from LP85 to alu80 - how much more lead?

[NYCrecdiver]

Hi there all you sidemount divers,
I dive with drysuit, relatively thick undergarments, LP85s and 6 lbs lead in fresh water.
Any of you can guesstimate how much lead I would need if I dive with drysuit, thin undergarments and alu80 tanks in fresh water?

 

[Mobulai]

umm, I can't guess for undergarment variation; and my guess is also gonna be kinda bad for the tank change (I only dove steel/fresh -Alu/salt).. I would say 3-4KG more (accounting for a very floaty end of dive at 50 bar each and maybe the undergarments)
Maybe less if I remove my saltwater bias

(that's 6-8 more lbs in freedom units )

 

[Mobulai]

Wait, I think I am mixing the cylinders -- do lp85s get a bit floaty near empty?
Probably I was initally thinking of lp108s that are much more stable

 

[flymolo]

Updated SCUBA tank specifications list -- in PDF and spreadsheet

Hello! I have wasted my entire day re-working a SCUBA tank specifications list. I've been working with the Huron Scuba list for *years*, but I'm suspicious of the information: where did it come from? Also, it includes a lot of junk I've never seen in real life, as well as tanks that no one...

scubaboard.com

you want to weight for neutral with empty (~500) psi tanks

 

[Rilelen]

I add about ten pounds in sidemount when I go from LP85s to AL80s in freshwater but ymmv.

 

[Mobulai]

dialing in the change from LP85 to Al80 in SM on Info - Optimal Buoyancy Computer
got me from 1KG to 5KG, no change in suit tho (I used 1.5mm wetsuit so ignore my total)

Probably a good time to check out that tool btw

 

[grantmac]

An AL80 is roughly neutral with the regs and 500psi. So what I do is place one with long hose on in 6 ft of water, no tanks on my rig and add just enough lead so I can descend while breathing off it.
Guessing 4# because that's the difference from LP72s for me.

 

[VikingDives]

Hi there all you sidemount divers,
I dive with drysuit, relatively thick undergarments, LP85s and 6 lbs lead in fresh water.
Any of you can guesstimate how much lead I would need if I dive with drysuit, thin undergarments and alu80 tanks in fresh water?

No, but you can. Go in the water, no tanks and all your gear on, no weight.

Try to descend (obviously you should be water that you can stand up in). Add weight until you can descend on a full (think free diver) exhale and stay under without a problem. Now add 3 lbs to the weight you're holding and go diving. You should be very close to properly weighted.