Stage bottle types Al or steel

[Doc Intrepid]

Bingo. ScubaDad nailed it.

 

[JDostal]

I like AL40's. Very small, compact and neat. Buoyancy is great - on them!!

A few of my friends us al80's...they like them because of the higher volume and they are really not much more hassle than a 40. And you can find 80's used for a lot cheaper than 40's...

 

[matt_unique]

My last few times up at Lake Tahoe I used two AL80's each dive because it held enough deco gas for a weekend of diving without having to get a fill in between days, which can be hard to find up there. I would have preferred to use AL40's but I only have two. What I found was that after the initial adjustment to having such big tanks, I forgot they were even there. We were diving off a small boat so we put the AL80's in the water, rolled off the boat and then donned them while we were in the water. Worked real well. On the second day the AL80's just floated up and out of the way because they were low.

Biggest benefit was that the next time I used an AL40, it felt like nothing.

It's handy to have an AL80 stage when you can't get deco gas at your destination. It seems like a bear on the surface but once you are in you forget it's there. There is something to be said for having a crazy amount of gas with you too. It gives me a warm fuzzy feeling

--Matt

 

[JDostal]

That's what my friends say too. When we're doing a weekend of shorter deco dives (15-20 minutes of deco...) they can use one tank for 4 dives whereas our 40's only last a day.

 

[flw]

One usually sends tanks up the line when carrying larger tanks such as 80 cubic foot stages that are used up. Less hassle than dragging them around for the rest of the dive.

I'm still not sure why I would want to do that. If you use a 'live' boat, shotline and lazy shot, then by the time you're in a position to have used up cylinders, you are just floating around anyway, and they aren't in the way to start with. I'm not about to start floating them up with others still on the line above me.
Faber lightweight steel are nice and neat and aren't particularly negative evn when full. Al if used as bottom gas bail-out are irratatinly floaty with high He in, and so personally I prefer steel for that, and either Al or steel for 50%/O2.
Al are hard to source, even harder to get hydro'd
With only one stage, I hardly notice a 7l Steel, it certainly doesn't off-centre you.

 

[filtered]

I'm still not sure why I would want to do that. If you use a 'live' boat, shotline and lazy shot, then by the time you're in a position to have used up cylinders, you are just floating around anyway, and they aren't in the way to start with. I'm not about to start floating them up with others still on the line above me.
Faber lightweight steel are nice and neat and aren't particularly negative evn when full. Al if used as bottom gas bail-out are irratatinly floaty with high He in, and so personally I prefer steel for that, and either Al or steel for 50%/O2.
Al are hard to source, even harder to get hydro'd
With only one stage, I hardly notice a 7l Steel, it certainly doesn't off-centre you.

Another alternative is to gather the team's empty 80 cu ft stages together, and send them up with a liftbag for the boatcrew to pick up.

 

[J1M1]

Also if you are going to take off a cylinder to give to another diver, which i have done with a steel deco bottle, the weight shift to the light side and huge change of bouyancy are very evident. This may not be ideal in an emergency situation. ....JD

 

[flw]

Also if you are going to take off a cylinder to give to another diver, which i have done with a steel deco bottle, the weight shift to the light side and huge change of bouyancy are very evident. This may not be ideal in an emergency situation. ....JD

It depends very much on the characteristics of the cylinder itself though - Faber lightweights widely used in the uk are not particularly negative - although I think those in the US are more so.