Here's a picture from 1970. Our neighbors from Toledo, Ohio were making surfboards for Cypress Gardens water Ski Shows. We bought one and attempted to surf behind Dad's 16 ft, 55 HP outboard.
That's my oldest sister on the board and Dad's feather weight ski boat in the back ground. I'm in the boat watching and my older brother is driving.
We never pulled off free riding but the surfboard was probably the first thing I road on behind a boat.