Cylinder type and proper weighting (SPLIT FROM 'Pull Dumps - Lose them')

[woodcarver]

Archimedes, when used to be neutral in the water, is about the weight volume ratio, the smaller tank changes the volume, and to maintain a proper ratio you need less weight as well. Your body and kit are the same but the tank is different.

We need to be doing this in person and with beers in hand. With the empty bottles and a tub of water we could work out examples.


Cheers

Bob

^^^^^This! (Including the beer part)

^^^^This! Got banged around close several times getting here.

 

[BRT]

It is not just the internal volume that makes a difference. The HP 100 is filled to a greater pressure, so it takes less tank volume to hold more air. If you filled an HP 100 to 3000 PSI, like an AL 80, it would not have a whole lot more gas than the AL 80.

I mentioned the benefit of higher pressure earlier but a 3442 psi HP 100 would hold 87 cf at 3000 vs 77 for the AL80, still 13% more and 10cf is not insignificant.

 

[graham_s]

AP Diving still makes BCDs (Buddy and Commando) to which you can connect a small air bottle topped up from a tank. The bottles valve design looks like either a yoke or DIN regulator connector so it matches perfectly to be topped up from the tank. They have been making these for decades.

A much greener solution than disposable CO2 cartridges.

I have a couple of their jackets, they are, or were ubiquitous in UK diving. The stuff is bombproof with a life time warranty.
You can even breathe off the jackets, adding air as required from the emergency cylinder.
I've been using my Commando since 1993, still good as new.

 

[Umuntu]

I have a couple of their jackets, they are, or were ubiquitous in UK diving. The stuff is bombproof with a life time warranty.
You can even breathe off the jackets, adding air as required from the emergency cylinder.
I've been using my Commando since 1993, still good as new.

They still are in widespread use.

I have a bright Orange "Commando" that's still fully functional. It has the original "APV" breathable inflator. The great thing about AP Diving is the product support. Every product they made is still supported with service kits available or, where things have been upgraded, exchange programs.

Absolutely First rate company.