DIR- GUE Adjust weighing for stage bottles?

[steinbil]

Since stage tanks are usually (always?) aluminum tanks, they will be positive when empty. This affects the balanced weighting of the entire rig. I have heard that stage tanks are not calculated as part of your weighting, since you need to be balanced in the event that you drop/stage/leave tanks. But does that also hold true for the positive buoyancy of empty stage bottles?

Having let's say two more or less empty AL80s (bottom stage + deco stage) when you arrive at your final deco stop would provide quite a bit of positive buoyancy, that you need to deal with. Or is there something I'm missing? I realize there will usually be gas reserves in play, but in the worst case scenario with gas sharing, I assume you wouldn't want to struggle with being too light on top off an already sticky situation.

TLDR:
Do you adjust your weighting to account for positive buoyancy of empty stages. If so, how? Do you just add the weights you estimate for the buoyancy characteristics of the stage bottle? Or do you do a weight check with each configuration?

PS.
I assume this will be covered in a tech class, but I like to get a head start on the topics covered before I take a class.

 

[PfcAJ]

That makes a lot of sense. I forgot about ditching empty stages in the worst case scenario.

That’s one of the big drivers behind halves on stages. Thirds doesn’t really allow you to ditch them the same way halves does. It’s empty (or darn close to it) when you make it back to the next stage. If you’re having a bad day, chuck it and keep movin.

 

[tursiops]

I don't think you understand 1/2+200.

I do, and I don't use it. Too complicated, too much room for error, too unnecessary for my dives.
You do you...breathe your stage all the way to zero. I don't care.

 

[steinbil]

I do, and I don't use it. Too complicated, too much room for error, too unnecessary for my dives.
You do you...breathe your stage all the way to zero. I don't care.

How is divide by 2 and add 200 more complicated than divide by 3? Hardly advanced math either way. And what do you mean room for error? If you run a little short on a stage, can't you just switch to your plentiful back gas and comfortably get to your next gas?

 

[tursiops]

How is divide by 2 and add 200 more complicated than divide by 3? Hardly advanced math either way. And what do you mean room for error? If you run a little short on a stage, can't you just switch to your plentiful back gas and comfortably get to your next gas?

Take your class, THEN ask quesrions.

 

[PfcAJ]

Well I’ve taken a class.

Thirds is intellectually “simpler”. But absolutely not better. It’s more complex in the water if things go sideways.

Your reserve is spread out over multiple bottles. So let’s say you’re out of gas. You get to your stage. Great! It has 2/3 remaining. You start breathing it and when you get to the next stage, it has 1/3 left. So now you have to drag that thing with you to have access to the gas. 2 stage tanks on you is always slower and more cumbersome than one.

So you Bg is empty (or damn close to it) and you have two tanks clipped off, one that’s got a scrap of gas in it and another with 2/3.

With halves, you’d NOT have empty backgas, and your stage will be empty when you get to the next one so you can leave it behind.

You do need to do a scrap of math before the dive (honestly just doing it once or twice is enough to understand the rules behind it), but that’s it.

 

[rddvet]

I don't think you understand 1/2+200.

There are a HUGE amount of divers that don't understand stage management.

 

[rddvet]

I do, and I don't use it. Too complicated, too much room for error, too unnecessary for my dives.
You do you...breathe your stage all the way to zero. I don't care.

Not being rude, but how the hell is 1/2s too complicated? I literally can't understand what would make it difficult.

 

[rddvet]

Take your class, THEN ask quesrions.

He's attempting to learn why not answer his questions? He may learn something or have fodder to bring into class when they discuss the pros and cons of both systems. ( i know there are some people who are asking questions before taking a class that can be annoying. I don't the OP is one of them. He seems to want to learn).
Getting annoyed and making comments like "you do you" as you said in another post isn't helpful and it's just a shortcut ploy to try to win an argument that doesn't benefit anyone(gaslighting, a term I despise). As AJ said, this is the DIR forum. 1/2+2 is pretty standard across DIR in my experience. So if you don't dive DIR but want to make a counterpoint go for it. But don't "take all your toys and run home" when people who do subscribe to DIR disagree. It's an open discussion. No need to shut people down who have different opinions.

 

[tursiops]

No need to shut people down who have different opinions.

You mean like I was shut down?

I don't think you understand 1/2+200.

I should know better than to post in the DIR forum. Too much rigidity.

 

[rddvet]

You mean like I was shut down?

I should know better than to post in the DIR forum. Too much rigidity.

Its always the same stuff with you. Very sad. It's a discussion. If you can't have people disagree with you, then don't join in.