repainting a mid '70s fiberglass crestliner

[screamingabyss]

I just bought a 1975 crestliner. The paint is very faded and I would like some advice on prepping it for new paint. It is fiberglass, and I have never painted fiberglass before. What is the best way to prep for a new coat? Do I need to sand all the way down to the glass? What kind of paint was commonly used on a '75 crestliner? Any advice would be most appreciated. Thank you.