Trim? Let's discuss how to manage trim

[Storm]

The loose BC was the issue my wife was having. this past weekend we finaly found the issue... an ill adjusted crotch strap on her backplate arness. It's the little tings.....

 

[Charlie99]

My trim has improved greatly, but time to time I would roll left or right. How or what could I do to correct this. Thanks, Ronnie

One thing not mentioned so far is that having a whole bunch of weight up on your back and a positive wetsuit and body below that can result in an unstable situation. If you just let yourself continue to roll and go into a stable position where you are horizontal, but face up / tank down, then this is your problem. To solve that problem you have to move some weight off your back, and onto your gut/front side.

Are you using a backplate? If so, go to aluminum rather than steel and move the weight to lead weights on your waist harness or on the frontside of your weightbelt.

When trying out a 5 pound backplate w/o STA and a single tank I would be nice and horizontal with good head to toe trim, but if I rolled the tiniest bit to one side, then I'd just keep on rolling until inverted. (Horizontal head to toe, but face up / tank down). I had to overweight a bit with another 4 pounds in the stomach area to get to the condition where I could take assume roll or pitch position and stay there motionless.

 

[dumpsterDiver]

One thing not mentioned so far is that having a whole bunch of weight up on your back and a positive wetsuit and body below that can result in an unstable situation. If you just let yourself continue to roll and go into a stable position where you are horizontal, but face up / tank down, then this is your problem. To solve that problem you have to move some weight off your back, and onto your gut/front side.

Are you using a backplate? If so, go to aluminum rather than steel and move the weight to lead weights on your waist harness or on the frontside of your weightbelt.

When trying out a 5 pound backplate w/o STA and a single tank I would be nice and horizontal with good head to toe trim, but if I rolled the tiniest bit to one side, then I'd just keep on rolling until inverted. (Horizontal head to toe, but face up / tank down). I had to overweight a bit with another 4 pounds in the stomach area to get to the condition where I could take assume roll or pitch position and stay there motionless.

This has always seemed very important to me also. You want to have as much of the lead on your weight belt as possible on your hips or more forward on your belly. This functions as a natural keel weight which makes you more stable in the horizontal position and also reduces the tendency for the weight belt to rotate and shift during the dive.

I also notice this when using a steel tank and no weight belt. The rig is somewhat unstable in that if I roll to one side, I have a strong tendency to "turtle" onto my back since all my weight is behind me. I am much more stable with a weight belt and weights on my belly (in the front) and a very light aluminum tank above/behind me. Something to do with the center of bouyancy and the center of mass I think.

 

[fire_diver]

Loose BC is also easy to get. Feels all snug on land with gravity pulling it down but rolls around under water. Practice, practice, practice....

No kidding! I thought I had my plate nice and snug, until I got back into the water with it. After a little bit, I noticed my manifold was again at the back of my head and my shoulder D-rings were now down to my chest. I took another 3-4 inches out of the shoulders. I can still get it on, but it's a little more work. I noticed that my crotch strap automatically snugged up when I tightened the shoulder straps. Hopefully I can get back in the water soon to give it another shot. Thank God that walking with 100 pounds of dive gear is easier than carrying it in my hands!

FD

 

[Storm]

No kidding! I thought I had my plate nice and snug, until I got back into the water with it. After a little bit, I noticed my manifold was again at the back of my head and my shoulder D-rings were now down to my chest. I took another 3-4 inches out of the shoulders. I can still get it on, but it's a little more work. I noticed that my crotch strap automatically snugged up when I tightened the shoulder straps. Hopefully I can get back in the water soon to give it another shot. Thank God that walking with 100 pounds of dive gear is easier than carrying it in my hands!

FD

You may have adjusted the wrong part of the harness I (but if it works for you, go for it). My wife had a similar problem, plate riding up in the water. Instead of tightening, the shoulder straps, we tighened the crotch strap. Now her plate stays in the same position whether upright on dry land or horizontal in the water column.

 

[grazie42]

One thing that I found when I tried to "stay still" to check my trim was that I was unconsciously moving my fins...A good way to make sure that you´re not finning is to cross your ankles and clasp your hands.

With the abundance of cheap digital cameras another idea is to ask your buddy to film you during a dive, the camera doesen´t lie...