Most any paint will stick to fiberglass
if the boat is sanded and cleaned properly. As far as lasting, doubt you'll get much wear and life out of semi gloss latex or any other common household paint. For all the work that's involved in prepping the surface, it would be a real shame to waste it and have to do it again in a year or so.
The minimum paint I'd use is Interlux
Bright Side Polyurethane
enamel. Not all that expensive and reported to last for a decent amount of time. I'd really look at doing a roll and tip job with a two part linear polyurethane
, however. They are pricey but wil last for a decade or more with minimal care. You didn't say what size boat you have but even LPU won't be all that expensive for a reasonable sized boat. You don't need AwlGrip as their are cheaper and easier to apply paints from other manufacturers out there. If you can find someone with a commercial
account that will buy the paint for you, you'll save a lot of money
. Paint is one of the highest markup items in a chandlery
If it was me and I couldn't afford to buy a decent marine
paint, I'd just buff and wax the gelcoat
and wait till I could afford the materials to do a decent job. The labor involved in removing crappy paint when you want to do a good job of painting makes doing it right in the first place look like an easy job.