Re: fiberglass/restoration paint?
Compound works good for light damage. Wet sand to remove heavy damaged (yellow) gelcoat. Depending on how bad it is a combination of grits like 300, 400, 600, 800, 1000 and end with 1500. Polish with angle grinder polisher and foam pad at 2000 rpm using Meguires fine polishing compound. The deck side can be done in a day for a small runabout (or 2 if first time) and will look awsome for white gelcoat. Apply your favorite finish protectant.
Metal flake gelcoat is different and IMO requires a clearcoat refinish if gel is damaged badly.
Paint is costly, difficult and results are usually not what you expect for the do-it-yourselfer. Lots of good results posted here for Interlux though.
A tip for wet sanding is to always soak sandpaper in water for 20 minutes first.