I seriously doubt that your insurance company is going to cover it. They will claim water damage/defective manufacture/you must have been driving like an idiot so you are going to have to make the best of a bad situation. Cut the broken fiberglass back to the next stud and then do a sheet aluminum overlay and glue and screw it on. Use a piece of the cut off glass gelcoat for a paint match and spray it on with a decent HVLP spray set from Northern Tool or Harbor Freight. Use something like .062" sheet for the aluminum and you can easily cut it with a jig saw. A full sheet will cost about $120 at a metal supply store, figure $100 to get the paint mixed, and another $100 for the spray gun on sale. If you like the trailer and can't afford to buy another one, this should buy you a couple of more years at least.
