How does AluS080 11.1 ltr for deco/stage tanks sound?

[Wibble]

You sidemount your ali80s when you use them as your rebreather bailout cylinders



One thing about ali80 cylinders is they're very heavy, certainly in comparison with aluminium 7 litre cylinders. You'll probably end up with both as diving's like that, we collect more kit.

For CCR, I use:

• 1x ali7 for bailout to 30m
• 2x ali7s for bailout to 50m
• 2x ali80s beyond there

For OC diving (don't do much of that these days!), I would take 1 or 2 ali7s as decompression gas cylinders for dives down to about 50m and two (or three with a bottom stage) ali80s below that. Depends largely on the decompression plan and how much it requires as contingency (should one cylinder fail).

The dry weight of ali80s really is the biggest challenge for me. They're really cumbersome on the boat, but they're fantastic in the water, unless it's a rich helium mix in which case they're very tail light (sidemount, bring the waist clip forwards).

 

[Alekseolsen]

Since Alu tanks are used for stage due to price, since I've found new Tecline military steel 11 liter tanks with cheaper price than new Polaris Alu 11 liter tanks, then maybe I should go with that option for my stage tanks too, as I do most of my dives in cold water with dry suit.

I would avoid that if I were you. As sidemount tanks, sure, but using negative tanks as stage seems like a lot of hassle:
- Your heeded weight will change when using the stage
- You trim will change as a result of the stage.
- picking up and dropping the stage during a dive will have a huge impact on your buoyancy
- as per Wibbles post, folks prefer aluminium 7litres over 11 liters due to weight on land. A steel cylinder will be even worse.