I make a point of practicing 1-fin diving about once per month. PADI has never mentioned it to me in their courses, but it seems like a sensible thing to learn. Same with no-mask diving & some other variations on the theme.
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
I second springs.
I have a pair of old US Divers with rubber straps. As I have neoprene DS socks and neoprene boots my foot would compress and get drawn into the fin at depth. Time after time I ended the dive only to find the heel straps dangling free of the heel. Nothing holding the fin on. The only saving grace was that my foot was so sucked into the fin it couldn't come out without a crowbar.
Dale.