Trim Help

[Scotttyd]

Can anyone advise me on my trim needs. I am 6'3" 240, I dive with HP130 tanks, and a zeagle brigade BC. In fresh water I turtle up, I do not use any extra weight in freshwater and am nearly perfectly weighted with 0 lbs. When I am swimming I do fine, but when I stop I go and roll over on my back if I do not keep finning. I am still horizontal (more or less) so ankle weights would not help in any way. In salt water I wear about 8 lbs of lead and keep it in the weight pouches (none on the cam bands) and I am much more evenly weighted. Any advice as far as moving tank up or down on my bank that might help?

 

[sandmanz32]

i would say all the weight being on your back is causing your problem. try a few trim weights on your belt and see if that helps

 

[Scotttyd]

i would say all the weight being on your back is causing your problem. try a few trim weights on your belt and see if that helps

so that being said, in order to achieve proper trim in fresh water, I have to be overweighted because I dive a big tank, that sucks! My fresh water diving is just local quarry diving, and I am looking at getting a smaller tank for those dive, likely an AL80 or HP100. Maybe once my drysuit comes, that will help as I have to add more weight to the front.

 

[TSandM]

Learning to balance a tank on your back is kind of like learning to balance on a bicycle. You get the hang of it with time. But -- If your BC is loose on you, the tank will have the ability to move from side to side, and if it does so, it will STRONGLY encourage you to turn turtle. If the tank is immobile and perfectly centered on your back, this tendency is decreased.

 

[sandmanz32]

so that being said, in order to achieve proper trim in fresh water, I have to be overweighted because I dive a big tank, that sucks! My fresh water diving is just local quarry diving, and I am looking at getting a smaller tank for those dive, likely an AL80 or HP100. Maybe once my drysuit comes, that will help as I have to add more weight to the front.

id just use 1 or 2 1lb trim weights

 

[David P]

hmm semantics... trim is generally head/feet up/down. This is "helped" by moving weight up on cam bands, down on weight belts, ect. You are rolling left to right, correct? That is because YOU are buoyant, and your tank that is attached to the top side of you is very heavy. You are like a reverse hot air ballon, with the heavy basket above the light weight balloon. I agree with Lynn's assessment that a loose BC will persuade you to watch your bubbles go up (must admit I got visuals on this...) Need to ask, where are you in the water when this happens, are you kneeling on the bottom? If so try adding some air to your bc, that should help buoy up all that extra weight. I see you don't have very many dives, what makes you so sure you are perfectly weighted for fresh water? Did you do a weight check with ~500 psi left in your tank? Couple things to think about, if non of these help, I would guess a few more dives and you will start to get the hang of it.

HTH

 

[Scotttyd]

hmm semantics... trim is generally head/feet up/down. This is "helped" by moving weight up on cam bands, down on weight belts, ect. You are rolling left to right, correct? That is because YOU are buoyant, and your tank that is attached to the top side of you is very heavy. You are like a reverse hot air ballon, with the heavy basket above the light weight balloon. I agree with Lynn's assessment that a loose BC will persuade you to watch your bubbles go up (must admit I got visuals on this...) Need to ask, where are you in the water when this happens, are you kneeling on the bottom? If so try adding some air to your bc, that should help buoy up all that extra weight. I see you don't have very many dives, what makes you so sure you are perfectly weighted for fresh water? Did you do a weight check with ~500 psi left in your tank? Couple things to think about, if non of these help, I would guess a few more dives and you will start to get the hang of it.

HTH

1. I need to update my dive count, I am around 50, but still a newbie, most this year

2. Yes I did a weight check at 500 psi, with no weight in fresh water and I sunk slowly.

3. What was a doing when I "turtled up". I was trying to hold trim in the water and be horizontal, not kneeling, trying to hover in the water

 

[Ken abucs]

A drysuit will require more weight, and should fix your balance issue. Another thinh you could try is arching your back. Just stick you chest out, and pull your shoulders back. Not so hard that it's stressful, just slightly exaggerate the natural arch of your back. I've never had an issue with turning turtle, but for me this greatly improves the stability of my hover.

 

[don Francisco]

Simple physics apply here. If your center of gravity is above your center of bouyancy, which is close to your centerline, you'll have a tendency to turn turtle. It's why the keel is on the bottom of a sailboat, not on top.

As TS&M said, as long as the tank is kept centered directly over you, it won't apply too much torque, but if shifts or you begin to roll, the torque will rise greatly and you'll have to work hard to avoid turning turtle.

You can add weight to your belly and be overweighted slightly, and/or you can wear a drysuit, or thicker wetsuit so as to require the extra weight on your belly.

If you're not mechanically declined, you can fashion a float from a piece of PVC pipe capped at both ends, and attached it securely to the tank. At 2#s per quart of volume, this device will pull your center of bouyancy up while the corresponding added weight at your belly will pull it down, thereby improving stability.

Personally, I'm not a fan of larger steel tanks if they're going to cause instability. I find the the extra effort of managing them uses more air thereby negating the original purpose of using them.

Aluminum tanks are much closer to neutral bouyancy than steel so in your situation, I'd consider an AL100 or 105 and save the steel tanks for colder salt water dives. dF

 

[Jim Kerr]

If you're finning all the time then I can see why you would need a 130cf tank. You'll suck up alot of air constantly finning. Try down sizing your tank and "then" add trim weights to compensate for the weight difference.

Also what TSandM said is very important. If your tank and/or BC is loose, then it will shift, causing the weight to shift.