New to BP-wing: upside-down
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I've read this a number of times, and it still isn't clear to me what is actually happening.
If you stay still, are you rotating around your long axis? Rolling to the side, in other words? If that's the case, then something is off center. Are your weights evenly distributed from side to side? Is your tank well centered and stable on the BP? Is the plate centered on your back?
Do you consistently roll to the same side, or does it differ? If you are trapping some air in one side of the wing or the other, you will tend to roll away from the side that has more air.
Having too much weight up on your back would tend to make you tip head down; too much at your waist will tip you feet down. But rotating around your long axis is suggestive of weight imbalance from side to side.
I use weight pouched on my cambands to trim out, and I had the experience in Maui of having a DM set my rig up and not realize that one of the weight pouches was not tucked nicely up against the plate. I did the whole dive right side down, which was distinctly unpleasant.
If you stay still, are you rotating around your long axis? Rolling to the side, in other words? If that's the case, then something is off center. Are your weights evenly distributed from side to side? Is your tank well centered and stable on the BP? Is the plate centered on your back?
Do you consistently roll to the same side, or does it differ? If you are trapping some air in one side of the wing or the other, you will tend to roll away from the side that has more air.
Having too much weight up on your back would tend to make you tip head down; too much at your waist will tip you feet down. But rotating around your long axis is suggestive of weight imbalance from side to side.
I use weight pouched on my cambands to trim out, and I had the experience in Maui of having a DM set my rig up and not realize that one of the weight pouches was not tucked nicely up against the plate. I did the whole dive right side down, which was distinctly unpleasant.
H2Andy
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Dani_diving:
what this would do is tilt you forward, head down, feet up
what you were describing sounds more like a "roll" to the side, though...
not sure i follow
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Dani_diving
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Thanks for all your responses.
First, as to what happened: If I stop moving completely, after about 15 secs I started rolling to the side (along the long axis) until I stabilize tank down, belly up!
I do not think I was overweighted. I just added a 2 lb weight for that dive because I could not hold my position at 10 feet in the previous dive, with no air in the wing. The comment of Lynne is interesting. I had not noticed this before, so it may well be that the 2lb added were off-centered. I cannot say if I tended to turn always to the same side (I just tried twice), but tend to think that is the case!
Also, it may well be that, as I drive wet, once the neoprene compresses the weight belt becomes loose (it does) so even if the weight was centered at the beginning of the dive, it changes its position. Sounds logical?
Thanks again.
First, as to what happened: If I stop moving completely, after about 15 secs I started rolling to the side (along the long axis) until I stabilize tank down, belly up!
I do not think I was overweighted. I just added a 2 lb weight for that dive because I could not hold my position at 10 feet in the previous dive, with no air in the wing. The comment of Lynne is interesting. I had not noticed this before, so it may well be that the 2lb added were off-centered. I cannot say if I tended to turn always to the same side (I just tried twice), but tend to think that is the case!
Also, it may well be that, as I drive wet, once the neoprene compresses the weight belt becomes loose (it does) so even if the weight was centered at the beginning of the dive, it changes its position. Sounds logical?
Thanks again.
Where did you put the 2 lb? I've had camband weights that weren't centered, and once hung a tank weight around the valve and discovered it flopped from side to side, creating a very unstable instability 
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Dani_diving
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TSandM:
In the weight belt. Like the idea of having some ditchable weight, at least until I get a drysuit.
Charlie99
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If you have a whole bunch of weight above the center of floatation, then you have unstable equilibrium. This will show up most dramatically at shallow depths with no air in the wing. Once you put air in the wing, the air bubble moving around adds stability. This may sound strange, but what happens is that if you roll to one side, the air bubble moves to the other side and you still have a stable equilibrium in that rolled position.TSandM:Where did you put the 2 lb? I've had camband weights that weren't centered, and once hung a tank weight around the valve and discovered it flopped from side to side, creating a very unstable instability
When using a 6 pound plate I found that swimming along while horizontal was fine. Even stopping and hovering motionless was fine. But if I rolled about 15 or 20 degrees to either side, then went motionless, the backplate and tank would roll me over to face up, tank down. That was a stable equilibrium. It sure sounds like the original poster experienced something much like this.
Moving all of the weight on my weightbelt to the front and artificially adding a few pounds so that I'd have some air in the wing solved the problem.
I assume that an aluminum plate (less weight up high when horizontal) would also solve the problem.
I'm with Charlie on this one - sounds like you need to move your center of gravity toward the tank (ie - more weight away from your tank) especially since you are using a steel tank.
Since you wear 12# on a belt, try moving them forward a couple of inches at a time until you get right balance on your long axis. I have one friend who wears most of his weight in front of his belly... everyone is built differently, so it's a matter of finding where your body and gear are balanced.
Aloha, Tim
Since you wear 12# on a belt, try moving them forward a couple of inches at a time until you get right balance on your long axis. I have one friend who wears most of his weight in front of his belly... everyone is built differently, so it's a matter of finding where your body and gear are balanced.
Aloha, Tim
Humuhumunukunukuapua'a
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This happens to me too, if I completely stop and sort of cross my ankles and bring my arms close in. I think it's pretty much going to be typical for cold water divers, since so much weight is on the back and so much buoyancy on the front.
For me, I have to basically try to make it happen. When I'm swimming around checking stuff out, it's no problem and I stay trim without effort. But equilibrium is definitely turtle-on-back position. Most cold water divers I have met experience the same thing.
I guess you could stick a bunch of weight on your chest, but, for me anyway, it really isn't worth it. It's much better to have my weight out of the way, and it isn't a struggle to keep from rolling.
YMMV
Maybe the REAL way to dive is with a chest plate. Next big thing?
For me, I have to basically try to make it happen. When I'm swimming around checking stuff out, it's no problem and I stay trim without effort. But equilibrium is definitely turtle-on-back position. Most cold water divers I have met experience the same thing.
I guess you could stick a bunch of weight on your chest, but, for me anyway, it really isn't worth it. It's much better to have my weight out of the way, and it isn't a struggle to keep from rolling.
YMMV
Maybe the REAL way to dive is with a chest plate. Next big thing?
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