Dr Wu
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How do you "know" it can't be too confusing?
dual tank BCD'S
- Thread starter gyellow
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Aaron_Grey
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What is is other empty hose for? Do double tank wings take two hoses for inflation?
Also, with a double tank setup like that, though the regulators are attached to seperate first stages, you can deplete both tanks by breathing from the primary regulator right? Does the air automatically breath from both tanks, equally, or do you have to manually switch tanks? Silly questions, I know.
Hi Boozegood,
No question is a silly question. The manifold joining the two tanks has a seperate valve handle that can be turned on so that the air between the tanks is shared.
Also, the two empty hoses you can see are for attachments. In a typical setup, one of them would attach to your BC and the other to your gauges/computer.
I'm still fairly new to diving so if I've made a mistake I apologize. Hope this helps.
Cheers,
Aaron.
The second LP hose is for the dry suit or for the redundant connection on a double bladder wing
There are no stupid questions.
The way a set of manifolded doubles works is that either regulator has access to all the gas in both tanks, so long as all the valves are open. Closing either of the outside valves stops the gas flow to that regulator -- so, if you have a freeflow or a big leak, you can close down that valve, and the other regulator still has access to all the gas in both tanks. If you have a leak from the valve itself, or the manifold, you can close the knob in the center and isolate the tanks from one another. That way, you only lose half your gas, because the tank away from the leak is isolated from it. (That's why the center valve is called the "isolator".)
That's the primary value of diving doubles -- redundancy. When you are doing very deep dives, or diving under a rock overhead, you can't afford to have a single regulator failure force you to surface, because regulator failures, although not an everyday occurrence, aren't actually rare. Manifolded doubles are one way of providing redundancy to the diver, but you'll notice that only works if you can actually reach back and close those valves when you need to, and do it quickly. It takes some practice to learn to do that, especially learning to do it without changing depth or losing awareness of your buddies and where you are.
If high gas consumption is your reason for thinking about double tanks, you're generally better off working on the things that are causing the high consumption, or switching to a larger single tank. Doubles have a bunch of disadvantages -- they are heavy and hard to move around on land, often cost more to fill (many shops charge you for two fills, even if you're only putting one tank's worth of gas in the setup), and often don't fit well on charter boats. The primarily usage of double tanks is for people who are diving deep or diving in caves, and they often use dry suits because deep water is cold, and because they like the redundant buoyancy of having a wing and a dry suit, in case one isn't working properly.
The way a set of manifolded doubles works is that either regulator has access to all the gas in both tanks, so long as all the valves are open. Closing either of the outside valves stops the gas flow to that regulator -- so, if you have a freeflow or a big leak, you can close down that valve, and the other regulator still has access to all the gas in both tanks. If you have a leak from the valve itself, or the manifold, you can close the knob in the center and isolate the tanks from one another. That way, you only lose half your gas, because the tank away from the leak is isolated from it. (That's why the center valve is called the "isolator".)
That's the primary value of diving doubles -- redundancy. When you are doing very deep dives, or diving under a rock overhead, you can't afford to have a single regulator failure force you to surface, because regulator failures, although not an everyday occurrence, aren't actually rare. Manifolded doubles are one way of providing redundancy to the diver, but you'll notice that only works if you can actually reach back and close those valves when you need to, and do it quickly. It takes some practice to learn to do that, especially learning to do it without changing depth or losing awareness of your buddies and where you are.
If high gas consumption is your reason for thinking about double tanks, you're generally better off working on the things that are causing the high consumption, or switching to a larger single tank. Doubles have a bunch of disadvantages -- they are heavy and hard to move around on land, often cost more to fill (many shops charge you for two fills, even if you're only putting one tank's worth of gas in the setup), and often don't fit well on charter boats. The primarily usage of double tanks is for people who are diving deep or diving in caves, and they often use dry suits because deep water is cold, and because they like the redundant buoyancy of having a wing and a dry suit, in case one isn't working properly.
I notice the OP is from Jupiter FL, where cave fills are possible. If cost is a factor, a single LP95 or LP104 with H-Valve will hold more gas than the AL doubles shown in the picture (yes, I know these aren't his doubles). While I prefer doubles, a single tank with an H valve is pretty affordable not requiring a new bcd or bp/w. Just a thought.
The OP also posted this three years ago and hasn't been on since 10/2010.
Haha! sillyness.
Rex Aubrey
New
Here it is, two years later, and this thread is still helping people make a choice about diving doubles or not.
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