I just took GUE Fundies, and I am making some major changes ! :-)

[danvolker]

One of the first things I want to change is how to describe the important elements Fundies students have picked up….One of the WORST descriptive terms used is a “Balanced Rig”…It is fine when used in discussionswith other GUE divers that have experienced what this means—but for everyone else, it sounds like rhetoric, and falls far short of explaining the real issues.

1. Balanced Rig …I began class using a lp 120 and an 18 pound lift wing. Normally I use big monster freedive fins, swim easily at 2 mph or faster, and can stop and hover at what I had thought was no effort J I learned this was NOTa balanced rig….not because I could not swim up the tank from the bottom if the wing failed—in fact, very little gas was in the wing at the bottom on a dive. Balance was really about balance in this case. While it is cool that a bp/wing diver can switch from double tank set up to single tank, by just removing the doubles wing, and adding an STA and the singles wing..this removes a lot of side to side balance. First, the STA which attaches the tank to the backplate, adds vertical profile to how high the tank extends above your back. Think walking on stilts, versus walking on sneakers. Second, if the single tank is a really big single tank, like my lp 120, then the vertical rise—the weight quite far from your back, gets even higher, and ends up pulling you left or right with more leverage---the tank wants to roll to be at the lowest point in the center of gravity—the bottom. This tends to pull you to one side or the other. Now choice of wing can mitigate this quite a bit…..worst would be the 18 pound wing I liked, for it’s lack of drag in the water, great when trying to keep up with bottlenose dolphins. For stability when stopped ( when your body is not acting like an airplane wingfrom the swim speed) , it is terrible because it has no “pontoon effect”, and because it is a horseshoe design, so air can’t quickly run from one side to the other always. The 30 pound Halcyon wings on the other hand, DO have a “pontoon effect”…they spread out at the sides like pontoons, and the small amount of air you have in them at the bottom, makes the tank become a much lower center of gravity, and you feel left to right stable, as if aided by pontoons. If you were using doubles, the sta is absent, so the tanks are quite a bit closer to your back—really close, so center of gravity is very low for the tanks—very little pull possible to left or right---AND, the 40 or 50 pound lift wings run quite a bit further to each side of the diver, causing the pontoons to be almost twice as far apart---spectacular stability. So when you stop with doubles on , and want to hover motionless, and effortlessly….there is nothing to fight..unlike the setup I had been using. Maybe no big deal if you will only stop for 10 seconds….but imagine in a shipwreck or cave for 10 to 20 minutes, or on a spectacular coral reef, where your buddy was photographing a rare nudibranch,and there are NO handholds or places you dare touch---perfect trim and buoyancy, plus balanced rig as just explained, and you can hang 4 inches above the coral, not have to even move your feet, and stare effortlessly at the Nudibranch. Anyway, this is what I am taking away as the real meaning of balanced rig. It also means you need to be able to swim it up from the bottom with a total wing and suit failure, but this is more common sense…Some guy using massively heavy steel tanks and tank weights, to get neutral on the surface with a 7 mil wetsuit, who then dives to 150 feet, could easily weigh 35 pounds at depth ---if his wing fails, he can not swim this up. If some of his weight was on a weightbelt, he might ditch 15 pounds, but may still have so much negative weight left that he could still not effectively fight the weight to make it to shallow water and more wetsuit buoyancy. So this guy MAY have carried a redundant liftdevice like an SMB he could inflate at depth, but this is a hopelessly convoluted way to solve the problem, with it’s own potential to create major problems at the worst possible time. The double 80s are almost neutral, so at 150 feet, even if the big wing failed, the diver could swim them up.

The doubles diver desiring a “balanced rig” would not use a thick wet suit for a deep dive, knowing that it would cause a massive shift in buoyancy at depth—requiring the wings to hold a lot of gas. This is drysuit territory for balance. If a thick wetsuit HAD TO BE USED for the deep dive, then it would require ditchable weight, but once you were in shallow water, you would be too positive to hold your stop at even 30 feet. So now you would be looking at the redundant lift solution, which perhaps should get it’s own thread to point out all the dangers of using this approach.
I am going to add several more descriptive term suggestions, where they will make much more sense than how presently used…..but this post is too long already… J

[danvolker]

Part 2 of descriptive changes needed....
Good Bouyancy control.....this was something I acidentally hit on decades ago, so was easy enough in fundies, however, the way it is expressed can use a revamping...

Many new divers think that good boyancy skills, mean figuring out just how much air you need in your BC, and making small corrections till pretty close.
In Fundies, the diver learns that the BC or wing, is only a "rough" tool for achieving near neutral in the water collumn....the REAL tool, or the fine bouyancy control, is perfecting how much air is in your lungs, in each breath, and getting your lungs to run on "auto-pilot" with this....

Clearly, this is way easier to be very effective, if the amount of air in the BC is minimal--much less change in lift from a small change in depth. So Fundies class will get you to the lowest amount of weight you actually NEED for a safe and perfectly controlled dive, given the gear and suit you are using. When a new student ion an OW class is handed 15 pounds too much weight, for EXPEDIENCE in getting the class going, and then must use lots of air in the BC to compensate, this is an extreme act to sabotage the bouyancy control learning of the student---99.9% of the time I am sure this was NOT the intent of the instructor, it is more about juggling an impossible timeline for a large group of students.

Trim.....Something poorly understood in OW certified divers.... Even harder would be how to easily hold perfect trim, without any effort. The worst trim is usually the horribly overweighted new diver, set up for expedience. Typically with much too much weight transfering to the legs, the diver swims head up and feet down, often at an angle half way to standing vertical. They end up swimming very hard, and moving very slowly, because the enormous frontal drag this swimming position developes is like a BARGE pushing a huge Bow Wave...it can only move slowly, and is very wasteful of energy. The diver should instead have a flat line running through their head all the way to their knees...feet can extend up to 90 degrees from knees ( shins pointing to surface, but feet/fins paralell to the bottom)...Then when they kick, they have the smallest amount of drag possible--think of pushing a missle through the water as opposed to a refrigerator standing upright) ... Each kick results in a nice easy forward glide, little energy gets expended, and little air gets breathed by the diver to do this exponentially smaller workload to move along the reef. Suddenly, the new diver is not hoovering, and a 60 foot dive is no longer over in 15 minutes :-) ...The other thing about the trim, the flat body is like an airplane wing as you glide along, and the wing of your body like this, helps to HOLD YOU in the exact depth you want---helps to prevent you dropping or ascending without desiring this. A diver half way to vertical, has little water resistance to prevent them from being pulled up or down--no body wing( not referring to bc here, just the hydrodynamics of a horizontal body with water passing over it).
As the new diver begins to perfect bouyancy and trim, they can soon feel extreme differences between how certain types of BC's will either enhance this experience, or detract from it.

[nimoh]

Always happy to read threads on this topic. I am planning on taking Fundies soon, and hoping to get to the point where I don't need to make major changes by considering opinions expressed in posts such as this one.

Although, I am open to major changes if it will help.

[Fishpie]

I too use a 120 and 17 and 18 pound wings.
I also like the small cross section mini wings for speedy swimming.
I also try and keep the tank as close to my back as possible even to the extent of not using the newer Halcyon STA which is bent at 90 degrees and holds the tank further out than their older type (not the oldest AL one that was the worst offender).
I have used 27 and 30 lb wings, and like you, felt they were overkill since I am very very anal about wearing the absolute minimum weight as I can get away with and only put a squirt or too of gas in the wing.

In my case I use a HP 120-"Genesis" 3500 (a few pounds lighter than the LP and smaller diameter) with a Al plate and two 2 pound weights on a belt.
Belt is worn fairly high on my torso just under my rib cage.
I start the dive with the weights slid as close to the buckle as possible to counteract the weight of the tank. As the tank gets lighter I can slide the weights around towards my kidneys.
Yes, it's a little top heavy at the very beginning of the dive but only noticeable if do a hardcore center of gravity check.
I an not a photographer and like to swim during my dives. As the tank empties my cg also centers and any stopped horizontal tasks such a playing around with a bag and reel and stops are done with no turtleing issues.
My perfect weight and trim goal is to get neutral both fore and aft as well as top to bottom.
I love the weightlessness of diving and like to do underwater aerobatics and don't want to be stuck in a horizontal position all the time.

Yes, an AL 80 and a Steel plate is marginally preferable with the mini wings...but we're really splitting hairs here.
I guess if I were to take a fundies class or be a still photographer I would make the switch to the big flappy wing.....but for now I'll keep the bats.

[Garrobo]

What are these guys talking about?

[NWGratefulDiver]

Nothing ... move on.

FWIW - I'm considering taking Fundies again sometime this year ... just because I think it's changed a bit since I took it last in 2006 ...

... Bob (Grateful Diver)

[fjpatrum]

Maybe I'm missing something, or perhaps I'm not diving big enough tanks or deep enough, but I haven't noticed any "keeling" effect when I stop and hover. (Could be that I'm not actually hovering but still sculling a bit...) I have an ~18 pound wing and I've never tilted to the side at all. I also don't seem to have the same issue wearing heavy neoprene holding a safety stop, even with a single AL80. I certainly wouldn't need a dry suit just to be able to hold a safety stop with a set of doubles.

Danvolker, for what it's worth, I always assumed "balanced rig" meant balanced in the sense you are discussing in your post as well as having a properly sized wing for lifting the rig. Maybe I'm too new to have assumed something different???

[Insta-Gator]

Good job, Dan. I enjoy the way you describe the skill and resultant effect.

[danvolker]

Maybe I'm missing something, or perhaps I'm not diving big enough tanks or deep enough, but I haven't noticed any "keeling" effect when I stop and hover. (Could be that I'm not actually hovering but still sculling a bit...) I have an ~18 pound wing and I've never tilted to the side at all. I also don't seem to have the same issue wearing heavy neoprene holding a safety stop, even with a single AL80. I certainly wouldn't need a dry suit just to be able to hold a safety stop with a set of doubles.

Danvolker, for what it's worth, I always assumed "balanced rig" meant balanced in the sense you are discussing in your post as well as having a properly sized wing for lifting the rig. Maybe I'm too new to have assumed something different???

Hi fjpatrum,
If I was using an Al 80 with my 18 pound wings, it would be very different...For one, the tank is near neutral, so very little keel effect occurs even if it is perched up high ontop of the STA... More than likely, this was the tank it was intended for by Robert Carmichael, when he added that to the Halcyon product line. However, current thinking for air supply needed on a 100 foot deep dive, both for your own margin of safety, and for that of your buddy, makes the al 80 a poor choice for much more than a bounce at the depth. It was/is fine for the 60 foot and shallower Breakers or Boynton Beach dives. The lp 120 has almost as much air as double 80's if you fill to 3400 or so psi..even just at 3000 it has more than enough reserve for both you and your buddy at DIVE END, in the event of a equipment failure of your buddy, right at the end of your planned dive to this depth ( assuming you pick non-hoovering buddies :-) ) ...

When we dive the North Palm Beach area, or deeper sites straight out of the Palm Beach inlet, 100 foot is a likely result, and the 80 ends up being a poor tank to be "ready for anything with"... this relating to the plan as boat leaves dock, and then CHANGES made on exiting the inlet, due to currents, viz, reports of marine life just spotted, and the majority opinion of where to dive from the divers on board....the 80's are just NOT optimal anymore in an age of Nitrox durations..
The lp 120 is still easy to swim off the bottom if the wing failed, but it has enough weight, and an extreme enough diameter, so that the leverage or keel effect is entirely a different experience than the 80...IF you try to stop and be motionless...

While cruising at speed, you could have never gotten me to admit or notice any keel effect--your body as a horizontal wing stabilizes very effectively. The stopping for many minutes, and NOT sculling or constantly correcting ( without even thinking about it), was not part of my dive plans in the past :-)


This was one of those issues where Bob Sherwood told me I would not want to use the 120, and I dis-agreed...

Bob was fine letting me show him why I was right and GUE was wrong....the Bastard !!! :-)

After I proved to myself, that I was wrong and he was right, it meant I have 3... , that's right, THREE lp 120's that were now bogus//the tanks Bill Mee, Sandra and I would use for the dives where 100 foot depth was possible.

Fortunately, a few days after I became depressed with this, , I good friend of mine needed a bunch of lp 120's for double set ups to use at Wakkulla..in big cave penetrations....he had a bunch of double 80's he did not know what to do with......a trade resulted :-)

[TSandM]

For you guys diving pretty warm water, the double Al80s probably make sense . . . but I really don't understand the disdain for a reasonable-sized single tank.

I dive LP95s and HP100s as singles, for dives to 100 feet in Puget Sound. I have no trouble at all hanging motionless for as long as I want, and I often want . . . the double steels I use in cold water take much more careful management for head-to-toe axis stability, even though they are both side-to-side and vertically more stable. Doubles can be a major challenge for people on pitching boats -- I will dive them when they are necessary, but I prefer a single tank setup for boat diving when I can use it and remain comfortably within rock bottom limits.

Come out and visit, Dan! We can do a challenge -- me in one of my single tank setups, and you in doubles, and we'll see who can sit still longest (while we slowly freeze to death!).