12L vs. AL80? I know capacity is similar, how about tank size/buoyancy characteristics?

[TT_Vert]

A liveaboard I'll be doing uses 12L alum. tanks (I think alum since they say "alloy") I have not found exact dimensions for 12L tanks nor buoyancy characteristics can anyone give a bit of input on this?

Thanks much.

Dave

 

[HantsDiver]

Steel is an alloy.

I'd ask the operator what you will have. You will do a weight check anyway so it doesn't really matter.

 

[RainPilot]

Here's a handy calculator for rough guesses: Scuba tank size and buoyancy calculator

If its Aluminium 100 CF then its going to depend on brand. A useful resource as well:

http://www.indianvalleyscuba.com/se...ction/information/CYLINDER SPECIFICATIONS.pdf

 

[Landau]

AL 80s are often called 12L tanks even though they are somewhat less than 12 litres. They are less than 80 cubic feet as well.

 

[RainPilot]

AL 80s are often called 12L tanks even though they are somewhat less than 12 litres. They are less than 80 cubic feet as well.

Generally I’ve heard them referred to as 10L tanks, I suspect that’s to do with the comparison between 10L steel at 232 bar vs the 11.1 L aluminium at 207 bar being pretty similar.

 

[TT_Vert]

Thanks guys, I have a message into this dive OP to see what exactly they are using. Between this and a new 3mm shorty I'm going to have to figure out my weighting. Prior to this w/ AL80s and my old 3mm shorty I was just a hair negative at ~500 psi w/o any belt but now I hope I don't need to take on lead. Looking at this calculator and if these 12L tanks are Steel i'm going to be in good shape as they're slightly negative even when empty.
AL80cuft (empty/full) 3/-2.9
Steel12L (empty/full) -0.9/-7.3

Are there actually 12L AL tanks? If so, Is the OD the same on these at least or am I going to have to adjust straps as well? It seems these 12L tanks may all be steel and are 1/2" smaller in diameter and a bit longer. PITA, i'd much rather larger diameter/shorter.
Dave

 

[BRT]

Thanks guys, I have a message into this dive OP to see what exactly they are using. Between this and a new 3mm shorty I'm going to have to figure out my weighting. Prior to this w/ AL80s and my old 3mm shorty I was just a hair negative at ~500 psi w/o any belt but now I hope I don't need to take on lead. Looking at this calculator and if these 12L tanks are Steel i'm going to be in good shape as they're slightly negative even when empty.
AL80cuft (empty/full) 3/-2.9
Steel12L (empty/full) -0.9/-7.3

Are there actually 12L AL tanks? If so, Is the OD the same on these at least or am I going to have to adjust straps as well? It seems these 12L tanks may all be steel and are 1/2" smaller in diameter and a bit longer. PITA, i'd much rather larger diameter/shorter.
Dave

If they are aluminum they will be AL80's

 

[TT_Vert]

Great thanks. So it appears if these are in fact 12L tanks they'll be steel and a different dimension than AL80s.

 

[RainPilot]

If they are aluminum they will be AL80's

Not necessarily. There are some ops that use AL 100 tanks which are 12L
Not massively common but enough.

 

[BRT]

Not necessarily. There are some ops that use AL 100 tanks which are 12L
Not massively common but enough.

Closer to AL80's
http://www.catalinacylinders.com/wp-content/uploads/2015/02/ScubaSpec.8-30-12color.pdf