when wet or dry.

You can dive aluminum, and I did for a while, but as soon as I started diving some LP95s, the aluminums' went in the shed and sat there waiting for a day when I couldn't borrow the 95s. Then as soon as a deal opened up on these Fabers, I quickly sold the 100s and haven't looked back.

However the 100s got me through Basic and I did one or two Basic dives after class before putting them, and leaving them, inthe shed

[FW]

You don't see many double 80s in FL anymore, but there isn't a problem, except they don't hold as much gas, and require weight to use with a dry suit.

[Rob Traynham]

Why do you guys prefer Lp over Hp can anyone truly explain the difference. I see all the time that the folks on here are diving LP's. Just curious hopefully this isn't a stupid question. I'm asking because Iam curently looking for my first set of doubles and need reccomendations from the experienced....

[marinediver]

LP tanks hold more gas at a given pressure than HP.

[paul19may]

Why do you guys prefer Lp over Hp can anyone truly explain the difference. I see all the time that the folks on here are diving LP's. Just curious hopefully this isn't a stupid question. I'm asking because Iam curently looking for my first set of doubles and need reccomendations from the experienced....

Given the general direction of the question, a little example might help: for the sake of argument let's define LP= 2400 PSI and HP= 3000 psi as these serve for the purpose of illustration (I know that the definitions vary- but bear with me as I am a Brit and am limited to understanding things measured in litres and bars).

So a LP98 will hold 98 cu ft gas at 2400 psi, or by overpressuring the tank to 3000 psi, you can get 120 cu ft gas (3000 * 98/ 2400).
Whereas the HP98 at 3000 psi will give you only 98 cu ft.
ta da! More gas for the same (high) pressure, although the LP and HP cylinders may be physically slightly different in size, they are both rated as holding the same gas volume when filled to their specified pressures.

The details and definitions may differ but the general idea is there.
Hope that helps and was not redundant.

Of course, even the high pressure of 3442 psi (237 bar) is considered weedy by we Brits where hp= 300 bar. No wonder we owned the globe, had an empire and to bastardise and misquote a Prairie Home Companion, Britain- where all the men are strong, all the women good looking and thechildren are above average!

Flame at will.

Best P

[Diverlee]

You don't see many double 80s in FL anymore, but there isn't a problem, except they don't hold as much gas, and require weight to use with a dry suit.

I used them for several years. They were all I had and also all I could afford. If I remember I used 15# of wt when diving dry in fresh and 26# in salt water.
When I had some extra money I changed to LP 85's which I still use today and love.

[scoupland]

I dove AL 80 doubles in Mexico. That was all they dove there. I saw a few steel tanks but they were novelties. In FL I sidemount with steel 133s (3442 psi). Big tanks I know, but I am 6'7", 260lbs so they are no problem for my size. When I purchased them from Diver's Direct they were sold to me as "high pressure" tanks. Whatever they are called, they can hold a lot of air.