When to start using doubles?

[mpgunner]

I'm not planning on doing this soon but I'm very curious to ask.

When did you make the switch to doubles? What are the factors to make this switch? Since I took the rescue diver class I've realized having extra air is a good think in case an emergency comes up.

How challanging is the switch with regard to buoyancy?

Thanks much

 

[Vie]

When did you make the switch to doubles? What are the factors to make this switch?

I made the switch when I started technical diving training. I do most of my recreational dives in doubles too.

I guess your question is really also about when to switch to doubles. I guess my answer would be get very comfortable with your single rig first, then ask yourself whether you need to switch. Sure, one can dive doubles for the sheer heck of it but if I'm diving doubles but all my buddies are on singles then it may be bit pointless.

There are many benefits to using doubles (I use manifold doubles, btw) - redundancy, ease of use (no need to switch tanks between rec dives, rig can be set up at home) and stability are a few I can think of.

There are drawbacks also. I do feel that one does need some training/informal instruction and practice in order to dive with doubles safely. Training/practice and an experienced buddy are crucial ingredients for dealing with failures (valve(s), manifold, etc) underwater.

Since I took the rescue diver class I've realized having extra air is a good think in case an emergency comes up.

Having "extra air" or enough gas to get you and another diver to the surface (in a controlled manner with enough gas to do necessary/minimal stops along the way) is really all about dive planning and setting aside the necessary gas reserve. This is true whether you are diving singles, doubles or more bottles.

How challanging is the switch with regard to buoyancy?

Strapping on and diving a doubles rig was for a bit strange initially. For me, the biggest change was adapting to having to actively add/dump gas to/from my BC as opposed to just using my breathing for buoyancy control like I did with my single tank setup. I was lucky to have more experienced divers accompany me on my initial dives and they helped me get comfortable quickly.

 

[Gombessa]

Availability of doubles and acquisition of a second reg I'm on my third doubles dive, and to be honest, I think I'm pushing the envelope just a tad too fast for my taste, but I absolutely love it. I'm not big on depth, but being able to extend my time underwater and see a bit more each dive without worrying about hitting rock bottom is great.

The buoyancy takes a bit of getting used to - you feel a whole lot bulkier in doubles, but buoyancy-wise it's starting to feel like it's more of the same - just needs familiarity. Needless to say I'm sticking with shallow (30-50ft) easy dives.

 

[TSandM]

I made the switch to doubles with an eye to doing cave training, and knowing it was going to take me some time to get used to the weight. I had a couple hundred dives by then, and a rec pass from Fundies. Buoyancy wasn't hard to manage in them, but trim was more of a challenge -- and I think it is in general, because the equipment begins to override your skills, if you have the wrong tanks.

To make doubles worth diving, though, you need to understand the function of a manifold, and you need to be able to manipulate the valves, and to maximize the value, you have to dive with somebody who understands manifolds and can assist in the event of a malfunction.

Doubles are great for allowing you to carry your rock bottom for deep dives and still have a good usable volume, but they are a PITA to wear on land, a challenge on unstable ground or steep entries (or surf), and a bear on boat ladders. They're hard to move around, and some boats aren't set up for them. Dive shops often charge twice as much to fill a set of doubles as to fill a large single tank (although the volumes may be essentially the same). They also require two first stage regulators and a backplate.

On the other hand, they dive beautifully. And you do have the ability to solve a lot of problems underwater with them that you can't solve with a single tank. When my husband's primary reg began gently freeflowing a couple of weeks ago, it was very nice just to turn it off and be able to stay underwater back to our entry point, rather than aborting and swimming back on the surface.

My advice would be to have your buoyancy and trim rock solid in a single tank before you go to doubles, but that's based on my observations of several people making the switch over the last couple of years. Certainly people manage without doing that.

 

[Trixxie]

I asked my cavern instructor the same thing. He said to dive doubles only when your dive time requires you to do so. Don't just dive doubles just for the sake of doing it. They cost a lot of money and can be very cumbersome out of the water to lug around.

 

[Colliam7]

I started diving (manifolded) doubles in anticipation of starting tech, around dive 190. The biggest challenge was trim - finding the right wing (shape more than bouyancy), the right band position on the tanks, the right tank position on the BP. Now, I don't have any backgas singles, dive primarily double 80s for recreational dives and HP steels for everything else.

... but they are a PITA to wear on land, a challenge on unstable ground or steep entries (or surf), and a bear on boat ladders. They're hard to move around, and some boats aren't set up for them. Dive shops often charge twice as much to fill a set of doubles as to fill a large single tank (although the volumes may be essentially the same). They also require two first stage regulators and a backplate.

On the other hand, they dive beautifully. And you do have the ability to solve a lot of problems underwater with them that you can't solve with a single tank. When my husband's primary reg began gently freeflowing a couple of weeks ago, it was very nice just to turn it off and be able to stay underwater back to our entry point, rather than aborting and swimming back on the surface.

WELL SAID! Agree with everything Lynne mentioned.

 

[WD8CDH]

I went to doubles not for the extra air but for the redundancy and trim. I dive multiple small tanks rather than single large tanks. For example, I will dive double 40s rather than a single 80 because the two tanks are slimmer and closer to my body. Better ballance both above and below water.

Depending on the amount of air that you need, you may find diving doubles to be EASIER than diving a large single.

 

[Peter Guy]

I started diving doubles because I was planning on doing some technical training/diving and that meant doubles. My first time in doubles was NOT what I expected -- that is, they seemed to fit "just right." I had been expecting to become a lawn dart or some such -- didn't happen. BUT, by the time I tried doubles, I was pretty solid in a single (from a buoy/trim standpoint).

I've spent the last 16 months diving doubles -- doubled steel 72's and doubled 100's (and doubled 80's in fresh water) -- learning how to use them, etc. It took some time to really get them dialed in and the biggest "problem" was figuring out really where to position them AND my back plate.

During this past year I've also picked up a pair of 130's (I had doubled my 100's). Now that I have the doubles pretty dialed in, I've pretty much switched back to diving my 130's -- unless there is a really good reason for diving the doubles. The 130's are just as stable, have more usable gas than the 72's, are easier to handle on land or on a boat -- they just don't offer me the redundantcy of doubles (see Lynne's mention of my free-flowing reg). But my teammate is my redundant gas in a recreational dive.

(I love the doubled 100's but they are sitting half-filled with trimix and I don't want to use it up between 30 and 60 feet!)

 

[ArcticDiver]

Another caution: Try not to do a class requiring good buoyancy and trim and do the transition to doubles at the same time. It makes for a pretty steep learning curve.

 

[skippy31]

(I love the doubled 100's but they are sitting half-filled with trimix and I don't want to use it up between 30 and 60 feet!)

We run into this all the time, and what we do in this case is to use a stage for the dive. You keep the doubles as reserve and only dive the stage for the whole dive. It makes for very efficient use of the gas since you can dive the stage to empty and still have 100cuft of gas or more in reserve. Then you fill the stage again for the next dive. It's nice in that you can use an entire 80cuft in a stage for a dive safely and still not have to use up the trimix in you back tanks.

Mat.