BP/W keeps flipping me on my back- help

[cool_hardware52]

There's another discussion going on about the XS Scuba weight pockets. With only 8 lbs to carry, she could ditch the weight belt and put a couple of these on her waist belt. They have the advantage of being able to drop only part of the weight instead of all of it, if that's what you need to do.

I'm not a fan of weight pockets on the waist belt;

Takes up room on the waist belt, and can interfere with a canister light if you use one.

Having all your ballast on your rig can require a larger wing, as your wing needs to be able to float rig if you ditch it. Ballast in a weight belt is not part of the rig, and the wing need not support it if ditched.

Having all your ballast on your rig can make in water donning more difficult, your buoyant exposure suit will pin you to the surface, think man over board from a crab boat. That makes getting vertical, and swimming up and into your rig a real challenge.

Having all of your ballast on your rig can make it a real nugget to hump around out of the water.

Weight belts are inexpensive and universally available.

Tobin

 

[jeffrey-c]

My girlfriend is using a 7mm wetsuit, DSS BP/W with SS plate and Torus 26 wing, and LP 85 steel tank. I think she had 8 lbs in a weightbelt. She feels that she is being pushed down and flips on her back. Any ideas?

I had a similar feeling the first few times I tried out my new DSS rig (SS plate, 3mm suit, AL80 in warm water). Properly weighted I only needed about 2-3 pounds additional, and it just wasn't enough to offset the buoyancy/mass configuration - unless the center of buoyancy for the buoyant object (me swathed in neoprene) is directly under the center of mass (tank/plate/gear) it is an inherently unstable configuration. But I looked at it like a bicycle, which is also inherently unstable until you learn how to ride it and subconsiously use your body to tweak trim. After about 4-5 dives I started to get it down, and after a dozen dives it seemed second nature. It just took a while to learn to ride without training wheels!

 

[Doc Harry]

I had a similar problem of rolling onto my back that only developed near the end of my dive when I had no air in the wing. I switched from steel to aluminum tanks and the problem was solved.

My recent personal experience with doubles also leads to agree with jeffrey-c. With more time in the water, my trim and balance problems evaporated without ever changing my configuration. I like the bicycle analogy.

 

[Ber Rabbit]

I had a similar problem as well even when I moved from a jacket BC to a back-inflate BC (Ladyhawk). I learned the hard way that body position means a lot and at first the correct position is uncomfortable. I actually did flips my first time in a BPW with doubles and I found I had to adjust my body position once more for that set-up.

I wear my lead in a harness weightbelt rather than a standard weightbelt so it hangs lower on my hips to help keep my feet down (I'm diving dry) and it stays out of the way of whatever buoyancy device I'm wearing.

Tell her not to get discouraged! She can do it! Once you find that "sweet spot" it's worth all the effort.
Ber :lilbunny:

 

[Charlie99]

- unless the center of buoyancy for the buoyant object (me swathed in neoprene) is directly under the center of mass (tank/plate/gear) it is an inherently unstable configuration. But I looked at it like a bicycle, which is also inherently unstable until you learn how to ride it and subconsiously use your body to tweak trim. After about 4-5 dives I started to get it down, and after a dozen dives it seemed second nature. It just took a while to learn to ride without training wheels!

Yes, one can use body muscles to constantly readjust to maintain the unstable equilibrium. IMO though, it makes a lot more sense to have a properly designed system. In the unstable configuration of a lot of weight up near the tank and no air in the bladder, you aren't going to be able to roll 45 degrees to one side and stay there. Move to a jacket BCD, or an aluminum backplate, or an aluminum tank and you can get the center of mass close to the center of buoyancy and will be able to easily move to any desired position, and HOLD IT WITHOUT MOVING.

A bit of air in the wing or BCD bladder makes everything much more stable, because as your roll or tilt, the air bubble will shift towards the new high point, making everything more stable. This means that the real test for stability is in shallow water with a near empty tank, with the resulting minimum amount of air in the wing or BCD bladder.

Why be limited to just a horizontal position and an unstable equilibrium? Why make life difficult? Get the proper gear and diving is easier.

Charlie Allen