One of my greatest challenges is trying to get students to do a fin pivot correctly. Surprisingly, doing the fin pivot is easy, but my challenge is explaining the technique to the students in a way that they can remember and apply.
For those who do not know what a fin pivot is let me explain briefly. The diver lays face down on the bottom of the pool in the deep end of the pool and by controlling their buoyancy, the diver should be able to pivot on the fins tips by moving the upper body up and down around 18 to 24 inches.
The problem seems to be that some people think that the way to start the pivot is by doing a "pushup" off the bottom. Alternatively, the students tend to over-inflate the BCD and shoot to the surface.
Occasionally students will just be terrific at the skill and that makes this instructor a very happy man.