Boat Deck Repaint

Good greetings all, i was thinkin about redoing the paint on the deck of my Baby Cat and i was hoping to get some good instructions and tips on doing it myself. There is nothing wrong with the hull itself but the color of the deck is like an off-white, yellowish color. Im getting the upholstery redone to white with blue strip on it so i wanted to redo the deck to a white color to make it match (and maybe the blue splatter if it comes easy).



Stupid question, but can i just sand down the existing paint and paint over it?



Thanks in advance!!!