If there's any oxidation your going to have to use a rotary, period. If it just needs a good shine put on , an orbital will be fine. Remember, a boats gelcoat is about 36 ml thick compared to 2-3 mls for a car. Buffing a boat is very forgiving as long as you don't burn an area using the rotary. I always use 1z UPP followed by Klasse AIO. If it only needs polishing, AIO will do the job perfectly. I own a 1998 Four Winns and have used AIO since day one and it still looks showroom new. Don't forget to do the inside fiberglass as well and finish by protecting the interior vinyl with a good uv protectant . I personally use 303. Take your time and enjoy the process of making it look showroom new again.
