Getting to the perfect buoyancy

[Walter]

Why break it if you don't know how to fix it?

 

[scubatexastony]

Arching my ankle once in a while to level off constitutes poor trim, so be it, I like my setup. I think swimming is the only way to learn to control your attitude, (BOTH mental and physical~!) along with adapting all this great input as to trim weights/ back plate/ ect. No person will be identical to another (point well taken as to the lungs being the largest positive area, and feet, legs the most negitive). We fell many times as tots before we mastered walking.

Swim, diver dudes and dudettes.

STT

ps. swim=get wet, dive, hover, invert, roll, PRACTICE! (but you MUST enjoy yourself)

 

[Zept]

My trim is broke and I don't know how to fix it :-(

If I keep perfectly still, my feet sink and I end up vertical. I'm just built that way. I can't move my tank because I'm small and short-backed... there's nowhere for it to go. My BC has pockets for trim weights, but I'm reluctant to use them because I only carry 4kg (8lb) of weight. If I put some of it on my back, I won't have much left to ditch. So, what's left? Ankle floats?

 

[scubatexastony]

I GOT IT>>>> NECK WEIGHTS, Mr. Ts gold!

tony

 

[Uncle Pug]

Originally posted by Zept
I'm just built that way. I can't move my tank because I'm small and short-backed... there's nowhere for it to go.

Ankle floats?

Most of us are built *that way* - lungs buoyant ... legs not...
1. Do you hit your head on your first stage? No? Raise the tank...
2. Your feet are heavy...move them closer to your body to balance the teeter-totter....how? you ask... I'll answer at the bottom of this post.
3. Ankle floats....I take it you are a watm water diver... wetsuit?...use wet suit boots and light fins.

Now for the real deal:

Let's try this out on the living room floor....get prone...(on your tummy)....now raise your lower legs with your feet pointing behind you....imagine you have fins on....do a little flutter kick using your ankles....did you move across the floor???.....no? Good, that would be really weird...but you get the idea - modified flutter kick. The power swimmers will howl because this will not speed you through the water but you will move with finesse and see a lot more too. View it here:
http://www.fifthd.com/divestore/classes/video/flutter.htm

Let's try something even better...but it does take more skill...and uses less air too! Back on the floor.....legs up as before... move your feet apart with toes still pointing back....now this is the hard part to learn but becomes second nature very soon....cock your ankles so that the bottoms of your feet are facing each other....well at least as much as possible....now bring your feet together trying to clap your heels....unless you are jointed very weird your feet will probably not come together flat but will be more open at the top while touching at the bottom edge....if you were underwater instead of on the livingroom floor and if you were wearing fins... the water would be channeled back and up....you would squirt forward and the bottom silt wouldn't even know you had past by - this is the frog kick. View it here:
http://www.fifthd.com/divestore/classes/video/froglicks.htm

 

[Uncle Pug]

Originally posted by scubatexastony
I GOT IT>>>> NECK WEIGHTS, Mr. Ts gold!

tony

Actually Tony this is the only legit use for ankle weights....snap one around the neck of the tank.....
However I would view this as last resort compensation....

 

[roakey]

Originally posted by Uncle Pug
Actually Tony this is the only legit use for ankle weights....snap one around the neck of the tank.....
However I would view this as last resort compensation....

Why do you consider this as a last resort? Given the small amount of weight that Zept has to work with (4kg/8lbs) a 1kg/2 lb ankle weight around the valve might be exactly what's needed in order to move the center of mass forward as much as possible with as little weight as possible. Which may be your definition of “last resort!”

Assuming that Zept is correctly weighted and diving an AL80, having 3kg/6lbs ditchable weight would make him/her (sorry Zept, you give us no clue ) exactly neutral if there was a need to ditch at the very start of the dive and positive once any amount of air has been consumed. The ultimate balanced rig (to introduce yet another DIR concept).

I'm taking a wild guess and assuming a skin, Polartec or *very* light wetsuit here, given that it's Singapore we're talking about.

The only other solution is for Zept to move to a colder climate and suffer like the rest of us, which would give us some more weight to work with.

If an ankle weight doesn't give you enough forward ballast, you’ll simply have to live with a slight trim problem. As UP states, relaxing with your knees bent so your legs are “shortened” will move your center of mass up and may fix your trim.

And if any of us ever give you a hard time about your trim, just point out that you get to dive tropical waters any day and we’ll slink off into our corners…

Roak

 

[Zept]

I am a she and I wear a 3/2 wetsuit (and I still get cold). I use an AL tank, but I'm not sure of the size, because it isn't mine. I can't move the tank up without hitting my head on the first stage (and I'm not sure it would help -- aren't AL tanks neutral to positive?), and I can't move it down because the band is already at the edge of the curved bit of the tank (if that makes any sense).

So far my best solution to the 'sinking feet' problem is to waggle them gently when I need to stay in one place -- not elegant, but it keeps them up without moving me forward. I'll give the frog kick a go next time I'm in the water.

Thanks for your ideas,


Zept

 

[CaptAl]

Okay, I've been to the pool and now know how much weight I need for various suiting-up options depending on where, when, water temps, etc (e.g., full farmer john, top only, bottom only, etc). The question is ... how much additional weight should be added to achieve the same buoyancy in salt water? Is there some standard or do I need go through all these suiting-up options again?

 

[Bob]

Zept,
The best thing I've ever done to improve my trim was to switch to steel tanks. The Al. 80's are like lift bags on your back from say, 1500psi on down. Try a couple of dives with steel, they are much easier to dive with than Al. LP steel bouyancy characterstics will range from negative at the start of the dive to neutral or slightly negative (more likely negative) at the end. It will make a difference in the quality and ease of your dives. :tree:Bob