Why recreational backmount doubles

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divezonescuba

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I am a purely rec diver. Started with twin tanks, in the seventies. Switched to single tank (15 liters steel at 200 bar) in 1990.
I did never need to switch back to twins, albeit they were more streamlined than a single tank of same capacity.
For many other things, a (cheaper) single is just "good enough".
I agree that when someone has a lot of money to spend, a compact twin tank provides some advantages, particularly if compared with a single tank having just one valve, while the twin tank has three (two posts plus the manifold valve).
However for 99% of rec divers a single tank is perfectly OK.
 
Yeah,
The first two minutes is 'I created a class'

Then five minutes of why rec doubles:
- more gas... 2x tanks of same size = more gas...
- Two independent first and second stages, yes. so redundancy, thus safer
- Use same tanks for both dives, with more flexibility

Cons: more weight, 82 lbs.

Then,
differences between ITT and their Rec doubles class for seven minutes, line item by line item.

More interesting would be mentioning using small doubles recreationally, not monster full size doubles.
 
These are better in every way compared to a single 80.

I made a bunch of double sets, 4 of these, they sold immediately, so people seem to be super interested.

I personally just want redundancy and twins do that with symitry vs pony setups

20211125_234450.jpg
 
This is all great for learning stuff and at 1.75 playback works well for me
 
Moved to twinsets quickly after starting to dive in the UK as diving here needs redundancy even if you're diving within NDLs. Means you can easily do two NDL dives with a single fill.

It's not excessive and not inconvenient.

If diving in warm, clear, benign waters with lots of other divers then a single is fine, maybe with a PONY if pushing it.
 
People often think single tank is lighter,
But unless you dive down south, with no wet suit,
I find the lead that gets stapped on usually makes it very close to the same weight as smaller doubles.
In just in smaller items,
Like the advantages of sidemount is usually given
 
If your favorite dive site is 60 miles away and driving + packing dive gear takes 4 hours, then do you really want to dive for one or two hours?

With doubles you can double your dive time.

You can, of course, swap single tanks too, but that requires exit and re-entry.
 
Plus the hours on the boat 'steaming' out and back from the dive site…
 
https://www.shearwater.com/products/swift/

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