Let's talk about balanced rigs

[JeffG]

Dude that thread is hilarious. Thanks man.

back in the better days.

 

[Doc Intrepid]

I had a big long post about why this is a load of BS...but then I lost the post.

I hate it when that happens....

Because I'm open to you enhancing my understanding, lets set up a dive.

230' wreck, open ocean, 65 miles offshore off a charter boat out of Ocean City, MD

I had a set of 130s, two sling tanks, (no argon - 6 cuft airgon bottle), scooter, drysuit, etc.

At the time I dropped, I could not swim up my rig from the wreck had something gone wrong. (Not that I planned to, or considered this a problem...)

Camera's, scooters, 40's, 14 are close to neutral and can also be jettisioned. So they are not part of the equation.

Would you in fact jettison full tanks of deco gas, and a scooter that you could use, so that you could swim your rig 230' straight up to the surface off this wreck?

It is not a "myth". Some rig's lend themselves to be balanced...others not so much, but hardly a myth. Backgas with nitrox in big doubles are always hard to balance.

But those are the dives you're doing.

The first thing is you need to do is to actually understand what a balanced rig is.

Okay. Its a teachable moment. How do you "balance your rig" for that dive? Is swimming up your balanced rig from that 230' wreck your primary contingency plan? How does 'balancing your rig' factor into your dive plan here?

 

[JeffG]

230' wreck, open ocean, 65 miles offshore off a charter boat out of Ocean City, MD

I had a set of 130s, two sling tanks, (no argon - 6 cuft airgon bottle), scooter, drysuit, etc.

Done that dive (Agamemnon Channel @242 ft wall dive. Bottom was ~500ft.) Had a balanced rig. 130's, 2 deco bottles. No scooter...but they are neutral anyways.

Here's another hint....What drysuit undies were you using? That's the "detail" behind the drysuit usage that means something.

At the time I dropped, I could not swim up my rig from the wreck had something gone wrong. (Not that I planned to, or considered this a problem...)

Were you using nitrox? Try using helium.

Would you in fact jettison full tanks of deco gas, and a scooter that you could use, so that you could swim up your rig off this wreck?

They are neutral (or close to it)...or don't you get that????

But lets say they were stages of nitrox (80's). If dropping it would save my life...then yes I would drop it.

At the start of the dive (when you are the heaviest) you have no deco obligation, so the lack of deco gasses do not matter.

At the end of the dive (when you need to do deco), you will be lighter by the gas you have consumed, so you will not need to jettison as much equipment (or maybe no equipment)

Okay. Its a teachable moment. How do you "balance your rig" for that dive? Is swimming up your balanced rig from that 230' wreck your primary contingency plan? How does 'balancing your rig' factor into your dive plan here?

answers are above.

 

[JeffG]

But those are the dives you're doing.

No..they are the dives you are doing and I guess you will need extra gear to compensate for the mistakes you made previously.

I don't do those.

 

[Slonda828]

Let me jump in on this because I have only recently begun to dive dry with a steel tank.

Last weekend I dove Dutch Springs. This was my setup:

-Sherwood HP 120
-Bare XCD2 Tech drysuit
-Polartech powerstretch underwear
-NTEC rig, 2lb al plate, oxycheq 40 lb singles wing.

I calculated that I was about 8 pounds heavy at the beginning of my dive. I made sure I could swim the rig up full (which I could). I also placed 4 lbs in each of my weight pouches on my webbing. Those pouches can be jettison individually. I figured if the world went to hell when my tanks were full, and I was somehow too tired to swim up that I could cut 4 lbs and swim it up. If somehow I was still too tired I could cut the other 4. Using this setup, I was perfect at my safety stop with about 13 cubic feet (500 PSI) of reserve gas left in my HP120 with no air in my wing.

Is there a way to make this better, or is this generally balanced? I know I felt heavy at the beginning of the dive and I couldn't stay neutral at 75 feet without gas in my wing for sure. By the end I was fine. I am open to better ways of doing this. Bear in mind that I am usually diving in a 3mm with an AL80.

 

[JeffG]

Is there a way to make this better, or is this generally balanced? I know I felt heavy at the beginning of the dive and I couldn't stay neutral at 75 feet without gas in my wing for sure. By the end I was fine. I am open to better ways of doing this.

Sounds just fine.

 

[Slonda828]

So if I was diving double 120's how would I balance this? I would just up the amount of removable ballast and call it good? I'm a pretty strong swimmer, but I am not sure I could leg up 16 pounds of gas...

 

[JeffG]

So if I was diving double 120's how would I balance this? I would just up the amount of removable ballast and call it good? I'm a pretty strong swimmer, but I am not sure I could leg up 16 pounds of gas...

I doubt you could add more removable ballast without making yourself extremely negative.

That was a solution given by Nearass...but then again..he learned how to dive on the internet.

You could get more buoyant underwear, that will help a bit. Diving a helium mix helps.

Also, some rigs can't be balanced. (or its impractical to do so) So you need to decide if you want to do the dive (or not).

My dives with double 130's, Nitrox and in fresh water was very "unbalanced". I did the dive anyways, because if my BCD bladder failed, I would just walk on the bottom of the lake until I got out.

In salt water, with a helium mix. The same rig was very balanced.

 

[Slonda828]

I doubt you could add more removable ballast without making yourself extremely negative.

That was a solution given by Nearass...but then again..he learned how to dive on the internet.

You could get more buoyant underwear, that will help a bit. Diving a helium mix helps.

Also, some rigs can't be balanced. (or its impractical to do so) So you need to decide if you want to do the dive (or not).

My dives with double 130's, Nitrox and in fresh water was very "unbalanced". I did the dive anyways, because if my BCD bladder failed, I would just walk on the bottom of the lake until I got out.

In salt water, with a helium mix. The same rig was very balanced.

That's actually remarkably simple. I could cut over 5 lbs of gas weight by using mix instead of air. If I were diving double 120's, I would ostensibly be going deep (I'm not a caver) anyway, so it would be more conducive to the profile to dive mix. This would make me less negative at the start anyway.

If this isn't that terribly hard, why does everyone get so pissed off about it? (besides the fact that you antagonize them Jeff)

 

[JeffG]

If this isn't that terribly hard, why does everyone get so pissed off about it?

You got me

(besides the fact that you atagonize them Jeff)

Maybe that's the reason.