Keep Trim Position Without Any Movement

[Emantre.9900]

I'm really struggling of keeping my trim position underwater. I'm trying to maintain the proper trim position without any movement. But can't do it, when I'm using sidemount, legs didn't move too much, but once I switch to twin set, it start move a lot.
Does anybody know how to go thought this?

 

[divad]

In my case, I had to switch from a SS BP to an AL BP and put 4 lbs of weight on a rubber weight-belt.....but that may not help you at all.

 

[The Chairman]

It's time to close your eyes. Get in a pool with the offending tanks. Get into a hover 6 inches above the bottom. Close your eyes and 'let go'. Stop all movement. The part of your body that hits the bottom first is the heaviest. Shift your CoG either by moving your wing or moving your tanks. Keep at it. It can be a bit frustrating, but you can do this with patience and perseverance.

 

[Kharon]

+1 on moving weight - but - I had to move weight from my BC pockets to the tank strap. I also make my own weights in ½# increments starting with 0.5 through 3. I could then really fine tune my trim. I dive both steel and aluminum and can adjust for even a wee bit of difference in buoyancy.

 

[tbone1004]

it's also time in the water. Your body needs to learn to naturally compensate for any slight variations by adjusting the position of your legs. Your balance point may very well be off, especially in doubles, but you didn't say what you were feeling. Was it lateral instability vs sidemount so you want to roll over? Was it feeling head heavy? Lots of variables that could very well be easy to fix, or it could be something more involved, but odds are if you were using the same fins as you do in sidemount, when you switched to twinsets you became very head heavy due to the manifold and higher positioning on the body. Switch to a heavier fin and it will likely help to fix it

 

[DivemasterDennis]

What netdoc said. and what tbone said. There is no substitute for time in the water, and proper amount and distribution of weight. Body position control (trim) is made more difficult if you are under or over weighted. Once you establish neutral buoyancy, you should, with time and practice, to maintain it in any body orientation- inverted, head stand, horizontal, vertical. A good place to start if you have a deep enough pool, is to maintain a head down hover in mid water. If you can do that at pool depths, you will find you are at place where trim at depths of 30 feet or more is easy.
DicemasterDennis

 

[richboslice]

I was having the same issue. I dive a 98 cu ft steel tank rated for 3180. It's pretty long and I tend to be feet heavy with it. I switched to a an AL 80 on a pool session and trimmed perfect. I actually loaned my weight belt to a diver so I was 6 lbs lighter than usual but I trimmed perfect. I am trying to achieve this with my steel tank as well. I just read a post from 2012 where someone mentioned keeping your ankles close to your butt and your arms out when stationary really helps with this.

 

[The Chairman]

Here's another fun skill to try... one that I just added for my students to accomplish. Try Underwater Stone Jenga. Staying in just one spot, build a tower out of rocks you can reach. When you "get it", you won't be passing over the pile and then doing a lot of u-turns to get back to it. The pile should be right in front of you as you work on it.

 

[TMHeimer]

Time in the water. After about 2 years (50+ dives) I won a pair of split fins. They are negatively buoyant. When I am fully geared up diving my feet are ever so slightly heavier than torso and eventually will sink while hovering. So slight that I don't bother to adjust (such as weights to the tank strap). You'd never know it when I'm moving forward horizontally. Without a fair number of dives already, I wouldn't have noticed it myself.

 

[Kevrumbo]

My back begins to fatigue, and it aggravates a chronic pinched nerve condition in my neck -actively holding an extreme horizontal trim.

Hold an active hard horizontal trim for as long as necessary along with proper frog & modified frog/flutter kicks as needed to pass over a silty section of an Overhead Cave/Wreck for example, so as not to stir it up. Otherwise, go ahead relax your back & neck, let the legs/knees & head drop a bit and passively hover above the silt (or open water reef/sandy bottom) while looking around enjoying/examining the scenery.

The idea in the "passive horizontal hover" is to adjust weighting so that your whole body trim moves slightly up & down as a unit during nominal breathing cycles, without your head & upper torso coming up & simultaneously knees/fins rotating down into the silt. In tropical waters with a 1mil skinsuit/3mil hooded vest and AL80 doubles/AL BP&Wings, backmount and sidemount, I needed 3kg/6lbs weight between my shoulder blades to counter my upper torso coming up during inhalation; In cold temperate waters with a drysuit and AL80 doubles /Steel BP&Wings, used 2.5kg/5lbs tailweight and heavy jetfins to counter the floaty feet & legs.