Doubles or single tank with 2 first stages?

[El Orans]

I am thinking about getting a new tank for next winter. In this corner, a 15L tank to be used with the first stages (Y or H). In the other corner, a set of small doubles (2x7L).

I am not thinking about going technical. I just want to have some additional gas and more safety for cold water diving.

Any comments?

 

[Tek Adventure Diver]

I would say doubles but possibly a larger tank. It ends up being less gas. Although it is better because of the reduncey, but larger tanks,

 

[dannobee]

If those are the only two options, take the single rig with a Y or H valve. Most shops charge by the tank, not by the amount of gas when it comes to filling.

 

[aquaoren]

The 7ltr. tanks may be fairly short and a little difficult to balance out. Don't you think?

 

[jamiep3]

I opted for a HP120 with an H valve over a small set of doubles. Since I don't do Tec yet, it gives me enough gas for almost any profile I do and redundant regulators. Also as pointed out, one tank to fill not two.

 

[Packhorse]

I got a 15L Faber and I love it. If you choose doubles I would be inclined to go for something a bit bigger.Set them up as independant doubles and by a third to swap over with the least full one after your first dive.

 

[wedivebc]

I would say doubles but possibly a larger tank. It ends up being less gas. Although it is better because of the reduncey, but larger tanks,

Why would small doubles end up with less gas that a big single? (or am I reading this wrong?)

 

[Packhorse]

Why would small doubles end up with less gas that a big single? (or am I reading this wrong?)

7x2=14
15x1=15
big single wins

 

[grazie42]

This would be my preference in order:
1. 2x12
2. 15
3. 2x7

Double 12s give you more gas and better cost-benefit without being all that heavy. They will also allow you to do 2 dives on one fill.
I think a single 15 is a bit too unstable (sticks out too far from your back as a single...I dive double 15´s so nothing against the tanks themselves) to be a first choice but the economics are better than for small doubles.
Double 7s is a really nice package, easy to carry, sit well on your back etc but IMO they don´t carry enough gas to justify the expense...

 

[Jason Ooi]

Why don't use double tanks 12x 2 = 24lt instead of single tank,
You used 40lb BP setup single wing for 15lt and 7 x2 = 14lt?