I am thinking about fixing up a small sailing boat. Old GRP boats often look a bit scruffy on the outside (inside too) because of wear, tear, previous coatings or discoloured pigments in the gelcoat. I am wondering how practical it is to rub down clean and brush on a new coat above the WL. Just for the joy of it. I believe there are specialist products.
I think spraying will be too much faff. Old boats are of such little value that you have to be very sensible about not wasting too much time or money on them. The likelihood is that I will be the last owner before the scrapyard.
TW