My understanding of it is that due to societal issues, inner city blacks do not have the opportunity to use pools. It would be interesting to see if controlling for income and location, is there a difference between blacks and whites. I don’t know if beaches and suntanning are closely related but that could also have an impact.
Had a black guy try out for swim team in high school, and he had never swam before. He was pure muscle and sank like a rock. He eventually became a pretty good swimmer. He was like a shark, he had to be moving to stay afloat.
I twice passed the Red Cross (?) life guard class. As a sophomore in HS, I was a life guard for the summer program. The kids come out for the first day, first session and we just let them use the pool. Kid jumps in the deep end and just starts to thrash trying to stay above water. I couldn’t believe that someone was trying to drown on me in the first 45 seconds of my first day as a lifeguard. Grabbed the Shepherd Crook, scouped him over the side and pulled him out. Never had to worry about what I would do if a kid were drowning. The kid was black, but I don’t think that had anything to do with it outside of percentages of swimmers.