Floating legs

[AdivingBel]

I had a similar issue when I switched from a standard back inflate (stiletto) to a basic harness express tech (basically a soft plate bp/w). I had been diving with 10#s. 8#s in the std. weight pockets and 2#s of tank trim on the upper cam band. I had worked this out over time with pretty good trim. I used this as a starting point with the new rig. Right away I had "floaty" feet and felt the need to over arch my back. I moved out to the sand (away from the reef), got neutral, and hovered perfectly still. As I expected I went a little head down, but surprisingly I turtled to one side (couldn't specify a side, it was dependent on the slight current). I did a weight check at the end of the dive, and found I was also a little heavy. I dropped the 2#s of trim weight on the next dive and was much improved. No floaty feet, no turtle (less air in the wing & all the wt. lower and to the front), and felt no need to arch my back to compensate. The point is even just a small movement or reduction of weight can make a huge difference. Good luck figuring it out.

 

[Derffie]

My BCD is an Acqualung Axiom. In response to one of the earlier posts, best way to describe my shape is a broad shouldered marathon runner. So, I assume that my center of gravity is a bit higher than for most. As I think this through, the disadvantage of adding 1lb ankle weights is more exertion when kicking. However, the advantage over weight in the back pockets is that these are ditchable. I can try moving my tank down further, etc. but from a physics standpoint I would think that I would change my center of gravity more with a smaller amount of wt placed further away from my center of gravity.

 

[fire_diver]

My BCD is an Acqualung Axiom. In response to one of the earlier posts, best way to describe my shape is a broad shouldered marathon runner. So, I assume that my center of gravity is a bit higher than for most. As I think this through, the disadvantage of adding 1lb ankle weights is more exertion when kicking. However, the advantage over weight in the back pockets is that these are ditchable. I can try moving my tank down further, etc. but from a physics standpoint I would think that I would change my center of gravity more with a smaller amount of wt placed further away from my center of gravity.

You didn't mention how you are using your BC at the surface. Are you adding just enough air to keep your head out or are you going way past that?

 

[g1138]

I think I may have another reason. If the cumberbun is not snug on you, the back of the Axiom will stretch out a good few inches from your back. It basically fulcrums you face down into the water when you're on the surface.
You always want to be sandwiched between the backing and front strap, when you're standing up straight on land. If you're not there's a lot of wiggle room in your BC when you hit the water. And that will throw your CG & trim off.

Happens with a lot of Stock BC's with that style of cumberbun. Best way to recover is to go face down and roll over. Not doing this definitely makes you look unrelaxed when you try to recover by finning and leaning back. Which is my guess based on your OP.

There is no fix for this other than loading only the front weight pockets or keeping minimal air in the BC at the surface.
You could also install a crotch strap but that lead to different set of problems and training and is a DIY. Requires you to ruin your BC by doing a Macgyver essentially.
I had to do that on my own Sherwood Axis.

 

[Derffie]

This sounds pretty valid. I feel as if the front strap (there's no cumberbun) is tight. Most of the inflation is in the back and, with single weights in each side pocket they slide to the front of the pouch. I'm fairly comfortable lying on my back except that it's not easily to look around. I've tried using mimimal air to relieve the problem and the trouble is that I end up being low enough to require the use of my snorkel.

 

[g1138]

If you grab your BC at the front pockets and rock it when you're in the water, does it have give in the front and back?

Remember when the backing is away from you it will feel as if the front is really snug.
And yes techinically there's no cumberbun, same with my Axis where I discovered this problem.

 

[Altamira]

Wish I had that problem. My feet/legs drop like stones (a lot of soccer, tennis, and karate in younger days), especially now using negatively buoyant fins. I use 16# with full 3mil suit, beanie and boots, four in each integrated pocket and top band trim pockets. Guess I am going to have to raise the tank until it almost hits the back of my head and increase the trim pockets to 5# to get closer to an in trim condition when not finning.

 

[Peter_C]

I use 16# with full 3mil suit, beanie and boots, four in each integrated pocket and top band trim pockets. Guess I am going to have to raise the tank until it almost hits the back of my head and increase the trim pockets to 5# to get closer to an in trim condition when not finning.

My guess is you are overweighted and can probably drop at least a few pounds. Getting your trim right with heavier fins is fairly easy as you can bring your feet closer to your butt. This will shift your center of gravity pretty substantially. (If a person is head heavy, say in double steel tanks, you extend your legs out.)

[video=youtube;FRRCAO0mfCA]https://www.youtube.com/watch?v=FRRCAO0mfCA[/video]

 

[fire_diver]

Keep in mind the OP is asking about problems while at the surface.

 

[Peter_C]

Keep in mind the OP is asking about problems while at the surface.

It was a thread hi-jack! Happens often on forums...

This advice is probably some of the best advice in the thread pertaining to the OP's BC. Others saying do not fill as much should resolve much of it too.

If you grab your BC at the front pockets and rock it when you're in the water, does it have give in the front and back?

Remember when the backing is away from you it will feel as if the front is really snug.
And yes techinically there's no cumberbun, same with my Axis where I discovered this problem.