Buoyancy and Trim

[FSU_KURT]

Hello all,
I have a scubapro knighthawk weight integrated BC with trim pockets. I have been working on my buoyancy after every dive and have bouyancy fairly well tuned. My question is, what is the idea behind the trim pockets? Do I just want to change my center of gravity a little? Will this hold be in a horizonatal position easier? Is there a certian percentage of my overall ballast weight that should go in the trim pockets? Or do I need to just mess around and find the sweet spot? Thanks a lot in advance. Also the trim pockets are located on the mid to upper back of the BC (near the shoulder blades).

Thanks
Kurtis

p.s. I guess that was more than one qusetion... sorry

 

[drl]

The purpose of the trim pockets is twofold: to accomodate extra weight if you need to carry more than will fit in the main weight pockets, and to allow you to move the weight up on your body to improve your trim. If you can hover horizontally in the water as you are, you may not need to put any weight in the trim pockets. If you find that your feet tend to drop when you stop finning, you might want to try shifting some weight into the trim pockets. I don't know of any formula; it depends on many factors. Try putting 2 pounds or so in each trim pocket (and removing that much from the main weight pockets, of course!) and see what happens.
If a personal example would help, when diving dry with my Ladyhawk and an AL80, I carry 6 pounds in each weight pocket and 3 in each trim pocket.
Someone else might have ideas for a formula, but mostly you'll have to experiment, since everyone's body composition is different.

Hope this helps.

Deborah

 

[Guba]

The purpose is exactly as drl described. Achieving horizontal trim, for most divers, is preferable in order to reduce drag and to increase comfort. In addition, photographers and videographers usually find it much easier when they achieve an almost "head down" trim, one in which there is more weight forward (don't over do it, of course).
My personal formula has changed for achieving trim. At one time, I put about 30 percent of my weight in trim and the rest of it on my waist (belt). Now, I put about 60 percent in tank trim pockets and the rest on the waist. I still have enough "dumpable" weight, but it's much easier for me to stabilize camera housings with this configuration.
Of course, all of it depends upon your own gear configuration, so my suggestion is to experiment until you do, indeed, find that 'sweet spot'.

 

[FSU_KURT]

thank you both

 

[PerroneFord]

Kurtis, where are you diving? Do you want to get in a pool dive in town? Do you have access to a pool in town?

 

[TSandM]

A very nice essay on balance and trim is found here

 

[Willie]

I still have enough "dumpable" weight

How does one consider how much weight should be ditchable?

Willie