There are a number of posts in this thread that say that dry suit classes teach one to use the dry suit for buoyancy control underwater, since controlling two buoyancy systems (dry suit and BCD0 may be too complicated.
In fact, PADI threw that away in 2007 when they introduced revision 3 of their Dry Suit Diver course.
Starting in 2007, the PADI guidance is to use the BCD for buoyancy at the surface AND underwater if either diving a neoprene dry suit or doing tech diving; the dry suit for underwater buoyancy control is only suggested for shell dry suits if the control of two buoyancy systems is too much for the student. The reason given for the distinction between which buoyancy systems to use underwater -- for a shell or a neoprene dry suit -- arises from the neoprene suit having some buoyancy loss with depth, where as the shell does not; similarly, in tech diving one is often over-weighted at the beginning of a dive (steel tanks, deco bottles and stages, etc) so using the drysuit for buoyancy control might represent far too much gas in the suit, and thus a danger if some of the over-weight were lost.
For simplicity, since use of the shell dry suit for underwater buoyancy control is only suggested, and not mandated, the dry suit instructors I know simply ask the students to use their BCDs for buoyancy control in all situations, and to put jsut enough gas into the drysuit to avoid squeeze and stay warm. Thus, recreational dry suit training becomes congruent with tech training. Nice.
In fact, PADI threw that away in 2007 when they introduced revision 3 of their Dry Suit Diver course.
Starting in 2007, the PADI guidance is to use the BCD for buoyancy at the surface AND underwater if either diving a neoprene dry suit or doing tech diving; the dry suit for underwater buoyancy control is only suggested for shell dry suits if the control of two buoyancy systems is too much for the student. The reason given for the distinction between which buoyancy systems to use underwater -- for a shell or a neoprene dry suit -- arises from the neoprene suit having some buoyancy loss with depth, where as the shell does not; similarly, in tech diving one is often over-weighted at the beginning of a dive (steel tanks, deco bottles and stages, etc) so using the drysuit for buoyancy control might represent far too much gas in the suit, and thus a danger if some of the over-weight were lost.
For simplicity, since use of the shell dry suit for underwater buoyancy control is only suggested, and not mandated, the dry suit instructors I know simply ask the students to use their BCDs for buoyancy control in all situations, and to put jsut enough gas into the drysuit to avoid squeeze and stay warm. Thus, recreational dry suit training becomes congruent with tech training. Nice.
