First Time Diving Doubles

[nereas]

...My back plate is aluminum. I thought about getting a stainles steel, but really didn't want any more weight on me than I needed. Before the first dive I did as best of a weight check as I could, since the tanks were full. When I emptied the wings, with a full breath of air (& reg still in mouth), I immediately began to sink over my head (of course I immediately inflated my wings to get back above the surface). I basically dive a trilam drysuit with 200gram undergarment & some thick under armor underneath that to keep comfortable. With that drysuit & an AL80 tank in fresh water, it took 30#'s to sink me. When I was diving my LP85's as singles (using my BP/W & a single tank adapter), I was able to drop to 18#'s, but still felt a bit overweighted at times, yet neutral when the tank, as a single was near empty. I have since had several people also tell me that it's like learning to dive all over again. That's the absolute truth, no better way to explain it. I plan on conducting more dives in these tanks in the shallow waters of the quarry (15- 20') & make sure I'm fully comfortable about my ability to handle them when they become cantankerous. My technical instructor who was at the quarry (to dive with some very advanced divers) said the set up looked like it was in about the right position on me, but that some minor adjustments may need to be made. I would say that these "minor adjustments" may make a world of difference when trying to handle that much weight. Where, in general, the tanks are easier to balance, if it gets tilted just a little bit, it's all I can do to get myself back on an even keel. Anyway, I do appreciate everyone's input.

Until you solve the overweighting problem, it is going to be hard to set the trim.

You may want to keep the LP 85s separate, and go with lighter doubles, such as steel 72s, or even aluminum instead. Those are trim issues. You need to fix your weight belt first.

I am surprised that you tech instructor recommended twin LP 85s. Those are huge, heavy tanks. Its no wonder you are turning turtle with them on your back.

Girls (and women) are made of sugar and spice and everything nice (as the nursery rhyme goes). These things tend to be buoyant in the water, and so the pressure to turn turtle is perhaps more pronounced.

Maybe you need to find a female tech instructor instead.

 

[nereas]

Tstormwarning, thank you for the precise description of your experience. I will be diving in doubles in a few months, twin HP 130's, should be interesting. It reminds me when I first tried my BP/W and a single 130. Like you I was all over the place, using my hands, lifting up the bottom, up and down, the works. It has since improved a lot, so do what ScubaRandy said and for my part I will also abide by his recommendations when the time comes.

You are a guy, though, Belmont, and that is different. Your body is made up of dense bones (like mine), and twin 130s should be no problem for you. I love my twin 130s. Except on dry land, or on the boat. Then I absolutely curse them, and the law of gravity as well.

 

[nereas]

... I dive with 16 pounds on a weight belt, and that trims me out perfectly. On the other hand, I've dived a set of Al80's with an 8 pound V-weight and no other weight, and they trimmed out beautifully (this was in fresh water). If you can't trim out the steel tanks, you might want to try a set of aluminums, to allow you to put some weight on where you need it to balance. ...

As I said, I myself also use 14 lbs on my weight belt with twin steel tanks for cold water (I cannot imagine water much colder than Wash St, albeit Alaska!), together with a steel backplate. And this trims out perfectly for me. And this is about half of what I use for a single steel tank in cold water.

It may simply be that your weight belt is your entire problem.

But if not, and as TSM has also said, aluminum doubles may be warranted to solve the turning-turtle problem, ultimately.

 

[nereas]

...First off, let me state that I am working off of the Faber LP85 buoyancy specs... 2400 psi with a 10% Overfill Rating to 2640 psi, 7 inch Diameter, 26" Tank Height
33 lbs. Tank Weight, negative 6 lbs full / Neutral empty Buoyancy in salt water
Triple Coated with spray galvanize, epoxy paint and polyurethane coating

You have introduced 6 more pounds of buoyancy swing in there by adding the 2nd tank. At first you are negatively buoyant since the tanks are full... This is why you were sinking like a rock.

...

The additional 6 lbs from the gas in the 2nd tank is most pronounced at first, yes. And it goes away eventually, yes, as you breathe out.

However, the bands have weight too. As does the extra regulator. As does the manifold.

No matter how you look at it, your weight belt needs to be lightened so that you are not exascerbating the issue of the extra 6 lbs from the additional gas on your back now.

Plus you are diving in a fresh water quarry. Fresh water. That means your tanks are not going to be neutral anytime soon. (Not until the quarry fills up with a lot of salt run-off.)

 

[crpntr133]

The additional 6 lbs from the gas in the 2nd tank is most pronounced at first, yes. And it goes away eventually, yes, as you breathe out.

However, the bands have weight too. As does the extra regulator. As does the manifold.

No matter how you look at it, your weight belt needs to be lightened so that you are not exascerbating the issue of the extra 6 lbs from the additional gas on your back now.

Plus you are diving in a fresh water quarry. Fresh water. That means your tanks are not going to be neutral anytime soon. (Not until the quarry fills up with a lot of salt run-off.)

Most likely her tanks aren't going to be neutral ever. Most tank manufacturers measure the buoyancy in salt water.

Tammy, if you need to try out a set of LP 77's you are more than welcome to try mine.

 

[PerroneFord]

Interesting timing. I allowed a female friend of mine to try my AL80 doubles this weekend. She was diving in a 2-piece 3mm wetsuit. We started her out in about 5 ft of water and let her get used to how they felt. Then we went down to about 12ft of water and let her swim around, get the feel of them, etc. She did a beautiful job maintaing trim, keeping her hands still, etc. She's a newish diver with about 35 dives after this weekend.

Some people have a harder transition to doubles than others. Mine was pretty tough, but I was pretty unskilled. I buddied with another SB diver last month who as doing his first doubles dives in a se of 130s. He is a VERY strong diver with nearly 400 dives. It looked like he had been in them all his life. I had no corrections for him when we surfaced in regards to his doubles diving.

Doubles reward good trim and buoyancy control. The increased mass makes it easier to stay still in the water in terms of buoyancy. However, movement once it starts, is harder to stop. I try not to let myself move more than a couple feet up or down before I am taking corrective measures. If you let things go to far, you'll be laying on the inflator or pull dump a LOT to fix things.

I hope you get your issues sorted out, and best of luck to you.

 

[pennypue]

As I said, I myself also use 14 lbs on my weight belt with twin steel tanks for cold water (I cannot imagine water much colder than Wash St, albeit Alaska!), together with a steel backplate. And this trims out perfectly for me. And this is about half of what I use for a single steel tank in cold water.

It may simply be that your weight belt is your entire problem.

But if not, and as TSM has also said, aluminum doubles may be warranted to solve the turning-turtle problem, ultimately.

My darling dear, nereas. No. Being of the sugar and spice persuasion and having personally experienced this, I don't think al80s are the solution. I know. I've dove them. When empty they become *****lite. And as I'm sure you've noticed, that is where we tend to store most of the sugar and spice. :blinking: She'll get them past half empty and not being able to hold her stops then too.

I have used double al80s, 104s and my purdy 130s. If I vent all the air from my wing I'll sink like a ROCK. With a cave fill I wear 400gs and some tilos fleece to keep me from dragging the bottom (and no additional weight in an aluminum plate). And I'm NOT a tiny girl.

My suggestion, come out to Blue Springs this weekend. I plan on being there, in my doubles, no scooter and working on trim, stops and other sundry skills. I'd LOVE the female company!!!

 

[tstormdiver]

My suggestion, come out to Blue Springs this weekend. I plan on being there, in my doubles, no scooter and working on trim, stops and other sundry skills. I'd LOVE the female company!!!

Thanks for the invite Penny. Unfortunately I'm going to be dry for the next couple of weeks due to work. ON Aug. 18th I may go to Pennyroyal with a newly minted diver. After that, I'm not sure what I'll be doing. I'd like to reciprocate the invite, if you're ever down this way towards Pennyroyal, feel free to look me up.

 

[nereas]

My darling dear, nereas. No. Being of the sugar and spice persuasion ...!!!

Wow! Could it be that I am falling in love ... ?

 

[tstormdiver]

Penny, watch out....