Am I the only one that thinks this is a pretty nasty gouge?
Given how long its been there, location and different layers of repair necessary, it looks like a job for a professional.
Boat is going to have to be removed from the trailer to do a decent job. I would leave it to a shop that has insurance if something goes wrong.
This is the right time of year to get a deal. Wait a couple more weeks or into early Jan. They will be hungry, looking for work to stay busy and pay the bills.