Balanced Rig: AKA "How much Lead do you REALLY need?"

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The goal is a balanced rig

Very cool. you don't need the pockets. What you need is a steel tank and add trim pockets to the top strap close to the BP and add 3lbs in each. After you set this up you want to perform this test:

1. While on the surface, drain your cylinders down to (30 Bar) 500 PSI
2. If wearing a drysuit, ensure that the dump valve is fully open, with all gas vented
3. lift the inflator above your head and dump gas
4. as the gas leaves your wing, inhale deeply and hold your breath
5. with most rec systems, you will stay at the surface with gas in your lungs
6. when the wing finishes dumping, exhale forcefully and hold the exhalation to descend.

In most cases, correctly weighted rec divers must exhale to begin their descent, thereby sinking slowly. Within a couple meters (a few feet), holding a stop and breathing normally will be easy. Divers will then be able to add gas to their drysuit (if needed) to support comfort. If the diver performing the check sink quickly, it is a clear sign of overweighting. If this happens, simply remove weight and repeat the test.
 
You cannot get a balanced rig when using a 7mm wetsuit in most cases. The lost compression at typical depths is more than you can swim up. You should not drop more weight than the weight of the remaining air you have -- otherwise ascent is uncontrollable when you so regain buoyancy. This is still likely enough not enough to get off the bottom.

A 7mm wetsuit mandates redundant lift (e.g., a larger DSMB) to get off the bottom without ditching all your weight.

Weight yourself to be slightly buoyant at the surface -- i.e., eye level with empty wing at reserve pressure. Yes, this is different than the normal "be neutral at the safety stop" advice because a 7mm probably gains at least 10 lbs of buoyancy from 15 ft to the surface. Avoiding corking after the stop is the more stringent criterion.
 
it takes 2lb per millimeter of suit thickness
Measure your suit's buoyancy with a mesh bag and weights. The 2 lb per mm is a very rough guideline, as it ignores size for starters.

A handheld luggage scale makes this even easier by measuring (when submerged) suit+enough weight to sink it and subtracting the submerged weight of the bundle without the suit. This way you don't have to get the weight exactly equal to the suit; any amount that sinks it is good.
 
It’s crazy the variability in weighting. I dive a freedom plate steel backplate, and a steel 10 liter tank with a drysuit. 4 kg (9ish pounds) is perfect for me. 5’7” 200 pounds. *shrug*
 
Hard to achieve balanced rig in a thick wetsuit.
Purge your regs to 40 bar/ 500 psi at the end of a dive. From nothing, incrementally add lead until you can just about maintain depth a few m below the water line. This is the minimum you need to descend with everything deflated and exhaling.
 
I've been diving for a while. The more I dive, the less I like a 7mm wetsuit. A few years ago, I reconciled with myself to not wear a 7mm and if the water temp required it, switch to a drysuit. In the event that I do need a bit more thermal protection (not in drysuit territory for me), I wear my 5mm wetsuit plus a 3 mm armless vest. I believe this is a reasonable compromise when for whatever reason a drysuit use is not feasible. And I always wear a hood no matter the water temp: the thickness of the hood varies from a thin beanie to a 5 mm.

The advice given above by various posters regarding a balanced rig is very good. A few have failed to mention to also exhale fully when testing your buoyancy at the surface with 500 psi.
 
The goal is a balanced rig

I think you should define what you mean by 'balanced rig' as there are a few different perceptions of that term. Some people use it to simply describe a set up that you can swim to the surface with no air in the BC, and some use it to describe a weighting strategy in which weight is split up between your body and the BC, so that if you removed the BC underwater, you wouldn't rocket to the surface while your BC plunged to the bottom. I tend to think of it as the latter of those two, because it means you have to balance weight between yourself and your BC. In terms of being able to swim your rig to the surface, in cold water with a thick wetsuit, generally speaking that means you will need some ditch-able weight. Traditionally that would be on a belt or weight harness, separate from the BC. Putting 30 lbs of weight in BC pockets is a recipe for disaster IMO. I personally don't like the idea of quick release weight pockets to begin with, and this is the hogarthian forum, so you want to emphasize simplicity and function in your approach to gear.

Just from reading your posts, one thing that comes to my mind is that you are probably way overweighted. Unfortunately many recreational agency scuba instructors load on the weight for their students. It's bad teaching, plain and simple, and it's done to just save time and get everyone in the class under.

So your first step would be to get an idea of how much weight you actually need, and there is one way to get that; a proper weight check. Once you get an accurate idea of how much ballast you need, you can figure out a plan. In cold water and AL tanks, a steel plate is a no-brainer. Forget the STA. If you need more weight on the plate you could hunt around for a used deep sea supply plate with the added weight plates. Those were fantastic for cold water divers.

Lets say for the sake of argument that you have a steel plate with an AL tank. They more-or-less cancel each other out in terms of ballast (maybe 2-3 lbs net negative once you figure in the regulator) and you determine that your wetsuit needs 15 lbs to sink. (You can check that by putting your wetsuit in a mesh bag, tossing it in a pool, and adding lead weights until it stays under) So you come up with needing around 12-14 lbs of lead as a starting point, and at that point I would put two 3 lb weights in camband pockets, and two 4lb weights on a belt and give that a try. If you're a little top heavy, replace the 3lb weights with 2lb, then if you can't stay down try adding another weight to the belt.

The benefit with a system like that is that it's very simple, you don't have worry about quick release pockets dropping unexpectedly and sending you on an 'emergency blow' ride to the surface. (It happens more often that you would think) You can take the rig off and the wing will float it on the surface, and in the rare event of a total loss in buoyancy, you can drop the belt.

Sorry for the long post, hopefully it's somewhat helpful.
 
because a 7mm probably gains at least 10 lbs of buoyancy from 15 ft to the surface.

If you would’nt mind, I would be interested in how you came to this determination.
 
@divezonescuba - more of a guess than a determination. @rsingler's weighting tool (stickied in the Advanced Forum) has some modeling equations and is what I believe I used. Another option is to directly measure the surface buoyancy and ballpark the compression loss at 30% of that. One could also measure buoyancy at 15 ft if you had a deep enough pool.
 
https://www.shearwater.com/products/perdix-ai/
http://cavediveflorida.com/Rum_House.htm

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