Double AL80 or LP85

[Compressor]

Friends: I have these tanks in inventory. Wanted to ask your opinion on using doubles for AL80 or LP85s in FL waters where I dive with the following:

BP/W (Steel Plate)
3 mm suit
Weights on when diving with single LP85 or tiny double (LP50s) is zero.

When considering buoyancy of AL80s when near empty (+8), doesn't the weight of the BP and manifold make the AL80s set up near neutral?

Thanks

 

[Superlyte27]

I'd never double 80's

 

[CptTightPants21]

AL80s are actually a nice tank doubled. Good trim, lighter. It is a shame they hold so little gas.

AL80s aren't terrible, but if you already have the LP85s I would use those.

 

[Superlyte27]

Not enough gas, not enough weight to offset the buoyancy of my Drysuit.

They suck for my needs.

 

[RyanT]

Hey Compressor, as you probably already know, the gas difference is not huge if you get the LPs filled to service pressure. If you can find a place that will overfill a bit, that helps.

Yes, a set of AL 80s with bands and manifold will be about neutral when empty. Depending on the tank brand and your particular bands, the rig might vary plus or minus a little around the neutral when empty but it should be close. The LP 85s will remain negative when empty.

The AL 80s will also get lighter in the tail end compared to the LP 85s, so you'll probably notice your trim change more with the AL.

 

[Jack Hammer]

Al80s are nice with a wetsuit in shallower warmer waters. Steels are nice with a drysuit. In Mexico I dive doubled 80s with a drysuit (we make longish dives) but have to add about 7 pounds, steels would be great.

 

[rjack321]

You must be diving salt water in that 3mm wetsuit. You'll be a bit negative in the 85s but not obscenely so if they have mix in them... You'll need a few pounds of lead for the al80s which could be ditchable. The bigger issue is what depths, what's your consumption, how much is rock bottom for your planned dive?

 

[NAM001]

use teh LP85's

 

[Compressor]

Hey Compressor, as you probably already know, the gas difference is not huge if you get the LPs filled to service pressure. If you can find a place that will overfill a bit, that helps.

Yes, a set of AL 80s with bands and manifold will be about neutral when empty. Depending on the tank brand and your particular bands, the rig might vary plus or minus a little around the neutral when empty but it should be close. The LP 85s will remain negative when empty.

The AL 80s will also get lighter in the tail end compared to the LP 85s, so you'll probably notice your trim change more with the AL.

Excellent point. I'll try Force E at Blue Heron Bridge to see if they will overfill.

Al80s are nice with a wetsuit in shallower warmer waters. Steels are nice with a drysuit. In Mexico I dive doubled 80s with a drysuit (we make longish dives) but have to add about 7 pounds, steels would be great.

Yes, its salt water.

You must be diving salt water in that 3mm wetsuit. You'll be a bit negative in the 85s but not obscenely so if they have mix in them... You'll need a few pounds of lead for the al80s which could be ditchable. The bigger issue is what depths, what's your consumption, how much is rock bottom for your planned dive?

My SAC is 0.5 or a bit less if I'm just watching fish.
Unless I go deeper via a boat, most shore dives I do are less than 1 ATA.


Thanks for all the replies.
I have a feeling that I will sell those AL80s.

 

[Scared Silly]

Which LP85?? The Faber LP85 IMHO are a better cylinder to double than the Worthingtons because they are lighter by 10lbs on dry land and have similar buoyancy (be careful reading buoyancy tables as Faber measures sans valve whereas Worthington includes the valve).

I dive my LP85 with a steel plate and dry suit which is balanced. I would not be in a 3mm suit which for that I dive AL80s.