Actually they probably really were parrotting the other definition of balanced rig which is more about steel doubles and wetsuits, which you rightly corrected them on since that wasn't all that much of a problem. They were probably also rightly looking at your rig and thinking it was a CF, but they didn't have the correct vocabulary to tell you what was wrong, so they threw "balanced rig" at you, and that's sorta close to the mark, but misses it.
What Bob pointed out to you with regards to the tendency of the tanks to roll around their long axis and be unstable that way is *not* what the term "balanced rig" has every been about, AFAIK. The "Balanced Rig" concept *is* about only being overweighted by the swing weight of your gas, and reducing the dynamic instability from diving with a big wing volume.
What is missing from the fundies curriculum and training is a concise explanation of why the Halcyon wing sizes and shapes are why they are designed the way they are designed. That is something in addition to the "balanced rig" concept which Bob brought in to the course.
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I'm still a little confused on why you sold the LP120s, though, but that's probably because I don't dive warm water. I would have thought that with a 30# eclipse wing that they'd dive fine as singles. As doubles you'd definitely want Al80s there since those steel doubles plus a wetsuit would be dynamically unstable even with an aluminum plate (plus that is just a lot of swing weight of gas to start a dive when you don't have a drysuit for redundancy).
The main reason for not using single al 80's here, ( what all the boats have on board for rental) is that they do not have sufficient volume for the 85 to 130 dives I like to do the most in South Florida--for you to follow the common sense GUE position on Minimum Gas for the dive ( meaning if your buddy has a reg failure/etc at the end of the planned dive, do you have enough gas to bring both of you up at a normal ascent rate after dealing with the emergency). In the 80s or 90s this more of a non-issue due to most divers using air, this limiting bottom time to match the volume of the tank better. Today with Nitrox durations at 80 to 100 feet, the smarter choice is going to be a much larger tank...or double 80's. When I saw how much more stable the double 80's were from the 120's, partly due to the closeness to your back, partly the pontoon effect of the way the wing cradles them so much further to each side....it became clear that for the best videographic advantages I could get in the challenging locations I want to shoot videos---the dual 80 choice was better for me. I don't want to shoot what 1000 other video guys are shooting...I want the shots that most recreational divers would not even try to get. So penetrating deep into holds of a shipwreck where I can get a cool back drop for dozens of 400 pound Goliath Groupers, becomes a primary mission, and being rock steady without effort in mid water collum inside the hold, offers more mental energy for being creative with the camera. Easy is good
The 120's can do this with the 30 pound wing,
but not as well.
The big advantages of speed and low drag for the 120 so far have usually been in shallower water, as in bottlenose dolphin encounters on 60 foot reefs.....for this I "could" have used an 80. For sailfish shots I want to get this winter, I can use a single 80--it will be shallow with the fast--and for this I can even use the 18 pound wing, as it would only be fast--these sailfish don't really stop to pose
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Also you mentioned that buoyancy control is about lung volume and breath control -- but it really isn't. That will breakdown with rebreathers and even on OC if you start breathing out of the top of your lungs you'll start to build up CO2. You still need to be adjusting your wing and drysuit in order to keep breathing out of the middle of your lung volume. It also reduces a divers SAC rate to not be breathing out of the top or bottom of their lungs.
Lamont, I am not talking about rebreathers...and I actually think they are a big mistake for
most divers.
What I was talking about was how typical OW classes never teach bouyancy beyond the rough control of BC only. So for precision in the hold of a shipwreck or in a cave, there are going to be times when lung volume is going to be used for optimizing where you are in the water collumn, particularly when doing something with a reel or camera, etc. I am expecting you are talking about something else....
The rebreather issue to me is mission specific....I don't want to be diving one, unless it is the only way to achieve a very extreme dive. For 100% of the extreme dives I can imagine off south Florida, open circuit is safer and better for my "missions"...If I was doing lots of 400 foot deep stuff on oculina banks, racking up massive bottom time and deco, carrying sufficient gas supply would be so problematic, that a rebreather would be necessary.....As of now, I don't see a good reason to be shooting that stuff, and OC will be more practical for what I and most S Florida divers want to dive on.
