doubles

[rsldonk]

I am on the verge of ordering my first set of doubles. I have been diving about two years now and have over 100 dives. I have a Halcyon BP/W already, set up for singles with the long hose regs and all that. I have my eye set on GUE fundies as soon as I can afford it. I was just curious as to what sort of advice any of you could give for doubles, what to look for, what sort of things I would need with that. The tanks I'm looking at are 95cf aluminum and as of right now, I would not be doing anything beyond recreational depths. Thanks for the help.

 

[Captain12Pk]

I would tell you that 95 cf tanks may be alright for training, but are too small for any deco dives. I know you said you're not exceeding that, but you likely will eventually. But before you buy anything, select your instructor and ask him these questions. Most Tech. instructors (at least those that I know) are likely to be fairly particular about what equipment you can and cannot use in their classes.
BTW, where did you find AL 95's?

 

[Rainer]

Wait, you have money for doubles but not Fundies (or both)? In that case, I'd highly recommend taking Fundies now and saving up for doubles later. The class will help your diving A LOT more than the doubles (which won't add anything to your current recreational dives other than weight)....

For what it's worth, I've never heard of 95cf aluminum cylinders. My first set of doubles were LP85s. They work fine for two moderate recreational dives or one T1 dive (~25 min at 150'). Those are a lot more fun to dive than bigger sets...

I am on the verge of ordering my first set of doubles. I have been diving about two years now and have over 100 dives. I have a Halcyon BP/W already, set up for singles with the long hose regs and all that. I have my eye set on GUE fundies as soon as I can afford it. I was just curious as to what sort of advice any of you could give for doubles, what to look for, what sort of things I would need with that. The tanks I'm looking at are 95cf aluminum and as of right now, I would not be doing anything beyond recreational depths. Thanks for the help.

 

[Rainer]

I'm assuming he means double 95s (surely steel, though...). What kinds of beginner "tech" dives are you doing where 190cf isn't enough gas?

I would tell you that 95 cf tanks may be alright for training, but are too small for any deco dives. I know you said you're not exceeding that, but you likely will eventually. But before you buy anything, select your instructor and ask him these questions. Most Tech. instructors (at least those that I know) are likely to be fairly particular about what equipment you can and cannot use in their classes.
BTW, where did you find AL 95's?

 

[TSandM]

I would tell you that 95 cf tanks may be alright for training, but are too small for any deco dives.

Hmm . . . I ran the numbers for bottom gas and rock bottom for my 150 foot dive on Saturday, and my 85s were fine for it. I think that was a deco dive . . .

 

[rsldonk]

Wait, you have money for doubles but not Fundies (or both)? In that case, I'd highly recommend taking Fundies now and saving up for doubles later. The class will help your diving A LOT more than the doubles (which won't add anything to your current recreational dives other than weight)....

For what it's worth, I've never heard of 95cf aluminum cylinders. My first set of doubles were LP85s. They work fine for two moderate recreational dives or one T1 dive (~25 min at 150'). Those are a lot more fun to dive than bigger sets...

I haven't ordered them yet, but I do know they are aluminum and shop owner said they were 95s, but still need to check that. As for fundies, it's not just the money my instuctor wants me to lose another 30 lbs before I start. I'm half way there at least (amazing what dropping soda pop and beer will do). In the mean time, I am doing a 3 day liveaboard in California at the end of the month, so the doubles would help out a lot there. Instructor/friend won't start me in the class with the deco stuff, because of the belly being what he calls a nitrogen battery but has shown me the frog kick and others. Still working on that part at least. Meantime, my buddy dives doubles and so having a bottom time that matches his would be extra nice, plus the added safety factor of the capacity is very nice.

 

[Rainer]

How would doubles help on a CA liveaboard? I live here and try to dive singles whenever possible. In recreational depths that means a lot of singles diving.

Just having extra gas doesn't add safety (assuming competent gas management). Unless you're trained to handle failures (usually only covered in "tech" classes), having doubles basically just *increases* the chance of gas loss (extra regs, more o-rings, more failure points, etc).

What kinds of dives are you doing with your buddy such that you don't have enough gas? Big singles (e.g. HP130s) are almost always more fun to dive than even small doubles, and I find I'm NDL or boredom limited on such cylinders, not gas limited, in recreational depths.

In any case, working on your fundamental skills is always easier in familiar gear. Getting squared away in singles will only make the transition later to doubles easier.

Just some things to consider.

I haven't ordered them yet, but I do know they are aluminum and shop owner said they were 95s, but still need to check that. As for fundies, it's not just the money my instuctor wants me to lose another 30 lbs before I start. I'm half way there at least (amazing what dropping soda pop and beer will do). In the mean time, I am doing a 3 day liveaboard in California at the end of the month, so the doubles would help out a lot there. Instructor/friend won't start me in the class with the deco stuff, because of the belly being what he calls a nitrogen battery but has shown me the frog kick and others. Still working on that part at least. Meantime, my buddy dives doubles and so having a bottom time that matches his would be extra nice, plus the added safety factor of the capacity is very nice.

 

[rsldonk]

How would doubles help on a CA liveaboard? I live here and try to dive singles whenever possible. In recreational depths that means a lot of singles diving.

Just having extra gas doesn't add safety (assuming competent gas management). Unless you're trained to handle failures (usually only covered in "tech" classes), having doubles basically just *increases* the chance of gas loss (extra regs, more o-rings, more failure points, etc).

What kinds of dives are you doing with your buddy such that you don't have enough gas? Big singles (e.g. HP130s) are almost always more fun to dive than even small doubles, and I find I'm NDL or boredom limited on such cylinders, not gas limited, in recreational depths.

In any case, working on your fundamental skills is always easier in familiar gear. Getting squared away in singles will only make the transition later to doubles easier.

Just some things to consider.

This is exactly the sort of advice I was looking for. My buddy dives doubles because he does do tech. I don't as of yet and I'm not quite ready to. These were many of my same thoughts, so thanks for the answer.

 

[Jim Lapenta]

And steel 95's rarely have 190 cu ft of gas in them. Usually it's more like 230 to 250 cu ft if you get good cave or wreck fills. Plenty for deco dives.

 

[rongoodman]

I'd recommend trying out some different sizes while in the water with someone who understands how they're supposed to work, if at all possible, perhaps in conjunction with your Fundies class. Doubles come in a wide array of sizes, and there's no point in buying a pair that you're constantly fighting with to stay in trim. Al 80s might be a good place to start looking too, since you've probably used them in the past. You can always break them up for stages later on if you need more gas for bigger dives. (If you go to cave country in Mexico, they're about all you'll see.) I lucked out, and stumbled into LP85s, which work for me, and aren't too heavy for me to climb a boat ladder with, but it was more or less dumb luck that I did so.