Steel from Aluminum

[DXHI]

Making the swap .
Going to try my hand at diving with them next week. Wanting to get my weights close to right before I roll off the boat and then half to come back up for more …

Someone double check my thoughts please
With Aluminum 80’s and 3 mil suit
I have 10lbs in my pockets and, 4 lbs in trim pockets on BC

Websites list average weight at 28lbs

If I get Steel 100’s weighing at 34 lbs
Steel 120’s are weighing at 39lbs
I should be able to take out 5-6 lbs of weights or 10 lbs respectively and still be similar in bouyancy ?
Or will I still be pretty heavily overweight factoring in the buoyancy difference of each tank

 

[Zef]

It doesn't work like that.

The tank weights you are indicating are dry weights of the tanks. The weight you need to be concerned with is the weight of the tank in water when full and empty. For instance, a Faber 120 steel tank has the following specs:

(swiped from DGX)

Cylinder	Service Pressure (psi)	True Air † Capacity (ft3)	Diameter (inches)	Height * (inches)	Weight * (pounds)	Buoyancy ** Full : Empty (pounds)
F7 Steel HP120	3442	≈ 120.1	7.25	29.1	39.2	- 8.8 : + 0.7

** Buoyancy specification is for cylinder and valve in seawater at 500 psi.

This cylinder has an effective weight of 8.8lbs in water when full and will be positively buoyant by 0.7lbs at approximately 500psi.

You will need to check the specifications for the aluminumb tank(s) you are currently using and compare to the specs for the steel tanks you plan to use to estimate the amount of lead you should shed.

-Z

 

[James79]

This thread is what you want:

Info - Optimal Buoyancy Computer

The Optimal Buoyancy Computer A tool to help nail buoyancy and improve safety, before you splash 1) How much lead should I carry with my new wetsuit? 2) How big a wing should I buy? 3) Will my BCD support my lead, both at the surface and when my wetsuit is compressed at depth? 4) Will my BCD...

scubaboard.com

With it you can also sort other changes. Work it backwards first putting in your known info now and adjust personal buoyancy until it gives you your actual known lead requirements, then change the tank, and it will give you good data (or the exposure protection, salt/fresh, or any combination).

Respectfully,

James

 

[DXHI]

This thread is what you want:

Info - Optimal Buoyancy Computer

The Optimal Buoyancy Computer A tool to help nail buoyancy and improve safety, before you splash 1) How much lead should I carry with my new wetsuit? 2) How big a wing should I buy? 3) Will my BCD support my lead, both at the surface and when my wetsuit is compressed at depth? 4) Will my BCD...

scubaboard.com

With it you can also sort other changes. Work it backwards first putting in your known info now and adjust personal buoyancy until it gives you your actual known lead requirements, then change the tank, and it will give you good data (or the exposure protection, salt/fresh, or any combination).

Respectfully,

James

Awesome thank you