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!).

[Jax]

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.

Me, neither!


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!).

:huh: Are you kidding me?!?!?!?! You'd rather do that in the PNW, instead of you going to Florida into those lovely, clear, warm waters? :confused:

[Peter Guy]

Dan, Thanks for the writeup, especially about the expanded definition of "Balanced Rig." BTW, you hit one of the things I really like about my DSS singles setup -- no STA but instead, the cambands through the wing/plate keeping the tank on the plate along with the DSS weight plates which are also bolted to the edges of the plate. This system creates a very stable (balanced if you will) singles platform, great for an HP130 and cold water diving.

[Splitlip]

My first bpw rig was a hammerhead aluminum plate with a hammerhead sta and oxycheq 30# razor. The hh sta is huge and bulky, v shaped for a 7 1/4 inch tank. First time I used it was with a pumped up lp 98. The diameter the 98's is 8 inches so the sta held it out there.
First time I used the rig it definitely wanted to roll me. I moved me weights to the front and that helped a little. Next thing I did was to bend the sta so the tank fit a bit closer to my back. A little better. Finally I picked up an oxycheq lite weight sta which only holds the tanks off by the thickness of the carriage bolts head plus about 1/16 inch. That did the trick.
I now dive up steel 100's and don't have any issues with oxy 18 # mv.

Dan, I don't think that halcyon sta did you any favors.

[Jim Lapenta]

Another reason I like my HOG wings for singles again no STA and like Lynne I have no problems with stability with my single LP95's. But then I do use the 32lb wing. Have not tried them with the 23 and AL plate yet.

[Mayor]

I recommend weight to ditch for new divers but you still can start setting up a balanced rig. As time goes on they find weight placement is key to what many of us shoot for a perfect rig. Yes the STA does move the tank away from you but not enough to cause problems for me. I like the idea that the STA weight can be added if diving different tanks. Of course I have always used the donut shapped wing for all my tanks. Now doubles have always been more stable in the water and ride better. Bob got me hooked on alum 80 doubles and I have never looked back. Steel 100's and 130's never worked for me. Maybe the steel 120's but at what cost to my back.

[sea_ledford]

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 :-)

So you decided to ditch your 3 120s for Al80 doubles instead of getting a 30-40 lb doughnut wing that doesn't need a STA? Do you think that would have fixed it? That is not meant as snarky, I've always HATED HP100's because they flip me over in my 30lb Oxycheq wing. It also sounds as if you are suggesting that wing taco is a good thing in a single tank set up. Isn't that heresy? :)

And if you are looking at drag difference, what has more drag: a 120 with a tacoed wing to keep it stable or a set of AL80 doubles?

Chris

[Blue Sparkle]

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.

I'm not sure what to think about your assertion that "balanced rig" is "one of the WORST descriptive terms." I would agree that the concept needs some explanation to be understood the first time one hears it, but then I would say that also goes for a large percentage of the terms in Scuba diving*.

And that's not to say that one should continue on doing something badly just because there are other examples; but I see it more as stemming from the fact that numerous concepts in Scuba diving do not necessarily lend themselves to being condensed into one-word definitions that are instantly, completely understandable by just seeing that one word or term the first time.

In other words, for this concept as well as many others, wouldn't *any* term that was used to talk about it have to be explained, to some extent, to someone unfamiliar with it? (Obviously that doesn't mean we should just call it "Polka Dot," or something; but I don't see "balanced rig" as being so far off as to be misleading.)

On the other hand, if there were no "shorthand" term, it could make the concepts hard to talk about or refer to later.

Edited to add: I realized I forgot to ask what term you would use instead of "balanced rig" for the same concept. Maybe there is a better one.

Blue Sparkle

*Slight tangent, but related: When I first got into Scuba diving I quickly decided that it would handily win an award for the sport with the most acronyms ever ;)

[danvolker]

I'm not sure what to think about your assertion that "balanced rig" is "one of the WORST descriptive terms." I would agree that the concept needs some explanation to be understood the first time one hears it, but then I would say that also goes for a large percentage of the terms in Scuba diving*.

And that's not to say that one should continue on doing something badly just because there are other examples; but I see it more as stemming from the fact that numerous concepts in Scuba diving do not necessarily lend themselves to being condensed into one-word definitions that are instantly, completely understandable by just seeing that one word or term the first time.

In other words, for this concept as well as many others, wouldn't *any* term that was used to talk about it have to be explained, to some extent, to someone unfamiliar with it? (Obviously that doesn't mean we should just call it "Polka Dot," or something; but I don't see "balanced rig" as being so far off as to be misleading.)

On the other hand, if there were no "shorthand" term, it could make the concepts hard to talk about or refer to later.

Edited to add: I realized I forgot to ask what term you would use instead of "balanced rig" for the same concept. Maybe there is a better one.

Blue Sparkle

*Slight tangent, but related: When I first got into Scuba diving I quickly decided that it would handily win an award for the sport with the most acronyms ever ;)
I can't tell you how many times friends of mine that are GUE divers told me my 120 and 18lb wing was not a "balanced rig"....I told them I thought it was. They did not really have an explanation for me of the issues they really meant, so I ended up ignoring this for well over a year. What would I say now, if I see someone with something similar to my old set up, or worse? I would actually say what is wrong with it...I don't think a one word description is worth the air you expel :-)

[RonFrank]

I was very happy diving my Stiletto and steel 100's in FL. I have no idea if I could hover as I was busy shooting Rockfish at 100'! :D

I think there is maybe an 2 inches difference between my STA and STAless on my cold water Hammerhead setup. One can buy a low profile STA if that helps you sleep at night. In CA this setup worked very well. Stable with no roll.

I think we over estimate our precision UW. I can hover all day shooting photo's. If I were to dive my BP in FL I would be 12# heavy. I would need an ABS wing and travel STA. I like my Back inflate Zeagle. So is this a means to an end, or are you going to diving doubles for the sake of diving doubles? I know some tech divers who never dive tech. I also have friends who do dive tech. Some are DIR, some are not. They are more alike than different. Just remember Kool-aide Stains!

[Blue Sparkle]

I don't think a one word description is worth the air you expel :-)

Okay, I guess I differ on that, but there is surely room for two opinions :)

I find it handy to be able to say "buoyancy" or "trim" or any of dozens of other words or short phrases that signify various diving concepts (some which are not all that simple). That doesn't mean I wouldn't explain one of them to someone for whom they were new or not understood though (or, conversely, look up or have someone explain any to me that I didn't know).

[dumpsterDiver]

I can't tell you how many times friends of mine that are GUE divers told me my 120 and 18lb wing was not a "balanced rig"....I told them I thought it was. They did not really have an explanation for me of the issues they really meant, so I ended up ignoring this for well over a year. What would I say now, if I see someone with something similar to my old set up, or worse? I would actually say what is wrong with it...I don't think a one word description is worth the air you expel :-)

I think it is sad. You are getting old.

Not so long ago you were all about efficiency and minimal drag and the ability to move efficently in high currents. I even remember a Volkerism about being able to keep up with dolphins....

Now you goal is to be a stable, planktonic, drifter that remains static for long periods of time??? .:confused::confused::confused::D

[dumpsterDiver]

To be honest, I have developed a strong preference for an oval shaped wing over the horseshoe shape.. for single tank diving, which is all I do. I disliked the air trapping on one side.

[Kern]

Can't say I'v noticed a great deal of difference between the 2. I think wing design & size, rather than U or doughnut, have more to do with ease of bubble control.

Ps. It does seem an interesting change of hart.

[lamont]

I can't tell you how many times friends of mine that are GUE divers told me my 120 and 18lb wing was not a "balanced rig"....I told them I thought it was. They did not really have an explanation for me of the issues they really meant, so I ended up ignoring this for well over a year. What would I say now, if I see someone with something similar to my old set up, or worse? I would actually say what is wrong with it...I don't think a one word description is worth the air you expel :-)

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.

...

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).

Up here we use steel tanks all the time -- because Al80s have crappy trim characteristics (head heavy tanks are bad in cold water) and you need to add >12# of lead to sink them. I dove double-80s for a few years after Bob tried to convert me, and I've broken them up for stage bottles now. Much better to just use double-hp100s or similarly sized steel tanks up here.

...

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.

[DaleC]

Here are a couple of short clips of my daughter and I in the pool. I am diving doubles with a 4lb BP (snicker) and she is using a single (snicker snicker). No weightbelts or BC's. Is this acceptable gear for fundies and is she too old for the course?


https://dl.dropbox.com/preview/q3oo5fxwvoco0fy/MVI_8424.AVI

https://dl.dropbox.com/preview/q3oo5fxwvoco0fy/MVI_8430.AVI

[danvolker]

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.

...

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 :-)




...

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.

[TSandM]

I think one of the things Lamont may have been talking about is what we learn pretty fast in cave diving, which is that overusing your breath for buoyancy control (beyond momentary adjustments) is a good way to blow through gas . . . Cave divers learn to correct buoyancy with wing or suit so that breathing can remain controlled and rhythmic, because that allows the longest dive.

[danvolker]

I think it is sad. You are getting old.

Not so long ago you were all about efficiency and minimal drag and the ability to move efficently in high currents. I even remember a Volkerism about being able to keep up with dolphins....

Now you goal is to be a stable, planktonic, drifter that remains static for long periods of time??? .:confused::confused::confused::D


One of these days you will decide to grace us with your presence on a dive....and you will see I am not giving up on swimming at "cruising pace" or "spearfishing pace"....I do plan on being in many penetration environments, in which I will need the ability to stop and be without movement....
Even in doubles and with jets on, I sincerely doubt anyone, even you, will complain about my "pace" :-)


p.s.
We are planning on going out on Narcosis this afternoon, if you would like to join us !

[danvolker]

I think one of the things Lamont may have been talking about is what we learn pretty fast in cave diving, which is that overusing your breath for buoyancy control (beyond momentary adjustments) is a good way to blow through gas . . . Cave divers learn to correct buoyancy with wing or suit so that breathing can remain controlled and rhythmic, because that allows the longest dive.

And this gets to how hard it is to convey ideas like this on a discussion thread. My expectation, is that most cave divers with good bouyancy and trim, make their wing inflation adjustments to the lung volume they plan of averaging throughout the dive, and to the breathing rate...getting an average swing up and down, and the wing needs to have inflation adjusted to this average....I do NOT think OW divers think about this, or even are aware of such a thing.

I absolutely agree that doing too much lung boyancy wastes gas....while normally I would never be guilty of this in the ocean, during Fundies open water dives with drills constant throughout, I WAS guilty of this overuse of lungs for control, and my sac rate became very average, instead of very low as usual.
I'll blame this on performance anxiety having Bob watching :-)

[VooDooGasMan]

dan how about when shootin vid, I review yesterdays dive a little bit ago and a sealion buzzed around and I noticed I just kept sucking, I breathe in and a little more and a little more. The vid told me that and not sure if it was buoyancy or just not letting bubbles out as sealions like to bite bubbles. I mean running vid especially when in the 5th and 6th atm's, I use breathing for buoyancy to keep vid quality and add air fewer times for this reason.

[TSandM]

Dan, having Bob watching would ruin my SAC rate too, I'm sure!

[danvolker]

dan how about when shootin vid, I review yesterdays dive a little bit ago and a sealion buzzed around and I noticed I just kept sucking, I breathe in and a little more and a little more. The vid told me that and not sure if it was buoyancy or just not letting bubbles out as sealions like to bite bubbles. I mean running vid especially when in the 5th and 6th atm's, I use breathing for buoyancy to keep vid quality and add air fewer times for this reason.
Yeah..when we are shooting, we do NOT want to take our hands of the camera to pull dump valve or to inflate....we need rock steady camera, both hands on while shooting. Most clips wont run more than 2 or 3 minutes.

[VooDooGasMan]

And that is why you have no real difference in sac rate also, I think.

[lamont]

And this gets to how hard it is to convey ideas like this on a discussion thread. My expectation, is that most cave divers with good bouyancy and trim, make their wing inflation adjustments to the lung volume they plan of averaging throughout the dive, and to the breathing rate...getting an average swing up and down, and the wing needs to have inflation adjusted to this average....I do NOT think OW divers think about this, or even are aware of such a thing.


Well, you have to do it on the fly. You need enough gas in your wing to float your tanks so that if you empty your breathing gas you won't get pinned against the roof of the cave and have gas in the wing to dump in that instance. So you need to have some gas in the wing, and that means that the wing (and drysuit) will need to be adjusted continuously in order to keep breathing normally out of the middle of your lung volume. Its a constant adjustment throughout the whole dive.



I absolutely agree that doing too much lung boyancy wastes gas....while normally I would never be guilty of this in the ocean, during Fundies open water dives with drills constant throughout, I WAS guilty of this overuse of lungs for control, and my sac rate became very average, instead of very low as usual.
I'll blame this on performance anxiety having Bob watching :-)

Right, the effect on your SAC rate from overuse of lung control is what I was primarily talking about.

The whole story of how Bob took me from just using my lungs to also using my wing and my trim and fins for buoyancy control has a lot more elements to it though.

[Blue Sparkle]

My expectation, is that most cave divers with good bouyancy and trim, make their wing inflation adjustments to the lung volume they plan of averaging throughout the dive, and to the breathing rate...getting an average swing up and down, and the wing needs to have inflation adjusted to this average....I do NOT think OW divers think about this, or even are aware of such a thing.

Edited to add: Before you read this, I just got to thinking, and I realized that what I'm addressing may not even be what you are talking about, but rather maybe your point is about some part of buoyancy that I don't even understand yet, thus proving your point. If so, then please pardon my post (which I'll leave here anyway).

******
This seems to broad to me. I speak as an OW diver. I won't even begin to say that my buoyancy was polished at dive 20 (or even now), but I will say that by then I had figured out that one uses the BC to set up their basic buoyancy and then lungs for fine adjustments. I'm sure I don't do it perfectly even now, and I probably sometimes over-use my lungs compared to the ideal; but I don't either JUST use my lungs or JUST use my BC.

Rather, I get the BC close, then use lungs a bit, and then if/when the lung part starts to become too "obvious" (i.e. too much at top or bottom of lungs), I adjust the BC to get myself back to "the middle" again. I'm pretty sure usual buddy does the same thing (it just seems logical?), and I can't believe we were that special, in the group of OW divers -- especially in our <25 "early" dives.

I can't speak for every OW diver - but that's what I'm saying: I find it hard to believe that "OW divers," as a group, don't "know" or think about this at all (?). My early dive training was about as mediocre as it gets, but just diving and working on buoyancy outside of any class made the BC/lung relationship reasonably clear (granted, most of my dives have been in "easy buoyancy" Florida, where a 5mm suit is the most extreme; but then that's the area you are speaking of as well).

Blue Sparkle

[dumpsterDiver]

One of these days you will decide to grace us with your presence on a dive....and you will see I am not giving up on swimming at "cruising pace" or "spearfishing pace"....I do plan on being in many penetration environments, in which I will need the ability to stop and be without movement....

Even in doubles and with jets on, I sincerely doubt anyone, even you, will complain about my "pace" :-)


p.s.
We are planning on going out on Narcosis this afternoon, if you would like to join us !


Thanks Dan. So are you giving up the big fins and gonna go back to jet fins now?

[lamont]

Edited to add: Before you read this, I just got to thinking, and I realized that what I'm addressing may not even be what you are talking about, but rather maybe your point is about some part of buoyancy that I don't even understand yet, thus proving your point. If so, then please pardon my post (which I'll leave here anyway).

******
This seems to broad to me. I speak as an OW diver. I won't even begin to say that my buoyancy was polished at dive 20 (or even now), but I will say that by then I had figured out that one uses the BC to set up their basic buoyancy and then lungs for fine adjustments. I'm sure I don't do it perfectly even now, and I probably sometimes over-use my lungs compared to the ideal; but I don't either JUST use my lungs or JUST use my BC.

Rather, I get the BC close, then use lungs a bit, and then if/when the lung part starts to become too "obvious" (i.e. too much at top or bottom of lungs), I adjust the BC to get myself back to "the middle" again. I'm pretty sure usual buddy does the same thing (it just seems logical?), and I can't believe we were that special, in the group of OW divers -- especially in our <25 "early" dives.

I can't speak for every OW diver - but that's what I'm saying: I find it hard to believe that "OW divers," as a group, don't "know" or think about this at all (?). My early dive training was about as mediocre as it gets, but just diving and working on buoyancy outside of any class made the BC/lung relationship reasonably clear (granted, most of my dives have been in "easy buoyancy" Florida, where a 5mm suit is the most extreme; but then that's the area you are speaking of as well).

Blue Sparkle

My OW training wasn't particularly mediocre. Around dive #25 I took fundies and I was diving as DIR/GUE as I could manage from the start. I understood buoyancy control as well as you did and as well as you likely do now certainly around dive 100.

There's another level of buoyancy control which Bob showed me in a couple of classes I took from him, but I didn't understand it until I actually took cave and started running reel into cave, and started technical diving deeper. You need to be adjusting your buoyancy control a lot more before it becomes "obvious" for one thing. Swimming around at 60 feet, relatively unstressed, though, it just doesn't matter to that degree.

So, yes, I agree with Dan that OW divers as a class don't know and largely don't care about what we're talking about.

(And actually probably the majority of technical and cave divers these days don't know either)

[Mayor]

Dan, having Bob watching would ruin my SAC rate too, I'm sure!I don't know for sure if it was the camera or being in the water with yoda but we did suck some air at 25ft.

[Blue Sparkle]

Thanks, lamont. Sounds like my "second thought" (in my edit) was correct then, and there is a whole 'nother level. Of course now I want to know about it :)

[Scott L]

I think it is sad. You are getting old.

Not so long ago you were all about efficiency and minimal drag and the ability to move efficently in high currents. I even remember a Volkerism about being able to keep up with dolphins....


One of these days you will decide to grace us with your presence on a dive....and you will see I am not giving up on swimming at "cruising pace" or "spearfishing pace"....I do plan on being in many penetration environments, in which I will need the ability to stop and be without movement....
Even in doubles and with jets on, I sincerely doubt anyone, even you, will complain about my "pace" :-)


p.s.
We are planning on going out on Narcosis this afternoon, if you would like to join us !

I doubt you would ever see DD on a reputable charter boat. They check for licenses, poaching, Etc., Etc. ;)

[Scott L]

Amazingly, Dan was able to fin all over the place on a Palm Beach reef today with Al80's and jet fins. Oh, also with a camera in tow. He's hooked! :)

[danvolker]

Thanks Dan. So are you giving up the big fins and gonna go back to jet fins now?
I will not toss out the big fins....there are still dives I will go on where I know that the primary mission will be cruising and distance covered...sometimes this will be scooter diving, sometimes it will be with the DiveR's.
On dives where I know that I will have to stop and hold still alot, and this relates to the goal of the dive, then I'll use the Jet fins...though I just had a pair of DiveR's show up that are aimed by diveR at being DIR or GUE capable....they are much stiffer than my long blades, are meant to be shortened to the length that I want for motionless operation or exploration level penetrations. I will try to use them soon, but they need to be glued to some Riffe silent hunter foot pockets, and the glue for this sets over about 4 days I think...So it may be over a week till I can try these ..and then settle on the right length. They will be very high tech :-)

[elvisisalive]

I think hell froze over.

[jar546]

Dan, you left out the part where you converted to split fins.

:chairfight:

[danvolker]

Dan, you left out the part where you converted to split fins.

:chairfight:
Fortunately I have not seen any pigs flying around the area :-)