Will back inflation float an unconscious diver face up?
We usually hear this from divers who have always worn a jacket style BC, and we'd like to point out that it's irrelevant. It's true, the US Coast Guard requires an approved wearable Personal Floatation Device (PFD) to float the unconscious victim face up in the water. But a Buoyancy Control Device (BCD) for scuba divers is not designed to be a PFD for an unconscious boating accident victim, regardless if the BC is jacket or back inflation. We only offer back inflation style because experienced divers have learned the back inflation BCD is better than a jacket BCD, offering very precise control of buoyancy and trim as well as offering a more streamlined profile. An improperly fit back inflation BCD might cause you to tip forward, but a properly fit back inflation BCD worn with a crotch strap will allow you to assume and hold any position under the water or on the surface.
When on the surface, divers unfamiliar with back inflation will need to break the habit of holding down the power inflator until they feel squeeze (there won't be any) or hear the OPV release. With an over inflated aircell they will have a huge amount of buoyancy on their back, causing them to float too high in the water and tip forward. Instead, they should add only enough gas until their head is just above the water.