Swim a lap? That’s nothing. Drownproofing required that AFTER swimming laps (I don’t remember how many), we had tread water or float for 10 minutes, and then had with our hands tied behind our back, and our legs crossed at the ankles and tied. Basically for 30 minutes they tried to drown you, and if you didn’t have to be rescued, you got an A. I was in the section with the swim team, and I was one of two who weren’t on it, but good enough to be on it. So after 28 minutes I couldn’t stay above the water long enough, so they pulled me out and I got a B+.
I found out later that all the other girls who were in the second or third tier group never had to do the stunts that I did, and still got As. I was pretty upset, because it lowered my grade point average, but they were never impacted. In fact, for some of them, it probably raised their GPA.
The drownproofing sounds like a pain, but at least it made sense.
Swimming the lap just seemed like a silly annoyance—for those of us who could swim.