At the age of 12 I was bought a pair of bri-nylon square cuts for use in the schools outdoor pool. I really hated this swimsuit, it exposed my shy skinny body while at the same time feeling excessive and imprisoning. It was pretentious having a fake fly up the front.
If you don't remember bri-nylon look at this:
http://flashbak.com/sweat-the-nighti...d-1960s-16884/
My suit would have looked similar to the light blue bottoms in the Trend advert, though mine was a navy colour.
Please read the text in the Zing advert for a changing linguistics laugh.
Apologies for showing female advert, it was all I could find.
After leaving school I bought myself a 3" side black nylon Speedo. It felt so thin and shiny and liberating. I got hard first time I wore it between the changing rooms and the pool. I soon bought a 2" black nylon Speedo with red and white side trim, even more exciting for me. This was not long before the first Lycra suits started appearing locally.