Doubling Up Tanks

[yoda4x4]

The question I have deals with how much experience is recommended prior to considering going to doubles. I'm a reasonably new diver, 1 year experience, ~ 25 logged dives, but am very comfortable in the water. I know for myself that I would like to eventually get into the more technical diving, deco and such. I currently dive an Scubapro S-Tek with steel 85s. I've been toying with the idea of buying a set of high pressure steel 120s and using them as singles and taking my 85s and doubling them up. At what point do you feel a diver may progress to diving doubles? Do I have enough experience, and at what level should I consider it?

Just as some additional information, I'm Padi OW and AOW certified, and will be Nitrox certified once I complete my 2 checkout dives for it (bookwork has already been completed).

So, what do you all think? Thanks for any input you may have.

David

 

[saying]

Not being a doubles diver I can't give advice on this.

But I can tell you that I am also considering doubling up sometime this year and that the instructor at my LDS says the course requirement is 100 dives (or so).

 

[SCUBA STEVE]

I have never heard of having to take courses for doubling up on your tanks. Is this true?

 

[SCUBA STEVE]

We have been having a long discussion on double tanks (see hp 130's).

 

[DEEPLOU]

the 100 dive requirement is probably for the Tecrec course.
Moving up to doubles is an experience thing.
My old instructor said, get your breathing down to get the maximum out of a single tank, then consider if you NEED to move on to doubles.
If you are doing "no deco" dives, what do you need doubles of anything for?
On the other hand, when you get into deco diving, got to consider gas management more carefully and have the reserve for the "oh s...."

 

[cornfed]

I know for myself that I would like to eventually get into the more technical diving, deco and such.

I'm just curious why you already know this is the route you want to take?

 

[Uncle Pug]

get your breathing down to get the maximum out of a single tank, then consider if you NEED to move on to doubles.

As your gas consumption drops through experience you may find that an 85 will be more than enough for any NDL dive... even using nitrox.

This brings up another issue to consider when using doubles: the potential for entering mandatory deco. If you are not trained in deco proceedures it would be unwise to do so.

So I would suggest that you continue to dive your tanks as singles while improving your gas consumption rate, take a nitrox class and get some more experience diving.

Then you might want to consider a decompression proceedures class. Experience with diving doubles may or may not be a pre-req. for the deco class you take depending on the agency.

For someone who aspires to take a GUE Tech 1 class a DIR fundamentals class is mandatory. The period of time between DIRf and Tech 1 would be spent doing shallow practices dives with doubles.

 

[IndigoBlue]

...
So I would suggest that you continue to dive your tanks as singles while improving your gas consumption rate, take a nitrox class and get some more experience diving.

Then you might want to consider a decompression proceedures class. Experience with diving doubles may or may not be a pre-req. for the deco class you take depending on the agency...
.

I agree with that suggestion.

I myself am to the point where a single HP80 lasts me longer than my buddy/buddies ever wants/want to stay in the water, upwards of 45 mins or more. When I therefore wear doubles, I end up using them for two dives when not deco diving. It is not worth the weight on your back when out of the water. A single tank is far nicer for non-Deco applications.

A Deco Procedures instructor will go through the tank valve drills as part of their course. That is the best way to learn how to use doubles.

 

[saying]

I have never heard of having to take courses for doubling up on your tanks. Is this true?

Well, as others have guessed... it's for Advanced Nitrox & Deco, including the doubles config, not just a class on how to used doubles.

 

[yoda4x4]

UP,

Your point is well taken. I would never begin doing decompression diving without the training that's involved. However, with that in mind, I do watch my gauges throughout my dive and do know when I'm reaching or coming close to my NDL limit. Diving doubles wouldn't change that. Just because you have more air/Nitrox doesn't mean the NDL would change. It's independent of the volume of gas you are carrying.

However, when going deep ~100 feet, even with Nitrox, you can reach either your NDL or the end of your bottle pretty quickly. And I feel like "I've just got down here and now I've got to return". I'm sure I'm addicted to diving, but I just want to stay down there longer. Some of my favorite dives have been ones where I've been down an hour. And even then, I didn't want to return to the surface. I hope you see where I'm going with my mentality and why I'd like to get into the more technical stuff. Also, besides deco diving, I really like the idea of doing penetrations and cave diving. Again, I would take the necessary training to do so. The training I have in mind is:

Deep Specialty
Advanced Nitrox
Deco
... and a few others.

Thanks for your input.
David