So you’re saying first this then more polish after this? Yes it could use wax at very least. Just trying to get the worse of it gone for now because many struggle with this and don’t realize it can be made to look new quite easily.

Those are tough. The gel coat will be cracked down to the fiberglass chop strand (bottom layer) due to stress. Unless you want to sand off the gel coat and try reapplying it I think youre going to have to live with it. I did fix spider cracks on a full fiberglass Go Kart body of mine but that was painted on top and these are not. I grinded it down with a Dremel in the cracks maybe half an inch thick and applied short strand fiberglass resin. This should fill the spider stress cracks but I put paint overtop. In your case you could try grinding it and applying gel coat you get from amazon, Then sand and buff the new gel coat to make it blend but that’s allot of work. Note I did make a video of me fixing the go kart but it’s not up yet.

So if it works on this prehistoric seadoo I guess it will definitely work on yours.