What tanks for Doubles? 100s or bigger?

[Kirby Pollard]

I have been diving dual 100's for awhile now, perfect for a 5'9" 220 lb guy with a good sac rate. If your a small person, dual HP or LP 80s work great. Need more air to go deeper longer? Carry sling bottles. Bigger tanks are too heavy for shore diving. No one mentioned why duals are such a great choice. Redundancy. Every new diver should start with them, and a sling bottle. No more out of air emergencies. I really like the rule of thumb thats says, don't go any deeper than the size of your tanks. AL 80, 80 ft, ST 100, 100 ft. Unless your going to 260 ft, or you have a really bad SAC rate, you probably don't need dual 130s. If thats the case, dive alot more until you become more aerobically fit before you do deep dives.

Kirby

 

[Florabama]

To get back to the OP, personally, I don't think there's one tank that's right for all occasions. Over the years I've collected sets of LP 72s, 95s. 108s, 131s, several AL 80s, as well as a 63, and have access to many others.

I pick one or the other based on the dive plan. If I had to pick one, it would definitely be LP 95s.

 

[elan]

I don't see how moving to doubles is too far or too fast for a recreational diver. I've done a dive with doubles already and plan on moving up soon.

Why would you need to dive doubles within recreational limits ? You can blow up NDL even on Nitrox even on HP100 unless you are diving 30'. Even if you dive overhead things like ICE or you dive cold water you do not need hauling the double rig but can get away with H-valve or pony.

What options do you get that will make you diving doubles ?

Some buddies I dove with said they enjoy diving singles when they can as they do not need to carry the doubles rig.

 

[elan]

No one mentioned why duals are such a great choice. Redundancy. Every new diver should start with them, and a sling bottle. No more out of air emergencies.
Kirby

Kirby, in my humble inexperienced opinion OOA emergencies (unless it's total equipment failure with reg locking up closed) should not be happening with singles. If it does the person has to work on gas planning better. Even if the reg free flows it's possible to surface. Though I prefer carrying pony when I go deeper than 50' in cold water. My believe is relying on the redundant system to solve gas management problems is not a good idea. Doubles would probably be overkill to haul them all the time.

 

[DA Aquamaster]

Why would you need to dive doubles within recreational limits ? You can blow up NDL even on Nitrox even on HP100 unless you are diving 30'. Even if you dive overhead things like ICE or you dive cold water you do not need hauling the double rig but can get away with H-valve or pony.

What options do you get that will make you diving doubles ?

Some buddies I dove with said they enjoy diving singles when they can as they do not need to carry the doubles rig.

I like doubles just because of the way they trim out. They feel better in the water than a single, especailly a large single like a 130.

I have double steel 72's for the normal recreational dives because they are delightfully light (for doubles) with buoyancy traits similar to HP 100's and Faber LP 95's. I have double HP 100's for off shore wreck dives because they are substantially lighter than LP 95's and are easier to get up the ladder with in 6 ft seas but hold a lot more gas than steel 72's. And I have double Faber LP 95s for cave diving (they are basically 130's with cave fills to 3600 psi) although HP 130's would be fine in that role as well.

Given that my serious diving tends to be in caves, there are I think some significant advantages in diving the same configuration every time. The familiarity leads to responses that are automatic in the event a problem arises. Everything is in the same place every time.

Also, in 25 years of diving and 7 or 8 years on various internet boards I have seen and read about many OOA emergencies (and donated gas three times to OOA divers, 2 of which were not even in my dive group) but I have never heard anyone complaining about having too much gas. I have also noted that on "recreational dives when the NDL's get short, the depth gets deep, the water temp gets close to freezing and/or the viz gets bad, many of those same divers who feel doubles are overkill start sticking very close to me and all my excess gas. Its not a coincidence.

 

[WD8CDH]

People need to stop thinking about doubles vs singles. The more important things are gas volume, number of regulator fittings, trim and dive plan. I have doubles as small as double 12's with a single regulator fitting (old Survivair/USD rescue pack). You would be hard pressed to blow NDL with that and it's no more complicated to dive than a single rental 80.

You could go with a single 130 (or larger) with an H-valve and have all the need for the training to use multiple regulators and gas managment of a doubles "tech" rig and the easy ability of getting yourself "bent" with improper dive planning.

I too prefer doubles (and triples) for recreational diving primarily because of the trim. In addition to the tiny double 12s, I have double 30s, double 35s, double 40s, triple 30s, triple 35s, triple 40s and quad 20s. Every set dives better than singles. My absolute favorites are the double and triple 40s.

Plan your dive then dive your plan.

 

[BabyDuck]

just one point to the op - unless your group of buddies dives 130s, if you gas match you 'lose' the ability to use that gas anyway. if you & your buddies have similar sacs, diving the same tanks makes matching much easier.

for instance, your small girl buddy and your big guy buddy and you *all* turn on the amount of gas that's agreed on by calculations based on sac, and if they're using double 95s the extra gas in your double 130s, while very nice and certainly welcome in an emergency, won't ever get used on a normal calm dive.

just throwing that out there for thought.

 

[elan]

I too prefer doubles (and triples) for recreational diving primarily because of the trim. In addition to the tiny double 12s, I have double 30s, double 35s, double 40s, triple 30s, triple 35s, triple 40s and quad 20s. Every set dives better than singles. My absolute favorites are the double and triple 40s.

Plan your dive then dive your plan.

So I was not completely nuts having in mind an idea of eventually putting 2 40 cuf stage bottles together and use them as doubles.

 

[WD8CDH]

Not nuts at all. The only hard part is finding the close spaced manifold and bands. You make a dive with double 40s and make a dive with a single 80 and you will never want to dive an 80 again.

Another good small double combo is Double LP45s. Several companies make bands and the manifold. At least Dive Rite, Scubapro and Thermo if I remember correctly. Those tanks are the same size a the 7 liter tanks in Europe where they are very popular as doubles. They even make a one piece double boot for them.

Look at the lower left photo here:

cylinders

You can see that the Euro doubles are often closer spaced than US doubles.

 

[GTRio]

unless your group of buddies dives 130s, if you gas match you 'lose' the ability to use that gas anyway.

This is why I chose the 100s. Doubled them up last night and diving them tonight, frig they are heavy, lol.

Brandon