TR3 wax / polish / restorer (comes in a can and is a thick liquid paste). Been around for years and will do an amazing job on your gelcoat and fiberglass. It is available at most auto supply stores. Does require rubbing on and rubbing off but does not require very heavy effort to apply.
TR3https://www.amazon.com/dp/B000BOKO4W/?tag=googhydr-20&hvadid=186814863722&hvpos=1t1&hvnetw=g&hvrand=2085057177931791376&hvpone=&hvptwo=&hvqmt=b&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9030151&hvtargid=kwd-2131985111&ref=pd_sl_4ohoa4czdn_b