Can't get away from a feet down position at depth
- Thread starter cmfd404
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Stiil, it doesn't seem horribly excessive. The way to check to see if you are properly weighted is at the end of the dive at 10 or 15 feet, with your tank nearly empty, dump all the air from your bcd. If you sink you have too much lead. If you float not enough. You should be able to maintain control of your buoyancy with your breathing with no air in your bcd. Have someone check for trapped air when you do this, and don't swim with your hands or feet.
don Francisco
Contributor
Managing trim properly takes an understanding of both gravity and bouyancy. It also requires bit of undertanding of torque. Think back to your childhood and playing on a seesaw. Two children of different weights could balance the seesaw if the heavier one moved inward. Likewise moving weight up (towards the head) or down affects trim.
Most people concentrate their efforts on moving lead or the position of their tanks around, which works on the gravity side of the equation, but that's only half the solution.
The reason that overweighting tends to give divers a heads up trim is that as a rule the weights are lower on their bodies than the air bubble in their BC which always rises to the top. More weight means more air to offset it creating the torque that brings your head up. You can move the weight higher but only so far, so try to use the least weight possible, and carry it as high as you can. You can try taking an extra belt and strapping 2#s to the top of the tank for maximum effect.
The bouyancy side of the equation is more subtle. Most people are slightly denser below their waist than above, and tend to float with their legs below their heads. Athletic types, especially male runners, cyclists, skaters and dancers, usually are far denser below the waist than above, because muscle and bone are denser than fat and organs, and will naturally assume a heads up trim.
Your use of a shorty makes things worse by adding bouyancy above the waist, while not below.
My first recommendation is to scrap the shorty and always wear a full suit. Also, add floatation to your feet with thick ankle high booties, and if necessary consider buying fins that are less negatively bouyant (some even float).
If you work a combination of moving bouyancy down, while moving weight up, you'll be able to get your centers of bouyancy and trim to the same place on your body and maintain horizontal trim.
Most people concentrate their efforts on moving lead or the position of their tanks around, which works on the gravity side of the equation, but that's only half the solution.
The reason that overweighting tends to give divers a heads up trim is that as a rule the weights are lower on their bodies than the air bubble in their BC which always rises to the top. More weight means more air to offset it creating the torque that brings your head up. You can move the weight higher but only so far, so try to use the least weight possible, and carry it as high as you can. You can try taking an extra belt and strapping 2#s to the top of the tank for maximum effect.
The bouyancy side of the equation is more subtle. Most people are slightly denser below their waist than above, and tend to float with their legs below their heads. Athletic types, especially male runners, cyclists, skaters and dancers, usually are far denser below the waist than above, because muscle and bone are denser than fat and organs, and will naturally assume a heads up trim.
Your use of a shorty makes things worse by adding bouyancy above the waist, while not below.
My first recommendation is to scrap the shorty and always wear a full suit. Also, add floatation to your feet with thick ankle high booties, and if necessary consider buying fins that are less negatively bouyant (some even float).
If you work a combination of moving bouyancy down, while moving weight up, you'll be able to get your centers of bouyancy and trim to the same place on your body and maintain horizontal trim.
Last edited:
bfisher
Contributor
Along with moving the tank higher you could maybe use a 2# ankle weight around the neck of the tank. That's about as high as you can get any weight.
RonFrank
Contributor
I think you know what you are trying to achieve, but if not.. one should be able to hang neutral in a horizontal position without moving either body parts, or up/down in the water column.
This is easier said than done, and I find it's easier to do in 3mm/salt vs. fresh water in a dry suit for example.
There are only a few variables to consider. Tank position, the amount of weighting, and weight position are about it. I generally dive with an ankle weight on the top of my tank in fresh. In salt it does not seem to matter.
If memory servers Turtle fins are not light. You may want to try some lighter fins, and move the tank up if possible. An ankle weight on the tank may help.
This also maybe a comfort thing, or a mental block. What happens if you just try to hang? Do your feet drop? Using forward propulsion to maintain trim and buoyancy is not the best approach.
Finding some good solid divers to work with could solve your issue. It's hard to help with these types of issues online other than to offer the advice that you have been provided.
This is easier said than done, and I find it's easier to do in 3mm/salt vs. fresh water in a dry suit for example.
There are only a few variables to consider. Tank position, the amount of weighting, and weight position are about it. I generally dive with an ankle weight on the top of my tank in fresh. In salt it does not seem to matter.
If memory servers Turtle fins are not light. You may want to try some lighter fins, and move the tank up if possible. An ankle weight on the tank may help.
This also maybe a comfort thing, or a mental block. What happens if you just try to hang? Do your feet drop? Using forward propulsion to maintain trim and buoyancy is not the best approach.
Finding some good solid divers to work with could solve your issue. It's hard to help with these types of issues online other than to offer the advice that you have been provided.
I'm about the same size as the OP, and I had that same problem.
I moved some of my weight to my trim pockets, and worked on my bouyancy, which helped a little.
But the big thing was switching from a jacket style BC to a back inflate. Haven't had a problem since then.
I moved some of my weight to my trim pockets, and worked on my bouyancy, which helped a little.
But the big thing was switching from a jacket style BC to a back inflate. Haven't had a problem since then.
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