Small Doubles?

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rds4640

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I am currently using a pony as an emergency alternate. I understand the thoughts on why doubles are better but don't like the though of putting on 80lbs of gear on the boat or climbing it up the ladder. One thought I had was getting a small doubles set. I see that OMS offers both 45cf and 50cf cylinders that can be made into doubles. Has anyone used this setup? Pro/cons?
 
if I was going to put together a small set of doubles, I would use steel 72's. The weight wouldn't be too bad copared to 135lbs for double 104's. I actually considered this for my girlfriend. She is kinda petite, but I just couldn't afford 2 drysuits, and 3 sets of gear in one year.
 
Good idea with the steel 72's. These tanks are usually pretty cheap if you can find them. You could probably get set up for $300-$400 with tanks bands and manifold. Probably cheaper if you can find a set already assembled. Good Luck!
 
I was actually thinking smaller than 72 as I don't need that much gas. Comments?
 
With the smaller tanks like the OMS 45 and 50, you're probably stuck with the OMS bands and manifold, and I don't think you can get an isolator for that narrow combination. But check this! The rest of my post is written on that premise.

A larger tank like a 120cf (or even better, the new PST E series once they start shipping), with a H valve, is basically the equivalent in redundancy as a non-isolation manifold. A burst disc on either a non-isolation manifold or a H valve is going to ruin your day.

Plus you have to pay for two visual inspections per year versus one for a single tank.

A single large tank with H valve would weigh about the same, have the same equivalent redundancy (first stage redundancy only), give you more gas, and cost less, both upfront and in the long term.

But the small doubles would look really cool :D
 
I was thinking isolated manifold but now you have me thinking. I do like the fact that an isolated setup is COMPLETELY redundant though.
 
I guess I would have to go with 66's if I wanted the smallest. Probably be better off going with used 72's though and all of a sudden the weight starts to become rediculous (for rec diving). Hmmm, the h valve is looking better all the time. I am thinking that it would be just as redundant as a pony except for the tank valve oring. Have you every heard of a tank valve oring failing? I don't consider running out of air as a danger for myself as I am VERY vigilant at checking air preasure.
 
Scubaroo wrote...
A single large tank with H valve would weigh about the same, have the same equivalent redundancy (first stage redundancy only), give you more gas, and cost less, both upfront and in the long term.
And for taller divers, the long tank assists in trimming out vs. the short doubles.

Scubaroo wrote...
But the small doubles would look really cool :D
Trust me, after you've seen them on a tech-diving granny, the coolness factor kinda fades away.

:D
 
You use the same isolator manifold for the smaller tanks but custom bands. I get mine from Roman for about $50

http://members.aol.com/mrdeco/page/index5.htm

I have 4 sets of isolated double 72's and love them. I find them great for dives in the 100-200 ft range.

You want something smaller and lighter than than 72's think about double AL 40's - far cheaper than steel OMS 45's.

Dave D
 
https://www.shearwater.com/products/swift/

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