Tank Weight Relationship

[Taath]

All:

I am contemplating picking up a steel tank to use with my BP/W single tank setup. I have been using this chart as a reference: http://www.indianvalleyscuba.com/se...ction/information/CYLINDER SPECIFICATIONS.pdf.

Is my logic here correct:

Currently diving a Catalina S80 tank. Because of the +4 lbs buoyancy when empty I add 4 lbs to my ballast weight.

Contemplating to switching to a Faber HP-100. This tank shows approximately -7.26 lbs buoyancy when empty.

In this case would I be able to remove 4 lbs of ballast that I'm using to counteract the positive buoyancy of the empty or near empty AL80 and remove an additional 7 or so lbs due to the negative buoyancy of the HP-100? Thus in theory I could remove a total of 11 lbs of ballast?

Thanks in advance!

 

[eelnoraa]

Yes, in your example, you will remove totally of 11lb of ballast. But Fabor HP-100 is -7lb negative? Sounds a bit more than I expect

 

[thatmark]

Taath,

I believe most of the new "HP-100" Faber tanks for sale are the ones labeled as FX-100 on that chart, so it's -5# (I'm rounding) vs the AL80 when both are empty (-1# for the Faber vs +4# for the Catalina). Ignoring weight of valves and remaining gas...

Mark

 

[tbone1004]

@Taath the Faber HP-100 you see isn't made anymore and is very difficult to find. They are typically referred to as medium pressure tanks and they sink like bricks. Your math is correct on lead you can remove, however as mentioned above, you are unlikely to find any.

 

[johnnywulff]

In my experience a empty or near empty AL80 with regulartor set on, first and second stage sidemount configuration, to be neutral you only have to add 2 lbs.

 

[teknitroxdiver]

A 3442 psi 100cf tank is -1 pound or less when empty.

 

[tbone1004]

A 3442 psi 100cf tank is -1 pound or less when empty.

except the ones that aren't, particularly the Worthingtons that are more than 3lbs negative