Some did indeed allow suits whereas others made male nudity when in the pools mandatory. Usually it was a mutual participation, with one or two of each gender remainingpartially or fully covered. They would go with the boy they were supervising into the locker room to help him change. The girls wore suits, but we we weren't in the pool at the same time. One has to ponder why it was that even when there was no longer any logical reasons for boys to be required to participate in swim classes naked, many administrators, teachers and parents still fought to assure the customary requirement remained. Additionally, I later heard that the Oscoda High School pool was equipped with an underwater, glassed viewing room in the diving end of the pool. The preponderance of articles and stories all seem to indicate that in most situations, when boys were taking swimming courses in the nude, they were routinely taught by male instructors, and females entering the pool area was not permitted.
During the school day, PE classes would, at certain times of the year, have pool time set aside for them to use.
Men only swims
In the article, Mayor Law applauded the YMCA's swim classes for boys, which indicates they were for males between the ages of 10 and Janesville Daily Gazette, click on image to enlarge for reading The article to the left in yet another Wisconsin publication gives us an indication as to the changing times. This included swim time. One time in the Caribbean, I walked past a nude area of a beach. Just before our 30th high school reunion, I emailed the superintendent of the Oscoda Public Schools to recount the horrors of forced naked swimming in hopes of getting her to donate a keg to our reunion party. I remember it too, YMCA pool was suit-free unless it was a co-ed period schools didn't have pools where I lived. Only seniors, from age 13 up were allowed to wear swim trunks.