Doubles - How to learn?

[PerroneFord]

Nah, I've seen Seahunt.

 

[Divin'Papaw]

Hey Jim,

I run a doubles workshop that goes over the different types of doubles, setup, hose routing, long hose use, valve shutdown, the 9 failures, trim and balance. We do two dives to go over all of this. It's targetted for recreational divers who haven't done any technical training, but want to dive doubles within recreational limits.

It's a workshop format and no certification is issued. So you don't have to worry about a pass/fail.

How often do you offer the doubles workshop?

You started this you know! The email exchange we had back in June has had me giving serious thought to doubling my AL80s instead of buying larger steels and a pony.

 

[TSandM]

I'm sure there are a lot of things I still don't know about doubled tanks -- I haven't assembled a set yet, for example. But man, if you spend a fair amount of time on line, you can read a TON of stuff about choice of tanks, how to weight, what kind of manifold, etc. TDS has a subforum on "Transitioning to Technical Diving", where almost any question you can think up has been asked at some time.

I've got great buddy mentors, but frankly, they haven't had to do much. I have the 5thD-X DVDs, and the valve drill is well-demonstrated there. I cheated, and bought my regs from somebody who was already diving doubles, so hose routing was already set up. I'm still working on getting the set really perfectly dialled in from a weight and trim perspective, but other than that, it's just diving.

 

[SparticleBrane]

Nah, I've seen Seahunt.

LOL :lol:

 

[Walter]

Nah, I've seen Seahunt.

I have a set of those too.

 

[Bigcape]

I didn't read the whole thread but...

I bought a H-Valve. this way you get 2 posts just like doubles and the hose configuration is the same but without the painstaking weight of two tanks.

I know there is more too double like the banding, isolater, gas mgmt etc. However it is a great place for fundies.

 

[cool_hardware52]

My 2 cents:

Physically Managing doubles in (and out) of the water is not a difficult thing to learn. Start in a forgiving environment (pool etc)

Actually understanding how Isolator manifolds work, and the benefits and risks associated with them is not self evident.

Walking through the parking lot at a Dive Site one morning when I observed a diver bent over a hissing set of brand new doubles. He was about to remove the Isolator Bonnet nut from a filled set of tanks. He told me with some conviction that because both posts were turned off just the gas in the cross over was responsible for the loud hissing noise coming from around the almost loose bonnet. He was about 3/4 of a turn from having the bonnet and stem and seat embedded in his forehead.

What's my point? How doubles actually function is not universally understood. (Many fill station operators operators don't know either)

Doubles are kinda of unique in this industry, it's a piece of gear that can get you in trouble, but no specific cert is required to use them, have them filled etc. Even Drysuits require a cert, but doubles don't.

Fortunately most people on the path to doubles have mentors, and are exposed to some of this knowledge almost without realizing they have been.

If you don't have a quailfied mentor, find one or take a class.

Lastly don't forget the potential for exceeding the NDL's


Tobin

 

[Scared Silly]

Doubles are kinda of unique in this industry, it's a piece of gear that can get you in trouble, but no specific cert is required to use them, have them filled etc. Even Drysuits require a cert, but doubles don't.

I own a dry suit. Been in one since dive one. I ain't got no stinking cert for it. When I bought mine the shop did not even ask about any cert. So dry suits are not that much different than doubles.

That said with either it is a good idea to learn something about their use. My first use of both was under the supervision of an instructor.

 

[mania]

C'mon doubles ain't - let's say - actuarial services level (extremly advanced math)
Understanding how they work takes only few basic physics laws from primary school...

Few tips - first get a proper set up. Make sure your harness is well set (too loose will make reaching valves more difficult).
Second thing - proper weighting. To do so you will need just one dive and a good friend who will help you.
Once this is done comes the proper trim. You may need to adjust doubles' bands, so that tanks are a bit higher or a bit lower. The best position (at least for me) is when i slightly put my head back and it's blocked by the isolater valve.

Now you are ready to start diving doubles. But remember - they are heavy, so some training of your back muscules may be helpful.

The rest is just a practice. Reaching valves for vdrill is not that diffucult if you have well fitting dry suit (with wet suit it's easier but not always).
Try reaching them keeping elbow parallel to your body (if the elbow is perpendicular
to your body it will be almost impossible to reach valves).
My instructor taught me great way to find isolator valve - it should be placed exactly in the middle of your head. So start from your forehead and just go to the back of your head - you will find it.

All of this takes some practice but it's worth a try. But honestly a good course (such as Adv Nitrox) will teach you this much quicker

Mania

 

[cool_hardware52]

I own a dry suit. Been in one since dive one. I ain't got no stinking cert for it. When I bought mine the shop did not even ask about any cert. So dry suits are not that much different than doubles.

Perhaps I failed to make my point. By example there are any number of DrySuit courses offered, and in theory you maynot be able to buy or rent a DS without certification.

What is the equivalent for doubles?

That said with either it is a good idea to learn something about their use. My first use of both was under the supervision of an instructor.

A smart way to proceed.

Tobin