LP95 Doubles

[ArcticDiver]

If you don't have your buoyancy and trim down cold with a single tank don't do doubles yet. Get those nailed with a single tank first. Knowing what good buoyancy and trim feels like before adding the additional weight and mass of doubles helps a lot.

Get someone to go with you who knows the "why" of the various buoyancy and trim issues that may erupt.

Don't do it in conjunction with other training. Doubles by themselves are quite enough.

 

[ReefHound]

The gear setup involved in doubles is much more involved than with a single tank if you're talking about backplates, wings, and a harness. There are many different ways to adjust this gear, and malfunctions become much more complicated.

I didn't realize BP/W was a gear setup unique to doubles?

 

[darylm74]

I was used to a BP/W when I tried doubles, so I sort of used to the set up. You definitely want to get a double's wing though. Get them in the shallows and stay there till you're comfortable and then venture deeper. I wouldn't take them any deeper than 30 ft or so until you are used to them, but buddying up with someone, that has double's experience is not a necessity. I will say, however, like most things, it is nice to have someone to bounce your questions off of and it always helps. I say go for it, but if you have some input from others, then you are better off.

 

[xiSkiGuy]

Don't do it in conjunction with other training. Doubles by themselves are quite enough.

I agree with this. I've seen several people not learn as much from their training in Basic Cave or Advanced Nitrox because they were trying to figure out their new doubles.

But that said, if you are inclined toward research, there is plenty of information out there for you to learn how a doubles manifold works or how to adjust the setup. I don't think you have to take a class or have buddy show you the ropes. It probably speeds up the learning curve, but isn't necessary. I figured it all out on my own, and didn't find it difficult at all.

I used this to figure out how to assemble the doubles: http://diveriteexpress.com/library/doubles.shtml

I watched the 5thD-X videos for info on trim and valve management.

 

[JCDdiver]

metaldector, I don't think anyone is saying that it's OK to train yourself for overhead environments or deco diving. They are talking about getting the feel for it. Getting into the water, maintaining trim/buoyancy, and getting back out. Dive it like a single and stick to rec profiles. When they are ready for the next step, take the class. Then the class can focus on the advanced content and not basic buoyancy skills.

Well said ReefHound.

 

[TSandM]

Doubles aren't that complicated, and there are plenty of resources for getting things figured out. I did do my transition to doubles with people who already dove them, but I really don't remember them having to help me much, except to get some idea of how much weight I'd need (which, as it turned out, wasn't much help, because I needed a great deal more than my friends did).

Even if you can't do a valve drill at first (and I couldn't) you are no WORSE off with a malfunction than you are with a single tank.

There are videos of valve shutdowns on the web, and the 5thD-x Intro to Tech video is an excellent one to buy.

Figuring out balance and trim in doubles is challenging, but you can do it yourself. It's not rocket science, although recognizing that the reason you are diving feet LOW is because you are HEAD heavy is counterintuitive. Once you have identified the problem, it's just a matter of moving ballast around until you're balanced.

I think it's absolutely imperative to start diving doubles well in advance of any advanced scuba training you are going to take in them. And ArcticDiver is also right, in my opinion -- Make sure your balance and trim are completely dialled in before you transition, and the transition will be WAY easier. I've seen people do it both ways, and I'm convinced.

 

[limeyx]

Even if you can't do a valve drill at first (and I couldn't) you are no WORSE off with a malfunction than you are with a single tank.

i don't 100% agree with this.
Doubles can be more dangerous than singles (even when used like "large singles") due to the presence of the isolator.

This is not rocket science, but you can get a number of issues that you just dont get so much with singles.

- tanks filled with isolator closed, giving a dangerous mix.
- diving with isolator closed -- SPG will not drop (a lot of people say "of course I'd notice this instantly" but in practice, especially since you will be more task loaded, you may not)
- diving with left post closed -- SPG will not drop
- a valve becomes closed during a dive.

Again, not rocket science, but I think good reasons for at least having someone familiar with doubles help out for the first couple of dives, and really cover these issues.

 

[ReefHound]

limey, good points but what really needs to be covered beyond what you said in your post? I think anyone dumb enough to dive with the isolator or posts closed will be winning a Darwin award eventually anyway.

 

[texdiveguy]

limey, good points but what really needs to be covered beyond what you said in your post? I think anyone dumb enough to dive with the isolator or posts closed will be winning a Darwin award eventually anyway.

LOL...it happens though.....even divers forget to turn on the gas on singles.....now you have 3 knobs!

 

[texdiveguy]

Make sure your balance and trim are completely dialled in before you transition, and the transition will be WAY easier. I've seen people do it both ways, and I'm convinced.

We are never completely 'dialed in' if you dive various enviroments and gear configurations---BUT I understand your point!.....it is very advisable to have a handle on diving doubles prior to moving forwards into adv. level training.