Perfecting Buoyancy and Trim

[rmills]

My last dive I planned to follow some instructions I read where I dive until my tank is down to 750 psi and then I go to 15 ft, empty my BCD and then play with my weight until I'm neutrally bouyant. Then once I've achieved that I need to play with the position of the weights so that without trying I remain in trim.

The first step I came to realize that I didn't need any weight. Then I went to the next step and realized that when I start in trim and just let my body do what it's going to do I ended up in a vertical position. The challenge now is how do I achieve natural trim when I don't have any weight to move around?

 

[tursiops]

My last dive I planned to follow some instructions I read where I dive until my tank is down to 750 psi and then I go to 15 ft, empty my BCD and then play with my weight until I'm neutrally bouyant. Then once I've achieved that I need to play with the position of the weights so that without trying I remain in trim.

The first step I came to realize that I didn't need any weight. Then I went to the next step and realized that when I start in trim and just let my body do what it's going to do I ended up in a vertical position. The challenge now is how do I achieve natural trim when I don't have any weight to move around?

Use lighter fins, move your tank in the BCD, lay flat, face down, bend your legs at the knees so your feet are closer to your body.

 

[steinbil]

To add to the previous answer: extend or contract arms/legs to bring them further away or closer to your center of gravity to adjust the balance/trim.

Also: in some configurations it is unrealistic and not required to be in perfect trim when completely relaxed. A little bit of tension in your core will stabilize you.

 

[rmills]

Use lighter fins, move your tank in the BCD, lay flat, face down, bend your legs at the knees so your feet are closer to your body.

I could do lighter fins. I could move my tank a little but not sure how much it will help. I'll give it a try though. Thanks.

 

[lowwall]

In addition to the above.

Are you sure you got all the air out? It's pretty unusual to require no weight with conventional gear. You'd need a lot of lean muscle mass and a low body fat percentage. Do you sink like a stone when swimming?

What kind of BCD? Some fabric ones are a couple of pounds buoyant. Switching to an backplate and wing with a light aluminum plate might help with the trim.

What kind of wetsuit, if any, were you wearing? A shorty could contribute to this.

 

[scubadada]

Hi @rmills

Out of curiosity, what is your gear configuration that requires no weight? BC or BP&W with alum or steel plate, alum or steel tank, exposure protection, fresh or salt water?

Thanks

Edit: I see @lowwall was thinking similarly

 

[rmills]

In addition to the above.

Are you sure you got all the air out? It's pretty unusual to require no weight with conventional gear. You'd need a lot of lean muscle mass and a low body fat percentage. Do you sink like a stone when swimming?

What kind of BCD? Some fabric ones are a couple of pounds buoyant. Switching to an backplate and wing with a light aluminum plate might help with the trim.

What kind of wetsuit, if any, were you wearing? A shorty could contribute to this.

I'm pretty confident I got it all out. I used the hose and the dump valve. I do sink pretty hard while swimming.

I have an aluminum plate and wing. I was wearing a 5mm full wetsuit.

 

[rmills]

Hi @rmills

Out of curiosity, what is your gear configuration that requires no weight? BC or BP&W with alum or steel plate, alum or steel tank, exposure protection, fresh or salt water?

Thanks

I was using a BP/W with an aluminum plate, aluminum 80, 5mm full wet suit and in fresh water.

 

[scubadada]

I was using a BP/W with an aluminum plate, aluminum 80, 5mm full wet suit and in fresh water.

Don't take this wrong, but you must be pretty dense to not require any additional weight with that gear .

I would have guessed a steel plate and/or a steel tank, each adding around 4 lbs. Perhaps even less exposure protection.

Just for perspective, with a BC with little to no intrinsic buoyancy, an AL80, a 5 mm full suit and 5/3 mm hooded vest, in salt water, I use 14 lbs.

Best of luck with your goal of improving your trim. Let us know how you do.

 

[rmills]

Don't take this wrong, but you must be pretty dense to not require any additional weight with that gear .

I would have guessed a steel plate and/or a steel tank, each adding around 4 lbs. Perhaps even less exposure protection.

Just for perspective, with a BC with little to no intrinsic buoyancy, an AL80, a 5 mm full suit and 5/3 mm hooded vest, in salt water, I use 14 lbs.

Best of luck with your goal of improving your trim. Let us know how you do.

Hahaha... I suppose I am dense. I was surprised too. I had been carrying 4 lbs when I did this exercise. I kept dropping my weight until I had none. I tried again picking up just 1 lb and sure enough I descended.