When to Double?

[grazie42]

Frog, here in Sweden (kinda same conditions as you have), most people go for double 15´s or 18´s (liters, 232bar). I´ve even seen some with double 20´s but to me those people are taking the "you have to be fit do dive" thing to the extreme ;-)
My double 15´s weigh about 50kg/100 pounds with the backplate, I shudder to think about steel 20´s...

Double 12´s are nice because they´re so easy to handle but for me (and almost all the other people I´ve seen) they don´t give you enough air for more than "light" technical dives...It all depends on the depth and conditions of course, in Florida double 9´s or 12´s are plenty even for deep dives for me. I´m surprised that 12´s are so common in the uk...

Oh and we´re talking steel all the way here...alu is for decobottles

 

[FIXXERVI6]

I dive double standard AL 80's and I don't have a "cork" problem as stated in a previous post, throw a steel backplate on double AL and there is no problem as long as you properly weighted and your BC has enough lift to overcome the plate, lead, and the negative full AL 80's.

I just asked a lot of questions about doubles, made the investment, went out to athens scuba park and jumped in, since then I have talked with some locals that have done tech and made about a billion adjustments to the rig, for the better each time of course, with more planned.

I prefer my double 80's to a single, when I dive single I usually try to only dive a neutral 80 and I make it ride high on my back like the doubles.

For me it was do I want a pony or doubles, after pricing things out and talking to people, I felt is safer, more versital, and more economical for me to just do doubles, I don't regret it.

 

[matt_unique]

due to the dives involved in the class, something like
"Technical EANx" or "Extended Range" will 'teach' you to
use doubles. WITH THAT SAID, I concur with the comment they
ae best used FIRST TIME in a pool or other controlled
environment so you become somewhat familiar with the weight, etc.

I was once on a dive boat and overheard one
of the "divers" (and I use that term loosely) state
"this is my first time with doubles and my new BC". he
had heavy STEEL doubles with a wetsuit and was
about to step into 100 feet of cold, dark New England
water.

TDI courses hammer valve manipulation. Deco Procedures, Adv. Nitrox, Extended Range, and Entry Level Trimix all require you to demonstrate valve shut down procedures. I have not seen their other course descriptions.

GM - scary thing to over hear on a charter boat. The rule on my boat is to make sure there is air in the wing before you stand up. Imagine being foolish enough to test out a new bc with doubles on a 100' dive?

--Matt