I was watching some doggy paddle drills, when I came across Bill Kirby doing doggy paddle in a slightly mediocre way. He didnt seem to like the drill very much.
(dont listen to the swimsmooth bala bla ha ha)
When he switched over to his normal stroke it became obvious why.
This guy seems to like slicing through the water with his upperbody and using his above water weight to load his catch after reaching,stretching out and setting up, to let that weight transfer into a release of the spring from his anchor into his streamline again. This cycle repeats itself, and this mechanism isnt available in doggy paddle, where its more local shoulder arm action and a lot of drag all the time.
When he switches to normal stroke he exagerates the throwing the weight over the body to get into the groove again and find his rotational balance of the weight swinging above the narrow underwater torpedo. Finding the balance point where the torpedo roll to the left or the right, and how to set up his underwaterarm to move from torpedo into catch, using that weight transfer in the most optimal way.
finding his balance line:
loading catch on the left side:
and loading catch on right side: