Having learnt to dive in the days when men were men and women just made the sandwiches, I used to hear terms such as 'frogmen' and 'skin diver' a lot but these terms are not used much nowadays. Yesterday I chanced across a copy of 'The wreck detectives' by Kendall Mcdonald which was published in 1972 which I remember reading in my youth but never owned so I bought it. It's a great read but the skin diver references left me puzzled. I know why frogmen were so called but I've never known how skin diving got its name. any ideas?