Doubles?

[johnx15]

I was wondering about doubles. I'm Just OW. But Al80's just ant cutting It. I dive around 40' to 50' and I'm not a airhog. But I diving For long periods at a time. The max if got at 40' was 58 min cold water 46*. I'm wanting to stay for my max on the RDP. I was thing about Doubles I've been told by my LDS to get a Independent Regulator Set-up, But I was wanting something More like The solid Bar manifolds form US divers Or something.Like the ones with J-values?

I know the dangers of diving so don't tell me not to do It.....

 

[JDMerk]

I too am looking to go to doubles sometime in the not-so-distant future but im doing it for different reasons. You mention you want to max out your NDL times at 40'...you realize on the navy tables that is 200min (well over 3hrs). That is quite a dive and if you were on a charter i can imagine you would piss off a lot of the divers as well as the crew. Your 58 min bottom time really isn't that shabby from an AL80 and a newish diver, work on it some and you could get more. If however you own your own boat and that is what you really want and your staying fairly shallow you could always look into a hookah system...thats pretty much a limitless supply.

Me im going to get some steel 130's with H valves to get used to having two independent regulators and to extend my air supply THEN, if I see the need for even more air I will double up my AL80 or HP100's

Stay away from J valves...if you can even buy them anymore.

 

[Blackwood]

... so what's your question?

You mention you want to max out your NDL times at 40'...you realize on the navy tables that is 200min (well over 3hrs).

He said "RDP" which is a specific table (DSAT/PADI).

Off the cuff without actually pulling out a calculator, I'd say he needs about 200CF of gas (rounded in-my-head estimate) to max out the PADI NDL for 40 feet.




My question to the OP is: what's so special about the max of the RDP? Why do you want to hit that number exactly? Do you want to go past it? Why/why not?

 

[johnx15]

What I'm Trying to ask what manifold should I Go with? That the really ?

 

[Blackwood]

^^ Depends on you.

Do you want the ability to isolate one tank from the other / Do you really want a manifold or do you want independent tanks?

 

[PfcAJ]

Right...real talk, just go dive more. Really. You're SAC rate will plummet, you'll get the bottom times you want, and in the mean time, you'll build up the skills and knowlege you need to dive doubles.

 

[atedeschi]

find a good mentor that has experience with double and the proper setup or take an intro to tech and that will give you a good foundation.

 

[Rainer]

Yes, doubles are the solution for all new divers looking to extend bottom time. Getting out and doing two dives must be for losers.

 

[johnx15]

I want a Manifold where I can isolate them. In case of regulator failure. And I would want this reg so when I'm Able to get my tech cert.

 

[sschlesi]

You want to dive 140 minutes in 46F water? I'd worry about staying warm before I worried about carrying doubles. I've done up to 80 minutes in water that cold, but it takes a real man, or a LOT of underwear to do 140 minutes on open circuit in water that cold.

Based on your SAC above, a pair of 100's should put you in the ball park of 140minutes at 40'. Personally I'd look to a single 130 for long shallow dives before bothering to go to doubles. It'll be much lighter and easier to move around on land. It'll fit on your standard BC/singles wing, you don't really need redundant first stages for such shallow diving, unless your solo, and you may well be, diving that cold for that long . But, it won't get you all the way to 140 minutes. Brrrr.