Trim

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I'm sorry guys, isn't the answer obvious.... I don't know if anyone's suggested it yet but stop working out! It's that simple.

There's been lots of great advice so I don't think a comment like that is detrimental. I'm just shooting in the dark here but I'm pretty sure that when people throw this term "balanced rig" around, they don't really know what it means.(not this thread) I've noticed in OTHER threads/forums that people only think of it as the " not over/underweighted/neutral at the end of a dive" thing. I allways think of it as where the wieght is distributed as well. Is that not a better way to think of it? Anywho, moving to a steel tank simply moves weight from your belt to your back. This should deffinitly help you trim out better. BUT Did you say you where diving a thicker wetsuit? What happens if you have a catastrophic loss of buoyancy? Now that you've taken weight of your belt it might make the whole situation quite desperate with the compression of the suit etc. I would just make sure it is still swimable, especially if you are diving a nice wall or something. If someone could come up with "non-baffoonarily convoluted" ditchable weight placed higher up on the diver that would be ... awesome.
 
I have same problem, lead legs. I recently took DIR-F and the instructor commented on how odd my trim is. In doubles, no weight belt, knees bent severly my hips drag. The really sad part is that I was not wearig a weight belt only because I knew (I wasn't going to be burning all my gas. If I breathed down the majority of my gas I would have been light. I just put on a 10 lb weightbetween my tankis up as I high as I could place it, and I switched to light weight fins (OMS Slipstream) these two seemed to help but gave me other problems. I had the same problem in singles too, however it was easier to fix, my single tank is a 119 steel wich is much shorter than my double 120s, this centers more weight up on my chest, again I made a 7lb lead weight (just happend to work out to 7 lbs...) that is bolted to the top of my back plate. I've been told that my trim is great in my singles rig. Not trying to suck you into DIR, but maybe consider a backplate, it will remove 5 lbs from your lower waist and distribute it along your back.
 
DIR-Atlanta:
Not exactly - AL80s exhibit a characteristic called a "righting arm", which is a moment of inertia that results from the center of buoyancy not being the same as the center of mass/gravity. This is a phenomenon that is well-known in boating - it is the effect that causes boats to want to return to vertical (or "right themselves") when they are rocked by waves.

The center of mass on an AL80 shifts forward as the gas is consumed, which causes the valve of the tank to want to drop (which causes the tank to want to rotate into a bottom-up position). Steel tanks are less affected by this, because their center of mass is further from the valve.

Several people have suggested moving the BC further down on the tank to compensate for this. That's actually not that great a suggestion, because it doesn't really overcome the righting effect. All it does is mask it by changing the location of the tank's centers relative to your own body's centers. Moreover, it is "self-limiting" in the sense that it only gives you so much play, because you can only move the BC so far. It also does not work on all cylinders or cylinder configurations.

Take doubles for example - most doubles tend to be head-heavy, which tends to force the diver into a head-down position (an effect that is particularly pronounced on steel doubles). Logic dictates that to overcome this, you move the BC up on the tanks, by repositioning the bands. The only problem there is that in most cases, you can move the bands as high as they will physically go, and you will still be head-heavy!

It's clear that another, more general solution is going to be required to solve this problem. With doubles, the way we compensate for this is to more fully extend our legs. With Jetfins on (which are negatively buoyant), this increases the moment arm to the diver's rear, which brings him or her back into a more level trim position.

So it's mostly about weighting and body mechanics/positioning, not where the tanks are in the bands. The DIR approach to this problem is for the diver to adjust his or her body to the tanks, not the other way around. This will allow you to properly trim out almost any set of tanks, independent of their buoyancy, what type of exposure suit you are wearing, etc. It's really surprising just how much control you have over this type of thing, just by changing the position of your head or legs.

The key first step however, is to make sure you are properly weighted. My guess is that 10 lbs is too much for you now, and that excess weight is forcing your hips and lower body down. Do the weight check and try making some adjustments with your legs - if you can't get that to work, then start thinking about where or how to redistribute the weight.

This stuff is not that hard to do, but it does take a little bit of practice and some good feedback from someone who knows what to look for. Once you get it dialed in though, it will make you feel much more stable and comfortable in the water.

What he said
 
I think we may be over looking the possibility that Brandon may in fact be head heavy which in turn causes him to lean back to find a point of balance thus droping his knees.

I could not diagnose the problem without a proper weight check and seeing him in the water, but just a thought.

I have seen many people struggle with knees down trim try to move weight up higher on the body.
Only to figure out later that by actually moving a little weight to the lower half of the body they no longer have to lean back to compensate for an unbalanced rig.

Usually see this problem in people wearing doubles but it could still be the issue in a single tank.

Just a thought,
Chris
 
Yup, trim can be tough to diagnose in person, much less over the internet. I was getting feedback that I was too head-down initially, but that was just me overcompensating for heavy feet...
 
BRANDY:
Im having trim problems and figured the best place to post would be with you dir guys and girls. Problem is lead feet.Im 6'5' 250lbs athletic build.I usually dive a 3mm wetsuit,AL80 and sherwood bcd.

DIR Atlanta has given you probably the best advice possible for trying to fix this in your current rig. Particularly over the internet. However, the non-PC, DIR answer is that jacket style BCs suck and it is impossible to get as good of trim out of one as it is with a backplate and wings. If they worked better, we would use them. All of the BCs on the market, even back inflate ones, simply "float" around on the diver way more than a harness. This in itself makes it harder to get good trim because the lack of stability causes your center of bouyancy to move around making the leg based and other adjustments discussed above even harder to learn. Experienced divers can do it but it takes more (needless) effort. Before wasting money on unneded steel tanks and other fixes designed to put patches on problems rather than fix them, I would recommend a GUE fundamentals class. If you aren't interested in that consider a backplate and harness and getting someone to shwo you how to set up a balanced rig.
 
BRANDY:
Im having trim problems and figured the best place to post would be with you dir guys and girls. Problem is lead feet.Im 6'5' 250lbs athletic build.I usually dive a 3mm wetsuit,AL80 and sherwood bcd. In fresh water I use 10lbs of lead in the integrated belt or pockets whatever you call them ,this was fine when I weighed 220lbs but I started weight training and I cant get level anymore.I like my bcd and would prefer to keep it. I tryied moving 6lbs to the top weight pockets(My bcd has trim pockets higher up kinda at the back of my ribs closer to my shoulder) And it diddnt help.Is Tank placement a factor or will going to steel the answer.Maybe I will get some of those kids pool floaties and put on ankels(just kiddin).Ive heard of tank weights but I think there for the bottom of tank.Help Please

Brandy, I didn't hear you mention what kind of fins you have. If your fins are negatively buoyant, such as Jet fins, you may struggle to keep your feet up. Like you, I also dive a 3mm wetsuit and AL80, although with a SS BP/W and only 4 additional lbs. When I had Jet fins, even with my knees bent and my feet up under my butt, I found that my feet sank like a rock. I switched to buoyant fins, and it solved my sinking feet problem. Although I miss the control afforded by the Jets, and wished that they made a buoyant version.:(
 
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https://xf2.scubaboard.com/community/forums/cave-diving.45/

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