[alexrom1207]

I've always been told that a diver should be neutrally buoyant at 30ft (10m), so that he is negatively buoyant when deeper and positively buoyant when shallower. That way if he were to have a SWB he would float to the surface rather than sinking. Perhaps as a safety measure (if exhaling is part of SWB which I haven't heard about until now) then when determining how much weight to use, divers should calculate neutral buoyancy with empty lungs. Not sure if this is how this is commonly done, but like bill said, while we're on the topic of safety and SWB we might as well cover all the bases. Thanks for bringing it up Bill.