Double Aluminum 80's

[jonnythan]

http://www.divers-supply.com/index.asp?PageAction=VIEWPROD&ProdID=16910

Probably the heaviest bands you'll find. FWIW, in a backplate and wetsuit, I need no additional weight.

 

[Mambo Dave]

Thanks Jonny. I'll look into those.

 

[tlawler]

I'm really new to doubles in that I have two AL80's that I may double up. Does any company make tank bands that are heavier to offset the buoyancy of twin AL80's?

It would take some pretty substantial bands to add any weight to your doubles rig. Most SS backplates will add 6 Lb. I think there are some manufacturers that will make custom thickness plates that will add a couple pounds. I think a better idea would be to add some of those pancake weights that go inside the boot. This would help with the trim issues of Al tanks too. Another option is the v-shaped bar weight that nestles between the tanks and can be moved up or down for trimming as needed.

 

[jonnythan]

The amount of steel in some 2 or 2.5 inch doubles bands easily adds ~2lbs. Then ~1lb for the manifold and you've already accounted for most of the extra buoyancy.

 

[tlawler]

The amount of steel in some 2 or 2.5 inch doubles bands easily adds ~2lbs. Then ~1lb for the manifold and you've already accounted for most of the extra buoyancy.

I know my Dive-Rite bands add negligibly to the weight. If you went with Highland bands, they probably weigh more, but for the price, that's a lot of $/lb.

The manifold will add weight, but at the top, when you need it at the bottom to help trim out. I still think the boot weights would help more in this situation.

something like this: http://www.leisurepro.com/prod/AQUTBW.html

 

[paulwall]

I know my Dive-Rite bands add negligibly to the weight. If you went with Highland bands, they probably weigh more, but for the price, that's a lot of $/lb.

The manifold will add weight, but at the top, when you need it at the bottom to help trim out. I still think the boot weights would help more in this situation.

something like this: http://www.leisurepro.com/prod/AQUTBW.html

I'm always tickled by posts like this. People bash the steel tanks for being too heavy too double up, but then "recommend" adding unditchable weight to offset the buoyancy of the AL tanks.

Bottom line, as I see it, is that doubled Steel Tanks may be too heavy to "swim up" if you add in a 6lb SS backplate over a lightweight wetsuit. I find I still have to carry lead with my single LP95 and a 5mil. I may be neutral with doubled 95's, but I'm betting I'd still need a few lbs. Of course, those would be ditchable, unlike a 6lb SS Backplate. Of course, a comfortable layer of "bioprene" doesn't hurt, either.

 

[tlawler]

I'm always tickled by posts like this. People bash the steel tanks for being too heavy too double up, but then "recommend" adding unditchable weight to offset the buoyancy of the AL tanks.

Bottom line, as I see it, is that doubled Steel Tanks may be too heavy to "swim up" if you add in a 6lb SS backplate over a lightweight wetsuit. I find I still have to carry lead with my single LP95 and a 5mil. I may be neutral with doubled 95's, but I'm betting I'd still need a few lbs. Of course, those would be ditchable, unlike a 6lb SS Backplate. Of course, a comfortable layer of "bioprene" doesn't hurt, either.

DId you see me bashing steel tanks? I only dive steel tanks. I was just making a suggestion in lieu of getting rid of the Al tanks and buying steel. And the boot weights are ditchable, if you had looked at them. Never tried them, so I can't say whether they work well or not. Sheesh...last time I try to help anyone. I just get blogged to death.

 

[WarmWaterDiver]

....steel 85's. I did not get the chance to dive doubles however I was told that most tech divers dive aluminum 80's down in Florida Keys area. They had a few pairs and Diver's City and it prompted a whole lot of questions between my friend (and instructor) over a few beers and rounds of tequila. Bob at Diver's City left us thinking about the differences between diving the cold freshwater dives we were used to and the warmer dives in the Key's. He didn't give a thorough explanation on why so I figured I would ask here.

OK, no problem. For us, the "Why" is because that's what's available for rental when we arrive at our destination most of the time (aluminum 80's). Guess that didn't come across clearly.

It's easy to pack a few hand tools and a lightweight set of metal double bands and dive independant doubles for me, whether 63's or 80's. This has worked for me at Bonaire, Tahiti, St. Croix, Belize, and numerous other locations. We rented manifolded double aluminum 80's from Divetech on Grand Cayman when doing our tech cert checkout dives - why? - because that's what they had available (they also had manifolded double aluminum 100's available). But no double steel rental tanks - and no steel rental tanks of any sort - at these various locations.

 

[paulwall]

DId you see me bashing steel tanks? I only dive steel tanks. I was just making a suggestion in lieu of getting rid of the Al tanks and buying steel. And the boot weights are ditchable, if you had looked at them. Never tried them, so I can't say whether they work well or not. Sheesh...last time I try to help anyone. I just get blogged to death.

Sorry, didn't mean to offend you. I shouldn't have used the "quote-reply" as my post was meant as a general indictment of the narrow-minded "Steel Doubles are only to be used with Drysuit or Redundant Bladders - period" crowd. Your post addressed a fallacious solution to the "benefit" of AL doubles over steel.

 

[CobaltDiver]

I am not sure about weighted bands, but you might consider looking at compact 80's. They have a working pressure of 3300 psi, and are four pounds negatively boyant. I have a new set of doubles arriving shortly, and I am going this rought to compensate.