Let The revolution Begin!

[NAM001]

I hope all of it was "ocean-related" (well, not the fin-pivot). Neutral? Well, I practiced more later, but "staticly" neutral (i.e., not swimming) wasn't too hard anyway.
I spent over an hour in the LDS pool last weekend trying out my new Zeagle Ranger BC (Christmas present!). I was specifically thinking about bouyancy and trim and weighting. I had 14lbs with my own 5/3 full wetsuit at my OW cert (with a wrap-around jacket BC) -- ended up with 10lbs in the pool and was still able to be neutral with little or no air in the BC with 1000psi so I'm probably at least a pound or two "heavy" with the 10lbs. The trim was OK, but I did notice that I tended to be a bit head-down from horizontal (the weight was in the integrated weight pockets so a few inches higher than it would be on a belt). I'll be working on it!
I know how to follow an example and was observing the Instructor, assistant and DM(s) in the pool and the quarry. This was the only exposure to any type of non-flutter kick -- they weren't "taught" at all. When I did my AOW (with no dives between OW and AOW) I was able to do a couple of fun dives with one of the DM-in-training divers. They were great. I even was the "lead buddy" at the end of the weekend for an OW couple who had been in my OW class, but couldn't do the cert dives until the weekend that I had my AOW certs. They weren't entirely comfortable going in without someone else -- that I was only about 6-7 dives more "experienced" was enough!

As for the "pipeline," I think that makes a great deal of sense. Get your OW, then have several "steps" (not necessarily certs) that can be taken before/with/after AOW or specialties. Perhaps OW should require an "elective" between a "probationary" cert and the "full" OW cert. The instructor (and PADI materials, I believe) reminded the class that the OW cert was more like a "learner's permit" than a "license to dive."

-Rob

the probationary thing is an intereesting idea say you get the curse completed and you get a 90 day temp cert. if you dont get x amount of dives you have to take the coursre over again. that would tke care of the once a year diver on vacation nad also provide the new certie to get some time to woek on some weak areas and get some actual non class time in the water. kinda of like a pilots solo stage before being able to fly with passengers.

remember you have to add a couple of punds for salt water. move your tank around a bit and you may be able to take care of the trim, it took me a while i am close and every time the salinity changes i have to start over on the fine tuning. i am now carrying 4-5 in the bs and in the belt i run 2-6 depending on frosh and salt water. a couple times i took extra weight with me and tied to the anshor chain and put them on later as i used air. i wonder what some of teh large souble users do with 10+ pound weight shifts from air consumption. i am working n a gismo to counter this. got to keep an active mind. better to be a little heavy at 1000# but not so much that the bc has tu be filled to much with a full tank, (air compression at depth) it adds to the problem. i find that with my steel 95 over filled that there is perhaps 5 lbs difference from start to end. i have set 500# as my target neutral point with no air in the bc. then 800-1000 will make me a little on the heavy side and easy to handle on the surface with the bc but not light to make me pass the safety stop.

thanks

KWS

 

[perpet1]

An increasing number of charter operators are requiring AOW cards to go to the "cool" places (e.g. the SG) and if you actually would like to spend some time there, you need the Nitrox card as well.

This is why bundling those things is important. The Dry Suit is important because if you want to dive any of the charters north of Florida, you will want one and again, without the card nobody will rent you one.

So I read you proposal and without discussing if it is feesable to actually deliver this kind of class I would like to look at the "value proposition".

You claim that this would grant certification for ow, aow, nitrox,.... and I agree that this is the case if you run the class you proposed. Now those many dive operators that only take aow need to be addressed. HOW do you gain the international embracement (for lack of a better term) of your "certificatioon". Becuase this is going to be such a specialized intensive course there are going to be some obsticals like 1) you are obviously going to pump up instructor requirements such that you will never have a large instructor pool 2) the cost will be such that you will never have a lot of certified divers 3) as a result of 1 and 2 you will never have the recognition of the dive community (internationslly). I agree in the areas where your program is taught you will have extremly knowledgable and skilled divers but if you venture outside those areas you may find that it is not accepted.

So imagine you are this diver that went to the Genisis school of dive and has this awesome certification. Now you are on a small island and the dive operator does not recognize the certification.

I think the business case for this type of certification agency would be the hard part. Best of luck.

 

[dweeb]

You claim that this would grant certification for ow, aow, nitrox,.... and I agree that this is the case if you run the class you proposed. Now those many dive operators that only take aow need to be addressed....

So imagine you are this diver that went to the Genisis school of dive and has this awesome certification. Now you are on a small island and the dive operator does not recognize the certification.

Not really an issue. The word gets around quickly, and it's been widely speculated that you could make your own C-card,
from a ficticious agency, and if it looked good, few would question it.

Go to any operator who demands an AOW card, and show them an
entry level card from LA County, or an entry level YMCA card from earlier than 1985 (with evidence you've been diving regularly in the interim) and they'll take it. I've also been
places where I just show them an OW card for advanced sites and they accept it because of the instructor's name on the back.
The operators are very aware of agency differences. They won't tell you out loud, for fear of stepping on toes, but when they get a card, there are factors other than the certification title that they consider.

 

[Genesis]

So I read you proposal and without discussing if it is feesable to actually deliver this kind of class I would like to look at the "value proposition".

You claim that this would grant certification for ow, aow, nitrox,.... and I agree that this is the case if you run the class you proposed. Now those many dive operators that only take aow need to be addressed. HOW do you gain the international embracement (for lack of a better term) of your "certificatioon". Becuase this is going to be such a specialized intensive course there are going to be some obsticals like 1) you are obviously going to pump up instructor requirements such that you will never have a large instructor pool 2) the cost will be such that you will never have a lot of certified divers 3) as a result of 1 and 2 you will never have the recognition of the dive community (internationslly).

Very simple - according to the RSTC you will meet the requirements for an AOW, Nitrox, etc card(s). Therefore, the card itself will say so on the back, and of course there will be a way for anyone who questions it to get ahold of the "main office" and check it (and you) out - since your records WILL be there (as they are with SSI, PADI, etc)

You might get questioned once - but only once. Particularly once a given op sees you in the water. That'll be the end of the problem for that operator and for all who come after you with the same card.

 

[MikeFerrara]

i wonder what some of teh large souble users do with 10+ pound weight shifts from air consumption. i am working n a gismo to counter this. got to keep an active mind.

thanks

KWS

No need for a gismo. If your center of gravity and center of buoyancy are close enough to each other to start with the effect on trim as gas is used is minimal . A minor change in balanced can be compensated for with body position by extending or bending the legs a little, raising or lowering the head a little and arching the back and/or rolling the shoulders back a bit. It's like moving the balance point on a beam. Place a little more weight on one end of the beam and the beam tips that way. Lengthen the other end and the bean tips back that way.

This is the perfect example of simple but very important basics that typically aren't taught. Students dive 100% better much faster if they understand and practice this.

 

[Genesis]

DING DING DING DING DING!

Have a CIGAR Mike! Hot Damn!

One of the things that really gets to me is that NO class I've seen pays ANY attention to this fundamental principle.

For that matter, neither do some of the people complaining about various wings and BCs (but that's a topic for a different thread )

There are two balancing forces you are concerned with as a diver - CB (Center of Buoyancy) and CM (Center of Mass). These are both THREE DIMENSIONAL points.

If your CB is colocated with your CM, then you can freely move in any plane (pitch, yaw or roll) and are equally stable. Unfortunately, this is extremely difficult to achieve in practice and even harder to keep achieved.

It is, by the way, why diving with too much weight is so destabilizing, as any small shift in position causes large changes in where the air (in your BC and/or drysuit) moves to, which radically changes the CB and thus your stability - because you are carrying excessive gas in the wing/BC in order to compensate for the excessive weight.

With your CB/CM colocated you can do a barrel roll or sommersault and not change position (vertically) in the water, and you can easily go head-down, head-up, or to any other desired position without trouble. Unfortunately this ideal is not achieveable in the real world, because your BC does shift (the air in it tends to go to the highest point), but you can get as close as possible by minimizing the amount of gas you need in the BC. More on that below.

If your CB is ABOVE (towards the surface) your CM, then you are stable in the water and need exert no effort in order to remain level in your current plane of swimming. A CB slightly above (towards the surface) your CM is ok, as it makes keeping proper trim easy.

If your CB is BELOW (towards the bottom) your CM, then you are unstable. It requires constant effort to keep from starting a roll that will continue on its own. If you roll sideways a bit in this condition, you will tend to continue to roll until you "turtle" on your back. This is an unstable condition and is best avoided if possible; it is extremely uncomfortable and difficult to dive effectively in this fashion.

Likewise, if your CM is towards your HEAD in relationship to your CB, you will tend to float head down, and if it is behind your CB, you will float head-up. Unfortunately if your CM is below your CB (towards your feet) as you rotate feet-downard your CM now drops below the PLANE of your CB, which tends to make you go feet-straight-down! Bad karma! Likewise, if your CM is towards your head, you will tend to do headstands. Both are extremely uncomfortable as you end up "fighting" your natural position in the water.

Trim is the art of placing both your buoyancy (to the extent you can adjust it - with some systems, such as a wing with multiple mounting points you can to some degree) and mass (weight you carry) properly so as to result in a balanced configuration where, as nearly as possible, the CB and CM are colocated just below the surface, with an empty tank, and NO gas in your wing/BC. If you know the individual contribution (positive or negative) that each item in your diving kit makes, however, you can figure out roughly where to start with positioning various items to achieve, as nearly as possible, this ideal.

Now if you have ONLY the amount of gas in your wing/BC necessary to counteract the mass of the gas in your tanks at the beginning of the dive, plus any wetsuit compression if you are at depth, you minimize dynamic instability. If you are diving dry, the trick is to have no more gas in the suit than is necessary to offset squeeze; the volume of the suit does not change at depth, and thus it does not enter into the dynamic computation at all. This is one of the beauties of a drysuit, particulary compared to thick wetsuits.

It is for this reason that wetsuits are "harder" to dive deep, as their buoyancy contribution changes AND they force you to use too much air in your BC/Wing as you go deeper, and the more gas in the wing/BC, the more it can shift and cause dynamic instability. A drysuit with excessive gas in it is even worse, as that causes extreme dynamic instability.

 

[NAM001]

No need for a gismo. If your center of gravity and center of buoyancy are close enough to each other to start with the effect on trim as gas is used is minimal . A minor change in balanced can be compensated for with body position by extending or bending the legs a little, raising or lowering the head a little and arching the back and/or rolling the shoulders back a bit. It's like moving the balance point on a beam. Place a little more weight on one end of the beam and the beam tips that way. Lengthen the other end and the bean tips back that way.

This is the perfect example of simple but very important basics that typically aren't taught. Students dive 100% better much faster if they understand and practice this.

trimming your self and trimming a submarine use the same principle's obtain overall virtically stability. then distribute to get bow stern ballancing. it is a cake walk. i can lay horizontal and use very little effort to stay put. im not the best but i am adaquate. so long as people dont start running fwd and aft i can do the same to a submarine and have done it. the only difference is that with a sub you are controling ballast with a non a compressable unlike when diving. pull the car from the front or push the car from the rear it still moves forward. i think i used the word trim instead of boyancy with the doubles comment. i agree in trim is in trim. light and heavy overall is a different matter, and what i was refering to. my bag.

my question about the large doubles and large weight changes is tha to comp you need to have that air in the bc = to the negative weight of the tank air. use te air and you need less air in the bc to comp with. the more air use the more you have to use and vent to stay down unles you go to one depth and stay there. if you are doing a wreck and go over the thing, up 20 over and down 20, you have to vent for the shallower depth and fill when you get back down. some may argue this but the positive boyancy of air at 60 taken to 40 may not allow you to go back to 60 without venting. 100 to 80 is easier to handle. to carry 5 lbs neg from full tank you have to have 1/2 gallon of air in the vest. its a continual dynamic problem beecause of compressability. the more you can convert to static the more stable you are. i tried it a while back. i trimmmed for the full tank and took 4 lbs extra with me and left it at the anchor. needed very little air at all. then none then i put on a couple lbs . by the time i was at 800 i had all weight on and went up. not every situation would allow to do this. you cant roam a reef from one end to the other. but you can do a wreck like that. btw i would not have thought of doing this but i thought that if i was taking down weight for some others i would play and see what i could do. others were blowing and venting every time they changed depth. i did nt have to cause i had minimum dynamic bouyancy (air). i was static (lead) i have also been known to just pick up a rock from the bottom and pocket it just to stay slightly neg as i consumed air. am i doing it by someones prefrered book,, probably not... but the book is not the only way to get it done. too many have a one way fits all approach to a problem. look for any beginner to say what genisis has posted and explaine what it means and it will be like that star search program. genesis's explanation is darn close to sections of a ships ballasting and compensating manuals.

 

[MikeFerrara]

KWS,

You're right that when you're heavy adjustments need to be made more often. In a best case you will still be overweighted by the amount of gas you carry and with multiple large tanks that can be 16 pounds or more. Other equipment we sometimes carry can make us even heavier.

Drop weights have been used more for compensating for suit compression than the weight of the air. The problem of course is that you must be someplace where you know that you'll get back to your weights. A cavern maybe? If you try to compensate for the weight of the gas this way you would also have to get back to the weights in time.

 

[GDI]

Hey KWS, you sound like you are on thre right track. Check this web page out. I use it as a simple starting pont for my students
http://www.genesisdiving.com/buoyancy.shtml
Good Luck

 

[NAM001]

KWS,

You're right that when you're heavy adjustments need to be made more often. In a best case you will still be overweighted by the amount of gas you carry and with multiple large tanks that can be 16 pounds or more. Other equipment we sometimes carry can make us even heavier.

Drop weights have been used more for compensating for suit compression than the weight of the air. The problem of course is that you must be someplace where you know that you'll get back to your weights. A cavern maybe? If you try to compensate for the weight of the gas this way you would also have to get back to the weights in time.

yes and thats the gismo i am working on.


regards

KWS