Bouyancy characteristics of double AL80's

[Rainer]

I was skeptical till a bunch of people (including Tobin) on TDS tried it (after a shop sold a singles wing as a doubles wing to someone who then claimed it bent his SS plate), and yup, the plate will bend. Leverage over all large surface area.

 

[Blackwood]

Leverage over all large surface area.

I think the real deal is that it's bearing up against thin, unsupported metal.

 

[K Mejean]

He also said something about a pony reg. That would mean he will be carrying a pony as well. I think that would be too much for the single wing. Maybe you should get with someone to train you how to carry an additional tank as a stage bottle. Then you don't have to modify the wing and you can drop the pony. With the 2 AL80's set up with one as your back gas and the other as a side mount All you would need is to use your pony first stage as your sidemount first stage and you are done.
If I use a stainless backplate I don't need any weight with a single AL80. With an aluminum backplate I need about 10lbs.

 

[mksmith713]

I'm looking hard at independant doubles for one simple reason.
Not even a tech reason.....
My SAC is way higher than my wifes (dive buddy) and I hate to make her end a dive early because I blew through my air.
If I dive Ind. dbls, I can switch over after blowing one tank and burn part of the second by the time she's burned one.
Then, when we do our surf. Int., I can swap out the empty for a fresh and still have 1 1/2 tanks.
Exactly what I burn to her one tank.

Much easier to carry 3 AL 80's than 2 AL 80s and 2 ponys

 

[Fishpie]

Just get bigger single tanks.
You'll be much happier.

 

[Rainer]

Agree with Fishpie, doubles are hardly a good reason for a "poor" SCR. I'd first start with just diving more, getting more comfortable, working on trim, eliminating danglies, working out (i.e. hitting the gym more), and only then considering bigger cylinders. In any case, a large single (say HP130) is probably a better bet for what you're talking about. The added drag/mass of the doubles is just going to keep your SCR high.

Just get bigger single tanks.
You'll be much happier.

 

[rjack321]

Just get bigger single tanks.
You'll be much happier.

Exactly leave the wifey in the al80 and get a hp119 for yourself. You are going to huff and puff worse with doubles to her single tank.

 

[K Mejean]

It would be a royal pain in the ass to change tanks in and out of the bands all the time. I say get bigger single tanks or get some training on an additional side mount tank. That will be a lot easier.

 

[Jim Lapenta]

I'm looking hard at independant doubles for one simple reason.
Not even a tech reason.....
My SAC is way higher than my wifes (dive buddy) and I hate to make her end a dive early because I blew through my air.
If I dive Ind. dbls, I can switch over after blowing one tank and burn part of the second by the time she's burned one.
Then, when we do our surf. Int., I can swap out the empty for a fresh and still have 1 1/2 tanks.
Exactly what I burn to her one tank.

Much easier to carry 3 AL 80's than 2 AL 80s and 2 ponys

Actually proper procedure for independent doubles is to use 1/3 of the first tank, 2/3 of the second and you now have a full tank in reserve between the two. If you are planning for two dives use the rule of 1/6ths. Independent gas management is a bit trickier than what you are proposing. Better to get a 120, 119, or if you got the muscles a 130. Work your way into doubles with some training in them. And practice gas conservation, slow down, relax, make sure you are in trim and swimming horizontally. Correct weighting is a big plus as well.

 

[b1gcountry]

I think he's talking about putting the pony reg on the second independent tank. BTW, if you breathe the first tank down, and then switch to the one with the pony reg, exactly how are you going to donate a reg to your wife if she goes OOA?

If your wife is giving you trouble for making her come up before she gets low on air, then she needs to understand what it means to be a proper buddy. If she isn't worried about, then why are you?

Tom