If you didn't like the color, you shoulda bought a different boat. Fiberglass can be painted, but on a boat bottom, the water will peel it right off unless you use paint specially formulated for the purpose, and do the proper prep work, neither of which I can tell you how to do.
Go to an auto body shop and ask them how to do it, and where you can get the right materials locally. Maybe they could even offer to do it for you for not too much $$$.
By the way, this board is really intended for HOUSES, not BOATS.