I'm ashamed of you! Asking such a roodie question.
Actually I have, many times in my younger days. When serving in the Army, I have gone swimming off many an isolated tropical beach in that nude.
Mind you, the South China Sea is infested with horrible animalcules armed with nasty stingers and nippers and tooths and scratchy bits that are exceeding harmful to any unrestrained appendages they may find flapping about.
I have been bitten, stung, nipped, grabbed and generally savaged many times.
England is not the place to do it either.
Even at the height of summer, more than 45 seconds in a British sea brings on hypothermia. Also, my body is no longer lithe, athletic, sun-bronzed and sexy.
It is sort of, well, podgy and maggoty and white and hairless and dangly, and the sight of me now, in my harvest-festivals is the stuff of which nightmares are made.