Independant Double AL 80's

[jaybombs25]

Anyone ever double up tanks with Velcro bands and use them as independant tanks with two first stages. How difficult is it? How does the added tank affect buoyancy? How are they mounted i.e bp/w or is there another system? Whats the learning curve? and also how does it compare to a manifold i.e pros n cons when an extra set of regs isnt a factor.

Thanks

 

[ianr33]

I dont think it is difficult. The extra tank will obviously affect bouyancy. Overall weighting will stay about the same but double AL's tend to get floaty on the bottom.You can use a V-weight or put some weight on the bottom of the tanks using a cam strap.

BP/W is a foolproof way to do it

I have never noticed any rolling issues when one tank is down to 1500 psi and the other is full

Advantages of independant? 100% redundancy,can use rental Al 80's,dont have to carry 2 tanks at a time

Disadvantages? A little more task loading ,have to switch regs

I normally dive manifolded doubles these days but independants work great for solo dives or anywhere regular doubles are not available.

Edit- I see you are on St Lucia,in which case independant Al 80's would be perfect for you.

I use the Aqua Exporers doubles bands. They work very well http://aquaexplorers.com/double_bands.htm

 

[jaybombs25]

Is there anyway to hook them up to a conventional single tank BC?

 

[ianr33]

If you are using a conventional BC I would suggest slinging a second 80 as a "stage" Your BC may or may not have D rings to sling it from.Not as elegant as back mounted doubles but it will work.The net result is the same,2 independant tanks.

Using back mounted doubles on a BC designed for singles could interfere with the bladder inflation and certainly would not be very stable.

Also remember that 160 CuFt of gas is plenty to put you well into Deco even with a bad SAC rate if you are diving air.

 

[scubafool]

Have you given any thought to sidemounting? I have seen this done with relatively little modification to a conventional jacket BC. I don't recall the exact attachment method, but as I say, it looked rather easy to set up. Just something to think about.

 

[ianr33]

Have you given any thought to sidemounting? I have seen this done with relatively little modification to a conventional jacket BC. I don't recall the exact attachment method, but as I say, it looked rather easy to set up. Just something to think about.

I think what you are really talking about here is slung tanks not true sidemounting.


A buddy of mine recently got a sidemount rig and it aint simple.Will see if I can find some photos.

This is sidemount.the tank valves are tucked in the divers armpits.the tanks are horizontal and level with divers body.
The more common slung tank (stage tank,pony) would hang slightly below the diver. Looks similar at a casual glance but actually very different

 

[scubafool]

I never saw the setup in use in the water, but he called it his sidemount rig. I have also heard of the same thing being done more often, though I suspect it is done much less now that there are several factory ready sidemount setups available.

 

[Curt Bowen]

I never saw the setup in use in the water, but he called it his sidemount rig. I have also heard of the same thing being done more often, though I suspect it is done much less now that there are several factory ready sidemount setups available.

http://www.advanceddivermagazine.com/armadillo.html