I had an interesting situation a few months ago when I was asked to teach an OW refresher course in a pool for a father and son. They had not been diving for a year. The son arrived with Atomic split fins with spring straps that he insisted were his, even though they were so much too big for him that the spring straps did not even touch his heels. I assured him that wherever he had dived last, someone else had gone home with Atomic spit fins they could not even get their feet into. What to do? I gave him my fins, which were only a little too big for him, and I wore the Atomics, even though they were much too big for me as well. The spring strap did touch my heel, but I had to keep pulling them back on every few minutes.
My first shock came when I was in front of them, demonstrating some skills I wanted them to repeat. As usual, I went close to them as they did the skills, and then, out of habit, I back finned to my normal position. I had forgotten I was wearing those fins, and when I realized I was moving backward easily in them, I was surprised. Later on I went through all the kicks, and my only real problem came when the spring straps kept coming off. I realize a pool is not a silty environment, so I don't know about that effect, but that was the first time I had done those kicks in split fins, and I was pleasantly surprised at how well I did. I have done much worse in soft paddle fins.
