bouyancy yo-yo

[scubabrn]

When I'm at depth and swimming my bouyancy seems fine. But when I spot something to look at and stop swimming, I begin to sink. Is this normal, am I under weight, over weight....? I don't know. Any in put will be appreciated.

 

[dherbman]

When I'm at depth and swimming my bouyancy seems fine. But when I spot something to look at and stop swimming, I begin to sink. Is this normal, am I under weight, over weight....? I don't know. Any in put will be appreciated.

You are an airplane. You need to become a baloon.

It's possible, even likely that you are overweighted. This can be compensated for by adding air to your BC.

How much weight are you using?
What type of exposure protection are you using?
How long have you been diving?

Welcome to Scubahoard, the answers you seek are here.

 

[Michael Schlink]

You are NOT neutral and it doesn't show up until you stop swimming. Adding a burst or two of air should take care of it. Adjust for neutral buoyancy will "hovering" motionless. Not swimming. Also, time heals all wounds, that is practice and diving will help you develop the "feel" for when you are truly neutral

 

[Diveral]

Have you tried to see how much weight you need to be neutrally bouyant at the surface? You could be overweighted or not adding air to your BC as you descend. Also you have a delayed response when adding or venting air out of your BC. It tales a little practice to get the hang of.

AL

 

[herman]

Welcome to the board.
Your definitely not neutral, whether you are correctly weighted or not depends on a lot of factors like wetsuit type and air remaining in your tank. Another possible (likely) problem is your trim. If you are trimmed such that your "natural" position is head up/feet down you will need to be a good bit negative to keep at a constant distance from the bottom. You are basically swimming upwards and to compensate you have to be a good bit negative to keep from heading off to the surface. When you quit fining the upward (positive) force goes away but the negative (downward) force stays and you sink. This is pretty common with new divers and I suspect it’s a big part of your problem.

 

[lorien]

I agree, you are not neutral when you are swimming, you are negative and you are compensating for that with your swimming. So when you stop, you sink. You want to adjust your buoyancy so that you can hover when you are stationary and not moving at all. When swimming make sure you are trimmed out so that you are not swimming "up" and then compensating for that by making yourself negative. Often we tend to look up a bit and then our feet are somewhat below us so we are kicking upwards. Then you tend to compensate by making yourself negative. This is also a huge waste of energy and will cause you to use more air. Work on getting trimmed so that you are in the proper position when swimming, work on being neutral when hovering then work on swimming staying at that depth. Then you should have it worked out. Takes some time.

 

[Mr Carcharodon]

When I'm at depth and swimming my bouyancy seems fine. But when I spot something to look at and stop swimming, I begin to sink. Is this normal, am I under weight, over weight....? I don't know. Any in put will be appreciated.

Both trim and weighting are important. Check you weighting with a near empty tank, you should be neutral at your safety stop. A yo-yo effect if often due to being overweighted. You add extra air to your BC to compensate for the weight, and it then expands as you go up the the water column. That makes controling your bouyancy harder.

Trim is maintaining a horizontal position in the water. Try looking back under yourself and see if you can see your feet. Or have a dive buddy look at your postion in the water. All weight around the waist usually leads to poor trim. Most people need to move a few pounds up to the BC with a weight on a cam strap, or a backplate.

 

[Guba]

Sounds like you are swimming in a "heads-up" manner. As the previous posters have stated, trim adjustment is all-important. Get neutral and it won't matter what your position is, you'll be neutral. Then, when you swim maintain the attitude and trim that provides the least drag, which is usually totally horizontal. You'll know when you've achieved it because a heads-up attitude will actually MOVE you up. A heads-down will also move you down.
Practice will improve your skills...have fun diving!

 

[boulderjohn]

This is an important moment for you--seriously.

You have just truly sensed that you are overweighted at that moment--many divers never have that realization.

Yes, a little shot of air will help you, but...

The next time you dive, try taking a little less lead. The less air you have to put in your BCD to compensate for the amount of lead you have on your hips, the happier you will be.

 

[Damselfish]

Don't just take less lead, do a weight check at the safety stop. Or do it at the beginning of a dive then add enough weight to make up for the air you will use (5-6 pounds in your typical AL80.) You may be overweight, or you may be perfectly weighted - for all anyone knows from the info (not) given it's possible you're just not adding enough air to your BC at depth to compensate for suit compression.