Steel LP85 doubles way too negative

[rhwestfall]

I doubt I would dive any steel doubles in a wetsuit.

agree, but vintage 72's excluded from this statement..

 

[W W Meixner]

So, I just started diving doubles after taking an Intro to Tech class, and I am using LP85s. I think I probably made a mistake buying those. They seem to be way too negative, and even though I can get neutral by pumping a ton of air into the wing, I don't think that's the way to go.

Just to put my buoyancy in context, I carry 10lbs of weight on a 7mm suit diving a single aluminum 80. During class, they really advocated all the advantages of the LP85 so I thought it was the way to go. Right now after trying them out extensively it just feels uncomfortable and I want to try to become more balanced.

I am now thinking about switching to Al80 doubles, and probably also switch to a steel backplate.

Is that the way to go? Or is there anything else I can do and still use the LP85s?

AH...

Diving with steel doubles...HP/LP like everything thing else we learn...is an acquired skill...

Doubles are negative...plain and simple...even with a properly fitting dry-suit...

I think what's lacking in your case is the instruction you received...and time to acquire the skill..

Mastering your doubles will come with practice...if you have access to a deep ended pool it will come quicker...

Balance and stability has a lot to do with your harness...comfort/adjustment capabilities...and your wing...

I'm currently diving with HP 117's...OMS IQ pack harness/AL BP...60 pound lift bungee'd OMS wing...and full time dry-suit...no ballast...a little cumbersome on the surface...but in the water...the weight disappears...the OMS IQ pack keeps the cylinders snuggly positioned while remaining comfortable...

If you're diving heavy doubles with a wet suit...you may want to consider a double bladder wing...

I certainly wouldn't be considering swapping out what you have...for 3AL 80's...that's going backwards...

All the best with your new doubles...you'll be performing barrel rolls and somersaults in no time...

W.W...

 

[doctormike]

Steel doubles and a heavy wetsuit is just a bad combination. It's one of the few configurations where I would be concerned about an unbalanced rig. That's actually the reason why I bought a double bladder wing (don't use it any more).

 

[ofg-1]

get an aluminum or ABS backplate for the wetsuit with doubles. See if you can borrow one and try it.

 

[divezonescuba]

@divezonescuba why not get the FX100's? Can get them in galvanized and won't have to worry about getting "full fills" on them

The bouyancy characteristics between the LP85s and HP100s look significantly different. I also don’t like to have to put more than 3250 hot into tanks from my compressor.

When I fill HP100s, I have to pump up to 3600, cool, pump up to 3600 to get 3442.

 

[tbone1004]

The bouyancy characteristics between the LP85s and HP100s look significantly different. I also don’t like to have to put more than 3250 hot into tanks from my compressor.

When I fill HP100s, I have to pump up to 3600, cool, pump up to 3600 to get 3442.

The LP85's and FX100's are functionally identical. The LP85's hold 13L, the FX100's hold 12.9L, basically the same thing. At 2640psi, the LP85's hold 85cf, and the 100's hold 84.3 ish. At 3250, they're 104.6 and 103.8.
The FX100's have the advantage of being a "normal" diameter so you don't have to adjust cam bands, won't get short fills if you take it to another dive shop, can come in galvanized, and you can take 3lbs off of your weight belt if you have any. I'd only get the LP85's if that 3lbs of negative buoyancy pushes you to being dangerously overweight, AND you can guarantee that you will always get reasonable fills.

 

[Caveeagle]

get an aluminum or ABS backplate for the wetsuit with doubles. See if you can borrow one and try it.

that is exactly what I dove back in the 90s. With a 7mm farmer John, and double 95s, we also used a 4# drop weight at the start and end of the dive.

 

[galodoido]

After some adjustments it feels much better right now. I'll still try Al80s to see how it feels but I'm happy with the LP85s. I think it was just about getting used to the fact that I will be heavy in the beginning of a dive with doubles no matter what.

 

[ajanelle]

Yo, if you're getting rid of your 85s....





I'll buy them

 

[halocline]

I like AL80 doubles. I hate them as single tanks but with the bands and manifold I find that they trim out well. I had to fiddle around to find the right fins which ended up being Deep six eddys. That said, LP85s are classic doubles and people have raved about them over the years. But if you're too heavy, you're too heavy and that can be dangerous. You might try completely emptying your wing at some depth with full tanks and make sure you can swim up with your wetsuit compressed. That's really the danger.