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mselizann
08-21-2008, 07:52
Ok- hubby and I are thinking about switching to doubles. Where do we even begin? Any tips would be appreciated....thanks!:dunno:

BouzoukiJoe A.K.A. wrecker130 AKA Chuck Norris AKA joeforbroke (banned)
08-21-2008, 08:59
Diving with them is very easy (imo easier than singles) but you will need to learn some emergency procedures and aquire some more gear.

You will need to build, buy, or borrow a set of tanks. You will need a wing with enough lift. Since you will not be able to swim your rig to the surface, unless you can walk out of the dive site you *need* an alternate source of buoyancy- drysuit, lift bag, or a dual bladder wing (has its own issues). You will need two first stage regulators unless you wish to sacrifice the redundancy of your air supply. You will also need to learn some new emergency procedures- valve drills, loss of buoyancy, etc.

I love diving doubles but I don't own a set, yet!- I'm able to mooch double 80s, double 104s, and double 130s from friends. I recommend finding some smallish doubles and someone who can show you the ropes.

If you do not have a dry suit you might want to consider doubled AL80s instead of steel tanks. Double 104s, a wet suit, and open water are probably not the best combination.

Also... Never, never, never wear doubles anywhere near the water without the air on and the inflator hose connected. That includes walking them along the dock to and from the boat or into and out of a quarry. I might be dead today if I had not followed that rule.

Enjoy.

MSilvia
08-21-2008, 09:23
Guidance from a mentor is often the easiest way to get started. Do you know anyone in your area who uses them? Assuming you don't, I guess the best way to get started is by assembling a doubles rig. You'll obviously need two tanks, a set of bands to hold them together, and an isolation manifold connecting the valves. It may be best to get help from your LDS with the assembly (IF your LDS is comfortable doing that), but I recommend watching and asking questions when they put them together.
Once you have the doubles set up, you'll need a BC to mount them to, and a backplate is (in my opinion) the best choice by a long shot. You'll want a doubles wing that's adequate for the job too.

Unless you already dive dry, it might be best to start out with AL80 doubles, as these are among the safest doubles to use with a wetsuit since they're relatively easy to swim in case of a buoyancy failure.

There are a lot of good tips in this book, and you might want to get a copy even if you aren't interested in embracing DIR diving: Doing It Right: The Fundamentals of Better Diving | Global Underwater Explorers (http://www.gue.com/?q=en/node/159)

DO NOT go to Amazon for this book, or you might pay as much as 6 or 7 times the price!

I think you may want to start out with one set of doubles, so one of you can try it out while the other is diving a familiar setup. It'll make managing problems easier, I think. Once you both feel comfortable with them, you can get another.

Either way, I'm happy to answer any specific questions you have as best I can.

caroln
08-21-2008, 09:45
You guys might want to consider an intro to tech class where the instuctor has gear that you can try out. You'll learn a bunch of things that will be useful even in your single tank setups, but you'll also learn some doubles specific skills like valve drills, and maybe even get to try out a couple of different sizes of tanks etc so you can figure out what works for you. If you're out at Dutch, you are welcome to try out my double AL 80's.

DivingCRNA
08-21-2008, 09:53
Ok- hubby and I are thinking about switching to doubles. Where do we even begin? Any tips would be appreciated....thanks!:dunno:

Your husband is a very lucky man.... A pretty wife that wants to dive doubles!! What else is there?:smiley2::smiley20:

Gombessa
08-21-2008, 11:40
The best way to start is to borrow a set for a few dives. When I started diving doubles, I had quite a few experienced divers around who offered to loan spare sets, talk through the setup and valves, and of course dive with me. Taking an Intro to Tech class is a great idea too, as you should really know exactly how the doubles work, how they differ from singles diving, and what standard/emergency procedures you should be able to execute in a doubles setup.

Another issue is trim - IMO doubles can be quite finicky to get feeling just right - some sets are extremely top-heavy, others want to point you up. There's an endless combination of "solutions" for this, from adjusting hand/leg positioning to tail-weights to aluminum backplates and different wings - try to get a sense of what kind of tank capacity you need, dive a set for a while and dial-in your trim. Then spring for your own set.

Oh, did I mention you'll probably save 50% or more if you buy them used? A full set of LP95s typically go for $500 or so, and I regularly see LP80s and 85s for $5-600.

stairman
08-21-2008, 11:53
I went to doubles for cavediving.With a redundant 1st stage I feel they are safer.They are easy to swim with as well.For me it was anyway.You must have a plan for a bc failure so you can surface and realize the extra gas can put you in deco.The extra weight and cost is a factor and a tech course is advised.

RoyN
08-21-2008, 12:16
I agree with everybody, see if you could borrow your friend's double or take a intro to tech class. I tried using LP85, LP95, HP80, and HP100. Eventually I went with tanks that gives me 200cu.ft or air or more which helps me last throughout three dives. :smiley20: Oh and if you decide to get tanks for doubles, I think the Worthingtons are excellent. Fabers are good, but get the FX series only. :smiley2:
Also, once you get the doubles, here is the hose setting I use for the double tank.

http://www.costablancascuba.com/dir/

mselizann
08-21-2008, 12:44
Thank you everyone for the advice. Carol- maybe that will be a plan. Pat was saying just last night that he wants to go back to Dutch Springs- maybe we'll pop out there in the spring for a weekend.............

cummings66
08-21-2008, 16:15
I don't know what gear you have, but if you lack a BP/W then I suggest you start by buying the basic gear you need to support the doubles, but you could perhaps skip buying a singles wing if you're going straight to doubles.

I think that's step one. Step two is to get bands and manifold and cylinders. Many steel cylinders vary in height so you might want to buy a pair and specify doubles, if AL it's not as important.

Once you have that you're ready for the next step, if steel doubles I suggest a drysuit and class. Then learn the valve drills, the GUI website has a good description of the new procedures in their revised area.

Do many shallow dives, buoyancy while not hard is different and you might want more challenging dives to start with before you go deeper.

I practice valve drills on every single dive, it's that important and came in handy when I lost the HP hose to my SPG. Lots of noise and all, but you can shutdown a valve pretty fast if you're doing it routinely.

fire diver
08-21-2008, 16:53
dang it. Once again I come in to offer advise from my experiences too late. Everthing has already been said, and said well. SO the best I can offer, is "ditto".

CompuDude
08-21-2008, 19:25
dang it. Once again I come in to offer advise from my experiences too late. Everthing has already been said, and said well. SO the best I can offer, is "ditto".

errr.... "ditto".

:smiley31:

ScaredSilly
08-21-2008, 23:48
Everthing has already been said...

Not quite. The first question one should ask is why? Why do you want to dive doubles? Without first seriously answering that question you could just be pissing away a lot of money and time.

BouzoukiJoe A.K.A. wrecker130 AKA Chuck Norris AKA joeforbroke (banned)
08-22-2008, 07:30
Everthing has already been said...

Not quite. The first question one should ask is why? Why do you want to dive doubles? Without first seriously answering that question you could just be pissing away a lot of money and time.


I don't like 'why questions' and it's my general policy never to answer them. Often the question contains implicit negative judgements.

Your point is well taken, though.

My take is that the OP is now in the stage of evaluating the costs of time and treasure. I agree with you that she'll also need to evaluate what making the switch would buy her.

Whether switching to doubles is worth it depends not only on how it benefits your diving but also on how it benefits your ego and the extent of your financial resources. Since everyone's diving, ego, and financial resources are different, the answer is always a personal decision.

fire diver
08-22-2008, 13:33
I wouldn't say "why" is really needed. Maybe wants more gas, maybe wants a more stable rig, maybe wants to move into cave / wreck diving or general deco profiles. The why's don't really matter. THe exact type of double system can have a lot of small things (and a few large ones) to discuss.

If you are wanting to get into deco profile dives, a nice double AL80 would be a nice intro set. You can get used to wearing, diving and dealing with doubles. When you are ready to move into larger steels (if thats needed, and you have the extra bouyancy precautions), then the double 80's can be broken down in to stage/deco tanks.

Let us know what route of double you two are looking to get into, and you can get a lot of more specific details.

cummings66
08-22-2008, 14:10
Personally it doesn't matter why. All that matters is they have the money and want to do it. Why, because I like it.

ianr33
08-22-2008, 14:15
I wouldn't say "why" is really needed. Maybe wants more gas, maybe wants a more stable rig, maybe wants to move into cave / wreck diving or general deco profiles.

IF it is just wanting more gas then a 130 is a much simpler option than doubles.

fire diver
08-22-2008, 14:52
I wouldn't say "why" is really needed. Maybe wants more gas, maybe wants a more stable rig, maybe wants to move into cave / wreck diving or general deco profiles.

IF it is just wanting more gas then a 130 is a much simpler option than doubles.

But less gas than a double 80. :smiley2:

I was really just naming some possibilities, not the addressing the pro or cons of any.

ianr33
08-22-2008, 15:48
But less gas than a double 80. :smiley2:



Depends where you get it filled :smiley2::smiley2:

fire diver
08-22-2008, 15:53
But less gas than a double 80. :smiley2:



Depends where you get it filled :smiley2::smiley2:

LOL, true. true.

CompuDude
08-22-2008, 16:54
Personally it doesn't matter why. All that matters is they have the money and want to do it. Why, because I like it.

That's a valid reason, of course, but the why still helps tailor the advice... and can enable delivery of some good alternate ideas if there are misconceptions leading to the "want".

mselizann
08-22-2008, 19:55
Honestly? We do a ton of shallow shore diving- it takes us 20 minutes to get to 20 ft of water where the vis is decent.....swim 10 min more, and you have to turn around. If we had more air we could dive forever at those depths....

CompuDude
08-22-2008, 22:04
Honestly? We do a ton of shallow shore diving- it takes us 20 minutes to get to 20 ft of water where the vis is decent.....swim 10 min more, and you have to turn around. If we had more air we could dive forever at those depths....

Makes sense to me. A little overkill, however... an HP130 might be a significantly easier way to go than the complications and weight of doubles.

lemon lime
08-22-2008, 22:35
There are a lot of good tips in this book, and you might want to get a copy even if you aren't interested in embracing DIR diving: Doing It Right: The Fundamentals of Better Diving | Global Underwater Explorers (http://www.gue.com/?q=en/node/159)

DO NOT go to Amazon for this book, or you might pay as much as 6 or 7 times the price!


Thanks for the link, I've been interested in learning more about DIR. Looking around the GUE shop, they also have a PDF version (http://www.gue.com/?q=en/node/174) available if you prefer.

LCF
08-23-2008, 04:09
If that's the reason for thinking about doubles, I'd seriously consider a 130 instead (or a scooter!). Doubles are more work to swim, and much more work to walk in. They're harder to surface swim as well. Charter boats generally don't like them very much. They're much harder to move around (into the dive shop for fills, for example) and to get in and out of a car.

In addition, most shops will charge you double to fill doubles, even if you only brought them in half empty, or even fuller than that. They generally WON'T charge you double to fill a 130, even though it's a lot more gas.

That said, I love my doubles, and dive them whenever I'm not looking at difficult entries, exits, or surface walks. I got into them because I was going to do cave training, but I found they are very stable and pleasant to dive, and worth the extra hassle most of the time.

I borrowed a set of 72s to begin with, and bought a set of 85s after diving them once. Now I would love to sell the 85s and get a set of HP 100s like my husband's. Those are really sweet; lighter, more gas, and they trim out about the same.

Lone Frogman
08-23-2008, 05:08
There are a lot of good tips in this book, and you might want to get a copy even if you aren't interested in embracing DIR diving: Doing It Right: The Fundamentals of Better Diving | Global Underwater Explorers (http://www.gue.com/?q=en/node/159)

DO NOT go to Amazon for this book, or you might pay as much as 6 or 7 times the price!

.

Thanks for that link, I have been looking to get that book just could not see paying the Amazon price. Guess it makes good sense to buy from the source.

cummings66
08-23-2008, 11:11
I think that the dive profile listed as the need for doubles could be met with a larger single, but the real question is what cylinder do they do that dive with? How much air is left? How long are they at the deepest depth?

A 130 is not exactly a light cylinder and if you're slight of stature it might be too much to carry, but of course double AL80's aren't exactly featherweight either.

Doubles for a 20' dive, well, I'm probably doing double HP120's for a dive almost exactly like that this evening when the sun goes down.

mselizann
08-23-2008, 16:29
I dive a AL63....usually have about 1000 psi left. Hubby dives a AL80- may end up with 500-600psi. I would be really concerned about myself carrying a 130 physically.........

BouzoukiJoe A.K.A. wrecker130 AKA Chuck Norris AKA joeforbroke (banned)
08-23-2008, 19:35
Are there any doubles lighter than a 130? I don't know of any. Perhaps double 63s are the way to go if you go doubles at all.

pir8
08-23-2008, 20:28
I'm not sure if shes still there but there used to be a girl on staff down in Olympus DC in NC that used to dive double Al40s for the balance that it gave her

gregor
08-23-2008, 21:14
If you are diving a single 63 now, i think a 130 is quite a bit of overkill, and probably more than you want to hump down to the water.

According to the numbers you gave on a typical dive you use about 42 cubic feet of gas and your husband uses about 65. If your husband is up to the task of carrying a big tank like a 130 you could get by diving something like a lp85 which isn't much heavier than a standard al80 and i think about the same length, maybe an inch or two shorter. You could also go with a hp100 which is about the same size as the 85 (might even be shorter, but not sure).

Actually i think that would be the smarter call (HP130 and HP100), remember you are carrying his emergency gas, so while an 85 might be plenty for you as he sucks down a 130, if you have an issue at depth and at the furthest point from exit you might not have enough in your 85 to get both of you back to your starting point. Now i don't know where you dive, but sometimes it's better to be able to get back to your entry point underwater due to different factors (surface current, boat traffic, rough waves, etc), so having that spare gas is a good thing to make sure you can share back to your exit point.

I think doubles are probably more than you might need, but you could always try the bigger tanks, and if they don't give you enough, then get another of each and double'em up.

ianr33
08-24-2008, 00:12
How about a scooter?

CompuDude
08-24-2008, 04:18
I dive a AL63....usually have about 1000 psi left. Hubby dives a AL80- may end up with 500-600psi. I would be really concerned about myself carrying a 130 physically.........

As others have pointed out, if you're worried about the weight of an HP130, you're going to have a really hard time carrying doubles.

Smaller doubles might work out, but the doubles usually used (and referred to) pretty much start off with LP80/LP85/HP100/AL80-sized tanks ... all of those are fairly similar in size and weight, and all are going to weigh a considerable amount more than a single HP130.

fire diver
08-24-2008, 04:21
How about a scooter?

yeah, it only costs about 5x's the price of a set of doubles.

ianr33
08-24-2008, 08:08
How about a scooter?

yeah, it only costs about 5x's the price of a set of doubles.

Cost does not enter into it. You should either do the dive correctly or not do it at all.

Excuse me while I go and take off my DIR hat :smiley36:

fire diver
08-24-2008, 10:51
Well, it could be said that scooters are just using equipment as a crutch to make up for not carrying enough gas.

I'm just playing devils advocate here. I'd have a scooter myself if I could afford one.

Jack Hammer
08-24-2008, 22:42
A Worthington steel hp100 is around an inch taller and about 6 pounds heavier than an al63. Even underfilled to 3000psi you still get ~88cf of air, quite an increase. That could be a good size for you. For the hubby the biggest tank he can carry could be nice.

And as mentioned a few other times, look into a scooter. You could use a scooter to tow you both on the surface to where you want to dive. That could add 20-40 minutes to your dive time right there.

Jack

cummings66
08-25-2008, 07:31
I'd say an HP100 for you would give you much more air, almost like doubles but less weight and for him the HP120 would be nice. I choose HP because it's lighter than the LP cylinders of the same rated gas volume.

MSilvia
08-25-2008, 07:44
Well, it could be said that scooters are just using equipment as a crutch to make up for not carrying enough gas.
It could also be said that anyone who says that doesn't appreciate some of the best reasons for owning a scooter.

And as mentioned a few other times, look into a scooter. You could use a scooter to tow you both on the surface to where you want to dive. That could add 20-40 minutes to your dive time right there.
A pair of dive kayaks could do the same thing for a lot less money and maintainance, and then you can kayak too!

Jack Hammer
08-25-2008, 10:08
A pair of dive kayaks could do the same thing for a lot less money and maintainance, and then you can kayak too!
I like the way you think. :smiley20:

Jack

WD8CDH
08-25-2008, 10:55
I dive a AL63....usually have about 1000 psi left. Hubby dives a AL80- may end up with 500-600psi. I would be really concerned about myself carrying a 130 physically.........

There are a lot of choices for for multiple tanks smaller than a single 130. I personally have triple 20s, double 35s, double 40s, quad 20s, triple 35s, and triple 40s. They are all easier to dive than singles of the same volume and give me redundancy for safety.

Double steel 45s is also a good choice for a small diver.

ScaredSilly
08-26-2008, 14:22
I dive a AL63....usually have about 1000 psi left. Hubby dives a AL80- may end up with 500-600psi. I would be really concerned about myself carrying a 130 physically.........

If you are worried about this then forget about doubles. At 130 fully kitted is going to be just under 50 lbs. A set of small doubles like lp 65s will be over 60lbs. Going down to LP 45 will about the same as a 130.

As others have said there are other options that are more practical. I would second the dive kayaks.