DIR and Dual Bladder wings? Also Double reg set-up?

[rjack321]

Apparently double 80s are actually negative towards the end of the dive. While the tanks themseleves start to swing to positive, the bands and manifold counteract it--then you have the regs + backplate.

They definately don't float in freshwater, but might just barely in salt (never tried AL80s in salt, too buoyant for me in a drysuit)

 

[Life-Is-Good-Diver]

You can't have it both ways ~80-100 cf of gas weighs 6-7 pounds.

You can start that tank off:
-8 and end up -2 (a PST Hp100)
-6 to neutral (an LP85)
or -2 and end up +4 (an AL80)

You are way over weighted with steel doubles and a steel BP in a wetsuit. I'd switch to AL80s with a small weightbelt (~6 lb), keeping the steel plate for now.

That add's another delema.

What about when I dive dry then?

80% of my diving is wet though.

A few times year, i go upto the springs to cave dive, but mostley I'm always in the ocean. I tried diving my Dry suit this summer , with my 80's when i had them doubled up, and I did not like diving dry at all in the summer. I was sweating on the boat, and over heated in 85 degree water on the bottom.

Thanks for the swing's on the tanks. I had a general idea of the swings, but that helps.

I may just double up my 80's again


And I just dumped two steel 100's off all their air ;( , and they were fill

 

[amascuba]

Apparently double 80s are actually negative towards the end of the dive. While the tanks themseleves start to swing to positive, the bands and manifold counteract it--then you have the regs + backplate.

In my Luxifer double AL80's I need a 4# tail weight to be able to hold my 10' stop with 500psi. My tanks start getting floaty at around 1000 psi.

 

[amascuba]

That add's another delema.

What about when I dive dry then?

80% of my diving is wet though.

A few times year, i go upto the springs to cave dive, but mostley I'm always in the ocean. I tried diving my Dry suit this summer , with my 80's when i had them doubled up, and I did not like diving dry at all in the summer. I was sweating on the boat, and over heated in 85 degree water on the bottom.

Thanks for the swing's on the tanks. I had a general idea of the swings, but that helps.

I may just double up my 80's again


And I just dumped two steel 100's off all their air ;( , and they were fill

I dive double AL80's + 6# steel backplate + 4# tail weight with my drysuit. I've played around with weighting allot with my double AL80's this year and I've settled with the 4# tail weight as I can hold a 10ft stop with 500psi.

What I would do is see what the buoyancy swing is for your AL80 tanks and weight yourself based on that. Breath down the tanks to 500psi and try to hold your 10ft stop with little to no air in your wing.

 

[Life-Is-Good-Diver]

In my Luxifer double AL80's I need a 4# tail weight to be able to hold my 10' stop with 500psi. My tanks start getting floaty at around 1000 psi.

Thanks , I just sold on Ebay, my trim weights I was using.

I had the trim weights on, because with the Alum 80's, when i breathed them down, It was hard to hold stop at 10'

With the steel tanks, I trim out beautifully, I'm to dam heavy though in the water, diving wet

 

[reubencahn]

Thanks , I just sold on Ebay, my trim weights I was using.

I had the trim weights on, because with the Alum 80's, when i breathed them down, It was hard to hold stop at 10'

With the steel tanks, I trim out beautifully, I'm to dam heavy though in the water, diving wet

You would want to use a weight belt rather than trim weights. The idea being that if you lose your wing at depth early in the dive, you're already negative 12 to 14lbs for the weight of the gas and an additional x pounds lost by compression of your wetsuit. (Let's say your wetsuit is 12 lbs positive at the surface and is neutral at 100 ft. So you're now 24 lbs negative.) To surface, you need ditchable weight. Attaching trim weights or v-weights puts you in the same position as the double steels.

 

[Life-Is-Good-Diver]

You would want to use a weight belt rather than trim weights. The idea being that if you lose your wing at depth early in the dive, you're already negative 12 to 14lbs for the weight of the gas and an additional x pounds lost by compression of your wetsuit. (Let's say your wetsuit is 12 lbs positive at the surface and is neutral at 100 ft. So you're now 24 lbs negative.) To surface, you need ditchable weight. Attaching trim weights or v-weights puts you in the same position as the double steels.

Good point, I have a weight belt I could use, I'll try that.

I'm working on my Alum 80's right now, putting them together again, with the bands and manifold

 

[Bigcape]

Get longer fins.......J/K

 

[MonkSeal]

Thats a good idea. I was going to put a H-Valve on my 130 , so I'm configured for over head going into wrecks when diving singles, plus having the reduncey of two regs UW.

From a DIR perspective going into overhead with single tank is not a good idea. Regarding two 1st stages on single tank I can recommend a good article http://www.dir-diver.com/en/knowledge/single_hvalve_doubles.html

 

[Jason B]

Apparently double 80s are actually negative towards the end of the dive. While the tanks themseleves start to swing to positive, the bands and manifold counteract it--then you have the regs + backplate.

The point of double Al80's was brought up as an alternative to diving heavy steel doubles in a wetsuit and a dual bladder wing.

All doubles, steel or aluminum, are less negative at the end of a dive.
All doubles, steel or aluminum, are effected by the weight of the bands, manifolds and regs.

Aluminum tanks (being that they actually swing several pounds positive at the end) will be less negative than a set of steel doubles and more suited for wetsuit diving (easier to achieve a balanced rig).