How to fix a hole in the wall of a plastic shower/bathtub?
You can actually repair it. Generally make it dry. Sand down the surface around the effected areas. If there is an actual hole try using plywood to fill the hole. Apply fibreglass (you can buy strips of it) and coat each piece entirely in epoxy resin. Let it cure and repeat until there is a correct thickness. You can then sand that down as well to make it smooth and flush with the rest of the structure. You can paint it over with an epoxy based paint that will stick and not peel.