I would repair that “SOONER” than later! I don’t know if there is any wood under that, but that - NEEDS FIXED! As, I don’t know if there is actually any wood, which there probably is - If you don’t have time to fix right away – SEAL IT with 3M 4200 or 3M 5200! FYI.. I don’t remove any boat engines and/or outboardsI don’t have to and there is no way I would remove that outboard to repair that, unless?
First try ordering replacement parts? Drill out those rivets, remove old, check for water damage, seal, and install new.
Of course, the parts probably won’t be available – So, you want to know what I would do? Remove that old crap (try not to break it, as you may need as a reference or even a mold), inspect for any water damage! Go out and buy some biaxial woven mat fiberglass cloth, epoxy resin, a little color additive, and make the thing. Then simply sand and paint whatever color wanted. It can be painted to either match the hull or contrast it? Being where it is, I wouldn’t gel-coat, but that can done.
I have worked with fiberglassing quite often, and that repair can be done fairly easily. You can make the fiberglass in flat sections in your garage, which will be the easiest way to do. Pre-cut the sections, exactly how you want and then attach them to the boat. Cover all the sections with one piece of biaxial woven cloth, and fiberglass the separate sections together - right on the boat. Keep adding biaxial cloth, untill you have it the thickness and strength desired. Sand, paint, done! Just do an internet search on fiberglass repair and start reading – it really is easy than most think!
You can use the old parts to make mold, but I wouldn’t bother. Just building the mold would take you longer than above, but if you want… see:
Making a Fiberglass Mold
Now, if there is any wood under there and water damaged, I would really suggest reading the following website. The boat being discussed on the first link just happens to be a 1990 2302!
http://www.rotdoctor.com/glass/GLmain.html
http://www.rotdoctor.com/products/product.html