I think the issue is what hardware needs to be pulled out/away to access where the delaminating topcoat can be accessed. Regardless, the most appropriate repair is to scrape off to the best extent possible, the flaking gelcoat top coat then sand with 60 grit paper and ensure the existing gelcoat faying edges are blended to the FRP, wipe clean all areas to be coated with a suitable solvent (acetone is usually used), then re-topcoat with Interlux Bilgecoat paint. Remember, when using or handling any low vapor pressure solvent or hazardous material in a confined area use ample ventilation and the appropriate respirator; this may be a process to leave to a qualified company that has the appropriate equipment to do safely.It's there a "bandaid" procedure that can be done to at least waterproof the FRP - so as to "buy time" until a proper fix can be done?