Doubles - dilemma

[TheRedHead]

So why a double-bladder, instead of a stowed lift-bag and small spool/reel?

Because both TDI and IANTD (from which I've taken classes) require it. The best scenario is to dive a balanced rig that you can swim up from the bottom or dive dry. The lift bag and reel are supposed to be the last hope if you are really screwed.

 

[Vicente]

What is the objective/goal for the doubles?

Looks like rjack321 is cutting right to the heart of the matter. Good point!

 

[pescador775]

There are certain "tells" in the original post such as "play around", written several times. This does not sound like an objective driven agenda which requires a woman to wear a set of double tanks. However this may be, the average woman is going to have serious trouble with a set of double aluminum 80's. The steel 80's would be much better and even then primarily for boat dives, down and up the anchor line. The posts mentioning overwhelming negative buoyancy are nonsensical. A big set of "wings" or "double bladder" is not necessary. Lighten up a bit on the lead and screw the swami/pundit/gnomes of IANTD or whatever. So what if she's somewhat buoyant at the end? Means little to nothing. If the diver starts out neutral at 15 feet, then she will be only 14 pounds negative at 130 feet with full tanks. That holds if the suit has perfect compression. Chances are she would actually need to compensate for only about 10-12 pounds of negative buoyancy. When she gets to the safety stop and the tanks are partially depeted, she would be about 10 pounds buoyant. So what?

 

[TheRedHead]

However this may be, the average woman is going to have serious trouble with a set of double aluminum 80's. The steel 80's would be much better and even then primarily for boat dives, down and up the anchor line. The posts mentioning overwhelming negative buoyancy are nonsensical. A big set of "wings" or "double bladder" is not necessary. Lighten up a bit on the lead and screw the swami/pundit/gnomes of IANTD or whatever.

I had no lead and was seriously negative in HP 100s. I don't need any weight diving double AL 80s either in a wetsuit. A 30 lb wing has barely enough lift to keep my head out of water in a swimming pool wearing double AL 80s. So you just want to screw safety? That doesn't sound like sensible advice. Besides, the OP's wife needs to make the decision about her tanks. She's diving them. I gave my perspective as a woman. AL63s might be a good chioce too.

 

[pescador775]

I had no lead and was seriously negative in HP 100s. I don't need any weight diving double AL 80s either in a wetsuit. A 30 lb wing has barely enough lift to keep my head out of water in a swimming pool wearing double AL 80s. So you just want to screw safety? That doesn't sound like sensible advice. Besides, the OP's wife needs to make the decision about her tanks. She's diving them. I gave my perspective as a woman. AL63s might be a good chioce too.

Trade in your Asahi tanks for PST and you won't have that problem. Oh, yeah, dump that dumb azz steel plate, too.

 

[TheRedHead]

Trade in your Asahi tanks for PST and you won't have that problem. Oh, yeah, dump that dumb azz steel plate, too.

They weren't mine - rental tanks and they were PSTs. I own Faber 72s. And I'm probably going to buy a set of AL 63s too.

 

[Mo2vation]

What is the objective/goal for the doubles? Cave, wreck, or technical? Fresh or salt water? Matched with a wetsuit, drysuit, warm water or cold? What's her SAC rate?

I'm not against just playing with something new in a relatively safe place, but all this talk about cylinder X vs. cylinder Y is premature if they end product doesn't match her objectives.

As one in the middle of playing with doubles myself (17 of my last 20 dives these last 4 weeks has been with doubles) I can offer a newbie's perspective.

1) I have been borrowing them from the fine SoCal peoples. I've dived 4 different sets so far. They are all very, very different. Each set serves a different purpose. Its like golf (and I hate golf)... OK, I'll use Flyfishing - you need to use the right rod (club) for the job.

2) I dive drysuit. All of my doubles dives but one have been from the shore, through the surf, etc.

3) Everything has come easier than I expected. I get in, do a quick CG, figger out that I need to do and just do it. I've been completely shocked at how seamless this transition has been.

4) Everything about DIR (I'm DIR, you may not be) is clearly built around using doubles, and everything I've been doing for 4 years with a single tank instantly both became easier (like valve drills... a complete no brainer with doubles) and makes more sense (like hose lengths, routing, deployment, etc.)

I went into diving doubles with a specific objective in mind. I find after diving them for a month (about 17 dives) and a few pool sessions, my objective (or, "the destination") hasn't changed - however, but my strategy ("the journey") for achieving this objective surely has.

These last several weeks have also made me consider the tools required to reach my objective. Specifically which tanks, etc. I'm loving the LP 85's for surf doubles, but who needs surf doubles? Not where I live. The 112's are pigs, but closer to the gas supply I'll want to achieve my objective. The AL80's with V weight and steel plate weigh just a little more than the LP85's with tail weight, but I watched my very strong and accomplished dive buddy fighting them the other night as she was want to do a face plant the whole dive. The 72's were like jogging tanks and don't offer appreciably more gas than my 130 for the weight. Cute, fun, but not for me. Al50's are fine for valve practice but trim out like marshmallows. I'll likely double up a pair of 104's or 130's. I would love to have a pair of 85s in the wings for longer beach dives - but that seems a bit luxurious right now. Having already committed to doubles (another SS plate, AL plate, complete doubles reg set, etc.) I'm on the journey with no looking back.

Honestly - you may not be anywhere near this far down the road (objective in mind, lining up possible training routes to achieve objective, reviewing tools, tanks, etc, etc...) - you may just be at a place where you want to play with doubles. If that's the case, be careful, stay shallow and go out with someone who knows a thing or three about them. A thorough pool session will tell you TONS about how they'll trim out on you and what you'll need to do (tail weight, move the bands up, down, etc.) It sure helped me.

They are not anything like strapping on a single tank and splashing in - but I have found that they are not as far from that as I had been led to beleive. And as thick as I am, if I can get it together this quickly, others can, too.

---
Ken

 

[Scared Silly]

Some other data ... as originally posted she dives wet.

This past spring while in Florida my wife started working with a set of doubles. But she never felt comfortable in the set she was using in the 1.5 days that she was working with them in shallow water. Now that we are home in Utah, she would like to spend more time with a set and practice some skills in shallow water so that she decides a) she either feels comfortable or b) it is a PITA. Once we have that data point we can plan accordingly.

So here is real problem, we do not have alot of choice in the doubles I can rent locally. The one local tech shop can rent me either a set netural Al80s or a set of LP98s. Not sure they would be optimal over putting together our AL80 either. As such, my delima is either put together our AL80s her to use or just rent them so that
she can "play with something new in a relatively safe place."

So as I outlined I can rent for $25 a pop (really closer to $30 once I add tax, gas, etc) or put together a set myself.

 

[TheRedHead]

What kind of tanks were she using in Florida and what was her complaint about them? I've dived several sets of doubles, including AL 80s. I couldn't imagine diving LP95s wet. :shakehead

 

[rjack321]

So presumably this is for future dives in FL, in a wetsuit. I'd say AL80s. For most intro cave level stuff you'll want AL80s, bigger steel tanks would probably dictate a drysuit.

For ocean diving, in a wet suit, Al80s will take you most technical places. And if she's getting technical training, adding a stage is a possibility too. Steel will be pretty heavy and not very prudent without a drysuit or redundant bladder.

What's your wife's approx size? LP95s on a 98 lb woman is probably just going to be a fight, and she might lose.

I agree with Ken that you might not know exactly what your plans are, but there's the siren song of something attracting her to doubles right? (redundancy on deeper dives is just as fine an answer as any too)