What Is a Balanced Rig (and How to Check Yours)

A wing can fail. It's rare, but inflators stick, bladders tear and hoses leak. The question a balanced rig answers is simple: if your wing stopped working right now, what would happen?

At the end of a dive, with nearly empty cylinders, the answer is easy. At the start, with full cylinders and a compressed suit at depth, it might not be.

What does "balanced rig" mean?

A balanced rig meets two conditions:

1. At the end of the dive, at a shallow stop with near-empty cylinders and an empty wing, you can stay down. You're not underweighted.
2. At the start of the dive, at depth with full cylinders, a wing failure wouldn't leave you unable to manage the rig. You have a workable way to stay off the bottom and make a controlled ascent.

Most divers only ever check the first condition. The second is where heavy rigs get into trouble.

Why is the start of the dive the hard part?

Three things make you heaviest early in the dive:

• Gas weight. Full cylinders carry the weight of all the gas you haven't breathed. An aluminum 80 holds roughly 6 pounds of gas; doubles hold much more.
• Suit compression. A wetsuit loses buoyancy as it compresses with depth. At 100 feet, it has far less lift than at the surface.
• Steel. A negative cylinder or heavy plate can add substantial fixed weight. Cylinder buoyancy varies by model and remaining gas.

Your wing compensates for all of this. That's its job: it carries the gas weight and offsets suit compression, while your lungs handle fine buoyancy. A balanced rig is about what's left if the wing can't do its job.

What can you do if the wing fails?

The options depend on your rig:

• Swim it up. With a modest amount of negative buoyancy, a fit diver can swim a rig up to where the suit and the lightening cylinder help.
• Use the drysuit. A drysuit is a second source of buoyancy. A balanced exposure system is central to UTD's steel-doubles rule; see the agency exception above and Gardner's stricter local policy.
• Drop ditchable weight. Lead on a belt or in pockets can come off. A steel plate or cylinders can't.

The aim is a rig where at least one of these is realistic for you, at the depth and with the gas you're planning to carry.

How do you check whether your rig is balanced?

There are two parts, and you should do the second with your instructor.

1. The end-of-dive weight check. At the last stop, about 10 feet, with around 500 psi in an aluminum 80 and an empty wing, you should hold your depth with normal breathing. See How Much Weight Do I Need?

2. The start-of-dive assessment. Work out how negative your rig is at the deepest point of the planned dive with full cylinders: the weight of the gas, how much lift your suit loses at that depth, and any steel in the system. Then decide, with your instructor, how you would manage that if the wing failed, and whether the answer is realistic. Some instructors include a supervised wing-failure exercise in training. Don't turn it into a solo test at depth.

What makes a rig unbalanced?

• A cylinder/suit combination that cannot be managed after a wing failure. Follow the agency's balanced-exposure requirements and Gardner's stricter policy: no steel cylinders with wetsuits.
• All ballast fixed to the rig. A steel plate, a steel cylinder and weight on the cam bands leave nothing to drop.
• Heavy rigs for deep wetsuit dives. The deeper you go, the more lift a wetsuit loses.
• Extra lead "to be safe." Every unnecessary pound makes a wing failure harder to manage.

Is a balanced rig only for technical divers?

No. Technical rigs make the problem bigger, with doubles, stages and drysuits, but the principle applies to a single aluminum cylinder too. Knowing your rig's numbers is part of being in control of your dive.

Build it with someone watching

Weighting and balanced rigs are covered in Essentials of Recreational Diving, with your own suit and cylinders. For the bigger picture, see How to Master Scuba Buoyancy and DIR Gear Configuration, Piece by Piece.