dahodevil:
I am considering a back inflate but i am concerned about stability at the surface. It seems like it would push me face forward(air in the back+ weights in the front= face in the water).
You are thinking logically, which makes it easier for people here to respond. The issue with BI BCDs has been exactly what you think the point of lift is behind the frontal / coronal plane of the divers body (the vertical plane in the middle of the body, when looking at the diver from the side) while the weight is positioned forward of that plane. When the diver is wearing too much weight (in front of that plane), and then adds air / lift (behind that plane) to compensate, over they go.
You just might discern a consensus developing here: J
JimLapenta:
The face forward thing is a myth if you are properly weighted. You only need enough air in the wing to keep your chin out of the water.
rhwestfall:
You need to get your weighting proper, and play with where it works best to balance weight. Cam band pockets are quite often necessary if the rig isn't equipped with such options.
oldschool:
The face forward thing is a myth if you are properly weighted and inflate the bc on the surface to keep your head above water and not your entire upper torso.
Yes, it is possible that you will feel a tendency toward a face-forward attitude at first, particularly where you have too much weight (the usual culprit), combined with frontal weight-pockets on a weight-integrated BCD, combined with a floaty back-inflate BCD. And, if a diver new to such a unit does the logical thing in response adds a bit of sir to their BCD - it makes matters worse, at which time they add more air, go more face-forward, etc. It can be a problem, but by no means must be or even should be.
Things that help.
- Proper weighting
- Use of a streamlined simple back-inflate BCD which doesnt have noticeable inherent positive buoyancy (Zeagle Express Tech is a good example. On the other hand, a Zeagle Ranger, as one example, may not necessarily be.)
- Proper placement of weight (aft of the frontal / coronal plane)
- Use of a metal (stainless steel) backplate. This puts part of the weight behind the plane.
- Use of a negatively buoyant cylinder (e.g. steel). This puts part of the weight behind the plane.
- Crotch strap to keep the bladder / wing from rising / tilting.
While I really like the Express Tech, I personally prefer a simple stainless steel backplate. But, that choice also is influenced by how much weight I usually need when diving where I usually dive. If you are slender with low body fat, and usually dive on vacation in the warm waters of the Caribbean, and need only 2 lbs of weight, an aluminum (AL) backplate, or a soft BI unit is probably a better choice. If you dive in colder waters, and have a bit of bioprene, and usually wear 14 lbs of weight, a SS backplate is possibly a better choice.